2012 - Variable Energy Cyclotron Centre

Transcription

VECC--PR--2012
Government of India
Department of Atomic Energy
2012
VARIABLE ENERGY CYCLOTRON CENTRE
1/AF, BIDHAN NAGAR, KOLKATA-700 064
Tel: +91 33 2337-1230 (4 lines) Fax: +91 33 2334-6871/410 Homepage: www.vecc.gov.in
T
he room temperature cyclotron, VECC has delivered light ion (proton and alpha) beams for
about 2650 hours. Scientists from different research institutes and universities carried out
various experiments. Planned shutdowns were undertaken to repair resonator tank, Dee tank
interface air leak, renovation of control room, basement corridor etc. A few emergency
shutdowns consisted of R F problem, leakage in resonator tank, dummy Dee, vacuum system etc.
Various measurements of the internal beam behavior in the Superconducting Cyclotron
indicated towards the presence of magnetic field imperfections, which restrained us from
reaching the long awaited goal of beam-extraction. By performing a series of experiments, e.g., a
quantitative measurement of beam off-centering and estimation of the amplitude of coherent
betatron motion of the beam of particles using shadowing techniques with three beam-probes,
measurement of particle phase history based on RF frequency and magnetic field detuning
methods, as well as using a fast-scintillator based phase measurement system, brought out the
need for a detailed measurement of the magnetic field. Accordingly the magnetic field mapping
and correction program was undertaken.
Civil construction work at the Medical Cyclotron facility proceeded at a fast pace and it is now
nearing completion. Installation of other services like fire fighting system, telephone, public
address, LAN, domestic water supply, LCW/water treatment, external electrical works, internal
electrical works, EOT crane and HVAC etc. will start very soon. The trial run and commissioning of
the cyclotron and related systems are expected in late 2014.
At the Radioactive Ion Beam (RIB) front, this year witnessed a lot of exciting developments. First
production and acceleration of RIBs stands out among them. The measured intensity of various
RIBs like 14O, 42K, 43K, 41Ar was of the order of 103 pps. This also helped in establishing the gas-jet
recoil transport method in case of RIB transport and acceleration. Understanding the hollow
formation of sub-dominant species in a high current multi-species beam was another important
study towards developing high current accelerators.
Experimental groups of VECC used the light ion beams of VEC and heavy ion beams from other
accelerator centres in India to carry out exciting experimental research in the field of nuclear
physics, material studies, radiochemistry etc. GDR width at low temperature, measurement of
beta end point energy, angular momentum gated light particle evaporation spectra,
determination of impurities in graphite and alumina are just a few of the exciting studies.
Development of parallel plate avalanche counter, total absorption spectroscopy using BaF2
detectors are important work in the detector development front.
A vibrant group of theoretical physicist at our center made several important contributions in
various fields. On one hand a number of hydro-dynamical calculations were performed to
understand the properties of QGP at ALICE energies, on the other hand a systematic study of
properties of pure hadronic and hybrid compact stars have also been done. Conditions of
equivalence between statistical ensembles for fragmentation of finite nuclei are identified. The
effect of medium spectral modification of rho meson on the viscosity of pion gas has been
studied.
International collaborative efforts for the search and study of Quark Gluon Plasma continues with
participation in the STAR experiment at BNL, ALICE experiment at CERN and CBM experiment at
FAIR. The Photon Multiplicity Detector (PMD), which was fabricated at VECC for the ALICE
experiment has taken valuable data with proton-proton and lead-lead collisions at the LHC.
Detector developments towards large area GEM detectors and silicon-tungsten calorimetry
continued. Our scientists have excelled in the search for QCD critical point at RHIC, charge
fluctuation signals at the LHC and dimuon signals at FAIR. These have been considered as major
contributions to the field of high energy heavy-ion collisions.
Regional Radiation Medicine Centre (RRMC) at Thakurpukur routinely carried out in-vivo nuclear
imaging, in-vivo non-imaging and in-vitro diagnostic studies to bring the benefits of nuclear
science to the common man. Collaborative research projects were also undertaken in association
with Indian Institute of Chemical Biology, BRIT, Kolkata centre etc.
The academic activities of Homi Bhabha National Institute (HBNI) at VECC have continued as
usual with its Ph.D and M. Tech programme. Nine Ph.D and two M.Tech degrees were awarded
from HBNI and other universities. Several national and international schools, workshops, theme
meetings, colloquiums lectures and outreach programmes were successfully organized.
Dinesh Kumar Srivastava
Director
T
his report brings out the scientific and technical activities of Variable Energy Cyclotron
Centre, Kolkata during the calendar year 2012.The articles contributed in this report have
been written at different times during 2013.
The format of this report has remained identical to the previous one. Division of the
chapters and distribution of the contents are also very similar. Division of the chapters is
given in the contents. As the prime thrust of activities in the Centre was towards
implementation of various projects undertaken by the Centre, the contributions related to
the ongoing projects are given in a separate chapter (chapter 4) of this volume.
The activities of the Regional Radiation Medicine Centre at Thakurpukur, Kolkata are
available in chapter 5. The activities of the international collaborations are reported in
chapter 6. Chapter 7 provides a comprehensive list of publications as well as colloquia, thesis
and other activities in this Centre.
The editorial board has tried utmost to make this volume as complete a sourcebook of
information as possible about the research and developmental activities of this centre. We
regret for the errors or omissions that might have taken place in spite of our best efforts.
Editing of the contributions has been kept minimum. The affiliations of the authors of this
centre are not mentioned in their respective contributions, but those of the collaborating
authors are only mentioned. We acknowledge the co-operation extended by the board
members and other colleagues of this Centre in bringing out this report in present form. We
are thankful to Dr. Tapan Mukhopadhyay, former convener of Editorial Board for his valuable
suggestions and guidance in bringing out this annual report. Suggestions for future
improvement of the quality of the progress report are welcome.
Surajit Pal
Convener, Editorial Board
Editorial Board
Surajit Pal
Sandip Pal
Gargi Chaudhuri
Subrata Chattopadhyay
Pranab Bhattacharyya
Kaushik Datta
Anand Kumar Dubey
Shashi C L Srivastava
Santwana Kumari
1
Research 1
1.1 Nuclear Experiment
1.2 Nuclear Theory
1.3 Analytical Chemistry, Radio Chemistry,
Radio Pharmaceuticals
1.4 Material Research
1.5 Health Physics
2
24
32
52
67
2
Cyclotron 75
2.1 Cyclotron Operation
76
2.2 Accelerator Research
80
2.3 Accelerator Technology
84
2.4 Services
103
3
Computer and
Informatics 107
4
Ongoing Projects 129
4.1 Superconducting Cyclotron
130
4.2 Radioactive Ion Beam
139
4.3 Recovery and Analysis of
Helium from Hot Springs
164
4.4 Accelerator Driven Sub-critical
System
166
4.5 Superconducting Cyclotron
Utilisation Project (SUCCUP)
181
4.6 RF Superconducting Cavity
187
4.7 Superconducting Magnetic
Energy Storage (SMES)
190
5
Regional Radiation
Medicine Centre 197
6
International
Collaboration 203
7
Publications, Colloquia,
Theses etc. 243
7.1 Publications in Journals
244
7.2 Publications in Symposia,
Conferences and Reports
252
7.3 Thesis
259
7.4 Colloquium
261
7.5 Events & Other Activities
262
7.6 Awards & Honours
267
8
Personnel 269
9
Author Index 275
Research
1.1
NUCLEAR EXPERIMENT
Measurement of β
end point energy with LEPS detector
1
1
T. Bhattacharjee, D. Banerjee , P. Das, A. Chowdhury, S. K. Das , D. Pandit, S. Pal,
S. Mukhopadhyay and S. R. Banerjee
1
RCD-BARC, Variable Energy Cyclotron Centre, Kolkata
Introduction
T
RESEARCH
he experimental determination of Qβ
values providing information on one of the most
fundamental quantities, viz., atomic mass, requires the knowledge on the beta ray maximum
energy and the level scheme of the daughter nuclei. The information on beta decay maximum energy
has also been very important for the identification of the nuclear isomeric states when determined in
coincidence with the gamma rays de-exciting the excited levels of the daughter nucleus [1]. The
detection of beta particles has been explored since many years using a variety of detector systems
having a wide range of efficiency and resolution, viz., magnetic spectrometer, plastic scintillators,
silicon and germanium solid state detectors. The planar Hyper Pure Germanium (HPGe) detectors
having a thin Be window have already been demonstrated to be quite efficient in this purpose [2,3].
Moreover these detectors provide a very good energy resolution as well as can be calibrated up to very
high energy using appropriate gamma ray sources. However, the high atomic number of Ge gives rise
to high backscattering and bremsstrahlung production probability making a distortion at the low
energy part of the spectrum. The coincidence measurement with an appropriate γ
detector becomes
unique for determining the end point energies related to even very weakly populated levels of the
daughter nuclei. Very few studies are known that have employed the β
γ
coincidence technique
involving Ge detectors in order to measure the end point energies. It is important to study the use of
such technique with complicated level spectra of the daughter nuclei as the very high efficiency of Ge
detector is the only choice to measure the weak beta branches and high energy beta decays. In this
work, we have reported the success of the beta gamma coincidence technique utilizing the beta
response of a thin window Low Energy Photon Spectrometer(LEPS) detector for the measurement of
endpoint energies, even for very weak beta branching.
Experimental Techniques and Results
106
The β
endpoint energies for several known and unknown branches of Rh and the known branches of
22
90
210
181
Na, Sr, Pb, Hf decay have been measured using a coincidence setup consisting of a11mm thick
Ge Planar segmented LEPS detector and a 10% efficient coaxial HPGe detector. The LEPS detector
has a 300 µ
m thick Be window which is completely stops only beta particle with energy up to 223 keV
and the 10% Ge detector has response to only very high energy beta particles for its thick entrance
window. The front face of the 10% detector was covered with 11 mm thick aluminium plate in order to
ensure that no β
particle enters this detector. The open sources with high specific activity and
insignificant solid content were prepared and dried on an electro-polished stainless steel surface of 0.5
mm thickness. The detectors were kept at a distance of 2.9 cm from each other and the source was kept
2
at a distance of 0.9 cm from, and the
front side facing, the LEPS detector.
As the LEPS detector has response
for both β
and γ
radiations it is
important to properly delineate and
subtract all contributions from γ
radiations and to extract the required
β
spectrum. For this purpose the
coincidence measurements were
taken in two configurations, viz., (i.)
the open source facing the LEPS and
putting no absorber other than the
factory made Be window in front of
LEPS and (ii.) the open source facing
Figure 1. β
spectra obtained in the experiment and compared with the
the 10% Ge detector and keeping a 8
GEANT3 simulation. Left and right planel shows the known and unknown
branches respectively.
mm thick Ta block in front of the
LEPS detector. Gamma ray gate was
put in the 10% detector and the
corresponding spectra were
projected in four segments of the
LEPS detector. The spectrum from
measurement (i) consists of the
response both from beta and gamma
radiations whereas the spectrum from
measurement (ii) consists of that only
from gamma. The spectra were
normalized at the most intense
photopeak in coincidence and the
second spectrum was subtracted from
the first one in order to arrive at the
required beta spectrum. The
contribution from the unwanted low
energy beta branches were subtracted
by
Figure 2. The results from the analysis of Fermi-Kurie plot for different β appropriately subtracting the two
different efficiency corrected gamma
branches of 106Rh.
gates. However, many a times it is
difficult to subtract the contribution from the Compton profile of the detected gamma rays and the
lower energy part of the spectrum becomes different than expected. Experimentally, the spectra have
106
been obtained for the known 3.05 MeV, 2.4 MeV and 2.0 MeV β
branches of Rh decay in one segment
of the LEPS detector, by putting gates on the corresponding gamma rays, viz. 511 keV, 621 keV and
1049 keV respectively, in the 10% HPGe detector and correcting for the unwanted events as described
106
above. The results for the Rh decay [4] have been shown in Figure 1, where they have also been
compared with the response obtained using the simulation code GEANT3 [5]. The end point energies
to these known beta decays have been measured with an reasonable accuracy by using the Fermi-Kurie
plot and considering the attenuation at the Be window of LEPS, as shown in Figure 2. In the present
106
work, the endpoint energies for some of the unknown weak beta branches of Rh decay have been
3
RESEARCH
NUCLEAR EXPRIMENT
PROGRESS REPORT 2012
measured for the first time and are also shown in Figure 2.The end point energies have also been
2
measured by using the χ
minimisation technique comparing the experimental data with the simulated
2
one. It is observed that the χ
minimisation gives a better result in determining the end point energy.
Detailed analysis is in progress.
Acknowledgement
The authors acknowledge the effort of Dr. H. Pai and other members of Physics laboratory for the
maintenance of the detectors throughout the year.
References
[1] M. Dikšić, et al, Phys. Rev. C10, 1172 (1974)
[2] R. C.Greenwood et al, NIM A337, 106(1993)
[3] A. Osa et al., NIMA 332 (1993) 169
[4] D. DE Frenne and A. Negret, Nuclear Data Sheets 109, 943 (2008).
[5] R. Brun, et al., GEANT3, CERN - DD/EE/84-1, 1986.
Decay spectroscopy of
Gd
T. Bhattacharjee, D. Banerjee , A. Chowdhury and S. K. Das
1
1
Radiochemistry Division (BARC), Variable Energy Cyclotron Centre, Kolkata
T
he low lying spectroscopy of nuclei, from both the decay as well as in beam measurements [1–3],
has drawn considerable attention in recent years. Such measurements for the odd-odd transitional
nuclei in A ~ 140 region are crucial in understanding the role of neutron proton interaction in the N, Z =
50 – 82 subshell space. The nuclei in the
vicinity of the magic N = 82 and semimagic Z = 64 exhibit excitations due to
multiparticle-hole as well as quasivibrational structures. According to the
latest compilation in Nuclear Data
Sheets [4], the different measurements
on 146Gd EC decay exhibit a lot of
discrepancy in the observed levels, the
energy and the intensity of the decay γ
rays. In the present work, we have
reported the decay scheme of 48d 146Gd.
The decay scheme of 146Gd has been
modified considerably compared to our
previous work [5] following the
measurements of γ
-ray singles and the
Energy (keV)
decay half-lives.The 146Gd (t1/2 = 48
146
Figure 1. Total spectrum upto the EC decay Q value of Gd using 50% days), produced via 144Sm (α, 2n)
HPGe detector. γ-rays of 146Eu have been marked with their respective reaction with 32 MeV alpha beam from
Counts
RESEARCH
1
146
energy values.
4
K=130 Cyclotron at Variable Energy
Cyclotron Centre, Kolkata. The 144Sm
2
targets with a thickness of 300 µg/cm
2
were prepared on 6.84 mg/cm Al foils
by electro-deposition method using
93.8% enriched Sm2O3.The irradiated
target was counted on a 50% HPGe
detector for the measurement of γ
singles and decay half lives. All the γ
rays observed in the total spectrum are
shown in Fig. 1 and the γ
-rays,
relevant to the decay scheme of 146Gd,
were studied for the decay half lives.
The γ
-rays observed in the total
spectrum can be classified in four
categories, viz., (I) the γ
-rays from the
146
decay of
Gd (48d), (ii) γ
-rays
146
produced from the decay of Eu (5d), Figure 2.The decay plots of the γ transitions corresponding to EC decay of
146
(iii) γ
-rays from the decay of Gd. The γ energy and the half-life value are indicated inside each figure.
147
Eu(24d) and 149Gd (9.4d) produced in the reaction and (iv) the back ground and few unidentified γ
rays. The γ
-rays of latter three categories were not considered in the present work. The decay plots for
the relevant γ
-rays are shown in Fig. 2.
Figure 3. The decay scheme of 146Gd as obtained from the present work.
References
[1] A. Chakraborty et al., Phys. Rev. Lett. 110, 022504 (2013).
[2] S. N. Liddick et al., Phys. Rev. Lett. 92, 072502 (2004).
[3] P. E. Garrett et al., Phys. Rev. Lett. 103, 062501 (2009).
[4] L. K. Peker and J. K. Tuli, Nucl. Data Sheets 82, 187(1997).
[5] T. Bhattacharjee et al., Proceedings of the DAE Symp. on Nucl. Phys. 56 (2011).
5
RESEARCH
NUCLEAR EXPRIMENT
Decay spectroscopy of neutron rich odd-odd 150Pm
D. Banerjee1, T. Bhattacharjee, P. Das, S. K. Das1, A. Chowdhury, S. Dasgupta, S.
Bhattacharyya, R. Guin1, P. Mukhopadhyay, H. Pai and S. K. Basu
1
Accelerator Chemistry Section, RCD (BARC), VECC, Kolkata
Introduction
T
he N = 89 Pm isotope attracts considerable interest because of several aspects. Along with the fact
that only the ground state of the nucleus, with t1/2 ~ 2.68h, was known until very recently, this
150
nucleus provides the intermediate state for the double beta decay of Nd [1,2]. The neighboring odd148
odd Pm has been known as the branch point nuclei and has a significant neutron capture cross section
[ 3 ] that produces the next Pm isotope via s-process. There is not much understanding on the stellar
production and abundance of 150Pm which warrants measurement of various reaction cross sections for
reaching the nucleus. Very recently O. Lebeda et al., have measured the excitation functions of proton
induced reactions on natural Nd target[4].
RESEARCH
The systematic study of these neutron rich Pm isotopes reveals the presence of a high spin isomer that
undergoes β
decay with a half-life more than or of the order of the half-life of the ground state of these
nuclei. Till date, there is almost no information regarding the configuration of the ground state as well
as high spin states including the isomeric states which are indeed very important in understanding the
structure of these nuclei. Moreover, such high spin isomeric state could not yet be confirmed in the N =
150
150
89 Pm. However, recent in beam studies [5, 6] on Pm has given a little knowledge on the excited
states and the off-beam study has given an indication on the possibility of the existence of an isomer at
high spin having a half-life which is few minutes more than the half-life of the ground state [6]. The
detection of such a long lived isomeric state is not possible from the prompt in-beam spectroscopy. The
decay spectroscopy has been known to be an efficient tool for this purpose [7, 8]. In the present work,
150
150
we report the decay spectroscopy of Pm in order to identify the high spin isomeric state in Pm by
beta gamma coincidence technique and by measuring the (p, n) cross section corresponding to the
decay of the ground state and isomeric state of the nucleus.
Experiment
150
150
The Pm nucleus was produced by Nd (p, n) reaction at proton energies from 7 to 15 MeV, provided
by K = 130 AVF cyclotron of VECC, Kolkata, by using target irradiation technique. Five target stacks
were used in the experiment and were prepared by putting appropriate degrader foils in between the
targets and aluminium catcher foils in front of all the targets as well as the degraders. For the
measurement of incident beam flux, the Cu monitor foils were used as well as the current from the
electron suppressed Faraday cup was recorded. The oxide Nd targets were prepared by electrodeposition technique on 0.3 mil aluminium backing foils starting from the 97% enriched Nd2O3
powdered sample. Neutron activation technique has been used in order to estimate the number of Nd
nucleus in the prepared target by using the available facility at BARC, Mumbai. The irradiated targets
along with their catchers have been counted by using the efficiency and energy calibrated 50% HPGe
150
detector in order to follow the decay of Pm. The beta decay from the irradiated target, one from each
stack, were also recorded using the beta-gamma coincidence setup [9], consisting of a 11 mm thin
LEPS detector with 300 µ
m Be entrance window and a 10% coaxial HPGe detector.
6
NUCLEAR EXPRIMENT
Analysis and Results
The absolute cross section for the
Nd (p, n) reaction has been
measured for different residues
following the decay of gamma rays
belonging to the two said groups. The
result is shown in Figure 1. The
theoretical estimation of cross section
is in progress using the CASCADE
and EMPIRE3.1 codes. In order to
identify the isomeric state and to
measure its energy the Fermi-Kurie
(FK) plots have been studied for
measuring systematics of endpoint
energies corresponding to different
150
decay branches to Sm using the
procedure described in [9].The
endpoint energy corresponding to
1165 keV agrees with the difference
in the Qβ
value of 150Pm ground state β
decay and the energy of the level deEbeam (MeV)
exciting the 1165 keV transition,
corrected for the degradation at the Be Figure 1. Measured cross section for different residues of 150Nd(p, n)
window. However, the end point reaction
energies corresponding to 439 and
2033 keV, show larger values than
the expected one considering the β
150
decay from the ground state of Pm,
as shown in Figure 2. The 439 and
2033 keV also project a different
decay half-life. The results indicates
the presence of a high spin isomer in
150
Pm. The detail data analysis is in
progress.
Acknowledgement
Authors acknowledge the efforts of
the K=130 cyclotron operators to
provide a good quality beam. Authors
also acknowledge Dr. R. Acharya of
RCD, BARC for carrying out the
Figure 2. The Fermi-Kurie analysis for 2033 keV transition of 150Sm
neutron activation analysis.
References
[1] C. J. Guess et al. Phys. Rev. C 83, 064318 (2011).
[2] C. M. Raduta, A. A. Raduta, and I. I. Ursu Phys. Rev. C 84, 064322 (2011).
7
RESEARCH
σ
(mb)
150
[3]
K. T. Lesko et al., Phys. Rev. C39, 619 (1989).
[4]
O. Lebeda et al., Phys. Rev. C85, 014602 (2012).
[5]
D. Bucurescu et al., PR C85, 017304 (2012).
[6]
T. Bhattacharjee et al, Proc. DAE symp 56, (2011) 358.
[7]
William R et al., PR C4, 919(1971).
[8]
M. Dikšić, et al PR C10, 1172 (1974).
[9]
T. Battacharjee et al., DAE symp, 2012.
A modular setup for total absorption spectroscopy using
BaF2 detectors
G. Mukherjee, Balaram Dey, S. Mukhopadhyay, Deepak Pandit, Surajit Pal, S.Kundu,
C. Bhattacharya, K. Banerjee, T.K. Rana, S. Bhattacharya, T.K. Ghosh, R. Pandey, M.
Gohil, J.K.Meena, V. Srivastava, H.Pai and S.R.Banerjee
RESEARCH
A
Total Absorption Spectrometer (TAS) is a setup to measure the total energy of all the γ
rays
emitted in an event. Such a setup is very useful for the measurement of β
-decay feeding intensity
free from pandemonium effect [1]. Recently a modular TAS array has been set up at VECC using 50
BaF2 detectors.
The Set up
Figure 1. Closed configuration (left) and the two separate halves (right) of the TAS array.
3
Fig. 1 shows the TAS setup using smaller (3.5x3.5x5 cm ) BaF2 detectors at VECC [2]. The array
consists of two blocks having 25 detectors in each. The detectors in each block were arranged in castletype geometry. The blocks were brought together for a closed 4π
configuration and the source was kept
at the middle of the array. The closed configuration of the setup (left) and the two separated blocks
(right) are shown in Figure 1.
8
NUCLEAR EXPRIMENT
Measurements
10000
Counts
1000
100
10
1
200
400
Channel No.
600
Energy (MeV)
The array can be used to measure the β
-decay feeding intensity of radioactive elements. The array was
137
60
22
152
137
tested using one-, two-, three- and multi-γ
line sources Cs, Co, Na and Eu, respectively. A Cs
spectrum obtained from a single individual BaF2 crystal is shown in Fig. 2 (left). The energy resolution
of the BaF2 detectors was about 8%. Energy calibration and gain matching of the crystals were done
for obtaining the sum spectrum. A multiplicity spectrum, defined by the number of crystals hit in an
event, was generated and the sum spectra were generated using different condition of multiplicity (M).
A sum spectrum for 60Co source is shown in the right hand panel in Figure 2.
Discussion
Counts
The advantage of a modular sum spectrometer to distinguish between a single-peak and a sum-peak is
60
evident from the Co spectrum shown above. In a modular set up it is possible to choose different
multiplicity (M) conditions for obtaining the sum. It can be seen that the intensity of the sum peak at 2.5
MeV remains almost same while there is a drastic reduction in intensity of the individual (1.17 and 1.33
MeV) peaks for M ≥
2 and M ≥
3. Therefore, the lines observed in the high-M gated sum spectrum can
be directly considered as the energies of the levels to which most of the β
-decay take place.
Energy (MeV)
Figure 3. (Left) Sum spectrum of 152Eu source for 3 multiplicities and (right) comparison of experimental data of 60Co
(solid circle) with simulation (solid line) for multiplicity M > 1.
The sum spectrum obtained using a 152Eu source is shown in Figure 3 (left) for three different conditions
of multiplicity M. The 152Eu source has a complicated decay scheme with several γ
-rays as observed in
Figure 3 for M ≥
1 but at higher multiplicity condition, many of these peaks disappear and only three
9
RESEARCH
Figure 2. (Left) spectrum of 137Cs source obtained from a single BaF2 detector and (right) sum spectrum of 60Co source
obtained from the TAS array for 3 multiplicity (M) conditions.
peaks are seen at 1.1, 1.3 and 1.5 MeV energies. These correspond to the energy of the levels of the
152
daughter nuclei to which maximum β
-feeding take place for Eu [3]. To understand the sum spectrum,
60
we have done a simulation in the GEANT-3 platform for the γ
-rays in Co source. The simulated
spectrum is shown in Figure 3 (right) overlaid with the experimental data. Both the simulation and the
data are for multiplicity condition M > 1. There is a good agreement between the data and the
simulation except for the low energy part. It may be noted that the low energy absorption in the source
casing and in the structure of the array were not considered in the simulation.
Conclusion
A modular TAS setup using BaF2 detectors, first of its kind in India, has been successfully tested at
VECC. The test results are satisfactory and the set up is now ready for offline measurements.
References
[1] G. Mukherjee et al., DAE Symp. on Nucl. Phys. 55, 708 (2010) & references there in
[2] Deepak Pandit et al., Nucl. Inst. Meth. Phys. Res. A624 (2010) 148
[3] http://www.nndc.bnl.gov/nudat2/
RESEARCH
Study of angular momentum gated light-particle evaporation
spectra in 4He + 93Nb and 4He + 58Ni reactions
Pratap Roy, K. Banerjee, S. Kundu, T. K. Rana, C. Bhattacharya, M. Gohil, G. Mukherjee,
J. K. Meena, R. Pandey, H. Pai, A. Dey, T.K. Ghosh, V. Srivastava, S. Mukhopadhyay,
D. Pandit, S. Pal, S. R. Banerjee, and S. Bhattacharya
S
tudy of evaporation spectra of particles emitted by a compound nuclear source gives useful
information about the nuclear level densities (NLD). The knowledge of NLD can provide an
interesting test of microscopic approaches of nuclear structure from which NLD can be obtained.
Moreover nuclear level densities are important ingredient in the statistical model calculations of
nuclear cross sections. It is important and interesting to understand the dependence of NLD on some
key parameters such as excitation energy (temperature) and angular momentum (J). In recent years
there have been reviewed interests [1-4] in understanding the angular momentum dependence of NLD.
Although a few experimental and theoretical studies have been performed recently, no conclusive
picture of variation of NLD with 'J' was obtained from these studies. In order to understand the angular
momentum dependence of NLD in a systematic manner we have carried out measurement of angular
4
93
4
58
momentum gated light particle (n, p, and α) spectra in He + Nb and He + Ni systems.
4
The experiment was performed with 35 MeV He beam from the VECC K-130 cyclotron facility using
self-supporting foils of 93Nb and 58Ni (thicknesses ~1 mg/cm2). To detect and identify the charged
particles emitted during the compound nuclear evaporation process, a 3-element detector telescope
consisting of a 50µm single-sided silicon strip detector (16 channels), 500µm double-sided silicon strip
detector (16 X 16 channels) and two CsI(Tl) crystals (thickness 4 cm) at the back was mounted at the
0
0
mean angle of 147 covering an angular range of ±17.5 . Four liquid-scintillator (BC501A) detectors
10
NUCLEAR EXPRIMENT
were mounted at the back angles to detect the
emitted neutrons. In the present experiment,
populated angular momentums were recorded
by measuring the γ- multiplicity using a 50
element BaF2 based low energy γ-ray filter
array. Data from the neutron and the charge
particle detectors were recorded in coincidence
with γ- multiplicity in event by event mode.
Fig.1 shows the schematic of the typical
experimental setup for this experiment. The
fold (defined as the number of γ detector fired
simultaneously) gated α-particle, proton, and
neutron kinetic energy spectra were measured
to study the angular momentum dependence of
NLD.
Figure 1 A typical experimental setup
RESEARCH
The angular momentum distributions for
different folds were obtained by converting the
measured γ-fold distribution using the Monte
Carlo simulation technique based on GEANT3
toolkit [5]. The theoretical neutron, proton and
α-particle energy spectra were calculated using
the statistical model code CASCADE [6], with
the extracted angular momentum distributions
for different folds as the input.
The experimental neutron, proton, and αparticle spectra for 4He + 93Nb system, alongwith the corresponding CASCADE fits have
been shown in Fig.2. The shape of the kinetic
energy spectra were mostly determined by the
value of the level density parameter (a). In the
calculation the inverse level density parameter
'k' (k = A/a, where A is the mass number) was
varied to get the best fit to the experimental data,
while for other statistical model parameters
default values were taken. The extracted values
of the inverse level density parameters for
different angular momentum regions as
obtained by fitting the neutron (kn), proton (kp),
and α-particle (kα) data are given in TABLE: I
and II for 4He + 93Nb and 4He + 58Ni systems
respectively.
From TABLE:I and II it can be observed that the
value of inverse level density parameter (k)
decrease with the increase in angular
Figure 2: Experimental (a) neutron, (b) proton, and (c) αmomentum (J) for both the systems. The particle energy spectra along-with the CASCADE fits for
decreases of 'k' with increasing 'J' were different folds in case of 4He + 93Nb system.
11
observed from the analysis of all the (major) light particle spectra consistently. This implies increase of
nuclear level density at higher 'J' values. The observed variation of 'k' with 'J' is in accordance with the
observation of Ref [1]. However a increasing and a constant variation of 'k' with increasing 'J' were
observed in Ref [2] and Ref [3] respectively.
4
He + 93Nb
Table : I
Fold
(Avg. ang. Mom.)
kn
(neutron)
kp
(proton)
kα
(alpha)
Fold 2 ( 15.7 h)
9.7 ± 0.1
9.7 ± 0.8
10.4 ± 0.5
Fold 3 (15.7 h)
9.7 ± 0.8
9.4 ± 1.1
8.4 ± 0.6
Fold 4 ( 15.7 h)
8.2 ± 0.2
7.1 ± 1.4
6.0 ± 0.7
Table : II 4He + 58Ni
Fold
(Avg. ang. Mom.)
kn
(neutron)
kp
(proton)
kα
(alpha)
Fold 2 ( 15.7 h)
8.0 ± 0.5
9.3 ± 0.2
8.0 ± 0.4
Fold 3 (15.7 h)
7.0 ± 0.7
8.8 ± 0.4
6.5 ± 0.5
Fold 4 (15.7 h)
6.0 ± 0.8
8.2 ± 0.5
5.6 ± 0.7
RESEARCH
The present observation on the variation of NLD with 'J' could not be accounted by any known nuclear
effects such as 'shell effect' or 'collective enhancement' for the present systems. Microscopic
calculations and further investigations will be useful in understanding the phenomenon in more detail.
References
[1] K. Banerjee et. al, Phys Rev. C 85, 064310 (2012).
[2] Y. K. Gupta et. al, Phys. Rev. C 78, 054609 (2008), and references therein.
[3] Y. K. Gupta, et. al, Phys. Rev. C 80, 054611 (2009).
[4] M Aggarwal et. al, Phys. Rev. C 81, 047302 (2010).
[5] K. Bannerjee et. al, Proceedings of the DAE symp. On Nucl. Phys 55 (2010) 324.
[6] F. Puhlhofer, Nucl. Phys. A 280 (1977) 267.
Development of parallel plate avalanche counters (PPAC) ions
(HI) collision studies
R. Pandey, T. K. Ghosh, J. K. Meena, K. Banerjee, C. Bhattacharya, S. Bhattacharya,
M. Gohil, G. Mukherjee, S. Kundu, T. K. Rana, P. Roy, H. Pai, V. Srivastava and A. Chaudhuri
G
as detectors are widely used in nuclear physics experiments. These detectors are ideal for
detection of heavy fragments, particularly for measurement of masses of fission fragments
produced in a nuclear reaction. The main advantages of using gaseous detectors compared to
12
NUCLEAR EXPRIMENT
conventional silicon detectors are connected with large solid angles and total insensitivity to radiation
damage.
RESEARCH
One of the best methods to measure the masses of the fission fragments is to measure the time of flight
(TOF) of the fission fragments. This requires detectors with excellent time resolution. Usually, large
area multi wire proportional counters [1] are used to generate the STOP signal in a time of flight (TOF)
measurement setup and beam pulsing time (for pulsed beam) is used for the START signal. However,
the experiments using cyclotron, where the resolution of the beam pulsing is generally poor (few nanosecond) or the experiments with dc beam (from Delhi/Mumbai Pelletron), requires a suitable detector to
generate 'START' signal for the TOF measurement. Parallel plate avalanche counter (PPAC), are known
instrument for precise timing measurement. Since low pressure parallel plate avalanche counters
(PPACs) provide good timing resolution, PPACs are designed and developed at VECC for detection
of fission fragments at low pressure [2].
Figure 1. Photograph of PPAC
These detectors are mainly required to carry on our research activities on the study of fusion fission
dynamics with major accelerator facilities available in our country. These detectors provide fast timing
signal that are used as the "START" time for TOF measurement to know the masses of the fragments
generated in nuclear reactions. The PPAC that we have designed and developed in our laboratory
consists of three electrode wire planes. One anode was sandwiched in between two cathodes. The gaps
between each electrode are 3.2 mm. The active area of the detector is 50 mm x 35mm. The anode wire
planes consists of 10 µm diameter gold plated tungsten wires and the cathode wire planes are made of
20 µm diameter gold coated tungsten wire, placed 1 mm apart. The anode and cathode wires are
soldered on conducting strips. All the wire planes are made of G–10 quality single sided plated copper
board (PCB). The two cathode wire planes are shorted outside and connected to a power supply through
a charge sensitive pre-amplifier. This provides energy loss signal from the cathode. Stretched
polypropylene films (of thickness ~ 0.4 micron) are used as the entrance windows of the detector. 1 cm
× 1 cm wire mesh of stainless steel wires of diameter 0.4 mm is used as a support to the polypropylene
13
film. One inlet and outlet gas feed-through made of stainless steel are connected to the front and back
support frames to flow gas continuously through the detector at a constant pressure flow mode with a
close loop electronic flow control system ( make: MKS, USA).
252
The detector was tested in laboratory for energy read out and timing pulses. A Cf source was mounted
in front of the detector which was placed inside an evacuated chamber. Iso-butane was selected as the
circulating gas in the PPAC due to its large gas amplification. With precise regulation of gas pressure the
detector was operated in constant flow mode at a pressure of 2 Torr. The operating voltages for anode
and cathode were 300 Volts and 260 Volts respectively. Fig2a shows the typical timing signal from the
detector boosted by a fast current sensitive ORTEC preamplifier of gain 200 and bandwidth 1.2 GHz.
The signal pulse height was more than 300 mV with rise time ~ 3 ns. The signal to noise ratio was better
than 40. Since the detectors are operated at low pressure, heavy fragment loses only a fraction of its
energy in the detector. The energy loss signals are sometime useful to separate fission fragments from
the elastics/beam like particles. Fig.2b shows the typical energy loss signal from an amplifier
(ORTEC572, with gain 50) with pulse height more than 2 Volt.
RESEARCH
Figure: 2 (a), 2(b) Typical timing and energy pulses from PPAC.
We have developed two PPACs that are planned to be used in in-beam experiment soon.
References
[1] T.K. Ghosh. et al. Nuclear instruments and methods. A 540, 285 (2005).
[2] R. Pandey, T. K. Ghosh,et al. Proceedings of DAE symposium on nuclear physics, G36, 930, (2012).
14
NUCLEAR EXPRIMENT
Giant dipole resonance width at low temperature and the
critical temperature fluctuation model
1
Deepak Pandit, S. Mukhopadhyay, Surajit Pal, Srijit Bhattacharya ,
2
A. De and S. R. Banerjee
1
Department of Physics, Barasat Govt. College, Barasat, N24 Pgs, Kolkata 700124, INDIA
2
Department of Physics, Raniganj Girls' College, Raniganj 713347, WB, INDIA
he study of hot giant dipole resonance (GDR) has been a very successful tool in nuclear structure
physics for the last few decades. The damping mechanism of the GDR as a function of temperature
(T) and angular momentum (J) has been of particular interest in this field. While the main features are
understood, the temperature dependence of the Giant Dipole Resonance width, built on excited states,
below 1.5 MeV is still not understood due to the unavailability of experimental data. In fact, the
measurement of GDR width at low temperature is very challenging since heavy ion fusion reactions are
limited to higher temperatures due to the presence of Coulomb barrier in the entrance channel while
inelastic scattering experiments are less precise due to uncertainty in the excitation energy window.
Considering the above complexities, a systematic study has been carried out to study the GDR width at
low temperature by performing several experiments using the alpha beams from the K-130 Cyclotron
and employing the LAMBDA photon spectrometer [1] & the gamma multiplicity filter [2] to provide
new experimental data at low T in 63Cu [3], 119Sb [4] and 201Tl [3]. The high-energy γ
-ray spectra for 119Sb
63
201
are shown in the left panel of Fig. 1 while the linearized GDR spectra for Cu and Tl are shown in the
right panel of Fig. 1.
Figure 1. (Left panel): High-energy γ
-spectra (filled circles) for various folds along with CASCADE prediction (continuous
line) for 30 MeV and 42 MeV incident energies for 119Sb. (Right Panel): The linearized GDR plots for 63Cu and 201Tl at 35, 42
and 50 MeV incident energies. The filled circles are the experimental data while the continuous line represents the CASCADE
prediction.
15
RESEARCH
T
Interestingly, it has been found that the experimental GDR widths for all the three nuclei decrease
with decrease in T and reach the ground state value well above T = 0 MeV in complete contrast to
the Thermal Shape Fluctuation Model (TSFM) (dashed lines in Fig. 2) which predicts gradual
increase of the GDR width from the ground state values. It is evident from Fig. 2 that the commonly
accepted TSFM fails completely to explain the GDR width systematics at low temperature. To
explain this discrepancy at low temperature, we have proposed that the GDR vibration itself
induces a quadrupole moment causing the nuclear shape to fluctuate even at T=0 MeV. Therefore,
when the giant dipole vibration having its own intrinsic fluctuation is used as a probe to view the
thermal shape fluctuations, it is unlikely to feel the thermal fluctuations that are smaller than its
own intrinsic fluctuation. In other words, the experimental GDR widths should remain constant at
the ground state values until a critical temperature (Tc ) and the effect of the thermal fluctuations on
the experimental GDR width (i.e. increase of the apparent GDR width) should appear only when it
becomes greater than the intrinsic GDR fluctuation. Applying this novel idea, a new model has
been proposed which is called the Critical Temperature included Fluctuation Model [3] (CTFM)
(solid lines in Fig. 2) for a better understanding of the GDR width systematics for the entire range
of mass, spin and temperature.
RESEARCH
Figure 2. The GDR widths as a function of T for 63Cu, 120Sn and 208Pb. The red filled circles are the data from the present work.
The dashed lines correspond to the TSFM calculation while the continuous lines are the results of the new developed CTFM
calculation.
References
[1]
S. Mukhopadhyay et al., Nucl. Instr. and Methods A 582 (2007) 603.
[2]
Deepak Pandit et al., Nucl. Instr. and Methods A 624 (2010) 148.
[3]
Deepak Pandit et al., et al., Phys. Lett. B 713 (2012) 434.
[4]
S. Mukhopadhayay et al., Phys. Lett. B 709 (2012) 9.
16
NUCLEAR EXPRIMENT
the experimental estimates of the mean angular momentum dissipation are near the sticking limit
prediction.
Figure 4.The variation of angular momentum dissipation factor f with atomic number of the fragments. The solid circles (red),
solid triangles (blue), and inverted triangles (black) are the extracted values of f for (a) 11B + 28Si, (b) 12C + 27Al, and (c) 12C + 28Si
reactions, respectively. The solid (black) and dotted (pink) curves correspond to the sticking limit and the rolling limit
predictions for the same, respectively.
References
S. J. Sanders, et al., Phys. Rep. 311(1999) 487 and references therein.
C. Bhattacharya, et al., Phys. Rev. C72 (2005) 021601R
D. Shapiraet al., Phys. Lett. 114B (1982)111
S. Kundu et al. Proc. of DAE-BRNS symposium on Nucl. Phys. Vol 53 (2008) 493.
T. Mikumoet al., Phys. Rev.C21 (1980) 620
C. Bhattacharya et al., Phys. Rev. C69 (2004) 024607
Study of field profile of a mini orange spectrometer magnet
S. Dasgupta, A. Dutta, S. Bhattacharyya, P. Das, A. Reja, U. Bhuia,
S. Saha, S, Murali and M.H. Rashid
N
ucleus from an excited state depopulates by competing process of gamma and conversion
election emission. Various types of magnetic devices have been used to measure the conversion
electrons, such as, solenoids with strong field strengths, magnetic mirrors and orange type permanent
magnets etc. Out of these, the advantage of the orange type filters is its compactness in size and its
ability to measure electrons in wide energy range and its ability to operate in a high background
condition of in-beam experiments. Such type of spectrometer was first developed by Van Klinken [1]
for conversion electron spectroscopy. In the Mini Orange Spectrometer (MOS) setup, the magnetic
filter is a set of small permanent magnets, usually made of rare earth materials, such as SmCo5, due to
their capability of producing intense magnetic field with small quantities of bulk material. The
magnetic field strength of the setup is an important factor for the transmission of electrons through the
MOS filter. The present work reports the measurement of the magnetic field profile of an orange type
filter and compared the same with simulations.
Geometrical design
The magnet pieces are wedge shaped arranged around a central absorber, which reduces the
background due to direct gamma ray flux. The setup used for the present measurement consists of four
19
RESEARCH
[1]
[2]
[3]
[4]
[5]
[6]
wedge shaped sectors of magnets, attached to a brass ring holder. The 3D dimensions of the magnet
assembly are shown in Fig.1.
RESEARCH
Figure 1. The 3D magnet dimensions
Figure 2. The test bench setup.
Magnetic field measurement
To understand the magnetic filed lines through the
MOS magnet setup, field measurements have
been carried out with a 3D hall probe. The field
strength was measured within the gaps of each
magnetic sector at steps of 4 mm as a function of
the radial distance r from the centre of the filter
and as a function of z, i.e., along the axis of the
filter. For this purpose, one test bench with (z,r)
movement in millimeter scale was made, as
shown in Fig.2.
Simulation
Magnetic field distributions (Fig 3) of MOS filter
were simulated using finite element based 3D
magneto-static solver TOSCA (OPERA Version
15R1) [2]. 1/16th symmetric model was used for
simulating the field. Non linear B-H property Figure 3. Simulated distribution of Bmod component and
magnetic field vectors of the MOS filter.
with Coercive field strength (Hc) of -6.62x105
A/m and Remnant field (Br) of 0.867 T was used as permanent magnet material data input. Fig.4 shows
the measured resultant field as a function of distance along the filter axis z (z=0 being the median plane)
at various radial position, along with its comparison with the OPERA simulation.
20
NUCLEAR EXPRIMENT
References
[1] J. Van Klinken and K. Wisshak, NIM 98, 1 (1972).
[2] www.vectorfields.com, www.cobham.com.
Spectroscopy of 201Tl isotope
S. Das Gupta, S. Bhattacharyya, H. Pai, G. Mukherjee, S. Bhattacharya, R. Palit1,
2
3
2
2
2
A. Srivastava , S. Chanda , A. Chatterjee , V. Nanal , S.K. Pandit ,
1
1
S. Saha and S. Thakur
1
Tata Institute of Fundamental Research, Mumbai, India.
2
Bhabha Atomic Research Centre, Mumbai, India.
3
Fakir Chand College, Diamond Harbour,West Bengal
V
ariation of the nuclear deformation as a function of angular momentum for chain of Tl isotopes
makes them interesting candidates to test the predictions of different theoretical models
involving the coupling of the collective motion of the underlying core nucleus and single particle
degrees of freedom. Tl isotopes with one proton hole in Z=82 shell and a few neutron hole in N=126
shell are expected to have spherical structure at lower excitation while the deformation sets in for
higher spin states. For odd A Tl isotopes the πh9/2 orbital above the Z=82 shell closure is accessible by
the odd proton for oblate deformation. A rotational band built on 9/2- isomeric level has been reported
21
RESEARCH
At higher z values the field could be measured till to the centre of the filter, but at lower z values, the
central region could not be measured due to the presence of the central lead absorber. Overall good
agreement has been obtained between the measured and simulated fields at different positions.
However, at lower z and towards the centre of the filter, there is a difference of about 200-300 Gauss
between the measured and the simulated filed. This may be due to the difficulty in moving the hall
probe towards the narrow gap within the magnet sector and thus the possible uncertainty in the
corresponding position of the measured field.
NUCLEAR EXPRIMENT
201
-
Figure 3. Proposed level scheme of Tl above 9/2 isomer, as obtained from present work.
RESEARCH
References
[1] R. M. Lieder et al., NPA, 299, 255, (1978).
[2] J. O. Newton et al., NPA, 148, 593, (1970).
[3] M.G. Slocombe et al.,NPA, 275, 166, (1977).
[4] R. Palit et al., NIM A680, 90 (2012).
[5] A. Görgen et al., Euro. Phys. J. A 6 141 (1999).
23
1.2
NUCLEAR THEORY
Temperature dependence of QGP viscosity over entropy ratio
from hydrodynamical analysis of ALICE data in s=2.76 TeV
Pb+Pb collisions
A. K. Chaudhuri
W
ithin Israel-Stewart's theory of dissipative hydrodynamics, we have analyzed ALICE data for
the centrality dependence of charged particles multiplicity, elliptic flow and transverse
momentum spectra in Ö
s = 2.76 TeV Pb+Pb collisions and obtained the temperature dependence of
the QGP viscosity over the entropy ratio (h
/s). If temperature dependence of h
/s is parameterized as
h
/s = a
(T-Tc)/Tc+1/4p
, experimental data favor in the range 0-0.2. a
³
0.4 is not favored by the data.
RESEARCH
Experimental data in s = 200 GeV Au+Au collisions however, prefer a
= 0.4.
Comparison of results from a 2+1D relativistic viscous
hydrodynamic model to elliptic and hexadecapole ?ow of
charged hadrons measured in Au-Au collisions at √s= 200 GeV
Victor Roy, A.K. Chaudhuri and Bedangadas Mohanty
1
1
School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar
S
imulated results from a 2+1D relativistic viscous hydrodynamic model have been compared to the
experimental data on the centrality dependence of invariant yield, elliptic ? ow (v2), and
hexadecapole ? ow (v4) as a function of transverse momentum (pT ) of charged hadrons in Au-Au
collisions at √s = 200 GeV. Results from two types of initial transverse energy density pro? le, one
based on the Glauber model and other based on Color-Glass-Condensate (CGC) are presented. We
observe no diffrence in the simulated results on the invariant yield of charged hadrons for the
calculations with diffrent initial conditions. The comparison to the experimental data on invariant yield
of charged hadrons supports a shear viscosity to entropy density ratio (η/s) between 0 to 0.12 for the
0-10% to 40-50% collision centralities. The simulated v2(pT ) is found to be higher for a ? uid with CGC
based initial condition compared to Glauber based initial condition for a given collision centrality.
Consequently the Glauber based calculations when compared to the experimental data requires a lower
value of η/s relative to CGC based calculations. In addition, a centrality dependence of the estimated
24
In?uence of shear viscosity on the correlation between the
triangular ?ow and initial spatial triangularity
A. K. Chaudhuri
I
n a hydrodynamic model, with ? uctuating initial conditions, the correlation between triangular ? ow
and initial spatial triangularity is studied. The triangular ? ow, even in ideal ? uid, is only weakly
correlated with the initial triangularity. The correlation is largely reduced in viscous ? uid. Elliptic ? ow
on the other hand appears to be strongly correlated with initial eccentricity. Weak correlation between
triangular ? ow and initial triangularity indicate that a part of triangular ? ow is unrelated to initial
triangularity. Triangularity acquired during the ? uid evolution also contributes to the triangular ? ow.
Fluctuating initial conditions and ?uctuations in elliptic and
triangular ?ow
A. K. Chaudhuri
RESEARCH
I
n heavy ion collisions, event-by-event ? uctuations in participating nucleon positions can lead to
triangular ? ow. With ? uctuating initial conditions, ? ow coeffcients will also ? uctuate. In a
hydrodynamic model, we study the ? uctuations in elliptic and triangular ? ow, due to ? uctuating initial
conditions. Both elliptic and triangular ? ow ? uctuates strongly, triangular ? ow more strongly than the
elliptic ? ow. Strong ? uctuations greatly reduce the sensitivity of elliptic and triangular ? ow to
viscosity.
Rapidly rotating axisymmetric neutron stars with quark cores
Abhishek Mishra, Partha Roy Chowdhury1and D. N. Basu
1
Dept. of Physics, Govt. Degree College, Kamalpur, Dhalai, Tripura 799 285, India
W
e present a systematic study of the properties of pure hadronic and hybrid compact stars. The
nuclear equation of state (EoS) for β
-equilibrated neutron star matter was obtained using
density dependent effective nucleon–nucleon interaction which satisfies the constraints from the
observed flow data from heavy-ion collisions. The energy density of quark matter is lower than that of
this nuclear EoS at higher densities implying the possibility of transition to quark matter inside the core.
We solve the Einstein's equations for rotating stars using pure nuclear matter and quark core. The β
equilibrated neutron star matter with a thin crust is able to describe highly massive compact stars [1] but
find that the nuclear to quark matter de-confinement transition [2] inside neutron stars causes reduction
in their masses. Recent observations of the binary millisecond pulsar J1614–2230 by Demorest et al.
26
effective interaction that results into a simple algebraic expression [1]. The half-lives of the proton
emitters are calculated for the different Skyrme sets (27 out of about 240 which qualify tests for
application to neutron-rich dense matter such as neutron stars) within the improved WKB framework.
The results are found to be in reasonable agreement with the earlier results obtained for more
complicated calculations [2] involving finite-range interactions.
References
[1]
T. R. Routray, Abhishek Mishra, S. K. Tripathy, B. Behera, D. N. Basu, Eur. Phys. J. A 48, 77 (2012).
[2]
T. R. Routray, S. K. Tripathy, B. B. Dash, B. Behera, D. N. Basu, Eur. Phys. J. A 47, 92 (2011).
Conditions of equivalence between statistical ensembles for
fragmentation of finite nuclei
G. Chaudhuri and S. Mallik
RESEARCH
S
tatistical models based on canonical and grand canonical ensembles are extensively used to study
intermediate energy heavy-ion collisions. The underlying physical assumption behind canonical
and grand canonical models is fundamentally different, and in principle agrees only in the
thermodynamical limit when the number of particles becomes infinite. In any statistical physics
problem it is easier to compute any observable using grand canonical ensemble where total number of
particles can fluctuate. For finite nuclei in intermediate energy heavy ion reactions there is no particle
fluctuation, therefore canonical or micro canonical ensembles are better suited for this purpose. For the
nuclear multifragmentation of finite nuclei the total charge distribution and largest cluster probability
distribution is calculated in the framework of both canonical and grand canonical ensembles. It is
observed that when the fragmentation is more, i.e. the production of larger fragment is less, the particle
fluctuation in grand canonical model is less and the result from canonical and grand canonical model
converge. This condition is achieved by increasing temperature or freeze-out volume or by increasing
the source size or by decreasing the asymmetry of the source.
When the values calculated from two models based on canonical and grand canonical ensemble
formalisms are different, the grand canonical calculation can be used to deduce the exact canonical
results. The results of the two ensembles are transformed into each other with high precision. It is
observed that this transformation method does not work only when the system experiences a first order
phase transition where the ensembles are irreducibly non-equivalent.
28
NUCLEAR THEORY
Symmetry energy in projectile fragmentation
G. Chaudhuri and S. Mallik
S
The extracted Csym/T values from the primary fragments are close to each other for all the four
prescriptions mentioned above. The values of Csym/T obtained from the secondary fragments are close
to those obtained from experimental yields but they differ from those obtained from the primary
fragments and the input value used of Csym/T in the model. The experimental yields which are from the
'cold' fragments should not be used to deduce the value of the symmetry energy coefficient since the
formulae used for the deduction are all valid at the break-up stage of the reaction and secondary decay
disturbs the equilibrium scenario of break-up stage. Hence these formulae for deducing the values of
Csym/T should be applied after break-up stage only and attempts to deduce Csym/T experimental yields
from using these prescriptions might lead to wrong conclusions.
Analytic evaluation of non-linear response
by non-perturbative approach
Asish Kumar Dhara
U
sers of modern communication devices are annoyed by any source of background noise. Under
certain circumstances, however, an extra dose of noise can in fact help rather than hinder the
performance of some devices. It is found that in the presence of small noise a bistable system indeed
produces a periodic output much stronger than the input. The noise induced cooperative response
depends on the amplitude, A0 and the frequency, Ω
of the periodic input signal and the strength, D of the
noisy environment in which the system is embedded.
The exact solution of the Fokker-Planck equation describing this non-stationary process is not known.
One analyses the system perturbatively with the amplitude, A0 as an expansion parameter. The response
(signal amplification factor) of this nonlinear device is thus investigated. The first term in the
perturbation expansion is called the linear response. The higher order terms in powers of the amplitude
of the periodic force are called nonlinear responses.
29
RESEARCH
tudy of nuclear symmetry energy in intermediate energy heavy ion reactions is an important area of
research for determining the nuclear equation of state. The ratio of the symmetry energy
coefficient to temperature (Csym/T) is extracted using different prescriptions (isoscaling source method,
isoscaling fragment method, fluctuation method and isobaric yield ratio method) in the framework of
58
the recently developed projectile fragmentation model. Theoretical calculations are done for (i) Ni
64
9
124
136
208
and Ni on Be at 140 MeV/nucleon and (ii) Xe and Xe on Pb at 1GeV/nucleon and the results are
compared with the experimental data.
Linear response approximation provides the signal amplification factor independent of the amplitude
of the periodic signal while the numerical results show that the response does depend on the amplitude.
This suggests that in order to estimate true response one should calculate the nonlinear response.
Analytic study of the response was so far restricted to the linear response approximation (calculation of
the first term of the perturbation series). Recently we published an analytic expression for the leadingorder nonlinear response (the second term of the series). It is seen from our analysis that the usual
method of perturbation approach by truncating the series fails in this case. Violent oscillations of the
consecutive higher order terms emerge and as a result reasonable finite response is not obtained if we
truncate the series. Therefore we put forward a scheme which takes into account all the infinite number
of terms of the perturbation series.
RESEARCH
Analytic evaluation of the response (signal amplification factor), η in this scheme involves the
summations of several strings of infinite number of oscillatory terms. The preliminary calculation of
the analytic expression (solid line) with only two strings is illustrated and compared with the numerical
results (dotted lines) in the figures below for the amplitudes, A0 =0.1 and A0 = 0.2. As the truncation is
avoided, the finite response is achieved through subtle cancellation of infinite number of oscillating
divergent terms in a desired way in our non-perturbative scheme. The figures more or less agree with
the numerical values (denoted by η(pap) in the figures) for both the amplitudes. This shows that the rest of
the strings need to be evaluated for having better agreement with the numerical values.
The effect of in-medium spectral modification of the rho meson
on the viscosity of a pion gas
Sukanya Mitra, Sabyasachi Ghosh and Sourav Sarkar
W
e have evaluated the shear viscosity of a pion gas in the relativistic kinetic theory approach. The
in-medium propagator of the rho meson at finite temperature is used to evaluate the pi-pi
scattering amplitude in the medium. The real and imaginary parts of the self-energy calculated from
30
NUCLEAR THEORY
one-loop diagrams are seen to have significant effects on the scattering cross-section. The
consequences on the temperature dependence of the shear viscosity evaluated in the Chapman-Enskog
and relaxation time approximations have been studied.
Reference
RESEARCH
[1] S. Mitra, S. Ghosh and S. Sarkar, Phys. Rev. C85 (2012) 064917.
31
1.3
ANALYTICAL CHEMISTRY, RADIO CHEMISTRY,
RADIO PHARMACEUTICALS
PAC study of the static and dynamic aspects of Cd and Hg
atoms inside Fullerene cage
1
1
1
2
3
S.K. Das , R. Guin , D. Banerjee , K. Johnston , P. Das, T. Butz ,
V. S. Amaral2, J.G. Correia2 and M. B. Barbosa2
1
Accelerator Chemitry Section, RCD, BARC, VECC, Kolkata-700064
2
ISOLDE, CERN, Geneva, Switzerland
3
Leipzig University, Germany
T
Intensity (arb.units)
A2G2 (t)
RESEARCH
he endofullerene compounds (atoms or cluster of atoms inside the fullerene cage) have
applications in the areas of superconductivity, lasers, ferroelectric materials and nuclear
111m
199m
medicines utilizing the behavior of atom(s) inside the cage [1]. The Cd and Hg beams with
2
energy 30-50 keV from ISOLDE, CERN were implanted into C60 target (1mg/cm ). The coincidences
for the 151-245 keV cascade of 111mCd and 374-158 keV cascade of 199mHg were used for TDPAC
measurements on a six LaBr3 (Ce) detector system coupled with digital electronics. The endofullerene
compound was separated by filtration of the toluene solution of the implanted C60 target using
micropore filter paper followed by solvent extraction with 6M HCl. The endofullerene sample was
counted for TDPAC measurement and results for 111mCd probe are shown in Fig.1.
Time (ns)
Frequency (Grad/s)
Figure 1. TDPAC spectrum for the 111mCd@C60 endofullerene (left) and the corresponding Fourier spectrum (right).
32
ANALYTICAL CHEMISTRY, RADIO CHEMISTRY, RADIO PHARMACEUTICALS
Similarly the 199mHg@C60 endofullerenes were counted on the same TDPAC setup and the results with
Hg probe have been shown in Fig.2.
Figure 2. TDPAC spectrum for the 199mHg@C60 endofullerene (left) and the corresponding Fourier spectrum (right).
Table1: TDPAC parameters for two systems.
Sample
ω
Q
(Mrad/s)
η
δ
(%)
Fast λ
(ns-1)
111m
8.14(42)
0.42(9)
9.3(5.7)
0.003(3)
0.06(9)
Cd
199m
Hg
281.6(16.9)
0.1(1)
0.01(2)
202.3(22.7)
0.2(1)
0.08(5)
The PAC parameters are tabulated in Table1. results indicate that in case of both Cd and Hg atoms, there
exists a static part along with a dynamic fraction due to a rapidly fluctuating electric field gradient. The
static part might be attributed to a fraction of atoms externally trapped by fullerene-clusters formed
during the implantation process. However, the dynamic part is attributed to the movement of the atoms
2
inside the fullerene cage. Since λ
is proportional to ω
Q τ
c (correlation time) it follows that τ
c for Hg is 12 orders of magnitude smaller than that for Cd, i.e. Hg atoms remain loosely bound inside the fullerene
cage due to its Inert-Pair effect.
References
[1]
T. Braun (Ed.), Developments in Fullerene Science, Nuclear and Radiation Chemical Approaches to Fullerene
Science, Vol. 1, Kluwer Academic Publishers, The Netherlands, 2000.
[2]
Encapsulation of radioactive isotopes into C60 fullerene cage by recoil implantation technique, S.K. Saha, D.P.
Choudhury, S.K.Das, R. Guin, NIM Physics Research B 243 (2005) 277-281.
33
RESEARCH
199m
The determination of elemental impurities in high purity
graphite and alumina at trace and ultra trace levels
by charged particle activation analysis
J. Datta1, R. Verma2, A.V.R Reddy2 and D.P. Chowdhury2
1
Analytical Chemistry Division, BARC, VECC, Kolkata
2
Analytical Chemistry Division, BARC, Mumbai
T
RESEARCH
he elemental impurities have been determined in high purity graphite and alumina materials used
in nuclear reactors at ppb – ppm levels by Charged Particle Activation Analysis (CPAA) using
proton beam from VEC machine. This work has been carried out to develop an in-house nuclear grade
standard reference material and the concentrations of all the impurities present in the graphite and
alumina are required to know to obtain the boron equivalent of the material. The boron equivalent of the
material to be used in the reactor should be less than 5 ppm including all the impurity elements
including the host materials. CPAA has the characteristics, in contrary to NAA, of producing more
than one isotopic product from a target element through different reaction channels depending on the
nature and energy of the ion beams. Both proton (12 – 20 MeV) and a
-particles (30 – 50 MeV),
available from VEC machine, can be used in CPAA. Proton has certain advantages, compared to a
particles, for the determination of trace elements by CPAA through instrumental approach like, (1)
large cross section of (p,n) reactions (100 – 800 mb), (2) less matrix activation (3) less heat production.
The cross sections of higher reaction channels like (p, 2n), (p, pn) are found to be less than 1 mb below
13 MeV proton by theoretical calculation using ALICE 91 computer code. Therefore, 13 MeV proton
beam was used to irradiate the graphite and alumina samples along with standards, Lake (IAEA-SL-1)
and Marine (PACS-2) sediments, both in pellet and powder forms. The irradiation was carried out with
Table 1 : Concentrations of trace impurities present in graphite and alumina samples and their sensitivities by CPAA in
ppm
Element
Reaction product & t1/2
Ca
44
44m
Ti
48
V
51
Cr
52
52
Fe
56
56
Ni
58
Cu
65
Ca(p, n) Sc, 2.44 d
Graphite
Alumina
Sensitivities
5.3 ± 0.7
330 ± 26
0.5
1.10 ± 0.08
21.1 ± 1.3
0.01
0.8 ± 0.1
4.9 ± 0.7
0.03
0.16 ± 0.02
2.1 ± 0.3
0.02
Fe(p, n) Co, 78.8 d
44.1 ± 3.8
2890 ± 256
0.04
57
Ni(p, pn) Ni, 36 h
0.22 ± 0.03
3.5 ± 0.4
0.01
65
1.2 ± 0.2
4.7 ± 0.6
0.2
Zn
67
67
Zn(p, n) Ga, 3.3 d
1.2 ± 0.2
8.5 ± 1.0
0.1
Ga
68
69
Ga(p, n) Ge, 39 h
0.20 ± 0.02
92.7 ± 7.0
0.03
Ge
74
74
0.10 ± 0.02
0.81 ± 0.15
0.01
Sr
88
88
Sr(p, n) Y, 107 d
0.14 ± 0.02
2.9 ± 0.3
0.01
Zr
90
90
2.3 ± 0.2
14.5 ± 1.3
0.005
Mo
96
0.040 ± .005
0.10 ± 0.02
0.005
Pb
206
Ti(p, n)48V, 16 d
V(p, n)51Cr, 27.7 d
Cr(p, n) Mn, 5.6 d
Cu(p, n) Zn, 244.1 d
Ge(p, n) As, 17.8 d
Zr(p, n) Nb, 14.6 h
96
Mo(p, n) Tc, 4.3 d
Pb(p, n)206Bi, 6.2 d
Possible to determine with 22 MeV proton beam
34
The measurement of surface erosion of zircaloy materials of fuel
pin during laser ablation process by thin layer activation
technique
J. Datta1, Rakesh Verma2, D.P. Chowdhury1
J.P. Nilaya3, D.J. Biswas3 and L.M. Gantayet4
1
Analytical Chemistry Division, BARC, VECC, Kolkata – 700064
2
Analytical Chemistry Division, BARC, Mumbai – 400085
3
Laser and Plasma Technology Division, BARC, Mumbai – 400085
4
Beam Technology Development Group, BARC, Mumbai – 400085
T
he outer clad surface of zircaloy fuel pins gets contaminated by deposition of fuel particulates
during loading operation of mixed oxide (MOX) fuel pellets. Due to high radiotoxicity of MOX it
is essential that the outer surface of fuel elements is cleaned before the fuel elements are removed from
the glove box after loading operation. The laser assisted cleaning has emerged as an ideal method,
compared to current method of ultrasonic cleaning, for decontamination of MOX powder due to certain
advantages. However, it is important there should not be any removal of zircaloy material during laser
cleaning operation. The thin layer activation (TLA) technique has been applied to measure the surface
loss of zircaloy materials during laser ablation process in the ranges of nanometer to micrometer. A thin
layer of activity (~ 250 µm) of suitable isotopes like 92mNb (10 d) and 95Nb (35 d) was produced in
samples (14 × 12 mm) of zircaloy fuel elements (both autoclaved & non-autoclaved) using 40 MeV particles from VEC machine at Kolkata. An activity (~ 105 Bq/A.h) was produced by irradiating with a
beam current - 100 nA for 12 h. The active samples were then undergone laser exposure using a single
pulse laser of 300 ps, fluence 200 mjoules/cm2, wavelength – 1064 nm, pulse repetition rate – 10 Hz,
derived from Nd-YAG laser. The loss in activity observed before and after laser ablation, when
compared with the calibration curves, provides the rate of surface erosion during laser ablation. The
calibration curves were generated with 92mNb and 95Nb by stacked foil activation using thin Zr foils (~ 4
m thickness), as shown in Fig. 1.
35
RESEARCH
50 nA to 1µ
A beam current for 10 min to 10 h depending on types of samples and standards. The beam
current was measured by Faraday cup and also checked by putting Ti monitoring foil before the target.
It was possible to determine the elements of Ca, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Mo, Zr, Ge, in graphite and
alumina at ppb – ppm levels by (p, n) reactions with 13 MeV proton. For Ni element, there is no suitable
product from (p,n) reaction and hence 58Ni(p, pn)57Ni reaction was used to produce 57Ni using 18 MeV
proton beam to determine Ni. Lead was attempted through the product 206Bi from (p, n) reaction using
18 MeV proton due to high coloumb barrier (12 MeV). However, yield was too low due to poor cross
section (~ 80 mb) at 18 MeV proton and it may be possible with higher cross section (~ 400 mb) at 22
MeV proton. The sensitivities of all these elements, listed above, have been estimated based on the
experimental parameters of graphite samples. The concentration of the elements present in graphite
and alumina samples along with the sensitivities are presented in Table 1. The irradiation of samples
with 20 – 22 MeV proton is yet to be performed for completion of this work.
The surface erosion of zircaloy samples by laser exposure was carried out for two cases. The laser
fluence (200 mjoules/cm2) was first chosen which provides a satisfactory cleaning of decontamination.
It was found that there was no loss of activity and it indicated that the laser parameters used to clean did
not lead to any erosion of zircaloy material. The laser fluence was then enhanced to 20 jouls/cm2 and the
entire active area was then inpinged with 50 – 350 laser pulses through controlled scanning. A total of
18 ablations was carried out with both types of zircaloy samples and the cumulated ablation thickness
due to surface erosion by laser energy is shown in Fig. 2. A total loss of 50 – 60 m thickness of zircaloy
material was observed by applying laser energy up to ~ 15 kjoule. The rate of surface erosion of
autoclaved zircaloy was found to be less than that of non-autoclaved material. The minimum detectable
ablated thickness has been estimated to be 80 nm ± 25 nm by TLA technique. It has been planned to
apply TLA technique to measure rate of surface erosion in S.S. fuel pins by laser exposure.
RESEARCH
Figure 1. Calibration curves using isotopes 92mNb & 95Nb for
zircaloy based materials
Figure 2. Surface erosion of zircaloy materials during laser
ablation process
Reference
[1] Applications of thin layer activation technique for the measurement of surface loss of materials: an India1n
perspective; D. P. Chowdhury, J. Datta and A. V. R. Reddy; Radiochimica Acta 100, (2012) 139-145.
The characterization of hydrogenated diamond like carbon thin
films by Raman Spectroscopy
J. Datta1, D.P. Chowdhury1 and N.R. Ray2
1
Analytical Chemistry Division, BARC, VECC, Kolkata
Surface Physics division, Saha Institute of Nuclear Physics
2
T
he several hydrogenated diamond like carbon (HDLC) thin films were prepared at 20-70 SCCM
(standard cubic centimeter per minute) flow of methane during plasma enhanced chemical vapor
36
size of the sp3 C–H domains in the HDLC film is reduced by the loss of bonded hydrogen atoms in the
hydrogenated hexagonal crystal structure of carbon atoms.
RESEARCH
Figure 2. (a) First-order (b) Second-order Raman spectrum of as-prepared HDLC film. And (c) First-order (d) Second-order
Raman spectrum of annealed HDLC film.
References
[1]
J. Datta, N. R. Ray, P. Sen, H. S. Biswas, and E. A. Vogler, Mater. Lett. 71, 131 (2012).
[2]
F. Tuinstra and J. L. Koenig, ,” J. Chem. Phys., 53, 1126, (1970).
[3]
H. S. Biswas, J. Datta, D. P. Chowdhury, A. V. R. Reddy, U. C. Ghosh, A. K. Srivastava, and N. R. Ray, Langmuir,
26, 17 413 (2010).
Gamma ray spectrometric analysis of coal ash samples from a
thermal power plant
K. Pariwal*, R. Guin, D. Sengupta*, D. Banerjee and S. K. Das
*
Department of Geology & Geophysics, IIT, Kharagpur
C
oal, like any other natural material, contains radioactive elements in various quantities
depending upon the coalification process. During thermal power generation, subjected to
38
combustion at a very high temperature, a residue of coal is left commonly known as coal ash. The
coal ash shows considerably high and enhanced radioactivity as compared to the feed coal. The
most commonly used coal for Indian thermal power sector is of bituminous or sub-bituminous
type which is rich in Thorium-232 followed by Uranium-238. In some seams the coal might have
potassium-40 as a radioactive source. This ash, disposed in the environment either in dry form or in
wet form, adds to the natural radiation dose to a large extent posing a serious threat to the life forms
in the neighborhood. Therefore, the ambient radiation in the vicinity of ash ponds was studied by
measuring the activity concentration of the ash samples.
Each sample was measured for 80000 seconds. 238U was calculated using its decay products 214Pb
(295,352 keV) and 214Bi (609 keV) and 232Th was calculated using 228Ac (338, 911 keV), 212Pb (239
keV), 212Bi (727 keV) and 208Tl (583 keV) activities, assuming the series in secular equilibrium.
Potassium was measured using its own gamma ray (1460.8 keV). Activity concentrations were
determined by taking weighted average from the gamma rays of each decay product. The activity
(in Bq/kg) of each radionuclide was determined using total net counts under the selected photopeaks after subtracting the background counts, and applying photo-peak efficiency, γ-intensity of
radionuclide, weight of the sample and the counting time. The measured activities of a few
samples are presented in Table 1.
Table 1: Average activity (Bq/kg) and concentration (ppm) of 238U and 232Th
Sample no.
238
232
238
232
U
(Bq/kg)
Th
(Bq/kg)
U
(ppm)
Th
(ppm)
N1-16
59.3
343.8
4.80
85.10
N1-10
102.3
193.9
8.28
48.00
N2-16
52.9
123.6
4.28
30.59
N3-D1
112.4
134.3
9.09
33.24
9M FINE
100.8
242.8
8.16
60.10
SLURRY
72
129.2
5.83
31.98
6M DRY
123
81.7
9.95
20.22
The mean natural radionuclide concentration in coal is 35 Bq/kg for 238U (range:17-60) and 30
Bq/kg for 232Th (UNSCEAR, 1993,2000) and Kolaghat thermal power plant feed coal samples
are reported (Mondal et. al., 2006) to contain 37 Bq/kg and 24 Bq/kg 238U and 232Th
respectively. The Table 1 shows that the ash samples contain 2-3 times (in case of 238U) to 5-10
times (in case of 232Th) higher radioactivity compared to the feed coal. The results also indicate
a preferential increase of thorium over uranium. The enrichment of radionuclide concentration
in the ash adds up to the environmental radiation dose to the nearby locality.
39
RESEARCH
Ash samples were collected from ash ponds around Kolaghat Thermal Power Plant, West Bengal.
The samples were air dried and sealed in plastic vials for more than a month to attain secular
equilibrium. The radioactivity concentration of the samples was determined by gamma ray
spectrometric analysis using a 50 % HPGe detector. The detector was properly shielded with thick
lead bricks to minimize the interference due to background and cosmic radiation. Standard 152Eu
activity sealed in similar vials as of the samples was used to determine the efficiency of the
detector.
References
[1]
UNSCEAR, (1993): Sources and Effects of Ionizing Radiation. Report: United Nations Scientific Committee on
the Effects of Atomic Radiation, United Nations, New York.
[2]
UNSCEAR, (2000): Sources and Effects of Ionizing Radiation. Report: United Nations Scientific Committee on
the Effects of Atomic Radiation, United Nations, New York.
[3]
Mondal, T., Sengupta, D., and Mandal, A., Natural radioactivity of ash and coal in major thermal power plants of
West Bengal , India. Curr. Sci., 91(10),1387 (2006).
Study of K-isomeric pairs in the mass region A ~ 180
R. Guin, D. Banerjee and S. K. Das
M
RESEARCH
ass region A ~ 180 in the nuclear chart has been found to show K – isomerism. Transition
between the initial state and final state of a nucleus in this region is governed by the K –
selection rules. Thus the study of formation of isomeric pairs in this region will give information on the
182,184
role of K–quantum number in nuclear reactions. The isomer ratio of
Re is therefore being studied.
These nuclides can be produced by p-irradiation of tungsten targets as well as by α-irradiation of
tantalum targets. The study of the isomer ratio of these nuclides through these two roots will give added
information on the role of entrance channel parameters in their formation.
The experiments were carried out by stacked-foil technique using 12.5 µm tantalum foils. For tungsten
irradiation, 15 µm foils were used in the stack. For (Ta+α) reactions, α-energies from 30 MeV to 60
MeV were used. In each stack irradiation, the α-energy degradation was maintained at about 12 MeV.
Figure 1. Experimental cross-sections for 181Ta (α
, xn) 185-xRe reactions
40
Standard copper foil was used in each stack as an internal monitor for the irradiations. The irradiations
were carried out using about 500 nA beam for suitable durations to produce the required products of
sufficient activity. For (W+p) reactions, 15 MeV p-beam of about 400 nA current was used in the
irradiation of a tungsten stack containing a copper foil as internal monitor.
After the irradiations, the activity of each irradiated Ta and W foil was assayed by off-line γspectrometric technique using a 50 % HPGe detector. The activity follow-up was continued for
sufficiently long time according to the half-life of each product. From the activity data, the production
of each isomer in the experimental energy range was calculated using standard radioactive decay
equations. The Fig.1 shows some of the experimental results :
Performance evaluation of SOL-COL generator system and
comparison of labeling efficiency of Tc-cold kits with
99m
Tc obtained from different types of generators
Sishir Kumar Sarkar 1, Sankha Chattopadhyay2, Luna Barua2, Anirban De, Sujata
SahaDas2, Sangita Joshi1, P. Kale1, Tara Pillai1, Malay Kanti Das2,
S.S.Sachdev1 and N.Sivaprasad1
1
Radiopharmaceuticals Programme, BRIT, BARC Vashi Complex, Navi Mumbai
2
Radiopharmaceuticals Lab., Regional Centre, BRIT, Kolkata
T
he generator system has been originally developed by BRIT, REGIONAL CENTRE, VECC,
Kolkata.
99m
The generator system is based on solvent extraction of Tc in methyl ethyl ketone (MEK) from
aqueous alkaline (n,γ) Na299MoO4 solution and subsequent purification of 99mTc through basic and
acidic alumina columns.
The system consists of the existing solvent extraction generator apparatus with the main glass mixing
vessel for organic MEK and aqueous alkaline sodium molybdate-99Mo solution confined in lead
shielding, two alumina columns (basic and acidic of 5g each) kept in shielding connected in tandem,
connector, tunings, needles, two & three way stopcock, valves, glass vials of different capacity,
99m
measuring cylinder and an on-line 0.22µ membrane filter with needle for collecting purified Tc in
0.9% NaCl solution. A glass tube has been inserted in the solvent extraction generator glass apparatus
99m
to suck Tc in MEK from the top of aqueous layer in the solvent extraction apparatus using a vacuum
pump. A hole has also been made in the lead shielding of solvent extraction apparatus to connect tubing
for suction of MEK using a vacuum pump.
99m
Tc extracted in MEK is passed down to both the alumina columns. Basic alumina traps traces of
99m
Mo co-extracted in MEK and acidic alumina traps Tc. The acidic alumina column is then dried up
by passing hot air (~90°C) to remove MEK and then washed with doubled distilled water (10ml).
99
41
RESEARCH
Few more irradiations will be carried out to complete this study. Theoretical interpretation of these
experimental results in terms of the role of K-quantum number is being carried out.
Trapped 99mTc is then recovered from acidic alumina through a 0.22µ on-line membrane filter in 10ml of
99
normal saline using evacuated vial.(n,γ) Na2 MoO4 solution remains in the generator assembly after
99m
99m
Tc separation and used for subsequent days separation of Tc.
99
Generators containing 40ml of (n,γ) Mo solution (22ml) including 5N NaOH solution (18ml) along
with 40ml of MEK was prepared in the modified generator assembly. Sol-Col generator systems with
99
99
99m
Mo activity ~400mCi of Mo (on Tuesday) were prepared and evaluated. Tc yield was in the range
99
-3
of 70-75%, Mo breakthrough was less than 10 % and radiochemical purities was more than 95%. The
labeling efficiency of pertechnetate with Tc-cold kit such as Tc-MIBI, Tc-ECD, Tc-MDP, Tc-DTPA,
Tc-DMSA(III),Tc-GHA, and Tc-Phytate were ~ 97% compared to ~ 95.3% with 99mTc availed from
other 99mTc generators system.
99m
99m
Qualities of Tc from Sol-Col system are similar to other generator system of Tc. The generator
99m
system could be used in centralized hospital radiopharmacy for extracting large quantities Tc from
99
(n,γ) Mo.
RESEARCH
Design, development of automated 99mTc-TCM-AUTOSOLEX
generator for separation and recovery of 99mTc from
low-medium specific activity 99Mo
Sankha Chattopadhyay1, Luna Barua1, Anirban De, Sujata Saha Das1, Sasanka Shekhar
Pal, Umesh Kumar1, Santwana Kumari, Mousumi Garai, Tapas Malick, Sujit Ghosh,
Kalyan Sarkar and Malay Kanti Das1
1
Radiopharmaceuticals Lab., Regional Centre, BRIT, VECC, Kolkata
T
echnetium-99m (t1/2= 6.02h; 140.51 keV (89%), principle γ
-emission energy) is known to be the
most useful radioisotope in diagnostic nuclear medicine. More than 80% of all diagnostic
99m
procedures done worldwide in nuclear medicine centre are performed with Tc. An automated closed
cyclic module (TCM-AUTOSOLEX) for separation and recovery of various isotopes, radioactive or
non-radioactive, using solvent extraction technique, and in particular, for separation and recovery of
99m
Tc from low-medium specific activity 99Mo obtained from a research reactor has been indigenously
99m
developed jointly by VECC and BRIT, Kolkata. The module may also be used for separation of Tc
produced in cyclotron. The module is safe and reliable and operated remotely through a PC, thus
avoiding direct handling of radioactive and hazardous chemicals by an operator. The TCMAUTOSOLEX generator system is based on the selective extraction of pertechnetate (99mTcO4- ) in
methyl ethyl ketone (MEK) from aqueous alkaline (n,γ
)Na299MoO4 solution and subsequent
purification of the organic phase by passing through an alumina column to remove traces of Mo, alkali
etc. and careful evaporation of the organic phase. Finally, the residue obtained after evaporation is
reconstituted in physiological saline (10 ml), purified through an on-line 0.22µ membrane filter to
obtain pharmaceutical grade 99mTc and collected in a vacuum vial. A 16-bit microcontroller based
embedded system has been designed indigenously to automate the entire process. A PC based graphical
42
user interface (GUI) has also been developed that communicates with the controller electronics over a
serial link. The user sets the timing of each sequence of the process and also the temperature of a
thermal bath that is used in the evaporation stage. These settings are sequentially sent via a serial link to
the controller electronics that operates the heater system, valves and pump accordingly. A conductivity
detector has also been designed and implemented to automate the separation of the chemicals based on
difference in resistivity of the two liquids. Apart from setting and command interfacing between PC
and the process, the controller unit also provides monitoring over the actuators, conductivity detector
and heater temperature (±50C) and sends the status to the GUI. An additional feature of time-stamped
data logging is also built in the GUI for diagnostics purposes.
RESEARCH
A prototype was installed in BRIT, Kolkata and several cold runs were carried out and demonstrations
done. It was then shipped to BRIT, Mumbai and tested with actual activity. It was demonstrated
successfully there and also in RMC, Parel.
(Clockwise from top) The Autosolex radiochemical process assembly inside fume hood,
Screenshot of PC base GUI for Autosolex control, Autosolex electronics assembly inside 19” rack
43
99m
Tc-Paclitaxel is a potential theranostic agent: novel synthetic
method, quality control, characterization, biodistribution
and scintigraphy
Indranil Banerjee1, Ashok Behera1, Kakali De1, Sankha Chattopadhyay2, Amal Kumar
Bandyopadhyay3, Bharat Sarkar, Santanu Ganguly and Mridula Misra1
1
Department of Infectious Diseases and Immunology (Nuclear Medicine Division), CSIR-IICB,
4 Raja S C Mullick Road, Kolkata
2
Radiopharmaceuticals Laboratory, Regional Centre, Board BRIT, VECC, Kolkata
3
Division of Pharmaceutics, Department of Pharmaceutical Technology,
Jadavpur University, Kolkata
P
RESEARCH
aclitaxel is an anticancer drug with a diterpenoid structure and a molecular weight of 853 Dalton.
99m
The aim of the present study is to synthesize Tc-paclitaxel by using sodium borohydride as a
reducing agent and its potential as theranostic agent. The radiolabelling efficiency was assessed by
99m
ITLC method using acetone as mobile phase. The radiochemical purity of Tc-paclitaxel was
validated by HPLC. Stability of radiolabelled complex was measured by ITLC up to 24h. In vitro
stability of the complex was checked in PBS (up to 24h), rat serum (up to 24h) and in different
concentrations of diethylenetriaminepentaacetic acid (DTPA). Plasma protein binding and Log P value
of the complex were calculated by following standard procedure. Biodistribution and scintigraphy
studies were performed in Sprague-Dawley rats (approximately 200-250gm).
99m
Sodium borohydride was successfully used for radiolabelling of paclitaxel with Tc as greater than
95% labelling efficiency was achieved by this method. The complex was stable up to 24h in a closed
container and passed in vitro stability tests. Log P value (-1.46 ± 0.03) suggested that the complex was
hydrophilic in nature and low plasma protein binding (26.13 ± 2.59) was observed as well, indicating
higher amount of free 99mTc-paclitaxel in the system. Quantitative biodistribution indicates that higher
99m
99m
accumulation of Tc-paclitaxel in the liver up to 24h. Tc-paclitaxel was distributed to almost all
organs initially after injection but cleared from the body gradually after 1h owing to extensive
clearance from the body. Scintigraphy also supports this result. Sodium borohydride (instead of
stannous salts) can be used to radiolabel drug molecules with 99mTc. The interference of colloidal tin
99m
oxides on the biodistribution of Tc radiolabelled drugs can be prevented by this method. The liver
uptake of 99mTc-paclitaxel was significant in rats, and 99mTc-paclitaxel may be used as a theranostic
agent.
Figure 1. Structure of paclitaxel (Ph = C6H5, Ac = COCH3) Figure 2. Rate of complexation with respect to stirring time for
99m
Tc-paclitaxel
44
Figure 3. Blood clearance curve for 99mTc-paclitaxel
Figure 4. Scintigraphic image of 99mTc-paclitaxel at
Synthesis, conformation analysis, characterization of a cyclic
conjugated peptide and biological evaluation of 99mTc-labeled
peptide as a novel tracer for the imaging of somatostatin
receptor positive tumors
Ashok Behera1, Indranil Banerjee1, Kakali De1, Rudra Narayan Munda1,
Sankha Chattopadhayay 2, Amlesh Samanta3, Bharat Sarkar,
Santanu Ganguly and Mridula Misra1
1
Infectious Disease and Immunology Division, Department of Nuclear Medicine,
CSIR-Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Kolkata
2
Radiopharmaceuticals Laboratory, Regional Centre, Board of Radiation and Isotope Technology,
Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata
3
Department of Pharmaceutical Technology, Jadavpur University, Kolkata
P
eptides are becoming of increasing interest in nuclear oncology for targeted tumour diagnosis and
therapy. New cyclic octapeptides conjugated with HYNIC peptide was synthesized by Fmoc solid
phase peptide synthesis using peptide synthesizer. These were purified and analysed by RP-HPLC,
1
13
MALDI mass, H NMR, C NMR, HSQC, HMBC, COSY, NOSEY and IR spectroscopy.
Conformational analysis of HYNIC conjugated peptides were performed by circular dichorism
spectroscopy in pure water and trifluroethanol-water (1:1), revealed the presence of strong secondary
structural features like β-sheet and random coils. Labelling was performed with 99m Tc using Tricine and
EDDA as coligand by SnCl2 method with an excellent radiochemical purity of 99.5%. Metabolic
stability analysis did not show any evidence of breaking of the labeled compounds and formation of
99m
free Tc. The internalization study and IC50 value were determined in somatostatin receptorexpressing C6 glioma cell line, rat brain cortex membrane and compared with HYNIC-TOC as
99m
99m
3
standard. The IC50 value of Tc-HYNIC-TOC (2.87 ± 0.41 nM) and Tc-HYNIC-His -Octreotate (21
± 0.93 nM) proved to be comparable. Biodistribution and image study on normal rat under gamma
camera showed very high uptake in the kidney and urine, indicating that kidney as primary organ for
metabolism and route of excretion. Biodistribution and image study on rats bearing C6 glioma tumor,
45
RESEARCH
5, 15, 30 and 60 min
found high uptake in tumor (1.27±0.15), pancreas (1.71±0.03). Using this property of peptide new
99m
derivative can be prepared to develop Tc radiopharmaceuticals for imaging somatostatin receptor
(SSTR) positive tumors.
RESEARCH
When (AA3) is Tyr3 and –COOH is -CH2OH = compound 1
When (AA3) is His3 and –COOH = compound 2
3
Reaction Scheme 1: For synthesis of HYNIC-TOC and HYNIC-His -Octreotate
Figure 1. Organ biodistribution of complex 99mTc-HYNIC-His3-Octreotate (500 µl) in normal rats (N = 16) (%ID/g).
46
Figure 2. A Planar static images of normal rat C6 glioma tumor-bearing rat at 45 min after i.v. injection of 99mTc-HYNIC-His3Octreotate (500 µl). B SPECT image on C6 glioma tumor-bearing rat showing blocking (100 µg of cold HYNIC-TOC) of
99m
Tc-HYNIC-His3-Octreotate uptake in receptor positive organs and tumor. C SPECT image on C6 glioma tumor-bearing rat
at 10 min showing uptake in receptor positive organs and tumor. D SPECT image on C6 glioma tumor-bearing rat at 45 min
showing uptake in receptor positive organs and tumor. E Tumor developed rat after 20 days subcutaneous injection of 107 C6
glioma cell into flank of 6- wk-old male Lewis rat.
Accelerator-based alternatives to non-HEU
production of 99Mo/99mTc
Malay Kanti Das1, Sankha Chattopadhyay1, Luna Barua1,
Sujata Saha Das1 and Anirban De
1
T
echnetium-99m (t1/2= 6h; 140 keV) is known to be the most useful radioisotope in diagnostic
radiopharmaceuticals. More than 80% of all diagnostic procedures done worldwide in nuclear
medicine centre are with 99mTc. High specific activity 99Mo (10kCi/g) is obtained by thermal neutron
fission of 235U. 99mTc used for the purpose may also be produced via 98Mo (n,γ
) in a natural MoO3 target or
47
RESEARCH
100
99
100
99m
99
through Mo(n, 2n) Mo or Mo(p, 2n) Tc reaction. Production of high specific activity Mo
(fission molybdenum) is solely dependent on the five very old (40-50 years) research reactors
worldwide which requires unscheduled shutdown for maintenance. In the fission produced 99Mo, the
target material is highly enriched uranium (HEU) 235U which is a weapons grade substance requiring
99
100
extensive safeguards. Currently, there are also proposals for production of Mo through Mo(n,
2n)99Mo or 99mTc directly through 100Mo(p, 2n)99mTc , in a cyclotron to meet the worldwide shortage of
99m
Tc.
All targets irradiated were of natural Mo metal. Two types of targets were irradiated. For irradiation at
low beam intensity and of short duration 25micron Mo foil stacks (containing 4-7 foils , each 10mm x
10mm)) with a 8-10 micron thick Cu monitor foil in front were used. Irradiations for longer duration
and at higher beam intensities were carried out on circular (10 mm diameter) Mo pellets which were
prepared by pressing about 400mg Mo powder in a dice plunger at 10 ton pressure. Irradiations were
carried out with 15/16/18 MeV proton beam. Irradiation of Mo foil stacks were carried out at 10-50nA
beam current for 5 min. Thick Mo targets were irradiated with 3µ
A proton beam for 1h, 3h and 6h.
About 1.5h after irradiation irradiated foils in the stack were directly counted in a HPGe detector. Thick
Mo targets were used for isolation of Tc radionuclides from Mo isotopes (active and stable) utilizing
two radiochemical separation techniques.
RESEARCH
Irradiated target taken in a conical flash was dissolved in 3ml 30% w/w H2O2.When the target reacted
completely with H2O2, the flask was brought to room temperature and 1ml 3M ammonium carbonate
was added. A clear solution was thus obtained from which Tc radionuclides were separated by any one
of the following methods.
By MEK solvent extraction: Usual practice of separation of Tc from Mo was followed. This method
has been automated [Communicated for publication].
By Dowex-1 resin and HNO3: A small Dowex-1 resin column was used for this separation. Here, the
resin holds 99mTc and 99Mo passes through the column. 99mTc is eluted with 5ml 4M HNO3 and then nitric
acid is evaporated from the eluate by heating under vacuum and the dry residue of Tc- radioisotopes is
reconstituted with saline. This method of separation will be automated soon.
Radiolabelling: MDP and MIBI were successfully radiolabelled with the isolated Tc-radioisotopes .
Quality control: Radionuclidic purity of the
final product was assessed by gamma ray
spectrometry and radiochemical purity by
ITLC. Chemical purity assessment includes
estimation of Al, Mo, nitrate, peroxide and
MEK content in the final preparation. First
four was done by colorimetric spot tests and
MEK content by iodoform test.
From stack foil irradiation data thick target
yield (TTY) of various Tc-radioisotopes were
99m
calculated. Fig.1 shows TTY of Tc as a
function of incident proton energy. Overall
recovery yield of Tc radioisotopes in both the
separation methods was about 80%. Figure 1. Extrapolated thick target yield of 99mTc from 100Mo(p,2n)
Radiolabeling yield with MDP and MIBI was
reaction as a function of proton energy.
48
above 95%. Q.C. analysis of the final product is given in Table-1 below.
Table 1. Typical data for the quality control tests of Na99mTcO4 prepared in cyclotron.
Q. C. Parameter
Separation method
Clarity
pH
99
MEK
Dowex-1, HNO3
Clear
Clear
6-7
6-7
-4
<10 %
<10-4 %
>99 %
>99 %
Al and Mo
< 10 ppm
< 10 ppm
Nitrate
< 10 ppm
< 10 ppm
Peroxide level
< 5 ppm
< 5 ppm
MEK content
<0.1% (v/v)
-
Mo breakthrough
RC Purity
Preparation and evaluation of a SnO2-based 68Ge/68Ga generator
made from 68Ge produced through natZn(α, xn) reaction: post
purification of 68Ga eluate
Sujata Saha Das, Sankha Chattopadhyay, Md Nayer Alam, Madhusmita,
Luna Barua and Malay Kanti Das
68
Ga, a PET imaging agent, is getting a lot of attention for last few years as it can be linked to tumor
68
68
68
targeting peptides that bind to cancer cells. Ga is obtained from a Ge/ Ga generator. The use of
68
68
Ge/ Ga generators in nuclear medicine is very attractive for several reasons: (a) Long shelf life of the
generator (potentially up to 1 year or even longer), (b) its 68 min half life matches with the
pharmacokinetics of many peptides and other small molecules owing to rapid diffusion, localisation at
68
the target and fast blood clearance, (c) Ga forms stable complexes with various types of chelating
agents with its +3 oxidation state. Eluates from most of the commercially available generators have low
68
concentration of Ga radioactivity, high acid concentration and traces of various metal contaminants
and thus it is not suitable for labelling work. Therefore, pre-concentration and purification of the initial
generator eluate is required.
68
nat
68
Ge was produced by Zn(α
, xn) Ge reaction in VEC cyclotron, Kolkata and its production yield was
31.82KBq/µAh (0.86µCi/µAh) at the end of irradiation (EOI). A simple chromatographic method
68
using a SnO2 column was employed to separate Ge from the target material and the co-produced non68
68
68
isotopic radioisotope impurities. Ge retained in the column served as the Ge/ Ga generator. Elution
efficiency of the column was about 60%. First 2ml of the eluate contained more than 95% of the
elutable activity. Post elution purification cum concentration was done with a small cation exchange
resin column [Zhernosekov et al., 2007] or Solvent extraction with MEK [Bokhari et al., 2009] or
49
RESEARCH
Chemical Purity
68
Solvent extraction with ether [Nelson et al.,1963]. Presence of the inactive tin ions in the Ga eluate
was determined by ICP-OES technique and was found to be about 0.03 ppm. Radiochemical purity of
the final 68Ga preparation was more than 99.99% and it was found to be suitable for making complex
with ethylenediamine-N,N,N´,N´-tetrakis(methylene phosphonic acid) (EDTMP). Possible 68Ge
break-through was assessed following a decay period (post EOI) of at least two days to allow for decay
68
65
of unsupported Ga. Any other long-lived radionuclidic impurity (e.g. Zn) if present in the eluate was
68
also detected. Ga activity, estimated (from 1077 keV γ-peak) in the eluate, represented the equilibrium
activity of 68Ge that passed through the column during elution. 65Zn impurity in the eluates was
65
estimated from the 1115 keV peak of Zn.
68
In the Ga eluate, one of the potential chemical impurities was tin ions which might come from the
column matrix. Trace level of the metal ion contamination in the decayed samples was determined by
68
ICP-OES technique using iCAP 6500 ICP spectrometer (Thermo Scientific). In the primary eluate Ge
65
68
and Zn activity was 0.023% and 0.0001%, the total Ge activity in the generator, respectively. Sn
68
concentration in the primary Ge eluate was 0.03 ppm. The results of post elution purification by three
methods are summarized below. All the three purification of primary eluate from 68Ge/68Ga generator
produce final preparation suitable for labelling work. Dowex method is slightly better and it can be
easily automated.
Generator evaluation results:
RESEARCH
Separation
Method
Purification
yield %
68
pH
Ge Breakthrough
65
Zn
impurity
% of 68Ga activity
eluted
Inactive metal ion
concentration, ppm
Sn
Zn
Dowex (n=26)
90
6-7
0.0008
0.00002
0.03
0.024
MEK
80
6
0.0042
0.00002
0.03
0.024
88
6
0.004
0.000008
0.03
.01
Ether
(n=12)
(n=12)
Figure 1. Elution profiles of the 68Ga eluates
50
References
Bokhari, T. H., Mushtaq, A., Khan, I, U., 2009.Concentration of 68Ga via solvent extraction. Appl. Radiat. Isot. 67
(1), 100–102
[2]
Nelson, F., Murase, T., Kraus, K.A., 1963. Ion exchange procedures I. Cation exchange in concentrated HCl and
HClO4 solutions. J.Chromatogr. 13, 503–535.
[3]
Zhernosekov, K.P., Filosofov, D.V., Baum, R.P., Aschoff, P., Adrian, H.J., Bihl, H., Razbash, A.A., Jahn, M.,
Jennewein, M., Rosch, F., 2007. Processing of generator produced 68Ga for medical application. J. Nucl. Med. 48,
RESEARCH
[1]
51
1.4
MATERIAL RESEARCH
Stick-slip response of dislocation core
A. Dutta1#, M. Bhattacharya and P. Barat
1
Dept of Metallurgical and Materials Engg, Jadavpur University, Kolkata 700 032
#Financially assisted by CSIR, India
T
RESEARCH
he core of a dislocation remains under such a large strain that the linear elasticity fails in this region
and nonlinear effects come into play. As a consequence, the process of crossover of a dislocation
core from a Peierls valley to the adjacent one under an applied shear load is non-trivial and obscure.
Here we study the atomistic simulation of adding shear strain (or stress) to edge dislocations in bcc
molybdenum and fcc aluminum in a quasistatic manner. This technique of quasistatic simulation is
often used for determining the Peierls stress of a dislocation at T = 0 K [1,2]. In this method, an edge
dislocation is introduced in a simulation cell [3] and shear strain is added to the cell in small steps. Each
step of increasing the shear strain is followed by energy minimization using the conjugate gradient
relaxation algorithm [3]. We obtain the atomic trajectories of all the core atoms at sub-Burgers vector
resolution and the span of data collection is up to the next Peierls valley, that can be marked by a sudden
fall in the potential energy or shear stress of the system. The data is represented in terms of the
differential displacement, which quantifies the extent of atomic displacements at a given step with
respect to the previous one. These values are plotted in Figs. 1(a) and (b), where we find that instead of
exhibiting a continuous response to the applied shear strain, the atoms in the dislocation core undergoes
rearrangement in abrupt and discrete bursts. This can hence be regarded a quasistatic form of the stickslip phenomenon often observed in many dynamical processes.
Shear strain
Shear strain
Figure 1. Differential displacement profiles of the edge dislocation core atoms in (a) bcc molybdenum and (b) fcc aluminum.
We also investigate the effective dimensionality of this quasistatic process using the principal
component analysis [4]. This yields the sense of unidirectional motion to the core structure selfassembly and is important since other methods of designating the core position, e.g. by marking the
centre of mass of the core atoms lacks the requisite resolution at sub-Burgers vector length scale. We
convert the atomic trajectories to covariance matrices, the diagonalization of which yields the
52
MATERIAL RESEARCH
Figure 2. Principal projections of the core atoms in (a) molybdenum and (b) aluminum. The flat regions in these profiles
correspond to the stick states, whereas the sudden jumps show the slips.
References
[1] D.L. Olmsted, K.Y. Hardikar, and R. Phillips, Modelling Simul. Mater. Sci. Engg. 9, 215 (2001).
[2] R.E. Voskoboinikov, Yu.N. Osetsky, and D.J. Bacon, Mater. Sci. Engg. A 400-401, 45 (2005).
[3] V.V. Bulatov and W. Cai, Computer Simulations of Dislocations (Oxford University Press, Oxford, 2006).
[4] I.T. Jolliffe, Principle Component Analysis (Springer-Verlag, New York, 2002).
Frequency-adapted phase transition of an interacting ensemble
of nano-magnets
Nilangshu K Das, P. Barat, Sounak Dey1 and T. Jayakumar2
1
Indian Statistical Institute, Kolkata
2
MMG, IGCAR, Kalpakkam
T
he aggregation of interacting nano-magnetic dipoles, demonstrate both experimentally and
theoretically as a model system to detect intriguing co-operative physical phenomena. Here we
show a new variant of phase transition from paramagnetic to diamagnetic phase by changing the
frequency of the applied sinusoidal magnetic field for a nano-magnetic ensemble. This phenomenon
unravels a new insight of physics and it may be significant on the design and development of magnetic
devices.
53
RESEARCH
eigenvalues. The principal eigenvalues are found to be in excess of 90%, indicating the strong effective
dimensionality of the system. The projections of the data on the principal directions are plotted in Fig. 2
(a) and (b) for the metals under study. It is remarkable that even though the core remains within the
same Peierls valley, it can still be perceived as moving in an effectively forward direction. Moreover
the stick-slip modality can be recognized in the staircase-like profile, where the sudden jumps coincide
with the peaks in Fig. 1. Thus, the tool of principle component analysis has been used here in an
innovative way to analyze the atomistic data of complex 3-D structure of the dislocation core atoms.
Study of deformation and recrystallized texture and
microstructure in rolled copper
Santu Dey, N. Gayathri, J. Ghosh1 and P. Barat
1
Central Glass and Ceramic Research Institute, Kolkata
I
t is a well known fact that deformation texture and microstructure significantly affects the properties
of deformed metals and alloys and also the recovery and recrystallization behaviour of the deformed
material. The final property of the recrystallized metals and alloys depends strongly on the final
recrystallization texture and the final microstructure. The evolution of the recrystallized texture and
microstructure from the deformed properties is a complex process. A thorough understanding of the
microstructural details of the deformed state and the recrystallization process is thus required to
understand this evolution.
RESEARCH
Rolled electrolytic copper sheets with various percentage of reduction by cold rolling are used for this
study. The sheets with 20%, 40%, 50%, 60%, 70%, 80% and 90% reduction were prepared using a
roller mill of diameter 6.5 inches at a speed of 20 rpm at room temperature. The optical micrographs of
the samples were obtained using a high resolution metallurgical optical microscope. The optical
micrographs revealed a clear change in the grain morphology as a function of deformation (Fig 1.).
Equiaxed grains are seen in the as-received sample. With deformation the grains clearly gets elongated
along the rolling direction but are almost unchanged in the transverse direction. The shape of the grain
thus gets oriented in respect to the principal directions of the rolled material. Systematic X-ray
diffraction studies were carried out on the samples to evaluate the change in the crystallographic
directions as a function of rolling percentage. The x-ray diffraction results are shown in fig 2. The
continuous increase in the intensity of peak corresponding to the {220} planes gives a strong indication
of the texture evolution with deformation. To get a qualitative estimate of the texture evolution with
deformation, the relative intensity ratio of the peaks is obtained using equation (1) and is plotted in Fig
2(b). ihkl and Ihkl are the peak intensities of the {hkl}planes corresponding to the deformed sample and the
random textured sample (as-received) respectively and the summation is carried out over all the major
peaks in the pattern. Significant peak broadening is observed as a function of deformation which
indicates clearly the change in microstructure of the samples due to introduction of defects during
rolling.
ihkl
I
Phkl =hkl
i hkl
∑
I hkl
(1)
Figure 1. Optical micrographs of the deformed sample with different % rolling.
The red arrow indicates the rolling direction.
Macro texture measurements on the deformed samples were carried out at CGCRI, Kolkata. The pole
figures obtained from these measurements also clearly indicated the texture evolution with
deformation. From the {220} pole figures (Fig.3) of different percentage rolling Cu sheets, it can be
54
MATERIAL RESEARCH
seen that the {220}poles are getting concentrated more with increasing deformation. The results of the
x-ray diffraction (Fig 2) and the pole figure (Fig 3) analysis clearly indicates that during deformation
the grains are getting oriented with {220}plane parallel to the rolling plane and the inverse pole figure
of the 90% rolled sample indicates clearly that the rolling direction is the [111] direction.
RESEARCH
Figure 2 (a): X-ray diffractograms of the deformed samples. (b) Relative intensity ratio of the peaks as a function of
deformation. (c) Integral breadth of the peaks as a function of deformation.
Figure 3. {220}Pole figures as a function of deformation and the rolling direction inverse pole for the 90% rolled sample.
Having established the texture of the deformed samples, it is now important to understand the
recrystallization behaviour. Samples of 80% rolled Copper sheets were chosen to carry out this study
and were immersed in a silicone oil bath at 1270C, 1410C, 1680C and 1980C respectively for fifteen
minutes. The temperature range was chosen taking clue from the available literature. The samples were
characterised using the x-ray diffraction and the results are shown in Fig 4. Recrystallised grains are
0
clearly visible in the optical micrograph of the 198 C (Fig 5) sample. A dramatic change in the relative
intensity ratio of the peaks (with respect to the 80% rolled sample) clearly indicates the change in the
0
texture after 168 C. The sample shows strong texture along the {200} direction. To understand the
55
dynamics of this texture evolution on recrystallization, in-situ XRD measurements are being planned at
different temperatures.
Figure 4. XRD results of the 80% rolled samples different
tempertaures
Figure 5. Optical micrograph of the subjected to
1980 C sample
RESEARCH
Materials science beam line activities of the DAE
medical cyclotron
N.Gayathri, P.Barat, M. Bhattacharya, S. Dey,
K.G.M.Nair1, T. Johny1, P. Selvaraj1 and S. Murugan1
1
Indira Gandhi Centre for Atomic Research, Kalpakkam
T
he civil construction of the DAE Medical Cyclotron is presently underway in full swing and
during the report period, various civil and service related activities have been carried out. The
various embedded parts related to the different services such as water, Helium gas, cables etc, which
have to be brought into the cave were fabricated, inspected, accepted and kept ready for installation
during various stages of the civil construction. Prospective users of the facility were invited to
participate in the users meeting organised at VECC in which a detailed overview of the facility was
presented. Scientists from BARC, IGCAR and IUAC (New Delhi) participated in the meeting.
Multiferroic BFO nanorod developed at VECC
S.K.Bandyopadhyay, Nabanita Dutta, Pintu Sen and A.K.Himanshu
M
ultifunctional materials are of today's quest. Miniaturization, i.e. development of these
materials in the form of nanomaterials is of primary need considering their application in
devices. Moreover, if these are obtained in nanostructured form, they can bring wonders.
56
MATERIAL RESEARCH
RESEARCH
Recently, a simple chemical method has been adopted for developing multiferroic BiFeO3 (BFO) with
simultaneous antiferromagnetic, ferroelectric & ferroelastic behaviour in form of nanostructures like
nanorods, nanowire etc. by employing Anodised Alumina (AAO) template with various pore sizes
from 20nm with solution route followed by controlled vacuum filtration and sintering. Ion milling with
4keV Ar ion of current 4µ
A was needed to remove the agglomerates. The vacuum filtration guided the
directionality to form the nanostructures and the sintering facilitated the growth. Partial etching of the
templates after sintering revealed the nanostructures. Scanning Electron Microscope (SEM) picture is
shown in Fig. 1. Magnetic and ferroelectric properties are being investigated.
Figure 1. Nanorods protruding out of nanopores by cross sectional SEM
Enhanced magnetization from the network of agglomerated
Bismuth Ferrite (BFO) nanoparticles
S.K.Bandyopadhyay, Nabanita Dutta, A.K.Himanshu and Pintu Sen
B
ismuth Ferrite (BFO) is a well known multiferroic material. We have developed a network of
agglomerated BFO nanoparticles (size ~50-80nm) following a contemporary protocol of sol gel
chemistry using bismuth nitrate and ferric nitrate as starting materials and 2-methoxymethanol as
solvent. Magnetization studies revealed unusual substantial enhancement and this has been explained
through the interparticle interaction of agglomerated network. Polarisation showed no leakage current.
57
Effect of 15MeV proton (VECC) and 40 MeV alpha particle
(VECC) irradiation on LEXAN polycarbonate membrane
Pintu Sen, S.K.Bandyopadhyay, A.K.Himanshu and K Hareesh1
1
Microntron Centre, Mangalore University
T
here is a remarkable reduction in microvoid (~15%) during 40 MeV Alpha particle irradiation
compared to proton irradiation (~12%), reveled from the measurement of Positron annihilation
Lifetime studies. UV-Visible spectroscopic indicates a red shift in the absorption edge with decrease in
optical band gap, which may lead to increase in conductivity of the polymer.
Effect of 35 MeV alpha particle (VECC) irradiation on
bismuth ferrite
RESEARCH
Pintu Sen, S.K.Bandyopadhyay and A.K.Himanshu
D
C Magnetization measurement at low temperature (5 K) under the field of 1 Tesla, shows that the
saturation magnetization (Ms) has been reduced from ~ 6 emu/gm to 0.80 emu/gm with
increasing the fluence up to 5x1016 ions/cm2, but the squreness (i.e Mr/Ms = 1) of the system essential
for magnetic storage device, has been increased from 0.52 to 0.78.
Cyclic voltammetry studies of the arsenic adsorbent of
nanostructured cerium incorporated manganese
oxide (NCMO)
Pintu Sen, S.K.Bandyopadhyay, A.K.Himanshu, Arup Ghosh1 and U Ghosh1
1
Presidency University
T
o assay the arsenic adsorption mechanism of newly developed nanostructured cerium
incorporated manganese oxide (NCMO), Cyclic Voltammetry was performed at different scan
rate in the range of 0.3 V to -0.3 V. A clear indication of surface oxidation of arsenic(III)
was obtained from the comparison of Cyclic Voltagrams of pure NCMO and arsenic(III) adsorbed
NCMO.
58
MATERIAL RESEARCH
Synthesis and structural refinement of Sr2+ substituted modified
PMS-PZT ceramic
A.K. Himanshu, Yashwant Kumar, S K Bandyopadhyay, Pintu Sen, Kumar Brajesh1,
Kiran Kumari2, Rajeev Ranjan3, , N. K. Singh3 and T P Sinha4
1
Department of Physics, Veer Kunwar Singh University Ara -802301, Bihar, India
2
P G Department of Physics, R N College Hajipur (Vaishali) Bihar India
3
Materials Engineering, Indian Institute of Science, Bangalore -560012, India
4
Department of Physics, Bose Institute, 93/1, A.P.C Road, Kolkata, 700009, India
P
Synthesis and dielectric studies of polyorthotoluidine-polyvinyl
pyrrolidone conducting polymer composites
A.K. Himanshu, Rajni Bahuguna1, D. K. Ray2, S. K. Bandyopadhyay
Pintu Sen and T. P. Sinha3
1
Department of Applied Physics, Thakur College of Engineering & Technology, Mumbai-400101, India
2
Department of Radiotherapy, CNCI, 37, S. P. Mukherjee Road, Kolkata, 700 026
3
Department of Physics, Bose Institute, 93/1, A P C Road, Kolkata-700 009, India.
T
he intrinsically conducting polymer, polyorthotoluidine (POT) was synthesized by chemical
polymerization process with the help of water-soluble support polymer acrylamide (AAm),
polyvinyl pyrrolidone (PVP) . The dielectric measurement of POT-PAAm, POT-PVP was measured in
the temperature range from 308-398 K at frequency 10 kHz. Above the temperature 370 K,
conductivity shows weak temperature dependence.
Neutron diffraction study of Ba(Fe0.5Nb0.5)O3 Perovskite
A. K. Himanshu, S.K. Bandyopadhyay, Pintu Sen, B.K. Choudhary1, Uday Kumar2,
B. K. Singh3, A. B. Shinde4 and P. S. R Krishna4
1
University Department of Physics, Ranchi University, Jharkhand, 834 001, India
Department of Physical Sciences, IISER-K, Mohanpur Campus, Mohanpur- 741252, West Bengal, India
3
University Department of Physics, T. M. Bhagalpur University Bhagalpur-812007, India
4
Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India
2
W
e have synthesised Ba2FeNbO6 (BFN) Perovskite by solid state reaction route through heat
treatment. To understand the structure of this material we carried out Neutron Diffraction
59
RESEARCH
yrochlore phase free [Pb0.94Sr0.06] [(Mn1/3Sb2/3)0.05(ZryTi1-y)0.95] O3 synthezied ceramics were converted
into piezoelectric bodies by poling. The kp, Qm, d33 and Pr values of these ceramics were investigated
as a function of Zr-content (i.e y = 0.46 to 0.60) and the composition y = 0.54 gives the best set of
piezoelectric properties.
measurements at the Dhruva reactor. We have done Rietveld analysis of the data and show that the
structure is cubic with space group of Pm-3m at ambient temperatures. The lattice constant is found to
be 4.0551Å. We found that the chemical formula matches with the single Perovskite Ba(Fe0.5Nb0.5)O3.
Magnetic and ferroelectric studies of double Perovskite
(KBi)(FeNb)O6 ceramics
A.K. Himanshu, B.K. Choudhary1, Uday Kumar2, S.K. Bandyopadhyay,
Pintu Sen, S.N. Singh and T. P. Sinha3
1
2
University Department of Physics, Ranchi University, Jharkhand, 834 001, India
Department of Physical Sciences, IISER, Mohanpur Campus, Mohanpur- 741252, West Bengal, India
3
Department of Physics, Bose Institute, 93/1, A.P.C. Road, Kolkata 700 009, India
RESEARCH
(KBi)(FeNb)O6 (KBFN) structurally characterized by powder X-ray diffraction is orthorhombic. The
magnetic properties of (KBi)(FeNb)O6 is found to be antiferromagnetic at temperature ranging from
~26K. The experimental results indicates that the magnetic moments of Fe3+ ion in (KBi)(FeNb)O6
order antiferromagnetically with a slight ferromagnetic moment below 26K and weak ferromagnetic
moments disappears above 26 K. The ferroelectric behaviour of polarization vs. applied electric field
measurements was studied for the KBFN pellet. The shape of the curve is not consistent with
ferroelectric behavior but rather indicative of conduction.
Study of the effect of alpha irradiation on the microstructure
and mechanical properties of nano-crystalline Ni
P.Mukherjee, N.Gayathri, Garima Sharma1, A.Chatterjee1, A. Sarkar1
and J.K.Chakravartty1
1
Mechanical Metallurgy Division, BARC, Trombay
T
he effect of irradiation damage on the microstructure evolution and mechanical properties in
nanocrystalline (nc) Ni with an average grain size of ~60 nm was studied. Samples were
irradiated at doses 1.6x1015, 2.3x1015, 5x1015, and 2.3x1016 He2+/cm2 by 12 MeV α- ion from Variable
Energy Cyclotron.. Microstructural parameters like domain size and microstrain were studied in detail
by X-ray diffraction (XRD) technique (Fig 1 shows the XRD profile of the samples) using Simplified
Breadth method and Williamson Hall analysis. The average domain size was found to decrease
systematically with the increase in irradiation dose.
60
MATERIAL RESEARCH
RESEARCH
Figure 1. XRD profile of unirradiated and irradiated nano-Ni sample as function of dose.
(a)
(b)
(d)
Figure 2. Bright field TEM images for nc-Ni (a) as received unirradiated sample; (b) irradiated to a dose of 2.3 x 1015 He2+/cm2;
(c) irradiated to a dose of 5.0 x 1015 He2+/cm2; (d) irradiated to a dose of 2.3 x 1016 He2+/cm2.
61
Microscopic observations made at Transmission Electron Microscope (TEM) (Fig 2) showed
dislocations loops and dislocation networks within the grain interior of irradiated sample. In addition,
irradiation at higher dose showed small amounts of the sand like black dots inside some grains which
could be due to the accumulation of point defects.
Tensile tests performed on the irradiated sample were compared with unirradiated samples. Irradiated
sample showed higher UTS and average work hardening rate as compared to unirradiated sample.
Nanoindentation studies were performed to study the effect of irradiation on deformation parameters
like strain rate sensitivity (m) and activation volume (V*). The value of m was found to increase
whereas decrease V* was found to decrease with increase in irradiation dose (Fig 3). Fracture surface
of the tensile sample were investigated by SEM. The fracture morphology of the unirradiated sample
showed dimpled rupture with much large dimple diameter and depth. The irradiated sample also
showed dimple rupture but with much finer dimple diameter with wide size distribution and shallow
depths.
RESEARCH
Figure 3. (a) Variation of instrumented hardness with irradiation dose in nc-Ni with inset showing P vs h profiles for different
irradiation dose; (b) Variation of m with irradiation dose with inset showing hardness vs strain rate plot slope of which yields
m; (c) Variation of V* with irradiation dose.
62
MATERIAL RESEARCH
Irradiation studies of T91 Steel using Ar9+ ions
Naveen Kumar1, R.Tewari2, P. V. Durgaprasad1, P. Mukherjee, N. Gayathri, G.S.Taki,
J.B.M.Krishna3, A. Sinha3, P. Pant4, R. Ajay Kumar4, B. K. Dutta1 and G. K. Dey2
1
2
Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400 085
Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085
3
UGC-DAE-CSR, Kolkata 700 093
4
Department of Metallurgical Engineering and Materials Science,
Indian Institute of Technology-Bombay, Mumbai 400 076
I
n the present study, ferritic-martensitic steel T91 has been irradiated with 315KeV Ar+9 ion at
different doses i.e. at 5dpa, 10dpa and 20dpa. Microstructure has been characterized by X-ray
diffraction line profile analysis using Grazing Incidence X-ray Diffraction (GIXRD) at two different
depths, one in the intermediate region (73 nm) and another up to the peak damage region (146 nm) as a
function of dose. Nano indentation technique has been used to find out the changes in the hardness and
yield strength values with dose of irradiation.
(i) Maximum deposition of Ar+9 ions in T91 steel has taken place at a depth of 100 nm with
maximum depth of penetration as 200 nm. Doses imparted on samples were estimated as 5, 10
and 15 dpa.
(ii) XRDLPA of the irradiated samples have shown that there is a decrease in the domain size (Fig
1).
(iii) Nano-indentation on irradiated material has shown increase in hardness with dpa which
appears to saturate at the value of 1.5 GPa with respect to the unirradiated material. (Fig 2)
Figure 1. Domain size and microstrain obtained from the XRDLPA.
63
RESEARCH
Main findings of the irradiation study could be summarized as follows:
Figure 2. The nano hardness (a) and change in nano hardness (b) as a function of irradiation dose
RESEARCH
An attempt has been made to simulate the effect of nano-indentation on Fe and Fe-10%Cr alloy with
irradiation induced defects (vacancies and loops). The simulated load displacements curves obtained in
all the cases exhibited remarkable similarity with the one obtained from the experiments. All L-D
curves show increase in the load with increase in the depth of indentation due to increased area of
indentation. From the atomistic visualization it was observed that dislocations were nucleated under
the indention region near one of the indenter face. The dislocations end points are always pinned at the
indenter and sample contact surface. As the load increases the dislocation end points move towards the
sharp edges of the indenter and free surface of the sample. It was found that in the presence of the
defects, the area under the loading and unloading curve was increased due to the partial recovery of
dislocations. The dislocations nucleated and grown under indenter interacted with the loops resulting in
the junction formation. No dislocation loop emission was observed, which were observed during the
indention of Fe with spherical indenter. This shows the loop emission is a function of the indenter shape
used for the indentation. The present study considers a nanometer scale domain (single crystal) in
comparison to macro scale samples (poly crystalline) used in experiments, so, no quantitative
comparisons can be made with experimental results of irradiation effects on the nano indentation
curves and irradiation hardening behavior. Fig 3 shows the initial and the final dislocation
configuration and also the loop interaction. The generated load vs depth curves (Fig 4) for the pure Fe
and the 10% Cr system clearly indicate the role of Cr in the system.
Figure 3. Initial and Final dislocation configuration of Fe-10%Cr (S2) system with uniformly distributed ½ <111> type loops
(arrows indicating the Burger's vector direction)
64
MATERIAL RESEARCH
Microstructural characterization of recrystallised zircaloy-2
after pilgering using X-ray diffraction line profile analysis
P.Mukherjee, N.Gayathri, P.S.Chowdhury1 and M.K.Mitra1
1
Materials and Metallurgical Department, Jadavpur University, Kolkata- 700 032
T
he present study deals with the characterization of microstructure of Zircaloy-2 by X-ray
Diffraction Line Profile Analysis (XRDLPA), after each stage of pilgering followed by annealing
during the fuel tube fabrication. Different techniques of XRDLPA like simplified breadth method,
Williamson Hall technique, double Voigt technique and variance method have been used to assess the
microstructure at each stage. Among these various techniques, double Voigt technique evaluates the
volume weighted domain size and upper microstrain values in a more detailed and accurate manner.
But the estimation of dislocation density cannot be performed by this technique. The mathematical
formalism of variance method is based on estimating average surface weighted domain size and
dislocation density ρ. The values of dislocation density obtained by this technique at different stages
can predict whether further deformation can be allowed. The values obtained from our analysis
indicate that further deformation can be carried out even with the values of dislocation density ~1015
2
nos/m where the dislocation density reported in the severely plastically deformed metallic materials is
1016 nos/m2. Plastic deformation at each stage of processing involves pile up of dislocations along the
slip plane and finally the buildup shear stress at the head of the pile up initiates the nucleation of
microcracks. Hence both double Voigt technique and variance method can be used as effective
characterizing technique of microstructure during the process monitoring in real life production.
65
RESEARCH
Figure 4. a) Load vs. depth of indentation curves and b) dislocation evolution in Fe and Fe-10%Cr system with vacancy loops
of type ½<111>
Radiation damage studies using proton beam from VEC
1
1
1
1
P.Mukherjee, N.Gayathri, D. Srivastava , R.Tewari , S.Neogy , A. Srivastava ,
1
1
B. Vishwanadh and G.K.Dey
1
Materials Science Division, Bhabha Atomic Research Centre, Mumbai
a) The effect of ion irradiation on Zr-1%Nb alloy which is the cladding material for 1000 MWe
VVER type pressurized water reactors has been investigated using 7MeV proton from Variable
Energy Cyclotron. Two sets of samples with different heat treatment have been irradiated with
similar doses to understand the subtle variation in the microstructure. X-ray diffraction line
profile analysis (XRDLPA) results and hardness measurements by nanoindentation technique
showed marked difference between these two sets of samples indicating that initial heat treatment
plays a significant role in determining the microstructure after irradiation.
RESEARCH
b) Irradiation studies of candidate structural material (Nb-1Zr-0.1C alloy) of Compact High
Temperature Reactor using 7.5MeV proton from Variable Energy Cyclotron have been carried
out. XRDLPA has been carried out on irradiated samples as a function of dose and the defect states
of these materials have been evaluated. With increasing dose, there is evidence of formation of
more number of vacancy loops. Studies on irradiation induced phase transformations,
characterization of defects generated due to irradiation and dissolution and re-precipitation of the
carbide phases in the alloy are being carried out under Transmission Electron Microscope (TEM)
at MSD, BARC.
66
1.5
HEALTH PHYSICS
Activities of Health Physics Unit, Kolkata
T
he Health Physics Unit of VECC is a part of Accelerator Radiation Safety Section, Health Physics
Division, BARC, Mumbai. It is providing radiological safety coverage during operation and
maintenance of the cyclotron. No accidental radiation exposure was reported during the calendar year
2012. In addition, following are the activities of this Unit in 2012.
1. Analysis and Certification of export and import items
In India, three laboratories, one each in Kolkata, Chennai and Mumbai have been authorized to carry
out analysis and issue certificates to importers and exporters. Analysis of radioactivity content and
certification of radioactivity content in food and other consumable materials are being carried out at
Health Physics Unit, VECC. This is a revenue earning activity.
A total of 1206 samples have been analysed and the total revenue earned was Rs. 24,12,000 (Rupees
twenty four lakh twelve thousand only) from January 1 to December 31, 2012. Figures 1a and 1b show
respectively, the number of samples analysed and revenue earned in each month during 2012.
Figure 1(a). Monthly breakup of samples in 2012
Figure 1 (b). Revenue earned in 2012
67
RESEARCH
Several countries have imposed statutory requirements for the analysis of the radioactivity content
(mainly Cs-137) in food and other items while importing, after Chernobyl Nuclear disaster. The
imported milk and milk powder in India has to be tested for its radioactivity content. The permissible
level in most of the food products has been set as 50 Bq/kg.
2. Radiation Protection Training
In accordance with the guidelines of AERB, radiation protection training (general and pertaining to
VECC specifically) has been given in the form of lectures followed by tests for 12 regular employees
(mostly new entrants) and for 5 other persons (including trainees, students etc.). Personnel monitoring
devices like TLD and Neutron Badges have been issued to those who qualified in such tests.
3. Emergency Response Centre
Radiation Emergency Response Centre, VECC is a designated unit by Crisis Management Group of
DAE to handle Radiation Emergency in and around Kolkata. The unit is equipped with emergency
handling kits & instruments. Director, VECC is the authority to take necessary measures. The unit is in
operation with a standard operation procedure. This unit also involves in training first responders of
radiation emergency of different government agencies.
4. Campus & Environmental Survey
Radiation survey has been carried out at 12 locations within the VECC compound once in every week.
Air sampling analysis (daily), discharge sewerage water analysis have been carried out (once a week).
Radiation survey at 26 locations up to a distance of 5KM from the VECC site has been conducted once
monthly.
5. Radiation Safety Analysis for K-130, K-500 and Medical Cyclotron facilities
RESEARCH
Radiation safety aspects, shielding & ventilation adequacy estimations, dose-rate estimations,
estimation of induce activity and other related safety analysis have been carried out time to time for K130 & K-500 cyclotron facilities and the forthcoming DAE Medical cyclotron facilities.
6. Research and Development Work
Streaming radiation through the service ducts of DAE Medical
Cyclotron: Kolkata
K. Srihari, Tapas Bandyopadhyay and R. Ravishankar
T
he 30 MeV DAE Medical Cyclotron Kolkata project (proton beam with maximum beam intensity
of 500 µA) is in the advanced stage of completion. The machine can extract two beams
simultaneously with a beam power of 100-150KW. The cyclotron facility has 5 experimental/utility
bunkers with 10 exit ports. During the cyclotron operation prompt neutron and photon radiations are
produced inside the machine and experimental bunkers. Penetrations through the shield walls in the
form of ducts are required for providing services such as electrical cables, liquid and gas cooling lines,
air conditioning/ventilation passages and other auxiliary provisions. Through these penetrations,
radiations will escape to the occupational zones. To minimize the streaming radiation in the accessible
areas these ducts are provided in the form of S- bends and multi legged ducts. Estimation of dose rates
have been done at the various ducts exits taking into consideration of beam design parameters and
worst scenario conditions. A total of 56 no of ducts have been considered with diameters varying from
1.5cm to 30cm. The source term was estimated very carefully taking into the considerations of beam
loss positions, service ducts entry points and room dimensions. The estimated dose rates at the duct
exits in the accessible zones are found to be well with in the mandatory regulatory limits. The fig.1
68
HEALTH PHYSICS
Figure 1. Schematic Layout with Ducts of Medical Cyclotron
RESEARCH
shows the schematic lay out of the different bunkers with the service ducts. The figure 2 describes the
internal profile of the ducts inside the shield walls and the assumptions considered with the parameters
taken for dose rate estimations.
Figure 2. Duct Profile
Table 1 : Exit dose rates from some vital ducts
SL.NO
EP NO
Equivalent radius of duct
(cm)
Dose rate just at exit
(Sv/h)
1
HVEP-19B
5
4.37E-09
2
HVEP-19C
5
4.37E-09
3
HVEP-19D
5
4.37E-09
4
HVEP-26
33
4.20E-04
5
HVEP-27
20
5.82E-07
6
HVEP-28
28
4.66E-04
7
HVEP-29
20
6.03E-05
The table (Tab. 1) shows the exit dose rates of a few ducts of radiological importance for 30 Mev Proton
beam with 500 µA beam current.
References
scc-vecc safety report.
Nucl Engg& Design 215(2002): koichi Maki
Particle accelerators, 12,169(1982)-Tesch K
69
Estimation and verification of neutron fluence-rate and dose
rate with standard neutron sources
R. Ravishankar, S.K.Mishra and Tapas Bandyopadhyay
I
n accelerator environment, the effectiveness of radiation surveillance depends on the radiation
measuring instruments being used and especially on their calibration status. Routine calibration
checks being carried out based on emission rate either supplied with source/data derived a few decades
ago. Fresh theoretical estimation on fluence-rates and dose-rates and experimental verification with
survey instruments needed keeping in mind the effects of prolonged frequent use over a period of time
such as source integrity, wear and tear etc.
Materials and Methods
For routine calibration check of area neutron monitors, neutron-Rem-counters (survey instruments)
standard sources are being used by Health Physics Unit, VECC. The sources being used are AmBe(30/10 mCi), Pu-Be(5Ci) and Cf-252(100µCi). Since most of these sources (except Cf-252) are
couple of decades old, it was decided to freshly estimate and verify with different instruments.
The neutron yield for (α,n) neutron sources for monoenergetic alpha energy is given by (1),
RESEARCH


Rα
Eα
σ
E


Y =
∫
N ( x) nσ
( E ) dx =
nN ( 0 ) ∫
dE
dE
0
0 


dx 
(
)
(
)
-------------- (1)
Where, N(0) is the no. of alpha particles available at zero distance.
n is the no. of target atom.
σ(E) is the cross section for (α,n) reaction.
The yield equation, taking into consideration of the distribution of alpha energy within the source and
applying the suitable stopping power and cross section values, reduces to Be converters as:
σ(E) is the cross section for (α,n) reaction.
3.82
Yield =
0.115Eα
for : 3.5 ≤
Eα
≤
6.5MeV
2.64
Yield =
Eα
for : 6.5 ≤
Eα
≤
10MeV
Where 'Yield' is for 106 incident alpha particles. By using this yield value, evaluation of fluence-rate
and dose rate (using DCF) for Am-Be and Pu-Be source has been done and compared with suitable
instrument response. Results are shown in Figure.
Figure 1. For Pu-Be source of 5Ci (Dose-rate)
70
HEALTH PHYSICS
Figure 2. For Cf-252 source of 100µCi (Dose- rate)
Discussions
* Measured values are in order with theoretically estimated values, except for very close
distances (in case of intensive sources) and for farther distances (in case of low active sources),
wherein geometry and distance corrections need to be applied.
* Victoreen 190 (AB type) generally appears to overestimate the dose rate.
Leakage radiation through shield door of K-130 cyclotron
– an approach to reduce the radiation dose
M. Sengupta Mitra, T.Bandyopadhyay, R. Ravishankar, K Srihari and S.K.Mishra
T
o reduce leakage radiation outside the shield door of Cave 1, a conservative approach was
initiated. Simulation related to exact scenario was performed. It was planned to provide local
shielding at that domain to reduce the leakage neutrons from cave. The purpose of this work was to
follow the ALARA principle even the zone was defined as Zone II.
Fluka – a Monte Carlo simulation was used to find out the distribution of fluence of neutron and gamma
at different positions. Optimization of the placement of the local shield from the target irradiation point
was done. The simulation geometry is described in fig.1. Five spherical detectors D1, D2, D3, D4 and
D5 were placed at different locations. The source was taken as parallel mono-energetic alpha beam of
energy 40 MeV, incident on a tantalum target.
Shield door
Concrete
block
Target
D1
D2
Door
D4
D3
D5
Figure1. Simulation geometry
71
RESEARCH
* Further work including improving the exercise, is in progress.
Figure 2. Distributions of dose equivalent at different positions with the concrete slab at a distance of
300cm from the target
RESEARCH
It was concluded from the result of simulation that with judicious placement of concrete block at a
distance of 300cm from the target the dose equivalent due to leakage radiation outside the shield door
could be reduced. After introduction of this concrete block the leakage radiation level was measured
with LUDLUM neutron gamma survey meter for neutron and gamma outside the shield door when 40
MeV alpha beam was incident on a Tantalum target in the experimental cave and found that the value
was reduced considerably.
Figure 3. The concrete block inside cave1 as local shield arrangement
Figure 4. Local shielding arrangement with HDPE block near target
72
HEALTH PHYSICS
For Further improvement, one movable local shielding arrangement made of HDPE block was placed
surrounding the target assembly as shown in figure 4. The HDPE blocks were arranged on a movable
wooden table. It was used to cover the target assembly during experiment in order to attenuate copious
neutrons generated as the beam hit target. This had also taken care of leakage radiation through
different service ducts of roof shielding.
The cave shielding door was also modified with extra thickness of HDPE block at both sides as shown
in figure 5 (one side). The combination of arrangement considerably reduced the dose to one third from
its initial.
References
[1] A. Fasso, A. Ferrari, J. Ranft, and P.R. Sala, "FLUKA: a multi-particle transport code", CERN-2005-10 (2005),
INFN/TC_05/11, SLAC-R-773
[2] K-130 safety report, VECC, Kolkata
[3] NCRP Report No. 144 – Radiation Protection for Particle Accelerator Facilities (2003)
73
RESEARCH
Figure 5. One side of movable shield door extended with HDPE block
Cyclotron
2.1
CYCLOTRON OPERATION
Variable energy cyclotron (K-130) operation
P.S. Chakraborty on behalf of cyclotron working group
T
CYCLOTRON
he variable energy cyclotron (K-130) has been accelerating proton and alpha beams of various
energies and transporting these beams through its high intensity beam lines to target stations for
doing experiments. A planned shutdown of about seven weeks (Sept-Oct, 2012) was taken to repair
resonator tank – Dee tank interface air leak. The work involved was huge and all four side flanges of the
accelerating chamber were taken out to replace damaged o' rings and at the same time four newly
designed corner post have been installed. To accomplish this work resonator tank was separated from
Dee tank by about 4 inches towards south side of vault. One of the diffusion pump was replaced with a
new one. One new diffusion pump was also installed. The interface air leak repair work has greatly
improved cyclotron functioning and reduced cyclotron downtime considerably. Additional water
cooling has also been provided for trimmer capacitor.
New corner post
One of the side flange was taken out
Another planned shutdown of two weeks (Dec, 2012) was taken to renovate control room, maintenance
of all shield door track, renovation of basement corridor etc. Few un-planned shutdowns have been
taken due to RF problem, contact spring burnt out at the shorting end of Dee stem, water leak in
resonator tank and dummy Dee, deflector system, vacuum system and national grid failure etc. The
attached pictures show the renovation activities in basement and control room.
76
CYCLOTRON OPERATION
Basement corridor
Control Room
The light ion beams (alpha and proton) were delivered on the target for about 2650 hours using all the
four beam lines. Beam development activities were also in full swing in terms of new beam and beam
current. Beam development activities were for about 1057 hours. The above mentioned planned
shutdown activities in all phases consumed about 1461 hours. Unplanned shutdown consumed about
2344 hours. Ion source filament change, power dip, channel change over, systems problem, trouble
shootings and maintenance of the sub-systems etc. took about 1272 hours. Beam utilization is shown
below in a pie chart.
Beam development
a. During the beam development program very low energy light ions were accelerated and
extracted. The beams which were developed range from 1.0 MeV to 5.5 MeV. Interestingly the
lowest energy was developed in fifth harmonic for the first time. The intensities extracted
ranged from 60 nA to 1 µA. We have accelerated singly charged helium which in a way helps us
to operate the machine at higher magnetic fields circumventing the problem of discharges at
low fields.
b. An extracted beam of 20.0 µA of 45 MeV alpha has been obtained.
Projectiles (utilized): During the above mentioned period, proton and alpha beam of energies 8 MeV
to 18 MeV and 30 MeV to 60 MeV respectively were utilized for the experiments.
77
CYCLOTRON
Beam Utilization
Projectiles (available): Presently the following ions with beam energy and current are available from
K-130 cyclotron for performing experiments.
Ions
Energy (MeV)
Extracted Beam current (max)
Alpha
30 - 65
8.0 µA
Proton
7.5 - 18
20.0 µA
User: The research work with the above beams has been performed by experimentalists of VECC,
BRIT/VECC, BARC, UGC-DAE-CSR Kolkata and Mangalore University.
Design, installation, testing & commissioning of PLC based
blower heated reactivated type desiccant air dryer
Joydeep Misra, Md. Islam Siddiqui , S. N. Das and Ritesh Karmakar
CYCLOTRON
H
igh quality dry compressed air is delivered to different equipments and pneumatic operated
instruments of Room Temperature & Superconducting Cyclotrons for reliable operation of
vacuum gate valves, ball valves and control
instruments. Air after compression contains
substantial amount of moisture and moisture
removal can be achieved by reducing the dew
point temperature of the compressed air using air
dryer. A special PLC based desiccant air dryer
with zero process air loss is designed, installed &
Commissioned to provide compressed air as per
ISO 8573.1 class II. This PLC based Blower
Heated Reactivated type desiccant Air Dryer
(Fig.-1) is used to dry 125 CFM compressed air
having inlet air pressure 7.5 kg/cm² &
temperature 45 °C with outlet air dew point 60°C.Desiccant air dryer consist of two towers,
filled with activated alumina & Molecular Sieves.
When one bed is on drying cycle the desiccant
absorbs moisture from the incoming wet air and
the other tower is on a regeneration cycle. The
process is automatically reversed from one tower
to another on a time sequence basis. This PLC
based desiccant dryer comprise of mimic diagram
for easy identification of its running status &
operation. The dryer was commissioned in the
month of December 2012 and is being used for
drying the compressed air.
Figure 1. PLC Based Desiccant Air Dryer Unit
78
CYCLOTRON OPERATION
Installation and commissioning of micro controller based air
compressor
Joydeep Misra and Md Islam Siddiqui
A
CYCLOTRON
Kirloskar make micro controller based air compressor was installed and commissioned in the
month of November 2012 (Fig.1) having capacity 3.11 m³/min with 7.5 kg/cm² discharge
pressure for continuous supply of compressed air to Room Temperature Cyclotron as well as Super
Conducting Cyclotron. During commissioning all the operating parameters such as load/unload
pressure, pressure drop across separator, discharge pressure, oil leakage and air discharge temperature
were observed thoroughly and found all the parameters are within the acceptable limits. The vibration
of bearing housing and other rotating parts were also measured and found suitable for continuous
operation. At present the compressor is running smoothly and is being used for cyclotron operation.
Figure 1. Micro controller based Screw Air Compressor
79
2.2
ACCELERATOR RESEARCH
Nuclear electronics section
G.C. Santra, P.Bhaskar, S. R. Narain and S.R. Banerjee
L
ow Cost Current Integrator: After its successful development and steady performance, another
unit as per the request of Material Science Section, VECC was made and delivered to them. The
performance of the unit was reported by the users to be satisfactory with cyclotron experiments.
Similarly, considering the steady performance feedback of the newly developed NIM module, Quad
Leading Edge Discriminator, more units are being planned to develop on user's requirement. Hence,
new Printed Circuit Boards with multiple options have been designed in house and electronic
components needed for more units are being procured. The proposed unit would give the user's two
discriminator output along with two fast NIM and one TTL output per channel having greater delay
and width timing as compared to commercial available Discriminator modules.
CYCLOTRON
Fabrication of NIM Module for Clover HPGe detector: The four Ge crystals of a Clover HPGe
detector requires four individual electronic channels for energy and timing measurements. These
detectors are usually set to operate in anticoincidence with a BGO anti Compton shield surrounding it.
To setup coincidence measurements with such Clover HPGe detectors require many commercial NIM
modules for processing of analog and logic signals. In this context a compact NIM module would be
very much useful and cost effective and it will reduce the amount of required electronics drastically.
A prototype NIM module containing Shaping amplifiers, TFAs, CFDs and logic
Figure : Block Diagram of Clover Electronics
80
ACCELERATION RESEARCH
Circuitry for processing signals from a Clover detector with Anti Compton Shield (ACS) is being
developed in collaboration with IUAC, New Delhi. For this purpose, a set of printed circuit boards have
been procured from IUAC, to make one such module. Necessary electronic components are being
purchased from outside vendors. Preliminary assembly work of the PCB has been started in house. The
unit being a very high density module extensively uses Surface Mount Components.
Estimation of induced activity in super conducting cyclotron at
VECC : Monte Carlo calculations
1
S. Chatterjee and T. Bandyopadhyay
2
TLD Unit, RP&AD, BARC 2Health Physics Unit, HPD, BARC
Variable Energy Cyclotron Centre, 1-AF Bidhannagar, Kolkata-700064
Abstract : This study has been carried out for the estimation of the induced activity in different parts of the
accelerator and in the radiation shield constructed around the accelerator and the dose rate after various cooling
times to estimate the dose to the radiation workers during the shutdown and maintenance of the cyclotron. An
effort was also made to estimate the residual activity for 80 MeV protons bombarded on Stainless Steel thereon
activity produced on different materials like Cu, Al, Concrete and SS of different thickness. Cu, Al, SS are among
many other materials which are widely used for fabrication of any accelerator.
Introduction
S
uper Conducting Cyclotron (K500) at Variable Energy Cyclotron Centre, Kolkata (VECC) is at an
advanced stage of commissioning and has successfully delivered many internal beams (light to
heavy particles) up to the extraction radius. Due to beam loss at several places and the interaction of the
lost beam of accelerated charge particles with the machine parts will undergo different nuclear reaction
and induced activity will be produced at the different parts of the machine. Moreover secondary
neutrons produced having energy maximum limiting to the beam energy will also produce
radioactivity in the different parts of the machine as well it will also induce radioactivity on the
radiation shield constructed around the accelerator. Radio-activation of different parts of an
accelerator, radiation shield walls around the machine and materials available in the room poses a
radiation hazard inside the machine vault and experimental caves especially during maintenance of the
machine. During the shutdown and maintenance period of the machine occupational workers will be
exposed to these induced activity produced during operation of the machine. An effort was made to
estimate these residual activity and dose for 80 MeV protons bombarded on Stainless Steel thereon
activity produced on different materials like Cu, Al, Concrete and SS of different thickness. Cu, Al, SS
are among many other materials which are widely
used for fabrication of different components of any
accelerator.
Monte Carlo Simulation
A simulation of the scenario was created using a
(1,2)
Monte Carlo approach using FLUKA 2006.3b-
81
Figure 1. Geometry of Simulation (FLUKA)
CYCLOTRON
1
general purpose multi particle transport code. Figure 1 shows the geometry, which was used for the
Monte Carlo simulation.
Estimation of the source term of neutron was done by bombardment of 80 MeV pencil proton beam on
SS(3). Dimension of the SS target/stopper was 2 cm x 2 cm x 2 cm to stop the beam. Neutrons produced
due the interactions in turn activate different materials. Radiological shield around the machine is made
up of Concrete. Considering the utilization of Concrete, Cu, Al and SS, two slabs of dimension of
diameter 10.0 cm, thickness 5.0 cm and diameter 9.0 cm, thickness 20.0 cm were placed one after
other at about 20 cm from the beam dump. Forward angle consideration was taken for all cases as a
conservative approach. Induced activity was generated for the cyclotron operation of seven days
followed by a shutdown period of 1 hr, 10 hrs, 100 hrs, 1000 hrs, 10000 hrs and 100000 hrs.
Results and Discussions
Figure 2 shows the variation of ambient
dose rate due to photons after different
cooling periods for different slab
materials considered. The dose rate also
includes the contribution from the
induced activation of Stainless Steel,
which is the target for the primary proton
beam.
CYCLOTRON
Figure 2. Shows the Photon ambient dose rate after different cooling
period for different slab materials.
Figure 3. Variation of activity having half lives in (a)
hours, (b) days, (c) years in the primary target (SS) for
different cooling times.
Figure 3 to figure 6 shows the variation of
activity in the primary target, as well as in
S L A B 1 w i t h d i ff e r e n t m a t e r i a l
composition. The plots has been
separated based on their half-lives (hours,
days, and years) for the easy
identification of the radionuclides for SS,
Cu and Concrete. 64Cu, 62Cu, 61Cu, 60Fe,
Figure 4. Variation of activity having half life in (a)
hours, (b) days, (c) years in the SLAB 1 (Cu) for
different cooling times.
82
ACCELERATION RESEARCH
60
Cu are the examples of few radio isotopes, which are found only in the primary target due to nuclear
reaction from proton.
Figure 6. Shows the variation of all activity in the SLAB
1 (Al) for different cooling times.
Conclusion
This study will be helpful to evaluate the dose to the personnel going inside the cyclotron vault for
maintenance and repair, where the activation of the different components is the only source for the dose
to the personnel. The dose rate can be estimated for different run times of the cyclotron operation. In
case of SS, the long lived isotope produced is 60Co having half-life of 5.271 years, which emits 1.17
53
6
40
MeV and 1.33 MeV gammas. Cu produce Mn, which is having a half-life of 3.74 x 10 years. K is
9
produced in concrete, which is having half-life of 1.26 x 10 years and emits 1.461 MeV gamma. In case
26
of Al, the long lived isotope produced is Al, which emits 0.511 MeV and 1.8 MeV gamma. These data
will be useful even during the decommissioning stages of the cyclotron, where activation of different
materials plays a key role.
References
[1]
"The FLUKA code: Description and benchmarking"G. Battistoni, S. Muraro, P.R. Sala, F. Cerutti, A. Ferrari, S.
Roesler, A.Fasso` J. Ranft, Proceedings of the Hadronic Shower Simulation Workshop2006, Fermilab6-8
September 2006, M.Albrow, R. Raja eds., AIP Conference Proceeding 896, (2007).
[2]
"FLUKA: a multi-particle transport code" A. Fasso`, A. Ferrari, J. Ranft, and P.R. Sala, CERN-2005-10 (2005),
INFN/TC_05/11, SLAC-R-773.
[3]
Superconducting Cyclotron Safety report, VECC, Dec 2007.
83
CYCLOTRON
Figure 5. Variation of activity having half life in (a) hours, (b)
days, (c) years in the SLAB 1 (Concrete) for different cooling
times
2.3
ACCELERATOR TECHNOLOGY
Design of air - lock tank for RTC
Tamal Ghosh, Suparna Patra, Chinmay Nandi and Gautam Pal
A
ir-lock tank in RTC is used for maintenance of ion puler and Dee insert without breaking the
cyclotron vacuum. In the existing system one inclined gate valve is used to isolate the air lock
tank vacuum from cyclotron vacuum. This inclined gate valve is not sealing and therefore not being
used for long time. The width of the opening is also not sufficient for dee insert to extract from the
cyclotron directly. As a result every time we want to do maintenance for the puller or Dee insert we need
to break the cyclotron vacuum. This leads to a considerable down time for the cyclotron operation.
Present tank is made from carbon steel and is quite heavy. So our objective is to redesign it with a lighter
material, (Al) with proper selection of gate valve and making proper opening dimensions for easy and
smooth removal of Dee insert.
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The tank is a rectangular pressure vessel operating under external pressure. The detailed design and
material selection is followed by ASME section VIII division 1, Appendix-13. In case of cylindrically
shaped vessels, pressure induces membrane stresses in the vessel walls and the geometry gets more or
less uniform. However in case of noncircular vessels, even low and moderate pressures induce heavy
bending stresses on the walls, which tend to bulge out the sides. Hence the noncircular vessels are
designed for both membrane and bending stresses.
Membrane Stress:
Short-Side Plates: Sm = Ph / 2t1
Eq. (1)
Long-Side Plates: Sm = PH / 2t2
Eq. (2)
Bending Stress:
Short-Side Plates:
2
2
2
(Sb)N = (Pc/12I1)[- 1.5H + h (1 + α K)/(1 + K)] . Eq. (3)
2
2
(Sb)Q = (Ph c/12I1)[(1 + α K)/(1 + K )] .
Eq. (4)
Long-Side Plates:
(Sb)M = (Ph2c/12I2) [- 1.5 +(1 + α2K)/(1 + K)] . Eq. (5)
2
2
(Sb)Q = (Ph c/12I2) [(1 + α K)/(1 + K)] .
Eq. (6)
Each component of the rectangular pressure vessel contains a load that causes a membrane stress and a
moment that causes a bending stress (Fig 01). The membrane stress due to pressure should not exceed
the allowable stress value of the parent metal (S) and at weld joints the membrane stress shall not
exceed the product of allowable stress and the corresponding weld joint efficiency (SE). The total stress
at any point is the summation of these two stresses. The combined membrane and bending stress should
be lesser than 1.5SE and 2/3rd yield strength of the parent material at the design temperature. Where S
84
Corner post replacement for RF Resonator system of
K-130 Cyclotron
Bidhan Ch Mandal, S Sarkar, D Adak, U Rai, T Debnath, A Chakraborty, B Hemram,
P Xaxa, K Majumdar, Chinmay Nandi and Gautam Pal
R
F (radio frequency) resonator system for VEC Cyclotron i.e. K-130 Cyclotron is a single co-axial
(λ/4) structure of 3.9 m long placed horizontally in the accelerating chamber. The system is
coupled with anode assembly to feed RF power of 150 kW through Burley make 4648 tube. The
designed frequency range is of 5.5-16.5 MHz. RF Resonating system (mechanical) is a huge Cavity
structure made of mainly OFHC copper. The resonator is placed inside huge vacuum tank- a
combination of Dee Tank & Resonator Tank.
Rectification of Interface air leakage
CYCLOTRON
The air leakage through sealing of “O” ring at the Resonator tank to Dee tank mating interface of K-130
Cyclotron was successfully rectified by
replacing the four nos. of Corner posts
along with “O” ring / ”H” seal of new
design in the interface of Dee tank and
Resonator tank of VEC Cyclotron. The
normal operation of Cyclotron was
restored in 35 days of shut-down.
Figure1. Seals of Dee tank for sealing of corner-posts, side plates and
top plates at K-130 Cyclotron
Figure 2. Distorted “O” ring at the interface of Resonator Tank to Dee
Tank
86
The corner post replacement was for the
first time. This is to improve the sealing
performance in the interface between
two major vacuum tank- Dee tank and
Resonator Tank dedicated for RF
resonator system. The newly designed
corner post (Fig.3) restricts the “O” ring
movement in the corner zone of Dee
tank and overcomes uncertainty in the
cross over “O” ring sealing by moulded
“H” sealing (Fig.1). The cross-over of
“O” ring lies in the present corner post
due to top plate “O” ring ( Fig.4) and
side plates sealing “O” rings. The Radio
Frequency(RF) cavity for K-130
Cyclotron is housed inside the vacuum
tank – part of which is Resonator
tank(3.125 x 2.362 x 2.386 m) where
resonator portion exists and the part of
the cavity is inside beam accelerating
chamber called as Dee tank (3.074 x
3.192 x 0.32 m). Both these
demountable structure are voluminous
ACCELERATION TECHNOLOGY
Figure 3. Replaced “H” seal and “O” ring on new corner posts
Even, application of silastic sealant
(elastic gel) suggested by technical
committee was also not fruitful to arrest
the leakage permanently. After a two and
half decades of cyclotron operation, age
old “O” rings(Fig-2) at the interface of
Dee tank to resonator tank and in the
demountable plates of Dee tank had been
replaced with new neoprene “O” ring and
modified seal called “H” seal. The “H”
seal was specially designed and
fabricated for the cross-over zone in the
Dee tank corners supported by corner Figure 4. Distorted “O” ring on the top plate of corner post Old design)
post, meant for grooves.
The 4648 Burle tube assembly, Dee DeeStem Assembly, Deflector assembly,
Pick off, Target probe, Puller, Beam
probe, Beam exit port line components
etc. were taken out of Cyclotron. The
resonator tank (12 ton) was taken out by
70 mm over rail, along with both
Diffusion pumps and vacuum
accessories. On replacement of “O” ring
and “H” seals, the resonator tank was put
-2
back and evacuated to 2 x 10 mbar for
qualifying He leak rate < 2 x 10-7 std cc/s.
An intermittent tightening of bolts in the
interface improved leak tightness from 4
Figure 5. Charred Dee stem Spring contact bar
87
CYCLOTRON
components for the entire cyclotron.
These two tanks are sealed with 7.5 mtr
long “O” ring in the interface to make a
single vacuum chamber inside which a
high vacuum of about 4x10-6 mbar is
maintained during beam acceleration
Recent frequent air leakage into the beam
chamber hampers the cyclotron
operation for couple of years. Both liquid
and spray type high vacuum epoxy
sealant have been applied for several
times for the last couple of years to
operate the cyclotron on make shift
rectification basis as the sealant
application in to the particular location
was not feasible. The situation was
degrading further over time and higher
beam energy operation.
-4
-7
x 10 std cc/s. to less than 2 x 10 std
cc/s.
The cyclotron is working
satisfactorily after this modification cum
rectification of vacuum tank with new
design of corner post and “H” seal.
Rectification of Dee Stem shorting end
An unusual flash cum burning occurred
in the shorting bar end of the Dee stem
(Fig. 5 & 6). The Dee stem rear hinge
contact bar, the spring contact bar, clamp
bar, Be-Cu spring (called as garter
spring) and their associated surface were
badly damaged due to severe burning. A
systematic rectification has been carried
Figure 6. Charred Dee stem rear hinge contact bar
out along with installation of temperature
sensors for monitoring rise of temperature if any. The system is running satisfactorily without silver
coating on contact bars.
The beam hours target for this year was achieved through regular monitoring and necessary
rectification of the RF resonator system.
CYCLOTRON
Design and development of bipolar 4-quadrant switch-mode
power converter for superconducting magnets
Yashwant Kumar, S. K. Thakur, M. K. Ghosh, T. P. Tiwari, Anirban De,
S. Kumari and S. Saha
A
uniform zero crossing magnetic field in a magnet can be achieved by using bipolar power
converter with four quadrant operation. A high current bipolar switch-mode power converter
(rated ±27 Vmax, ±7V flat top, ±300A, 100ppm) has been designed and developed indigenously at
VECC Kolkata. Four quadrants operation is accomplished by using power IGBTs in an H-bridge
configuration with switching frequency around 20 kHz. The switch-mode power converter is used
because of high dynamic response, low output ripple, high efficiency and low input current harmonics.
Figure 1. Schematic of Bipolar Magnet Power Supply
88
For the correction magnets, bipolar power supplies (BPSs) are required to produce either polarity of
magnetic fields. This power supply is equipped with a passive high frequency filter to reduce the ripple
components of output current. Danfysik make DCCT (model-866S) senses the output current and
provides a feedback signal to IGBT via PWM controller for the regulation. The current transducer
which has high precision and low drift (1ppm) is used.
PWM regulation Scheme
CYCLOTRON
The simplified regulator circuit used to generate PWM signals is shown in Figure (2). In order to
regulate the magnet current, the ramp comparison method and PI controller are used. The magnet
current information is fed back to an error amplifier input via a current measuring device (DCCT) as a
feed-back signal (Ifb). Analogue reference signal, Vref, is set from -10V to +10V corresponding to
magnet current -300A to +300A linearly with smooth zero crossing. A polarity signal, which
determines a set of switches to be controlled, is derived from error signal by using a comparator. This
PWM signal combined with the polarity signal using an AND gate to determine which switch, S1 or S4,
is to be controlled. A logic low signal, which selects switches S1 and S2, is obtained for a positive value.
Similarly, a logic high signal, which selects switches S3 and S4, is obtained for negative value. The
regulation is achieved by pulse-width modulation (PWM) method. Two dual packages Insulated Gate
Bipolar Transistors (IGBTs) are used as switching devices due to their ruggedness and simple drive
requirement.
Figure 2. PWM Regulation Scheme
Figure 3. Measured wave form of power supply
89
Test Results
Figure(3) shows measured wave form of power supply which consists of three wave forms. Channel- 1
shows gate pulse of IGBT, channel- 3 shows VCE pulse of switched IGBTs and channel-4 output
ripple ~1V peek to peek.
CYCLOTRON
Figure 4. Current Stability Chart
Figure (4) shows stability of power supply for ~ 4-hours with a sudden power dip in between.
References
[1]
Y.G, Kang “A current-controlled PWM bipolar power supply for a magnet load”, Industry Application Society
Annual Meeting, 1994, Vol.2p.805.
[2] S.H. Jeong, “Design and Implementation of bipolar power supply for correction magnet”, Proceeding of FEL 2009,
Liverpool, UK.
Design and development of digital feedback controller
for switch mode power supply
Santwana Kumari, Anirban De, V.K. Khare, M.K.Ghosh, S.K. Thakur,
Amitava Roy and Subimal Saha
T
he power supplies have been traditionally controlled by analog techniques, but there are potential
advantages of digital implementation of the controller mainly in terms of programmability,
elimination of discrete tunning components, less susceptibility to aging and improved flexibility. A
DSP based buck converter of rating 20 V, 10 A and voltage regulation< 0.01% is designed. The
controller was initially designed in the analog domain and then converted to discrete domain by
mathematical transformations. This controller was implemented based on Texas instrument make
floating point Digital Signal Controller TMS320F28335, and tested on rated load as shown in Fig.1.
90
CYCLOTRON
Figure 1. Test setup of the DSP based buck converter with rated resistive load.
Figure 2. (a) Shows the full scale step response of the designed controller. (b) Shows the Transient response of the designed
controller
The full scale step response and the load transient response is shown in Fig.2, when load current is
increased by 33% (at 1) and restored to rated load of 10 A (at 2) as shown in Fig 2 (b) .The response
times, regulations were satisfactory.
References
[1] T. W. Martin, S. S. Ang, “Digital Control For Switching Converters”, Proceedings of The IEEE International
Symposium on Industrial Electronics, ISIE, 1995, pp. 480-484 vol.2.
[2] M. Fu and Q. Chen, “A DSP based controller for power factor correction (PFC) in a rectifier circuit,” in Proc. IEEE
APEC'01, 2001, pp. 144–149.
91
Development of prototype high voltage power supply based on
pulse step modulation technique for IOT based RF amplifier
S.K. Thakur, Santwana Kumari, Anirban De, Yashwant Kumar, Vishal Lilhare,
V.K.Khare, Arbinda Bera, S. S. Pal, Anand Kumar Kushwaha, Amreshwar Patra,
Arbind Kumar, T.P.Tiwari and Subimal Saha
A
solid state based PSM (Pulse Switch modulation) technique is adopted to design and
development of high voltage regulated power supply, which has lots of advantages over
traditional way of regulating topologies such as SMPS or by using vacuum tube in series, which are
less efficient and bulky. On the other hand, it can meet very stringent performance such as fast response
so higher accuracy of output voltage, higher efficiency, high ripple frequency resulting smaller filter
and thus very less stored energy. This technique employs modular converters connected in series to
achieve desired voltage. A high voltage power supply (-40kV, 5A) is being developed based on PSM
technique, which will consist of 60Nos of power modules (Buck converter) connected in series.
CYCLOTRON
Figure 1. Power modules with DSP controller.
A prototype of this power supply with output of -2.2kV/2A has been developed as shown in Fig. 1. This
prototype power supply consists of four power modules (Buck converters) and its output voltage is
obtained by connecting all in series. Each power module consists of solid state switch (IGBT) and a fast
recovery freewheeling diode with rectifier and filter. Input 3-phase power is fed to each module from
secondary windings of multi secondary transformer. Switching pulses for each IGBTs is generated by
using Texas Instrument make floating point DSP TMS320F28335 as shown in Fig.2(a). Optical fibers
are used for isolation of DSP controller from power modules.
Each IGBT is switched with certain phase shift from each other, taking rotation into account such that
only voltage of one power module can be seen as the ac value at time. Phase shift between each IGBT is
calculated as follows.
92
Phase shift = Switching time period of IGBT/ No. of modules.
It results a constant voltage with ripple limited to one power module voltage and ripple frequency is
four times of switching frequency of individual module as shown in Fig.2(b).
(a)
(b)
The results of this prototype power supply were very satisfactory. For actual power supply of rating 40kV/ 2A a multi secondary transformer with 60Nos of power modules will be used. Each power
module is of rating 800V and some extra power modules will also be present for maintenance and
replacement.
Modelling and experimental verification of
chip deviation in oblique cutting
Tamal Ghosh and Chinmay Nandi
T
he literature survey clearly indicates the reasons for non orthogonality or obliquity in machining
and there are there distinct reasons; they are presence of finite nose radius, participation of the
tooltip in machining operation leading to restricted cutting effect yield chip deviation and presence of
non-zero inclination angle of the principal cutting edge. Further, it has been established that Stabler and
Rosenberg and Eremin models do not hold good in actual machining situations. The concepts of
effective cutting edge and its orientation have been introduced and employed in analysing oblique
machining. Though the effect of non-zero rake and inclination angle on a single point turning tool with
nose radius has been investigated but without the restricted cutting effect.
93
CYCLOTRON
Figure 2. (a). Shows shifted gate pulses from DSP controller
(b). Shows the output voltage wave form of four module connected in series
Thus the objectives of the present work have been defined as follows:
l
development of models for chip deviation in oblique cutting
l
using the concept of effective orientation of principal cutting edge and effective inclination
angle to capture the effect of restricted cutting effect – model 1
l
using concept of effective or average principal cutting edge angle and effective inclination
angle to capture the effect of restricted cutting effect – model 2
l
using
concept of effective or average principal cutting edge angle, effective chip load and
effective inclination angle to determine the direction of chip flow – model 3
l
analysis of efficacy of existing models against experimental data
l
experimental verification of proposed models
l
Study role of tool geometry and cutting parameters on chip deviation
l
study of role of work material on chip deviation.
CYCLOTRON
Model 3. Based on effective principal cutting edge angle and effective chip load.
Øav =
94
Development of additional probe and drive system for internal
beam centering of SCC
S. Roy, C. Nandi, G. Pal, N. Chaddah, R. Bhole and S. Pal
I
n order to centre the beam within acceleration chamber an additional probe was required along with
the existing diagnostics probes. The additional probe was inserted through the ports at 7O after
removal of the first electrostatic deflector. An insulated aluminum finger mounted on the tip of the
probe to measure the beam current. A vacuum feed through was used to take the current signal outside
of the cyclotron. The bellow sealed probe is moved radially in or out with the help of a compact linear
drive system (Fig. 1). The drive system comprises a set of parallel guide shafts and a lead screw driven
by a stepper motor. Position feedback was obtained from a rotary encoder mounted coaxially with the
lead screw. The entire system was developed , installed and successfully operated.
Figure 1. Additional probe with drive system for internal beam centering
95
CYCLOTRON
Design & development of low temperature refrigeration
machine for diffusion pump baffle cooling using two stage
vapor compression refrigeration (VCR) cycles
Md. Waseem Siddiqui, R.K.Sahoo1, R.Dey, Subimal Saha,
J. Ghosh, N. Sanyal, S. C. Saha, U.Panda, B.B.Sahoo, U.Patel and K.Mazumdar
1
Mechanical Engineering Department, NIT, Rourkela
V
ECC, Kolkata is having two nos. of very big Diffusion Pumps (Capacity 42,000 LPS each) for
creating vacuum in the beam line of K-130 Cyclotron. For reducing the back streaming and
improve the quality of vacuum baffles are required to cool with continuous operating low temperature
refrigerating Machines .Using the R404A/R-23 combination in two stage of vapor compression
refrigerating cycle can maintain a very low temperature ( -60°C to -70°C ) or below, definitely a better
choice over R-12/R-22 ( -40°C ) combination. Two stage cascade system for the long time continuous
running of D.P. a cheap and better option over the costly cryogenics system for producing the vacuum
in the range of ~10-6 Torr.
CYCLOTRON
The effort has been taken to
design and manufacture
low temperature two stage
(cascade type) refrigeration
units utilizing the
combination of R-404A &
R23 refrigerants, which are
environmental friendly
refrigerant having '0'Ozone
Depletion Potential
(O.D.P.). These refrigerant
are also easily available in
market. Detail analysis of
refrigeration cycle, cascade
design, control logics have
been worked out for
approaching towards a
theoretical system.
Design & fabrication of
tube in tube type cascade
heat exchanger, pre-cooler,
receiver, selection of pipe
lines & chilled water
cooled condenser, etc., are
one of the most important
achivements to develop and
explore such kind of low
Two stage cascade type Low temperature Refrigeration Machine
Low Temperature Machine connected with testing chamber
96
temperature refrigeration
job.
Machine has been tested at
load condition, for one
month long continuous run.
After getting shut down of
the cyclotron system this
machine will be installed
at pit and will be
commissioned with
Diffusion Pump Baffle,
where it will maintain low
temperature for reducing
the back streaming and
improve the vacuum.
Vacuumized Testing Chamber- evaporator inside with simulated heat load
CYCLOTRON
A n i n d e g e n o u s
development has been
materialized after the total
in house fabrication of
machine, which has been
commissioned and being
tested under the simulated
load condition. This
machine is running
efficiently after giving the
required temperature at the
evaporator (-60°C to -70°C)
with more than 1TR load.
Result- One Reading with Load condition
Performance at long continuous run
97
Vacuum test set-up instrumentation
T Das, T. K. Bhattacharyya, R. Rakshit and G. Pal
A
CYCLOTRON
data acquisition and interlock control system for vacuum test set-up (Figure 1) has been
developed. The system consists of a vacuum chamber with a few pumping ports. Turbo pump
backed by rotary and scroll pumps are connected through pneumatic gate valves. A few vacuum gauges
and a RGA are connected through some other ports. The main objective of the control instrumentation
is to acquire all the vacuum gauge data to a remote PC and log with time stamping. The philosophy of
the control interlock is to start the backing pumps, turbo-molecular pumps, RGA in a specific sequence
of time and vacuum condition and connect them to the system systematically as per gauge readings at
different locations. In case of any
unusual condition sensed from
the gauge readings, different
pumps and RGA are switched off
or disconnected from the system
by actuating gate valves. These
hardware interlock set-points
can be set by the user as per
requirement. Gauge readings
and interlock status can be
logged in an excel file with timestamp at user defined interval. A
distributed DAQ and vacuum
controller are used as the main
hardware to acquire and transmit
data to the remote PC via LAN. A
LabVIEW based user friendly
GUI has been developed to
monitor all the gauge readings,
interlocks and device status and
to set time interval for data
logging. The system has been
used to study water removal
characteristics in vacuum
environment and has been able to
produce large amount of faithful
data.
Figure 1. Vacuum test setup
98
Electrostatic Deflector for K-130 Cyclotron
Sumantra Bhattacharya, Sanjay Karanjkar, Sanjay Ramrao Bajirao, Chinmay Nandi,
Subhasis Gayen, Suvadeep Roy, Santosh Kumar Mishra and Gautam Pal
As the electrodes are being used for
more than twenty years these
electrodes needs to be replaced to
achieve high voltage for extraction
of different beams. 3D modeling of
the electrodes has been prepared in
CATIA. A prototype die and Punch
have been designed for a small part
of the deflector and fabricated to
check the feasibility of
manufacturing the deflectors
through pressing using the dieFigure 2. Down Stream Ground Electrode
punch. This attempt has been found
to be successful. A detailed
technical specification has been prepared to form the deflectors from inconel sheet using a suitable
vendor.
Successful development of 4K Cryo-cooler based
Cryogenic Test Set-up
T
he 4K cryo-cooler based cryogenic test set-up was designed, fabricated and successfully
integrated with two numbers of Sumitomo made 4K Cryo-coolers. The thermal performance of
99
CYCLOTRON
T
he electrostatic deflectors of K 130 cyclotron extract the accelerated beam from cyclotron. In K
130 cyclotron, there are two deflectors, upstream deflector (Fig. 1) and downstream deflector
having a total span of 108 degrees. Each deflector consists of two water cooled electrodes; high voltage
electrode and ground electrode (Fig
2). High voltage electrode is made
of inconel and the ground electrode
is made of tungsten and inconel. The
spark shield is made of SS 304. A
voltage around 50 -100 kv is fed into
the high voltage electrode. All the
deflectors are placed inside the
vacuum environment and the
movements to the electrodes are
Figure 1. Upstream High Voltage Electrode
given by motors using bellow seal.
Test set-up mounted on a movable table
CYCLOTRON
Sample mounting centre stick
4K-Cold heads showing thermal links and magnet support plate
100
the system was tested successfully
and different measurement was
carried out. This is a general
purpose test facility which allows
to cool the samples/devices to
4.2K without the inconvenience
and expense of liquid helium. It is
specially designed to feed large
current to the sample for the
measurement of transport critical
current of superconductors (both
LTS and HTS) under different
temperatures and magnetic fields.
It consists of two numbers of 4K
cold heads, each having cooling
power of 1.5 watts at 4.2K. A
central port of diameter 250 mm,
for sample loading and two pairs
o f H i g h Te m p e r a t u r e
Superconductor (HTS) current
leads are the main features of the
test set-up. One pair of current lead
will be used to feed current to the
sample and the other for feeding
current to the magnet. The limited
cooling power (2 × 1.5W) of two
cold heads is judiciously
distributed to intercept the heat
load from different sources,
primarily at two temperatures of
4.2K and 50K. The cooling power
at 4.2K is divided into two isolated
systems consisting of magnet and
sample space. The thermal
radiation load to the cryostat is
maintained at ~50K and is
provided by the 1st stage of cold
head connected to magnet system.
The major source of heat load
comes from two pairs of HTS
current lead whose two ends are
anchored thermally (electrically
isolated ) to the 1st and 2nd stages
of cold heads. The HTS based
conduction cooled magnet is under
development for integration with
the cold head. Several Niobium
(Nb) samples from BARC,
Mumbai was characterised for
purity
through
RRR
measurements. The phase
measurement was carried out
from 320K-4K of Cobalt-Tin
sample from SN Bose Institute,
Kolkata
for
different
compositions.
The overall performance of the
system with the following major
tests were carried out and obtained
satisfactory designed results.
l
Cooling
power at different
temperatures in both
magnet and sample circuits.
Magnet support plate
l
To ensure that the magnet and sample circuits are thermally isolated.
l
Operation
of magnet and sample circuits respectively with 300A and 400A of current at
l
Helium leak test both at warm and cold conditions.
l
Variable temperature operation
Different measurements to obtain cooling power data for both magnet and sample system under
different currents and temperatures are shown in figures below. In addition different works were
identified during measurements to enhance the system performance and its safety, which are
subsequently rectified and incorporated.
Cool-down of test set-up cryostat which requires about
5-6 hours of time to reach 4.2 K
Measurement of cooling power under different temperatures. It
also shows sample space temperature remains at 4K during
measurement indicating thermal isolation.
Characterization of Niobium (Nb) samples from BARC, Mumbai for its purity through RRR
measurement:
The purity of metal can be characterized by its residual resistivity ratio (RRR) which is defined as the
ratio of the electrical resistivity at room temperature (~ 295K) to the resistivity at low temperature ~ 0K.
The resistivity at a given temperature is proportional to the sum of resistivity's from impurities,
crystalline defects ( grain boundaries, dislocations etcs) and phonon(lattice) interactions. The phonon
101
CYCLOTRON
4.2K.
interaction continuously decreases with temperature and remains almost constant below certain
temperature as shown below. So at low temperatures residual resistivity depends on the impurity
content of the samples, which is temperature independent. In case of niobium the RRR has to be
measured at its normal conducting state being a superconductor at ~ 9K. Practically RRR is measured
as the resistance ration
[1] or
. At 4.2K induction of magnetic transition from the
superconducting to the normal state is required. We have used classical 4-wire method to measure RRR
using Cryo-cooler based Cryogenic test set-up. The sample holder is made to mount the Nb sample of
50mm length and 9 mm diameter and thermally connected with the cold head. The 40 ? /50W capsule
heater attached nearby maintain 10K sample temperature using Lakeshore temperature controller.
Sample #
Manufacturer
Critical Temperature
RRR
1
HEARAUS, GERMANY
9.1998 K
379
2
FIREL SOURCE
9.219 K
355
3
VARDHAN ENGG.
-
358
Measurement of phase
transition of cobalt-Tin sample
of two different compositions
(320K to 4K temperatures):
CYCLOTRON
Resistivity variation with temperature of one of the Nb sample
Phase transition of two different composition of Cobalt-Tin samples from
SN Bose Institute, Kolkata
102
The measurement was performed
on two samples from SN Bose
Institute, Kolkata from 320K to
about 4K temperatures with two
different compositions of Cobalt
and Tin. The phase transition was
obtained and the results was
provided to them for further
analysis.
2.4
SERVICES
Round the clock shift operation and maintenance of LCW &
compressed air system
J. Misra, Md. I. Siddiqui, S. N. Das and R. Karmakar
L
CW section is responsible for round the clock shift operation and maintenance of equipments such
as LCW pumps, Cooling tower system, Heat exchanger and compressed air system for both Room
Temperature and Super Conducting Cyclotrons. To ensure the smooth operation of the plant periodical
maintenance is carried out as follows.
l
Backwashing and replacement of filtering media for pressure sand filters.
l
Micron filter cartridge replacement both RTC and SCC LCW system.
of RTC cooling tower pump No. 2 including changing of bearing, shaft sleeves,
impeller, wear ring and stuffing bush.
l
Replacing of activated alumina and molecular sieves in old bower heated desiccant dryer.
l
As on
demand in maintaining conductivity of LCW system, Mixed Bed- A, B and C were
regenerated.
l
Replacement
of oil filter, gasket, pressure switch, cooling oil for IR Vertical compressor is
completed.
l
Replacement of GP, HE and AC elements of compressed air system is done.
l
Overhauling of IR screw compressor (ASE25) including Motor bearing replacement.
l
Replacement of suction filter, oil filter, thermal valve, cooling oil and cleaning of radiator of IR
screw compressor (ASE30) have been completed.
All the maintenance activities of the plant were carried out with proper planning without effecting the
cyclotron operation and there was no loss of productive hours due to LCW and Compressed air
operation.
Modernization of control system of the scattering chamber of
K-130 room temperature cyclotron
Tapas Kumar Bhaumik, Amiya Kumar Saha, Bidhan Chandra Mandal, Debabrata Adak,
Monirul Purkait and Sailajananda Bhattacharya
T
he internal diameter of the scattering chamber of K-130 room temperature cyclotron is 91.5 cm
and height is 35.6 cm. It has got a target ladder capable of independent up-down and rotational
103
CYCLOTRON
l
Overhauling
Figure 1. System configuration
CYCLOTRON
Figure 2. Scattering chamber & new control rack
Figure 3. Touch panel GUI for local control
104
motions, two detector platforms
capable of independent rotational
motions and one top lid plate for
closing and opening the chamber as
per requirement. In the old control
system, all the above mentioned
movements used to be controlled by
using geared 110V DC shunt motors
and a relay logic controller kept at the
counting room, 70 m away from the
chamber and connected by signal
and power cables. Ten turn
potentiometers were used for
position feedback and limit switches
were connected for protection. A
local panel attached to the chamber
was available for the operations
during setting up of the experiments
in the cave. The main purpose of the
control system of the scattering
chamber was to (1) position the
target by controlling up-down and
rotational motion of the target ladder
(2) position two detector arms by
controlling angular motions (3)
opening and closing the top lid plate
by its up-down motion and (4)
control the operation of vacuum
pumps. All the above operations
should be possible under
atmospheric pressure as well as
-5
under high vacuum of the order ~10
-6
-10 Torr. Computer Division,
VECC had corrected hardware
problems of the relay logic controller
of the chamber in May, 2007, made it
operational for nuclear physics
experiments and provided
operational and maintenance
support. However, the control
system was more than 30 years old,
developed multiple problems over
the years, and, the components of the
control system like relays,
potentiometers, limit switches,
radiation resistant cables were not
functioning as per specifications. It
was therefore targeted to modernize
SERVICES
the control system of the
scattering chamber employing
state of the art PLC based system.
The PLC communicates with the
touch panel and remote PC
through 100 Mbps Ethernet
switch and uses Modbus / TCP
protocol. The Graphical User
Interfaces (GUIs) of the local
control panel (Figure 3) and the
remote panel (Figure 4) have been
developed as per the requirement
of the users. All the old sensors,
limit switches, relays and cables
also have been replaced by new
items. Two potentiometers have
been coupled to two motors with
required gear reductions to get
position feedbacks from two
detector platforms. The analog
input module uses 16 bit ADC and
typical position accuracies of
Figure 4. GUI for position control from remote PC
CYCLOTRON
The new embedded control
system (Figure 1) has been
developed using AdvantechADAM-5510EKW 16 bit CPU
together with one 5017P analog
input module, one 5051D digital
input module and two 5056D
digital output modules. The
configuration of the control
system is shown in Figure 2.
MULTIPROG Basic V.3.3 and
Ladder Diagram have been used
as the programming software and
the programming language
respectively. A resistive type
touch screen based operator panel,
We b O P - 2 1 0 4 V- N 4 A E o f
dimensions 297×224×52 mm
having HMI RTOS has been
mounted on the control rack for
local control. iFIX SCADA, 75
tags Runtime Version 5.1 has been
used to operate from remote PC
connected to the PLC by 70m
CAT6 cable.
Figure 5. Touch panel GUI for calibration
Figure 6. Termination board
105
±1mm and ±1 degree for target ladder and ±2 degrees for detector platforms have been obtained. A
calibration panel has also been developed (Figure 5), where user would be able to calibrate the ranges of
all motions from local control panel in terms of convenient and user friendly data. These calibrations
would remain in the memory of the PLC for future operations. All the components like relays, ADAM
modules, power supplies, network switch, circuit breakers etc. have been mounted in the rack to have
easy access for testing, maintenance and repair / replacement. Three phase and single phase ac power
cables have been routed through cable trays mounted below the ceiling to isolate from the signal cables,
which have been routed through cable trays mounted on the floor. All the signal cables have been taken
to the termination board (Figure 6) through cable ducts and connected to the terminal screw connectors
to connect with the system and to have easy access for maintenance and repair. Rated MCBs have been
used for vacuum pumps, PLC, power supplies and control valves for protection and interlocks. Military
grade allied connectors have been used in the control rack for reliable operations. Silicone rubber
cables have been used as signal cables and would be able to work up to a total exposed radiation of
8
5×10 rads absorbed dose equivalent to 30 years of continuous operation of the chamber for
experiments. Security feature of hardware lock has been incorporated for the operation from the remote
panel. The system is designed to implement fully automatic vacuum control operation with required
interlocks in near future.
CYCLOTRON
106
Compute r
and Infor matics
Development of a fast scintillator based beam phase
measurement system for compact superconducting cyclotrons
Tanushyam Bhattacharjee, Malay Kanti Dey, Partha Dhara, Suvodeep Roy,
Jayanta Debnath, Rajendra Balakrishna Bhole, Atanu Dutta, Jedidiah Pradhan,
Sarbajit Pal, Gautam Pal, Amitava Roy and Alok Chakrabarti
A
COMPUTER AND INFORMATICS
t the extraction zone of the compact superconducting cyclotron the magnetic field falls sharply
and the beam phase changes abruptly. One needs to measure the phase accurately at short
intervals in this region to ensure efficient beam extraction. With this motivation, a phase measurement
system for VECC's K = 500 superconducting cyclotron is developed. The technique comprises of
detecting prompt γ-rays resulting from the interaction of cyclotron ion beam with an aluminium target
mounted on a radial probe in coincidence with cyclotron rf. An assembly comprising of a fast
scintillator and a liquid light-guide inserted inside the cyclotron was used to detect the γ-rays and to
transfer the light signal outside the cyclotron where a matching photo- multiplier tube was used for
light to electrical signal conversion. The typical beam intensity for this measurement was a few times
11
10 pps.
Experimental setup
The phase probe assembly comprises of an aluminium target-plate where the ion beam would be
allowed to hit to produce prompt γ-rays, a glass window with 'O' ring seal to isolate the scintillator
assembly from the cyclotron beam chamber vacuum, the scintillator placed behind the glass window
and the liquid light-guide to carry the scintillation signal outside the cyclotron where a matching PMT
is coupled to the light-guide. The front-end of the probe that is inside the cyclotron is shown in Figure 1.
The aluminium target plate is mounted on a radial steel tube. Except the aluminium plate the entire
assembly is isolated from the beam chamber vacuum. The beam induced prompt γ-rays were detected
by the cylindrical scintillator detector, inserted inside the 20 mm bore of the phase probe tube at a
distance of 50 mm from the target plate tip. The scintillator detector was covered by an aluminium
casing and one end of the liquid light-guide was inserted into the casing ensuring proper coupling with
the outer circular edge of the scintillator detector to minimize light leakage. A liquid light-guide of five
Figure 1. Sectional view of phase probe head.
108
meter length was used to transfer the light signal from the scintillator to the PMT. The PMT was placed
outside the cyclotron to minimise the interference from the magnetic field and the rf. interference. A
remotely operated linear drive system was used to move the probe along the radius and the radial
information was obtained from a position encoder attached with the probe assembly.
Figure 2. Schematic diagram of the phase measurement
setup.
Figure 3. Beam central phase curve after applying Garren and
Smith beam phase detuning technique.
Experimental results
The phase measurements with respect to rf voltage were done at radial positions along the straight line
path of the phase probe movement. Since the angular distance of phase probe form the reference dee
increases with radius due to spiral structure of hills and dees, the phase values were corrected. The
absolute calibration of the phase curve, as shown in Figure 3, was done by the Garren and Smith's beam
phase detuning technique [1].
References
[1] C. Baumgarten et al. Nucl.Instr. and Meth. A 570 (2007) p.10.
109
The NIM electronics and CAMAC-based data acquisition system were used to extract the phase
information as shown in Figure 2.
EPICS embedded modular beam diagnostics instrument
Shantonu Sahoo, Niraj Chaddha, Rajendra Balakrishna Bhole, Partha Pratim Nandy,
Tanushyam Bhattacharjee, Anindya Roy and Sarbajit Pal
T
he modular design of the beam diagnostic control instruments has undergone through several
modifications for multiple times due to fast changing and customized requirements. The overall
requirements were analysed and modular cards are developed based on basic functionalities like valve
operation, probe/slit/viewer control, position read-out, interlocks, aperture control of beam and
communication. A 32-bit Advanced RISC Machine (ARM) based card with embedded EPICS is
chosen as the master controller and different microcontroller families are used for functional modules.
The recent development introduces an EPICS embedded main controller card, interfacing with other
functional modules through dedicated serial lines on backplane [1]. This design has given liberty to the
developer of individual module for selecting his own tool chain according to the complexity of
functional requirements of the
module while keeping the same
software architecture.
Hardware Modules
The newly designed instrumentation
has a main controller card,
communicating with other functional
modules (Figure 1) and PC is used for
controlling diagnostic devices. The
main controller card is designed
using a Cavium ARM9 CPU based
SBC (Single Board Computer)
running on 250 MHz. The SBC boots
to Linux 2.6 from either an SD card or
4MB on-board flash. The other
modules are application specific e.g.
the Stepper motor driver module
which is designed to operate high
current, high torque motors having
unipolar/ bipolar configuration with
single stepping/ half stepping option.
Figure 1. Advanced RISC Machine (ARM) based master controller card,
one of the assembled module.
110
The Encoder read-out module is
interfaced with incremental type
optical encoder to give linear/
angular position information with 1x,
2x and 4x resolution. Other features
like auto correction and data saving
on power off makes this design
equivalent to absolute position
encoder. The other modules like X-Y
slit controller, isolated I/O card, relay
module etc. are also designed to have special features which are commonly required during beam
diagnostic and other applications.
All these modules are connected in the backplane through MODBUS communication protocol. There
is a dedicated serial line from the controller card to each modular card. Thus failure of any individual
module will not affect the functionalities of other peripheral modules.
Embedded EPICS
The total development process
involves various steps like assigning
the Command Set for individual type
of module, implementation of EPICS
Database, Device drivers and finally
cross compiling the sources for ARM
target. The communication protocol
i.e. the packet format for
communicating with all the
functional modules is developed at
first. A common packet format with
unique Command ID, 4 bytes of data
and LRC checking is implemented.
Then, a list of all the commands that
will be required to communicate with
each module is decided. The database
file is created which describes the
actual EPICS process variables
associated with the beam diagnostics
application. The device driver and
support files are written in C
programming Language which
provides the details of the
communication between the device
and EPICS. After proper installation
of the ARM cross compiler on the
development PC, application source
codes are built for arm-linux target
architecture. After successful
building of the base and the
application, the required binaries,
library files, database files and
database definition files are
transferred into the SD-card of ARM
board.
The ARM based embedded controller card is developed to replace the existing PC based system with a
small plug-in module that will contain the EPICS IOC (Input-Output Controller) and database of the
control parameters. This will have an
obvious advantage of embedding the
control intelligence thus reducing the
overall system complexities in the
PC based systems.
Figure 2. OPI of the diagnostics system viewed at the Control Room.
111
Operator Interface
There are standard EPICS tools e.g. EDM, MEDM etc. for developing Operator Interfaces in general
for Linux platform. But porting these X windows based OPIs to windows platform require third party X
server e.g. Exceed, Xming etc with expertise during installation. Microsoft ActiveX technology is
chosen to create reusable, platform-independent, distributed, object oriented binary software
components with encapsulated CA functionalities. Microsoft Visual Basic (VB) is chosen as the OPI
development platform considering its object oriented structure, rich GUI library and less complicated
coding style. EZCA is chosen to implement CA functionalities. Several CA ActiveX components,
commonly used in OPI, are developed and are used to develop the OPI (Figure 2) for beam diagnostics
purpose. Various ActiveX components that are used in this development include CA Text, CA Image,
CA Setpoint and CA button.
References
[1] Niraj Chaddha, Shantonu Sahoo, Rajendra Balkrishna Bhole, Partha Pratim Nandy and Sarbajit Pal, Modular Beam
Diagnostics Instrument Design For Cyclotrons, Proceedings of 9th International workshop on Personal Computers
and Particle Accelerator Controls (PCaPAC-2012), VECC, Kolkata, December 4-7 (2012).
Development and performance analysis of embedded EPICS
controller on ARM and FPGA based soft-core processor
Shantonu Sahoo, Tanushyam Bhattacharjee and Sarbajit Pal
A
robust architecture with soft
real-time responses is the
primary requirement to build a
distributed control system for
accelerators. In the control system of
several particle accelerators,
astronomical telescopes and various
large scientific experiments,
Experimental Physics and Industrial
Control System (EPICS) has been
adopted for its reliable and soft realtime performance. Using an
embedded system for designing
EPICS based control system will
have an obvious advantage of
integrating the control system inside
the hardware itself thus reducing the
overall hardware complexities of
field devices. To achieve this, the
EPICS open source is suitably
optimized to port on ARM9 and
MicroBlaze soft-core processor on
FPGA in this project. An EPICS
Figure 1. Architecture of EPICS based ARM controller card for Beam
Diagnostics
112
Figure 2. Results showing the maximum number of Process Variables allowed in different target platforms
Reference
[1] S. Sahoo, et.al , “Development and Performance analysis of EPICS Channel Access Server on FPGA based Soft-core
Processor”, PCAPAC'12 , Kolkata, December 4-7 (2012).
Development of fast controls for beam wire scanner for super
KEKB, KEK, Japan
Anindya Roy, Naoko Iida1 and Kazuro Furukawa1
1
KEK, Japan
T
he KEK 8-GeV linac injects electron and positron beams with different characteristics into four
storage rings: KEKB high-energy ring (HER), KEKB low-energy ring (LER), Photon Factory
(PF) and PF-AR. The wire scanners are used to monitor beam profile non-destructively along the beam
line. Again a set of four wire scanners are used to calculate beam emittance and Twiss parameter for
113
based ARM input/output controller has been designed and tested for beam diagnostics subsystem of
Cyclotrons at VECC. Figure 1 shows the architecture layout of the beam diagnostics system where the
EPICS IOC is running on an ARM9 based SBC. The EPICS performance on the two target processors
is analysed and compared with the standard linux-x86 PC. The CPU load and server processing time
for different numbers of Process Variables (PVs) have been studied for each platform. On the basis of
the analysis, critical parameters of EPICS on embedded platform have been derived and a few
modifications in the channel access protocol are proposed for MicroBlaze soft-core processor. Figure 2
lists the estimated limit of maximum number of process variables on x86 platform, ARM9 board and
MicroBlaze soft-core processor (with four different configurations of Cache Memory size and stages
of pipelining).
optics matching in LINAC & BT. The principle objective is to develop an event based data acquisition
system, synchronised with LINAC timing system, for acquiring multiple beam mode data
simultaneously to meet the stringent beam quality requirement of SuperKEKB.
In LINAC and BT, the simultaneous top-up injections to three rings, KEKB-HER, KEKB-LER, and
PF is realised by a global fast event-based control system. In this system, various beam line equipments
are controlled through a set of event codes, broadcasted sequentially for each beam mode. An event
generator, clock synchronised with RF, is used to sent event codes along with clock to various event
receivers distributed along the beam line through optical link. The event receivers decode the event
codes and generate timing signals for the related IOC's to control subsequent beam line equipments e.g.
klystrons, magnets etc. The data acquisition system for wire scanner is comprised of Motorola
MVME-5500 CPU, Hoshin V004 Scaler, Hoshin V005 Charge Sensitive ADC (CSADC), PVME
DAC, Agilent LAN/GPIB converter and Micro Research Finland Event Receiver (EVR). The system
is connected to LINAC timing system using single mode optical fiber through EVR. The EVR is used
to generate gate pulse for CSADC synchronised with incoming events from global event generator of
the timing system. The movement of the wire is controlled through stepper motor controller using
LAN/GPIB converter. A GPIB based multi-channel digital voltmeter is used measure the absolute wire
position through potentiometric arrangement. The DAC is used to control the PMT bias voltage. The
hardware architecture of the system is shown in Figure 1.
Figure 1. Hardware architecture of the system
The Experimental Physics & Industrial Control System (EPICS), a standard open-source dual layer
software tool for designing distributed control system, is adopted for implementing the supervisory
control software in LINAC as well as in all four storage rings. An EPICS Input-Output Controller
(IOC), running on VxWorks 6.8, is developed for control and data acquisition for the WS system. A set
of EPICS device drivers are developed for CSADC, Scaler and DAC hardware, while Asyn driver is
114
used for LAN/GPIB and
existing latest driver is
used for EVR. To meet the
software interface
requirement with existing
control system, a new
E P I C S r e c o r d , Wi r e
Scanner (WS) record is
developed. In this record,
data from various sources
e.g. CSADC, Scaler, Beam
Position Monitor (BPM)
etc are acquired through
input links and stored in a
ring buffer while
processing of the record.
There are various options
for defining parameters
e.g. maximum number of
data, obtaining BPM
signals and further
calibration of the BPM
signals. The Beam mode
data is appended
dynamically to the array
through an additional field
for correlating data with
Beam Mode. Since there
are three distinct positions
of the wire scanner for
maximum signal, peak,
i n P M T. H e n c e a
combination of slow and
fast speed is used during
scanning to get maximum
data at the desired wire
position keeping overall
scanning time to a
minimum.
Figure 2. Test result
The data acquisition
system is installed in the Sector – 5 of the LINAC. After installation, the gate delay and width are
adjusted with different beam modes. The wire speed, peak positions and width are optimised after
multiple scanning. The final system is tested with PF and PF Study modes. The test result is shown in
Figure 2. This system will contribute significantly for beam tuning during SuperKEKB
commissioning and subsequent stages.
115
Innovative instrumentation to measure magnetic susceptibility
Nilangshu Kumar Das, Sarbajit Pal and Partha Barat
A
simplified instrumentation with nominal circuitry has been developed to measure in- and out-ofphase complex magnetic susceptibility of bulk magnetic samples. A unique shape of the absolute
coil is implemented to improve the magnetic field homogeneity inside the coil. Complex susceptibility
of nano-composite is measured by an innovative phase detection circuit. In this paper, we also discuss
in detail the principle, design and the performance of the instrumentation. This susceptometer is also
suitable for liquid samples viz., ferro-fluids, blood samples etc.
The differential of magnetic flux (φ) in the solenoid with respect to the current (I) is the measure of self
inductance of the coil. The flux inside the coil depends on the magnetic permeability of the core and
hence the self inductance of the test coil, Ls is related to the magnetic properties of the sample inside the
coil (figure 1).
The change in self-inductance due to the insertion of the sample in the coil is proportional to the a.c.
susceptibility. Hence, χac of samples at different frequencies and temperatures is obtained by a well
calibrated precise inductance meter. In our instrumentation, the inductance of the coil is computed
from the voltage drop measured across the inductor coil. We assume a current Irms is passing through the
coil and RMS voltages developed across the coil are vrms-0 and vrms-s for air core and core filled with
sample respectively. The magnetic susceptibility χac of the sample is proportional to the change in selfinductance. Here r is the intrinsic resistance of the coil and κ is the constant of proportionality. This κ is
obtained from the samples with known susceptibilities and it depends on the coil parameters, volume
fraction, fill factor and geometrical arrangements of the sample.
A constant current, has been maintained through the L-R circuit. I0ei(ωt-θ0 ) is the current passing through
the air-core coil whereas I0ei(ωt-θs) is the current passing through the coil with the sample in the core. The
voltage drops across R are I0Rei(ωt-θ0) and I0Rei(ωt-θs) respectively. In addition to these voltages results in a
new amplitude B which carries the phase difference, ψ = (θs-θ0) linked to the sample.
The phase ψ is obtained from the ratio of B and the voltage drop across R (vs or v0) as given
by ψ
= 2 cos–1 B . Therefore, the complex susceptibility is obtained
2n
as
χ́
+ i χ́
´=χ
+iχ
ac cos ψ
ac sin ψ
0
The system has been developed for the measurement of
susceptibility of nano-composites. In- and out-of-phase
susceptibility of nano-particles of nickel-silica (10% and 20%) have
been measured. Figure 2 and Figure 3 show the complex
susceptibilities of Ni-Silica nano-composites. The susceptibilities
of the samples in liquid nitrogen temperature have also been
measured.
This AC susceptometer is novel in coil design and phase
measurement. The sensing part of this technique is small compared
to the mutual inductance type hence the cryostat can be smaller in
size and it can also be adopted in superconductors, ferro-fluids,
116
Figure 1. V0eiωt voltage is applied to
the L-R circuit where θ is a phase
between the source voltage and
passing current.
Figure 2. Real part of volume susceptibility of 10% and
20% Nickel-Silica nano-composites.
Figure 3. Imaginary part of volume susceptibility of 10%
and 20% Nickel-Silica nano-composites.
The measurement of RMS voltages at specific locations in the analog circuit is required to get the
complex susceptibility of the samples. The uncertainties of the measurement of this susceptometer
depend on the uncertainties in the measurements of B/A and those RMS voltages respectively. To
reduce uncertainties, higher resolution Analog-to-Digital converters are recommended.
A manuscript on the above work as per following details has been communicated to IEEE transactions
on Magnetics. Title: Innovative Instrumentation to Measure Magnetic Susceptibility. Authors:
Nilangshu K Das, Sounak Dey1, Sarbajit Pal and P Barat (1 Indian statistical Institute, Kolkata).
Application of dynamic partial reconfiguration method for
implementing a set of digital filters on FPGA for DAQ
Madhusudan Dey, Abhishek Singh and Amitava Roy
A
n FPGA based digital system is often employed for nuclear data acquisition in a harsh radiation
environment. The digital circuit designed for a particular purpose resides in a configuration
memory of an FPGA (Field Programmable Gate Array) in the form of a two dimensional array of bits.
The effect of radiation causes bit-flip and bit-stuck and the circuit encounters a fault condition and
starts malfunctioning. The FPGA has an advance feature getting reconfigured dynamically. This work
has exploited this advance feature to study certain parameters. The parameters are reconfiguration
time, response time to a fault condition and restoration time of the circuit to normalcy. A framework has
been constituted using a data converter and an FPGA boards. The FPGA board is designed to have a
static zone and a reconfigurable zone. A set of four digital filters are designed and the partial bit file for
117
biological samples. In this development the advantages of both self-inductance type and mutual
inductance type susceptometers have been amalgamated.
each of them is created. The size of the reconfiguration zone is made in such a way so that anyone of the
partial bit files can be accommodated in that. Two push buttons are used to generate the fault condition.
The framework takes the input pulse and digitises it. The digitised data are processed in a signal
processing block and converts to a processed analog signal. This signal can be viewed using an
oscilloscope. We have conducted an experiment to evaluate the parameters like reconfiguration time
and restoration time using this framework. This reconfiguration technique can be used effectively to
mitigate the upsets caused by the effect of radiation on an SRAM based configurable devices.
System Description
The system is a framework and it demonstrates the implementation of the work. The framework
contains two analog to digital converter namely ADC1 & ADC2 and two digital to analog converter
DAC1 & DAC2 and an FPGA board with Xilinx Virtex4 FPGA. The digital circuit implements ADC
controller, DAC controller, fault processing controller, ICAP (Internal Configuration Access Port) and
a BRAM (Block RAM) in a static area and a filter in a reconfigurable area as shown in Fig. 1.The board
has two dip switches to emulate the fault-condition which is expected from the harsh radiation
environment. Analog signals of 1.4Vpp with 40 ns rise time and 1.2 us fall time are sampled at 65 MHz
and fed to filter block and outputs are reconstructed using DAC.
Figure 1. System level block diagram
Figure 2. IIR CH (1) IN/ OUT CH (2) IN/ OUT
Signal Processing
The ADC samples the data and feeds data to filter block for signal processing. The block comprises of
st
one of two direct form-FIR and two 1 order IIR filters. This is a reconfigurable part of the circuit.
Depending upon the fault conditions, respective filters are configured dynamically without affecting
the other parts of the circuit.
DPR Architecture
Virtex4 and above family of FPGAs supports dynamic re-configurability fully or partially. DPR is the
ability to reconfigure the FPGA at run time without affecting the other logic. This sub-module consists
of a partial reconfiguration controller, ROM module that holds the partial bit files of the filters and an
ICAP primitive. The ICAP controller module manages the handshaking between the ROM memory
and the ICAP. Upon receipt of the fault signal, reconfiguration is initiated.
Results
The DAC output is tested applying 500 mV and 40 ns rise time pulse .The rise time of the pulse is
observed to be within 250 ns. The captured out at oscilloscope is shown in Fig.2. The partial bit file
size for each filter is 70.97 KB. The reconfiguration time is 182 us with respect to ICAP (En) signal as
118
shown in Figure 3. During the reconfiguration period, the filter output gets distorted. It reconfigures to
an IIR filter replacing the existing FIR filter dynamically as shown in Figure 4 and 5.
Figure 4. Reconfiguration initiated (zoom view)
Figure 5. Reconfiguration ended (zoom view)
Conclusion
To mitigate the effect of upsets in the firmware due to the simulated upset similar to the effect of
radiations, a run time reconfiguration technique called DPR have been successfully working in this
framework with the configuration latency of 410 ns / frame. The Virtex4 frame consists of 41x32=
1312 bits. A dedicated ICAP controller is designed to achieve one of the best performances.
References
[1] Madhusudan Dey, Abhishek Singh, Amitava Roy “SEU mitigation technique by Dynamic Reconfiguration method in
FPGA based DSP application”, DAE Symposium on Nuclear Physics, 57, 912-913 (2012).
[2] Yeong-Jae Oh, Hanho Lee, Chong-Ho Lee, Dynamic partial reconfigurable FIR filter design, School of Info. &
Comm Engg. Inha University, Incheon, Korea.
Design and development of a data converter board
(A part of a fault tolerant frame work)
Madhusudan Dey, Santu Ghosh and Amitava Roy
T
o implement the various methods of fault detection and correction in the nuclear pulse processing
system, two boards namely a data converter board and an FPGA board are essential. The FPGA
119
Figure 3. Reconfiguration time between cursors
boards are available in the
market and the selected
board is ML605. It is
difficult to get customised
data converter board for
nuclear pulse processing.
The objective is to design
and to develop the data
converter board [1]
according to our
requirement.
Circuit Schematic and
Layout
The data converter board
has 8-channel ADC for
digitizing the pulse and a
single channel DAC for
testing the proper
functioning of input in a
loop-back mode. The
schematic of the circuit is
shown in Fig.1. The PCB
layout has been completed
and a snap of layout is
shown in Fig.2. The quad
channel ADC has serial
differential output and the
sampling rate is 65 MSPS.
The most of the
components are SMD type
and their counts are 193.
Figure1. A part of circuit schematic
Board Description
The important input and
output signals, I/O
Figure 2. A PCB layout
Table.1 I/O MAP and Features
120
standard and connector type are shown in Table.1. The board is designed to take power either from
FPGA board or from external power source. The development of firmware to test the board is under
progress. The activities related to the fabrication of PCB, resourcing of components and assembly are
outsourced and are progressing.
Reference
[1] www.linear.com/docs/41403
Development & production of ROC SysCore Board V2.2
T
he FPGA based Readout Controller Board (ROC) is one of the important components in DAQ
chain of CBM experiments. The requirement of implementing more logic blocks demands
migration from ROC SysCore board V2 to higher versions.
Modification
Two ROC boards were fabricated and tested. It was working satisfactorily. But, they were used by
swapping two pair of data ports. It was modified so that a straight data cable can be used. A single ROC
board with XC4VFX60-10FFG672C was fabricated and it was observed that one of the clock-capable
LVDS pin from ROC to FEB was missing and working with only one data port of ROC.
Production Status
In this entire developmental process, three types of Virtex-4 with the same footprint were used. It
required two modifications in the layout designs.
Table.1
Device
SysCore Version
Quantity
XC4VFX20-10FFG672C
V2
02
XC4VFX60-10FFG672C
V2.1
01
XC4VFX40-10FFG672C
V2.2
24
Fabrication and Assembly
All the boards mentioned in Table
1 were fabricated, assembled and
tested in India. The modifications
of the layout design and test
routine were resourced from
CBM groups. The test setup as
shown in Fig.1 is used to carry out
the routine tests. The test
confirms the working of all ports
namely Ethernet and Optical
(SFP) ports.
Figure 1. A laboratory test setup.
121
Madhusudan Dey, Amitava Roy and Subhasish Chattopadhyay
The boards were subsequently distributed among different detector groups. These are being used
extensively in the CBM test runs.
References
[1] http://cbm-wiki.gsi.de
Software development activities for heterogeneous data
acquisition system
Partha Dhara, Pranab Singha Roy, Aruni Roy Chowdhury1 and Amitava Roy
1
Heritage Institute of Technology, WBUT, Kolkata
T
he modern nuclear physics experiments employ various types of detector systems in an
experiments. The response times for the detectors are not uniform. The events cannot be
synchronized with the common GATE signal. The events can be marked with high resolution
timestamps and the correlated events can be merged together using the timestamp.
Prototype hardware configuration using scalar modules
The proper timestamp hardware modules are in development stage. A prototype system has been setup
with the available pulsar and scalar modules for software development and testing. The VME scalar
are used in latched mode. The channel 0 is being used as 48bit scalar, that count a 5MHz TTL pulse
from the VME pulsar. The VME 3820 Scalar module and 3807 Pulsar module from M/s Struck are
being used. The CAMAC scalar unit is the CAEN C257N module, configured as 48bit counter.
The VME scalars are used in latched mode, with the GATE signal as the latch signal. The scalar value
is latched to a shadow register (48bits) on the leading edge of the latch signal. The reading logic works
in single event mode; on each accepted event a trigger is generated and the events are read from all the
modules in CBLT (Chained Block Transfer mode).
The software modification
The DAQ software has been updated with timestamp mode operation. The timestamp hardware access
class has been added. The event format has been changed to accommodate the 48 bit timestamp value
in the end-of-block marker. The CAMAC system assumes the first to read command in the CAMAC
NAF setup are for reading the timestamp hardware. So, the spectrum cannot be generated for the first
two channels as they are truncated away from each event as the timestamp value. The real ADC
channels starts from channel 2. The system directive in the configuration file defines all the parameters
associated with the timestaming mode.
The scalar and the pulsar are to be synchronized once on every power on, using a separate control
program. The DAQ software runs independently for each crate on different PCs. The timestamped data
is stored as list files. The list files are synchronized using one offline program.
The offline sorting
Global Event reconstruction using Functional programming methodology provides an elegant
solution to the problem when the file sizes exceed the capacity of main memory by the creation of lazy
122
Software based digital pulse processing system using
VME ADC
Payal Singhai, Soham Chatterjee1, Pranab Singha Roy, Partha Dhara and Amitava Roy
1
Heritage Institute of Technology, Kolkata
D
esign and implementation of
FPGA based digital pulse
processing has been reported in Progress
report 2011. Obtained FWHM of 7.7
KeV appears to be high due to amplitude
distortion of digitized input pulse
because of malfunctioning of 4th bit of
ADC (ADS5520). Hence we used
another 14 bit 100 MHz VME ADC
(V1724) available in lab and performed
the pulse processing at software level.
In this project implementation of digital
IIR filters for CR-RC and trapezoidal
shaping along with pole -zero
compensation was done using 'C'
programming language. The peak
detection of the filtered data was also
implemented using 'C'. The preamplifier
pulse was sampled with VME ADC
V1724, and the sampled data was stored
in its data buffer. Necessary programs to
handle this data i.e. transferring data to
PC via VME bus and removal of
fragmented data were also developed
using 'C'. The complete system was then
tested successfully using precision
pulsar, and HPGe series gamma ray
60
detector with Co source. The energy
resolution obtained from this system is
6.9KeV.
Figure 1. Block diagram of software based digital pulse processing
system
The VME ADC V1724 uses a block
transfer scheme. During the process of
acquiring data when buffer is full then
there is a lag in the system due to which
the next few samples are lost till the
buffer is free again and starts acquiring
data. This loss of data is a disadvantage
of this system. It appears that the fast Figure 2. Energy spectrum of Co60 obtained from software based system
124
amplifier, used to enhance preamplifier output, introduces additional noise to the system, which results
poor resolution. Further techniques are being studied to minimize the loss of data and to improve the
SNR for better resolution of system.
Reference
[1] P. Singhai, Amitava Roy, P. Dhara and S. Chatterjee, “Digital Pulse Processing Techniques for High Resolution
Amplitude Measurement of Radiation Detector”, 9th International Workshop on Personal Computers and Particle
Accelerator Controls, VECC, Oral presentation, 2012.
Job submission facility at GARUDA grid
G
ARUDA is India's first national grid computing initiative, bringing together academic, scientific
and research communities for developing their data and compute intensive application with
guaranteed quality-of-service. GARUDA grid is an aggregation of resources comprising of
computational nodes, mass storage and scientific instruments and hosts scientific application through
the National Knowledge Network (NKN).The NKN is a state-of-the-art multi-gigabit pan-India
network for providing a unified high-speed network backbone for all knowledge related institutions in
the country. VECC is one of the partner institutions of the GARUDA grid which facilitates the
students/researchers at VECC to utilize the enormous computing and storage facility of GARUDA to
run their compute-intensive and data-intensive applications. Moreover, the users can store the data
generated by their applications in a secure and reliable environment and access it as and when required.
All the users of VECCC connected to the campus LAN have access to the GARUDA grid through the
NKN router installed at VECC. The facilities offered by GARUDA grid have been explored to assist
the users in carrying out their activities. A demonstration was arranged to acquaint the users with the
pre-requisites for accessing GARUDA resources (such as getting a digital user certificate from IGCA)
along with the mechanisms for submitting jobs, storing data, retrieving data and other relevant tasks.
The users were assisted whenever required, to submit their compute and data intensive jobs on
GARUDA grid. The users have been made aware of the flexibility of selecting a cluster in GARUDA
grid to run their jobs, based on the past performance of the cluster. The NKN bandwidth used to access
the distributed GARUDA resources from VECC was also tested and found to satisfactory.
Implementation of version control system
Surojit Saha
V
ersion control system is a software, that helps the users to better manage their files and directories.
More importantly, the users can track the changes made to the files and the directories, over time.
125
Surojit Saha, Biswajit Sarkar and Debranjan Sarkar
At VECC, a centralised version control system based on Subversion has been implemented to facilitate
the users with the above features. Subversion has been configured in a centralised system accessible to
all the users connected to the local area network (LAN) of VECC. The centralised repository used for
storing users' data is maintained on a storage system configured with RAID (level 5), so as to ensure the
reliability and availability of the data. The server running Subversion and the storage system is
interconnected following Storage Area Network (SAN) architecture. An authentication mechanism
has been implemented to restrict the access to the central repository. The authentication mechanism is
implemented using the data stored in a centralised Light-weight Directory Access Protocol (LDAP)
server. The users are also provided with the flexibility of authorizing others to access or modify their
data. Presently, the users can communicate with the central repository over network through hyper-text
transfer protocol (HTTP) to access or update their data. It is being planned to use a secured access
protocol i.e., HTTPs by installing a valid host certificate in the server running Subversion to encrypt the
data communication.
Developments on educational software for the
hearing-impaired
Kaushik Datta, Biswajit Sarkar, C. D. Dutta and Debranjan Sarkar
C
omputer & Informatics Group of VECC, in collaboration with WebelMediatronics Limited,
Kolkata, continued the development of software for the hearing-impaired persons that was
initiated under the XI plan. Initial developmentsunder this project were reported in the 2008 and 2009
issues of VECC Progress Report. The release of the first version of the software – “Mounisara 1.0”
–thattranslatesinput Bangla text to sign languagewas reported therein. After its release, this software
was distributedfree-of-cost among several deaf schools within the state of West Bengal. This software
is in use in 45 special schools in
West Bengal. Based on the
feedback received from the
users, the scope of the software
has been enhanced. The latest
version of this software,
released in March, 2012, is
“Mounisara 2.1”.Encouraged
by the appreciation received on
the usefulness ofMounisara
1 . 0 f o r
d e a f
children,similartranslator
software with the input text in
Hindi (see Figure. 1) has also
been developed.
Figure 1. Graphical user interface of the Hindi version of Mounisara 1.0.
126
In addition, e-books for the
primary school children based
on sign language have also been
developed. These e-books
embody the contents of standard
text books of primary school
children in sign language, with
textual subtitle. So far, e-books
for the Bangla text books
Barnaparichay(Part I and Part
II)(see Figure. 2), Kishalaya (for
class I) and SahajPatha(for class
I) have been developed.A lesson
on conversation in sign language
has also been developed.These
softwares are freely available on
DVDs to all institutes and
organizations associated with
hearing-impaired persons. For a
c o p y, p l e a s e w r i t e t o :
cig.office@vecc.gov.in.
Figure 2. Graphical user interface of e-book (Text Book: Barnaparichay – II).
Development of computer interface software for pulse Link
extended range neutron area monitor
Rakesh Kumar Keshri, Kaushik Datta, Sujoy Chatterjee# and Debranjan Sarkar
#
Radiological Physics & Advisory Division, BARC
C
omputer Division, VECC has developed computer
interface software for a Pulse Link Extended
Range Neutron Area Monitor (Make: Health Physics
Instruments, Model: 6060) which can measure neutrons
of energy from thermal to 1 GeV. This software,
developed using Visual Basic 6.0, provides a suitable
user interface to set/adjust various system parameters of
the instrument like high voltage, discriminator level,
gain etc. and continuously read the neutron count from
the instrument for a specified time interval as set by the
user. The neutron counts as soon as obtained from the
counter are displayed with time stamping and saved in
the hard disk instantly. This feature helps users not to
lose any data received till any accidental failure of
computer or the instrument happens due to power loss
etc. during a session of counting. The saved data can be
127
Figure 1. Pulse Link Extended Range Neutron Area
Monitor with Moderator.
retrieved directly in Excel file for future analysis. The time stamp and the ability of thissoftware to put
different time scale of measurement helps the users to easily arrive at the variation of the neutron dose
rate due to different sources of neutrons at different times during several hours of its run. As the
instrument provides a RS232 interface, a RS232-to-USB converter is to be used to physically connect
the instrument to the USB port (which is normally available nowadays) of Laptop/PC. This
developmental work has been carried out for Radiological Physics & Advisory Division, BARC who
will use this instrument to measure various neutron dose rates in and around nuclear reactors, particle
accelerators and also to measure the cosmic ray neutrons.
Figure 2. User Interface for Reading Neutron Count.
Figure 3. User Interface for Setting Instrument Parameters.
128
Ongoing Projects
4.1
SUPERCONDUCTING CYCLOTRON
Modified phase control loop for the three-phase RF system of
K500 superconducting cyclotron
RF Division, ATG, VECC
I
n our K500 Superconducting Cyclotron, the phase stability of between the dees was not good with
the phase control loop adopting I/Q (In-phase/Quadrature) modulation technique only, which was
analog in nature. There were some problem of sudden deterioration in phase stability during operation.
ONGOING PROJECTS
Recently, we have modified the existing phase control loop and made the new one based on Direct
Digital Synthesis (DDS) technique in combination with the I/Q modulation technique. Direct Digital
Synthesizer (DDS) is a type of frequency synthesizer used for creating arbitrary waveforms from a
single, fixed-frequency reference clock. It allows user to change the frequency, amplitude and phase of
Figure 1. Phase deviation (middle plot) between the cavities with time for old phase loop (analog)
130
ONGOING PROJECTS
the RF signals through digital ports without any interruption to the latter. An automatic phase
correction system has been designed, developed and installed using this DDS module (AD9959) and a
programmable digital controller. There are significant advantages like 360o phase rotation, constant
amplitude irrespective of phase variation, linearity etc. of new control system. In fact, at the start up,
when the dee voltage is being increased, the analog phase regulation loop (with I/Q modulation) is kept
off and only the digital phase loop having very high dynamic range is in operation. During this period,
as a very high value of phase correction may be required before thermal stabilization of the cavity, the
digital phase loop is in operation. As soon as the required dee voltage is reached and the phase error
reaches around ±20, the digital phase loop is kept out of the loop and the much faster analog loop is
brought into operation, thus achieving the necessary phase stability between any two channels of the
three dee RF system. The performance of this new phase regulator has been remarkably enhanced
0
achieving the residual phase modulation generated by cavity resonator within the stability of ±0.1 (as
shown in Fig.1) for the radiofrequency system of K500 Superconducting cyclotron. A graphical user
interface (GUI) has been developed to monitor and change the phase of the resonator cavities, being
operated round-the-clock, from any PC working under SCCLAN through ethernet.
Figure 2. Phase deviation (middle plot) between the cavities with time for new modified phase loop (in combination of digital
and analog)
131
Development and commissioning of ion beam buncher for K-500
superconducting cyclotron
Anuraag Misra, P.Y.Nabhiraj, Gautam Pal and Alok Chakrabarti
A
common method to increase the efficiency of a particle accelerator with an external ion injection
system is to use beam bunching. A buncher installed into a beamline just before the accelerator
generates a pulsed beam from the continuous dc beam. Bunching takes place, when charged particles
are accelerated and decelerated periodically with an external electric field.
Buncher Electrode design
ONGOING PROJECTS
A double gap single harmonic gridded buncher is designed for K-500 superconducting cyclotron as
shown in figure 1.The electromagnetic design of grids was done in Poisson code considering the
buncher electrode as a lumped capacitor. The grids are made of 40 micron tungsten wire placed at 5mm
distance as shown in figure 1.The gap between the electrodes is fixed to be 13 mm optimized for 14
MHz operation of the cyclotron. The buncher is located 2 meter above the median plane between the
last two solenoids in the vertical injection line.
Figure 1. Gridded buncher for K-500 superconducting cyclotron
Buncher Electronics
The buncher electronics consists of automatic
level controller, phase modulator, variable gain
amplifier, VSWR interlock, 50-450 Ω broadband
matching transformer as shown in figure 2. The
RF reference is taken from cavity B pick up
signal, which drives the automatic level
controller and it outputs a 0dBm signal to the four
quadrant broadband phase modulator card whose
phase is modulated by a dc control voltage from
the field point modules. The low level phase
shifted signal is amplified by a 500W solid state
Figure 2. Block diagram of buncher electronics
132
amplifier. The amplified signal passes
through a coaxial line directional coupler
for monitoring of forward and reflected
powers. The broadband transformer boosts
the voltage across the grids by ~3 times due
to 1:9 transformation ratios. The initial
operation of the buncher electronics
resulted in some noise coupling to the phase
modulator card, so we have to introduce
some ground plane isolation provided by
the V/F and F/V cards developed using
AD650. The phase modulator linearity with
the dc control voltage is shown in figure 3.
Figure 3. Phase modulator linearity with control voltage
Buncher Commisioning Results
ONGOING PROJECTS
The buncher was tested with Ne3+ beam at
injection energy of 4.5 KeV with a
buncher voltage of 100 Vp-p and rf
frequency of 14 MHz. The current gain
due to buncher modulation was found to
be 1.5 times compared to un-bunched
case at 500mm inside the cyclotron as
shown in figure 4.
Conclusion
The beam buncher of K-500 cyclotron is
developed and commissioned with
bunching of Ne3+ beam at different radii in
the cyclotron. The increase in bunching
efficiency can be improved by
repositioning the buncher closer to the
median plane to minimize ion source
energy spread and axial hole debunching
effects.
Figure 4. Beam on main probe with buncher off (left), and beam
with buncher on (right)
133
Development of mechanism for online vertical movement and
rotation of inflector of SCC
S. Roy, C. Nandi, G. Pal, N. Chaddah, R. Bhole and S. Pal
S
ONGOING PROJECTS
piral inflector for superconducting cyclotron consists of two electrodes, RF Shield and electrode
holders. The charged particle beam is injected vertically at the center of the cyclotron and exits at
the median plane of the cyclotron horizontally by applying an electrostatic field across the inflector
electrodes. The inflector assembly is inserted at the compact central region of the Superconducting
cyclotron through the central plug hole at the bottom of the main magnet. The distance between the
central region connectors at rf potential and the inflector shield are very important for tuning the initial
beam trajectory. The vertical offset between magnetic median plane and the exit plane of inflector
causes vertical oscillation and loss of beam intensity during acceleration. In order to maximize the
beam current after the central region, the entire inflector assembly was required to rotate and move
vertically during the beam tuning. The bottom of the inflector shaft is therefore added with a bellow
sealed manual drive mechanism. The assembly consists of one geared drive with gearing ration of 1:5
for rotation and a ball screw mechanism for vertical movement. Two high torque stepper motors were
Figure 1. Drive system for online vertical motion and rotation of inflector
134
used for driving the mechanisms independently and rotary encoders were used to obtain the position
feedback. The carriage for the vertical drive slides on two guide shafts connecting the end plates. All
components of the rotary drive were mounted on the carriage plate whereas the components for vertical
drive were mounted on bottom end plate. The drive system has to be installed at the bottom of the
magnet through the restricted aperture between the hexagonal RF panels. The compact drive system
was designed to conform the space constraint. The entire assembly (Fig. 1) was covered with a hollow
cylindrical shell of mild steel to shield the effect of magnetic field at the vicinity of magnet. The system
was calibrated with the actual position of Inflector exit inside the cyclotron and limit switches were set
at terminal points. The inflector drive subassembly was fabricated and installed to provide additional
O
degrees of freedom for vertical motion of + 6mm and rotation of + 20 .
S. Roy, C. Nandi, M. K Dey and G. Pal
S
piral inflector for superconducting cyclotron consists of two electrodes, RF Shield and electrode
holders (Fig. 1). The surfaces of electrodes facing each other form a spiral helix. The gap between
the electrode surfaces is 4mm and the electrodes are placed inside a contoured profile shield made of
copper kept at ground potential.
Electrodes were made of aluminum and
connected to the power cable through two
feed-throughs mounted within insulator
base. The complex parts like electrode
and shield of the initial version of inflector
were fabricated at C D M, BARC due to
inadequate in house manufacturing
facility. The integrated stem of the
electrodes was not feasible for
manufacturing at C D M, BARC and a
joint was introduced between electrode
and stem. In order to accommodate the
joint the projected part at the back side of
the RF shield was increased substantially
in width.
Various modifications were implemented
in the new design of the inflector to
resolve the limitations of the initial
version.
a. The limited width of the electrode
surface was increased from 6mm to
Figure 1. RF shield, electrodes & insulator base of the inflector
135
ONGOING PROJECTS
Spiral inflector for high current ion source
development of spiral inflector for SCC at VECC
maximum available width. The effect of fringe field is expected to be less causing the enhanced
transmission ratio.
b. The cylindrical joints between each electrode and stem were eliminated after the successful
fabrication of integrated stem electrode. The width of the projected part of the RF shield at the
back side was reduced and the gap with the central region Dee connectors was increased.
c. The elimination of the multiple joints enables to assemble the electrodes with out special jigs
which were essential to ensure the orientation and position of the electrodes in previous design.
The down time for maintenance of the inflector electrodes would be reduced.
d. The Base of the stems is converted to a broader D shaped geometry to make the assembly more
stable and reliable against unforeseen vibrations during the insertion of the assembly inside the
cyclotron chamber.
ONGOING PROJECTS
e. The insulator is also separated into two segments which reduces the maintenance down time.
The top segment of the insulator is used for mounting the RF shield and electrodes and the
vacuum seals and electrical feed through are mounted on the bottom segment. The subassembly
comprising the top segment of insulator, Electrodes and RF shield is mounted on the bottom
insulator using a pair of precise push-fit connectors. It is possible to remove the subassembly
from top for cleaning the
contaminations or minor
modifications without dismantling the
entire inflector shaft.
Fabrication of the integrated stem electrodes
from single stock of Aluminium 2024 was the
most complicated part for the entire
development. It was not possible to access the
entire functional surface with cutter using a
single set up. The proper machining
strategies were planned and simulation were
carried out in PowerMILL software. The
machining was carried out in a 4axis CNC
milling machine having provision to impart
synchronized rotation on the job and generate
the electrode surface seamlessly with good
surface finish and accuracy.
Several
combinations of cutting parameters and
machining strategies were tried to reduce the
distortion and chattering during machining of
the slender (5.4x2mm cross section and
57.5mm long) stem (Fig. 2) in same set up.
The electrodes were and other components
were fabricated very precisely and it was
possible to achieve the electrode gap within
60micron
accuracy in final assembly.
Figure 2. Integrated stem electrodes assembly with spiral-helical
aperture
136
Development of modified extraction drive control system
T. K. Bhattacharyya, T. Das, R. Rakshit and G. Pal
he superconducting cyclotron extraction element drive assembly and its control system are
fabricated in-house. The complete control system with associated hardware and software is
successfully commissioned in October, 2009 and since then is in continuous operation. At present, this
combined instrumentation and control system is running smoothly up to our satisfaction. The drive
system takes care of precise movement of all the magnetic channels, two deflectors and M9 slit at the
extraction port of the superconducting cyclotron. Four deflector drives, ten magnetic channel drives,
one compensating bar drive are driven by synchronous motors and respective position feedback is
received from rotary encoders. M9 slit is driven by pneumatic cylinders based control mechanism and
the position feedback is obtained from linear potentiometers. Modifications of the hardware are felt
essential in order to have distributed modules for each individual type of drive elements in order to
facilitate better troubleshooting and minimum down-time in case one-to-one replacement is essential.
Standard 19-inch rack mounted modules have been designed and developed. Component lay-out and
power requirements have been optimized and the Advantech make ADAM 5000 distributed DAQ
modules have been added to cater to the requirements. In-house developed GUI (Figure 1) has been
upgraded in accordance with the feedback received from different operators.
Figure 1. Modified hardware and software for SCC extraction drive system.
Design and fabrication of vacuum chamber for switching magnet
Sumantra Bhattacharya, Chinmoy Nandi, Subhasis Gayen, Suvadeep Roy,
Santosh Kumar Mishra, Sanjay Ramrao Bajirao and Gautam Pal
V
EC K500 superconducting cyclotron will be used to accelerate heavy ion beams for basic science
research. The accelerated beam will be transported to different beam halls by using two large
137
ONGOING PROJECTS
T
switching magnets. Switching magnet1 will bend the beam by an angle of about 42 degree to transport
the beam in channel II. Switching magnet 2 can bend the beam in both directions by an angle of about
0
+/-32 . The magnets have been fabricated by a vendor. Design and fabrication for the vacuum
chambers of these magnets have been taken up. Fig.1 and Fig. 2 shows the vacuum chambers for these
magnets. Magnets have pole gap of 90 mm. The vacuum chambers are more than 1000 mm long. It has
a height of 85 mm and width varying from 100 mm to 360 mm. The material for the chamber has been
chosen as SS304. Preliminary Design of the vessel was done as per ASME Boiler and Pressure Vessel
Code, Section VIII, Division 1. A uniform cross section equal to the largest cross section was
considered for the design and the rules of Appendix 13 were applied. Design was optimized using stress
analysis software ANSYS.
ONGOING PROJECTS
Figure 1. Chamber for 42 deg magnet
The fabrication of the chambers was very critical as flatness of the top and bottom plates have to be
maintained within 2.5 mm with continuous welding at four sides of the chambers. All the welding
needed to be full-penetration to get desired strength under vacuum. A detailed technical specification
has been prepared and a strict quality control has been followed to fabricate these large vacuum
chambers. Proper fixtures have
been designed and fabricated to
achieve minimum welding
distortion and to get proper
curvature as per drawing.
Welding sequence has been
carefully devised to maintain the
required flatness of the plates.
During and after fabrication a
series of tests have been carried
out to assure the product quality.
MSLD test (local and global) with
helium under vacuum have been
carried out for both the chambers
at factory and at site to ensure
helium leak integrity of the
chamber under high vacuum.
Figure 2. Chamber for +/-32 deg magnet
138
4.2
RADIOACTIVE ION BEAM
Design of 4K-2K cryoinsert test setup for validating the
cryogenic circuitries to produce and deliver 2K liquid
He for superconducting e-linac
M. Ahammed, S. Ghosh, S. Saha, S. Singh, B. Hembram, S. Biswas, N. Mandal,
S. Sur, A. Dutta Gupta, M. Mondal, T.K. Bhattacharya, S. Pal, A. Mukherjee,
R. C. Yadav, R. E. Laxdal1, N. Mayer1, A. Kovesnikov1, V. Naik,
A. Bandopadhyay, G. Pal and A. Chakraborty
TRIUMF, Vancouver, BC, V6T2A3, Canada
D
esign of a 4K-2K test setup for validating cryogenic circuitries to produce and deliver 2K liquid
helium to injector cryomodule of superconducting electron linac is almost complete and
subsequently fabrication has also been initiated at VECC workshop. The test set up will be used for
evaluating the effectiveness of the conversion of the 4K liquid helium (LHe) to 2K superfluid helium,
the overall performance of the cryogenic layout and thermosyphon circuits, designed for ICM. Test-set
up consists of LHe reservoirs, cryostat chamber, heat exchanger, Joule Thomson(JT) Valve and
thermosyphon circuit etc. Design of all the components for the 4K-2K test set up including design of
Figure 1. 3D model of the test set up.
Figure 2. Schematic flow diagram of the 4K-2K cryoinsert test set up.
139
ONGOING PROJECTS
1
heat exchanger, selection of pump and JT valve have also been carried out. Figure 1 shows the 3D
model of the test set up and figure 2 shows the schematic of the test set up and process flow.
Pump Selection
The effective helium suction speed of the pump required for handling 2g/s helium flow rate is 1470
3
m /h at 31 mbar pressure. It is planned to use two mechanical roots pumps connected in series and
backed by a suitable dry pump in a close loop with the He plant. Maintaining purity of the helium is
paramount as the upstream flow of He from pumping module will enter into the compressor of the
helium plant in the actual system. Roots pump rotational speed will be controlled by a Variable
Frequency Drive(VFD) system to maintain 2K helium chamber pressure within ±2.5 mbar. Valve
before the pump is to be interlocked with the pump inlet temperature and the valve will be shut off if the
pump inlet temperature goes below 0oC.
A surge tank is used just before the backing pump so that speed variation of roots does not hamper the
smooth running of the backing pump.
Design of Heat Exchanger
ONGOING PROJECTS
A shell and tube type cross flow heat exchanger has been designed for gas helium flow of 2g/s which
is possible to occur in the event of cavity, operating as a electron recovery linac (ERL) in CW mode at
10mA current and 15MV/m field gradient with a consideration of 88% liquefaction at the end of the JT
valve provided the 3K temperature at the outlet of the heat exchanger is achieved. ID and length of the
shell side is restricted to 140mm and 150mm respectively from the availability of space. Number of
tubes was optimized to 140 with 5mm OD and 0.3mm thick tube. Graph 1 shows the dependence of the
effectiveness with the number of tubes (in primary axis) and outer diameter of the tubes(in secondary
axis).
Design of thermosyphon circuit
As the beam pipe, coupler port and tuner connections directly access 2K helium reservoir from room
temperature, therefore a thermosyphon circuit of liquid helium has been designed for the heat intercept
that is to be placed in between room temperature support and 2K helium reservoir. Graph 2 shows the
variation of mass flow rate with the heat loading at the intercepts taking diameter of the tube as
parameter.
Graph-1
Graph-2
140
Safety analysis and relief design
Mainly two modes of eventualities have been considered to evaluate the sudden rate of heat input to the
2K helium vessel - loss of isolation vacuum of ICM and cavity vacuum. Out of these two loss, latter one
comes out to be the critical one. Total heat load injected on the cavity surface for a duration of only 5.5s
is 2554 J. Analysis has been carried out to estimate the maximum possible pressure to be borne by the
chamber and it comes out as 3.5 bar-abs. Accordingly all the components were designed for 4 bar-abs
pressure.
First production and acceleration of Radioactive Ion Beams at
VECC RIB facility
R
14
42
43
41
adioactive ion beams (RIB) of O (71 sec), K (12.4 hrs), K (22.2 hrs) and Ar (1.8 hrs) have
been successfully produced at VECC, using a novel gas-jet recoil transport coupled Electron
14
Cyclotron Resonance (ECR) ion-source technique [1]. The RIB of O has been further accelerated
through the Radio Frequency Quadrupole (RFQ) accelerator to an energy of 1.4 MeV. Radioactive ion
14
41
42
beam of O was produced in one neutron evaporation reaction of proton on nitrogen whereas Ar, K
43
and K were produced from alpha particle reactions on argon gas target. Primary beam (proton &
alpha-particle) intensity was around one micro-ampere on target. The target chamber was placed inside
the cyclotron vault as shown in figure-1 for these experiments. Radioactive atoms produced in the
Figure 1. Floor diagram of the VECC K130 cyclotron and the RIB beam-line. The labeled items are: D1 - D4: HPGe
detectors; ECR: Electron Cyclotron Resonance ion-source ; FC1 - FC3: Faraday cups; RFQ: Radio Frequency Quadrupole
linac; QQ: Quadrupole doublet; L1 - L3: heavy-ion Linac modules; RB: Re-buncher; Sol: solenoid magnet.
141
ONGOING PROJECTS
Alok Chakrabarti
target were transported 15m away to the RIB project site through a 1.4 mm inner diameter tygon
capillary and injected online into the ECR ion-source for ionization. The low energy RIB was selected
in an isotope separator downstream of the ECR ion-source and further accelerated through the RFQ
linac to 100 keV/u. At the separator focal plane the measured intensity for 42K and 43K was 2.7x103
3
41
3
particles per second (pps) and 1.2x10 pps respectively whereas the same for Ar was 1.3x10 pps. The
14 2+
RIB energy was typically 10 keV. The measured intensity for O beam before and after the RFQ was
3
3
respectively 4.4x10 and 3x10 pps. Typical measured γ
-ray spectra are shown in Figure 2.
ONGOING PROJECTS
Figure 2. (a) Typical measured γ
-ray spectrum after ECR ion-source indicating extraction of radioactive ions of potassium
and argon, and (b) gamma-ray spectrum after the separator for 14O.
14
Study of super-allowed beta decay of nuclei such as O along with other experiments provides a test of
the unitarity of the CKM matrix which gives an important laboratory test for the Standard Model. The
14
RIB of O is also important for study of astrophysical reactions crucial in understanding the nucleosynthesis path from hot CNO cycle to rp-process. Radioactive potassium isotopes 42K and 43K have
41
several bio-medical applications whereas Ar is an industrial tracer also used in engineering and
environmental science studies. Table.1 gives a list of RIBs developed and their intensity.
Table 1. List of radioactive ion beams produced at VECC and their intensity measured at various stages
RIB
Prodn. route
T1/2
pps @ ECR exit
pps @ before RFQ
pps @ after RFQ
14
O
14
N(p, n)
71 s
6.7 x 104
5.0 x 103
3.2 x 103
42
K
40
Ar(α
,pn)
12.36 hr
3.1 x 104
2.7 x 103
–
43
K
40
4
3
–
41
Ar
40
3
–
Ar(α
,p)
Ar(α
,2pn)
22.3 hr
109 min
2.0 x 10
4.6 x 10
3
1.2 x 10
1.3 x 10
Reference
[1] V. Naik, A. Chakrabarti, M. Bhattacharjee, P. Karmakar, A. Bandyopadhyay, S. Bhattacharjee, S. Dechoudhury, M.
Mondal, H.K. Pandey, D. Lavanyakumar, T.K. Mandi, D.P. Dutta, T. Kundu Roy, D. Bhowmick, D. Sanyal, S.C.L.
Srivastava, A. Ray and Md. S. Ali; Rev. Sci. Instrum. Vol.84, (033301) 2013
142
Establishing a novel technique for acceleration of
Radioactive Ion Beams (RIB)
Vaishali Naik
on behalf of RIB team
T
The aerosols carrying radioactive atoms move with sonic velocities as the jet-emerges at the collection
end and need to be effectively stopped in the plasma. Previous studies at Grenoble [2] and Heidelberg
[3] indicate that this may be non-trivial and due to the high velocity of the jet even after the skimmer, the
aerosols may just pass through without getting stopped in the plasma. It may therefore be essential to
stop the aerosols on a catcher for on-line production of RIB. The catcher should be a high temperature
material that will withstand the plasma environment and should be porous so that reaction products
easily and quickly evaporate from the catcher surface.
Keeping these requirements in mind we devised a novel technique to stop the reaction products on a
porous catcher place inside the ECR plasma chamber. In addition to stopping the reaction products
carried in the gas-jet, the catcher was used as a second skimmer to obtain better vacuum inside the
plasma chamber. The technique was successfully tested at the 6.4 GHz ECR ion-source of the RIB
facility leading to the first ever on-line production of RIB using the GJRT coupled ECR ion-source.
The catcher is made from reticulated vitreous carbon fiber (RVCF) and has been positioned inside the
ECR plasma chamber so that the
reaction products are released close
to the main plasma zone. The
schematic layout of the gas-jet
coupled ECR ion-source with
internal catcher is shown in Figure 1.
Prior to the on-line experiments, offline tests have been conducted to (a)
choose optimum position of the
catcher (b) test the diffusion of
elements through the catcher (this
was tested successfully for
potassium), and (c) to check if the
surface of the catcher deteriorates
due
to plasma interaction.
Figure 1. Schematic layout of gas-jet coupled ECR with internal catcher.
The labelled components are – (1) capillary (2) gas-jet (3) skimmer chamber
(4) injection box (5) aerosols (6) catcher (7) roots pump (8) skimmer (9)
Turbo Molecular Pump (TMP) (10) plasma chamber (11) plasma zone (12)
plasma electrode (13) puller electrode. Inset shows the details of the catcher
used in the off-line and on-line studies.
143
After the off-line tests for stable
isotopes on-line measurements have
been done for fusion reaction recoils
and fission products from light-ion
ONGOING PROJECTS
he Gas-jet Recoil Transport (GJRT) method is a well established technique for carrying nuclear
reaction products away from the target to a remote measurement station and has been extensively
used by our group for nuclear spectroscopy studies [1]. In the GJRT technique nuclear reaction
products recoiling out of the target are thermalized in a gas and are transported in the form of aerosols to
a collection station via a thin capillary tube. This study was aimed at using the GJRT method to
transport radioactive atoms from the production target to the ion-source and to attempt first on-line
production of radioactive ion beams in the VECC Radioactive Ion Beam (RIB) facility.
induced reactions using the K130 cyclotron beams. Radioactive ion beams of gaseous and alkali metals
such as 14O (t1/2=71 sec), 42K (12.4 hrs), 43K (22.2 hrs) and 41Ar (1.8 hrs) have been produced as mentioned
in previous report. A combined efficiency ranging from 15±5 to 21±8% has been measured for
diffusion through the catcher, ionization and extraction of RIB through the ECR ion-source.
To test the efficacy of the catcher technique for non-volatile elements we transported fission fragments,
produced by bombarding 16 µm thick 232Th target with 50 MeV α
-particle beam, to the ECR ion-source
2
by the GJRT method. The target chamber was pressurized with 1 kg/cm helium and fission fragments
were stopped on the catcher as in the previous experiments. Preliminary data indicates the possibility of
many fission products diffusing through the catcher and getting ionized in the ECR plasma. This is
evident from the gamma-ray spectra measured before and after the ECR ion-source (Figure 2) - a large
fraction of gamma-rays seen before the ECR were detected in the detector placed after the ECR the ionsource. More studies are planned for detailed investigation of on-line ionization of fission products by
this method.
ONGOING PROJECTS
Figure 2. A portion of γ
-ray spectrum from α
-particle induced fission of 232Th measured in HPGe detector placed (a) before
and (b) after the ECR ion-source.
References
[1] A. Chakrabarti, D.P. Chowdhury, S. Gangadharan, J. Arunachalam and R.M. Iyer, Nucl. Instrum. & Meth. A263, 421
(1988).
[2] G. Gimond, A. Gizon, D. Barnéoud, J. Blachot, J. Genevey, R. Guglielmini, J. Inchaouh, G. Margotton and J.L . Vieux
Rochaz, Nucl. Instrum. & Meth. B70 (1992) 118.
[3] Christian Smorra, Thesis, page 111, 2012, http://archiv.ub.uni-heidelberg.de/volltextserver/volltexte/2012/
13604/pdf/thesis_V1_final_print.pdf
144
Heavy-ion linac development for the RIB facility
Arup Bandyopadhyay
on behalf of RIB team
S
ONGOING PROJECTS
o far ion beams such as 16O and 14N have been accelerated to an energy of around 414 keV/u in the
RIB facility using a Radio Frequency Quadrupole (RFQ) linac [1] and three Linear accelerator
cavities [2]. The fourth linac cavity (LINAC-4) will be used for accelerating ion-beams from 414 to
717.8 keV/u. LINAC-4 has been developed for operating frequency of 75.6 MHz and q/A (charge to
mass ratio) ≥
1/7. The LINAC-4 module has been installed and low power RF measurements have been
completed successfully. A photograph of LINAC-4 taken during installation in the test area is shown in
Figure 1. The measured frequency and Q-value match closely with the simulated values. Preparations
have been completed for high power tests of the module using a one kW solid state amplifier and these
will be conducted soon.
Figure 1. LINAC-4 during installation at VECC
The next linac cavity LINAC-5 has also been designed and ordered for fabrication. The output energy
of LINAC-5 is 1.04 MeV/u. Beyond this energy the beams will be accelerated in superconducting
quarter wave resonator (QWR) cavities. The super-conducting heavy ion linac (SC-LINAC) will
accelerate heavy-ion beams to an energy of around 2 MeV/u. Two heavy-ion cryomodules will be built,
each containing four QWR cavities with high acceleration gradients ( ~ 6 MV/m) and a
superconducting solenoid. These QWRs will be operated at a resonant frequency of 113.4 MHz and
have been designed for a beta value of 5.3%.
References
[1] S. Dechoudhury, V. Naik , M. Mondal, Avik Chatterjee, H. K.Pandey, T. K. Mandi, A. Bandyopadhyay, P. Karmakar,
S. Bhattacharjee, P. S. Chouhan, S. Ali, S. C. L. Srivastava and A. Chakrabarti; Rev. Sci. Instrum. 81, (2010)
023301.
[2] A. Bandyopadhyay, O. Kamigaito, S.K. Nayak, H.K. Pandey, M. Mondal and Alok Chakrabarti; Nucl. Instrum. &
Method A560 (2006) 182.
145
Alternate phase focusing in sequence of independent phased
resonators as superconducting linac boosters for the
ANURIB project
Siddhartha Dechoudhury and Alok Chakrabarti
D
esign of a long superconducting linac booster aimed at the upcoming ANURIB (Advance
National facility for Unstable and Rare Isotope Beams) facility has been done. The configuration
is capable of accelerating heavy-ions of A/q=8 from an energy of 1.3 MeV/u to 7 MeV/u. In the
ANURIB facility the RIB of interest will be selected in isotope separator and accelerated in a Radio
Frequency Quadrupole (RFQ) linac plus Interdigital – H (IH-Linac) to around 1.3 MeV/u. This energy
will be further enhanced to ~ 7 MeV/u in Superconducting Quarter Wave Resonator (QWR) Linac
boosters.
ONGOING PROJECTS
The present study was aimed at the design of heavy-ion Linac Boosters in A-APF (asymmetric alternate
phase focusing) configurations using double gap QWR's as independent resonators. The input and the
output energy for this design have been chosen to be 1.3 MeV/u and 7 MeV/u respectively for a
minimum q/A of 1/8. Stability analysis has been carried out to evaluate the parameters of the focusing
periods. Selection of number of gaps in each QWR and designed beta has been dictated by the need of
having appreciable transit time factor (TTF) over the mentioned energy range. Smooth approximation
taking into account the acceleration in SC Linacs has been used to calculate the RF bucket parameters.
The 3D fields of QWR have been simulated using CST Microwave studio. The resonant frequency for
all the resonators, the drift tube diameter and the gap to βd ratio for all the cavities are taken to be 100
MHz, 20 mm, and 0.2 respectively. In case of superconducting cavities, the resonant structure needs to
be optimized so as to minimize the peak magnetic and electric fields at the required acceleration
gradients (not exceeding 6.5 MV/m). The resonators are cylindrical at the bottom and conical at the top.
Different geometrical parameters and their dependence on peak electric and magnetic field formed the
basis of our structure optimization. The structures for designed beta of 0.06, 0.1 and 0.15 have been
shown in Figure 1. Longitudinal electric field along the axis has also been plotted in Figure 1.
Particle tracking has been done using the code GPT with the 3D fields for the entire energy range from
1.3 MeV/u to ~ 7 MeV/u. Steering effects have also been calculated for the chosen A-APF
Figure 1. (top) Schematic layout of QWR cavities with βd 0.06, 0.1 and 0.15 (right) CST simulated on-axis electric field for
the three resonators
146
configuration. In one APF period the individual phase of resonators changes sign resulting in lesser
vertical steering kick (being phase dependent) in a particular direction over the period, as compared to
individual resonators operating in same phase. To correct the steering, two remedies are possible – one
is off-axis injection of beam or alternately tilting the beam port.
Using CST simulated field profiles, the vertical kick have been calculated and compared with particle
tracking code GPT. For designed beta 0.15 QWR, the 9 degree tilt angle would provide an additional
Ey field which acts in opposite with magnetic field steering thus reducing the net steering effect. The
Ey field profile of βd = 0.15 QWR and the calculated steering kick for the fifth focusing periods are
shown in Figure 2. The steering for the first focusing period is also shown in Figure 2 for quantitative
comparison. It can be seen that the introduction of the tilt angle helps in reducing the net kick to a value
less than 0.2 mrad. The steering calculated using these analytical expressions is found to be in good
agreement with particle tracking results.
Figure 2. (left) Steering kick calculated using analytical expression (dots) and using GPT particle tracking code (black line)
for the first four periods. Blue dots in period #1 shows net steering. (right) the same for the next set of periods. In case of period
#5 magenta shows electric part, blue shows magnetic part while yellow dots are the net effect.
Update on the superconducting electron linac development for
the RIB project at VECC
Vaishali Naik, Siddhartha Dechoudhury, Manas Mondal, Manir Ahmed, Anjan
Duttagupta, Subrata Saha, D.P. Dutta, Gautam Pal, Sandip Pal, Alok Chakrabarti,
Robert Laxdal1, Freidhelm Ames1, A. K. Mitra1 and Lia Merminga1
1
TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada
A
50 MeV 100 kW cw superconducting electron linac (SC e-Linac) photo-fission driver for
production of neutron-rich RIB is being developed at VECC for the ANURIB (Advance National
147
ONGOING PROJECTS
In our case QWRs are of reduced diameter type (both inner and outer conductor), which reduces the
effective magnetic field in the beam drift region. Over a focusing period, phase oscillates from positive
value to negative value thus reducing effective kick in any one direction. So no special efforts have
been made to take care of the steering in the first 28 cavities contained in the first four periods.
However, for the last period comprising of QWRs of d ~ 0.15, the steering effect needs to be taken care
of. This is done by beam port and drift tube tilting which allows us to keep the longitudinal acceptance
area calculated from ray tracing program with real 3D field same with that calculated analytically.
facility for Unstable and Rare Isotope Beams) project [1]. In the first phase a 10 MeV injector for the SC
e-Linac is being developed [2] in collaboration with TRIUMF Canada, who will also be using a high
power 50 MeV SC e-linac for their radioactive ion beam production program called ARIAL (Advanced
Rare IsotopE Laboratory) [3].
The injector comprises of a 100 kV dc thermionic electron gun with a grid modulated at 650MHz, a
room temperature re-buncher operating at 1.3GHz, a low energy beam transport (LEBT) line, a
Capture Cryo Module (CCM) consisting of two 1-cell niobium beta=1 1.3 GHz elliptical cavities,
analyzing magnets and diagnostics, and an injector cryo-module (ICM) which will house one 9-cell,
1.3GHz niobium cavity. The beam dynamics design of the injector has been finalized. The mechanical
engineering design has also been almost frozen although minor modifications may be required as the
location inside the e-Linac test area is finalized.
ONGOING PROJECTS
The 10 MeV injector will be installed in the high resolution cave (HR cave-1) adjacent to the present
RIB facility. A test area is being prepared for the purpose. The layout of the injector as well as the layout
for the cryogenic lines, rf lines and other services in the test area is being worked out. The RIB beamline between LINAC-3 and LINAC-4 will be passing through the e-Linac test area. A 4m wide passage
will be connecting the HR cave-1 to the RIB annex building. The RIB annex building is in the final
stages of construction and presently the civil engineering work for making the connecting passage is
being initiated.
The ICM has been jointly designed by the VECC and TRIUMF team and is being fabricated in local
industry in Vancouver area. Under the VECC-TRIUMF MoU two ICM cryo-modules will be made and
tested at TRIUMF, one for each lab. The ICM for VECC is scheduled to arrive at VECC in late 2013.
The niobium cavities for the ICM will be made jointly by TRIUMF and M/s PAVAC, Vancouver. First
batch of cavities have been made and passed rf benchmarking tests at TRIUMF as well as at Fermilab
[3].
The TRIUMF SC e-linac will use a 300 kV electron gun and the beam from the gun will be directly
injected in the ICM. At VECC the e-Linac test area will not be able to accommodate a 300 kV gun and
Figure 1. The VECC e-Linac test area in the ISAC-II hall at TRIUMF
148
its SF6 infrastructure, so the 10 MeV injector will be tested using a 100 keV gun. The CCM will be used
for pre-acceleration of the beam from the gun to around 400 keV before injection in the ICM.
For testing of the two ICM cryo-modules at TRIUMF, the TRIUMF team has set-up a VECC e-Linac
test area in the ISAC-II hall. A photograph of the same is shown in Figure 1. Presently a 100 kV gun has
been installed in the above test area and beam properties measurement is being done. The beam tests
consist of beam profile measurements, tests of the phase optimization of the buncher etc. In early 2013,
the 100 kV gun will be replaced by the 300 kV gun and the beam tests with 300 keV beam will resume
by summer of 2013.
References
[1] Rakesh Kumar Bhandari, Arup Bandyopadhyay, Alok Chakrabarti, Vaishali Naik, “Rare Ion Beam Facility At VECC:
Present And Future”, Proc. of 2nd International Particle Accelerator Conference (IPAC2011), San Sebastian, Spain, 49 Sept. 2011.
[2] Vaishali Naik, et. al, “VECC-TRIUMF injector for the e-Linac project” Proc. of 25th Linear Accelerator Conference
(LINAC10), Tsukuba, Japan, 12-17 Sept., 2010.
[3] Shane Koscielniak et. al, “Electron Linac Photo-Fission Driver for the Rare Isotope Program at TRIUMF” Proc. of 1st
International Particle Accelerator Conference (IPAC2010), Kyoto, Japan, 23-28 May, 2010.
Laser nuclear spectroscopy program for the
RIB project at VECC
Ayan Ray, Md. Sabir Ali, Arup Bandyopadhyay,
Vaishali Naik and Alok Chakrabarti
A
Laser Nuclear Spectroscopy program has been initiated in VECC for the RIB project. The
program is primarily aimed at online detection and extraction of spectroscopic data on rare ion
beams. The data will be used to extract information about the nucleus of the sample. The experimental
activities to be covered under this programme can be subdivided into three major branches:
(I) co-linear laser spectroscopy, (ii) trap based experiments and (iii) resonant ionization spectroscopy.
Currently the program is centered on setting up of a collinear laser spectrometer at the ISOL beam line
area in high bay of the K130 cyclotron building. The striking point of this program is manipulation of
the techniques of atomic spectroscopy for studying the nucleus. Further Laser spectroscopy of atoms is
intimately related with the area of Quantum Optics, which encompasses the details of photon atom
interaction.
The ongoing program is also aimed at studying few key areas of Quantum Optics e.g. multilevel laseratom interaction, atomic frequency offset stabilization, laser cooling and trapping, photo-ionization
etc., which will be helpful in successful commencement of Laser Nuclear Spectroscopy program.
A Laser Hut has been set-up in the ISOL area for the Laser spectroscopy studies. Two external cavity
diode lasers and associated optics accessories are mainly used for this work. Two different experiments
149
ONGOING PROJECTS
[4] R.E. Laxdal, et. al, “1.3 GHz cavity development at TRIUMF” Proc. of 25th Linear Accelerator Conference
(LINAC10), Tsukuba, Japan, 12-17 Sept., 2010.
4
4
were conducted during this period. In the first study the D1 hyperfine transitions ( S1/2 P1/2) of K
(potassium) had been resolved earlier, is studied again as a function of potassium vapour pressure. The
study helps us in choosing the optimized temperature required for potassium vapour cell to conduct
saturation absorption spectroscopy. This experiment is conducted in view of carrying out collinear
42
43
laser spectroscopy of radioactive K and K atoms at the ISOL facility.
In the second part coherent pump-probe spectroscopy in the 5S-5P-5D domain of Ξ type Rb
(Rubidium) atom energy level is conducted. The subject of pump-probe spectroscopy in alkali vapour
medium provides a unique opportunity to study different perspectives of coherence, manifested
through results like Coherent Population Trapping (CPT), Electromagnetically Induced Transparency
(EIT), Electromagnetically Induced Absorption (EIA) etc. Important technical applications of
coherent photon-atom interaction encompasses key areas like slowing down the light, miniaturized
atomic clock, ultra-sensitive magnetometry and frequency offset locking. As a whole this particular
topic of quantum optics has generated tremendous attention in the physics community.
ONGOING PROJECTS
Nanopattern on carbon and by carbon
P. Karmakar, S. Bhattacharjee1, V. Naik, A. K. Sinha1 and A. Chakrabarti
1
UGC-DAE Consortium for Scientific Research, Kolkata -700098, India
W
e have reported nanopattern formation on carbon thin films and Si(100) surfaces by low energy
inert and carbon ion beams. It is interesting to observe the role of carbon as target as well as
projectile for nano patterning. Using carbon thin film as target, nano patterns of carbon are formed by
+
+
inert (Ar ) and self (C ) ion bombardment, whereas carbon ion beam is used to form well ordered Si
nano ripple structure in a cost effective way where implanted carbon plays an important role to form Si
ripple in relatively lower fluence than the inert projectile.
Self organization ion beam induced surface nanopatterning has received considerable theoretical and
experimental attention due to its potential applications and challenges to explore its complex physical
mechanism . Then again, there have been a lot of interests in carbon films in the last two decades
because of their beneficial chemical and physical properties like high chemical inertness, diamond like
physical properties and tribological properties suitable for industrial usage .
Here, we took two sets of samples, in the first sets carbon films are deposited on Si(100) surface and in
another set we performed the experiment with pure Si(100) surface. Both are bombarded with keV
energy C1+ ions and Ar1+ ions to develop the ripple like patterns and studied the ion beam induced
carbon nanostructures as well as role of carbon ion beams on nanopatterning.
The commercially available polished Si(100) samples are initially cleaned and degreased with
trichloroethylene in ultra sonic vibrator (USV) and then washed with methanol and distilled water. The
carbon film of about 100 nm thickness are then deposited on half of the Si(100) substrates by thermal
vapour deposition. The other half are kept in vacuum decicator. The samples (Carbon film and Si(100))
1+
1+
0
are bombarded with 8 keV C and Ar ion beams at an incidence angle of 60 with respect to the surface
normal. The fluence was varied from 5×1016 ions/cm2 to 7×1017 ions/cm2. The ion beam was extracted
150
from 6.4 GHz ECR ion source of the Radioactive Ion Beam Facility at Variable Energy Cyclotron
Centre Kolkata (VECC) .
The surface morphology of the virgin carbon film and the bombarded samples is shown in Fig.1. Fig.1
(a) shows the AFM image of the unbombarded carbon film deposited on Si(100) substrate. The surface
1+
0
topography of carbon films bombarded with 8 keV C ions at 60 with respect to the surface normal for
the fluences 5×1016 ions/cm2 to 7×1017 ions/cm2 are shown in Fig. 1(b1-b5). Similarly, Fig.1 (c1-c5) shows
the images of the films bombarded with Ar1+ ions at the same variation of ion fluence. It is observed
from the topographic AFM images that the ripples like patterns are formed on the film surface with the
increase of the ion fluence. For C1+ ion bombardment the initiation process was started with the fluence
5×1016 ions/cm2 and with the increase of fluence the ripple patterns are developed gradually. A good
17
2
quality ripple structure is observed at the fluence of 7×10 ions/cm with the ripple wavelength ~ 100
1+
nm.But in the case of Ar ions similar ripple patterns with wavelength ~ 100 nm are observed at a lower
17
fluence of 2×10 ions/cm2 only. With the further increase of Ar1+ fluence the ripple patterns are
randomized leading to kinetic roughening.
Figure 1. AFM images of the (a) virgin carbon film, (b1–b5 ) ripple like pattern form on carbon film due to C1+ bombardement
and (c1 – c5) due to Ar1+ bombardment for ion fluence varying from 5×1016 ions/cm2 to 7×1017ions/cm2 (given below the each
image) at an incidence angle of 600. Arrows indicate the direction of the ion beams.
The ion beam induced nanopatterning is described by the instability generation on the surface during
ion bombardment. The ion energy and momentum transfer to the surface atoms leads to mass
redistribution and sputtering which cause perturbation on the surface morphology. With continuous ion
irradiation, the perturbation grows and generates structure on the surface depending on the incident
beam and target parameters. The BH model or extended BH model, based on Sigmund's sputtering
0
theory describe the perpendicular ripple formation at oblique angle (60 ) ion bombardment.
Due to higher mass of Ar ions the penetration of the ion is less than the same energy C ion but effective
energy loss per unit length is higher that leads to higher sputtering and target atom redistribution
1+
compared to C ion. The total energy loss per unit length (stopping power) is 962 eV/nm for Ar and 332
1+
eV/nm for C on carbon. The sputtering yield for Ar projectile is 5.35 atoms/ion compared to 1.76
atoms/ion for C1+ ions.
151
ONGOING PROJECTS
The surface morphology of the carbon films and Si(100) samples before and after implantation were
examined in air using Bruker Atomic Force Microscopy (AFM) MM V at VECC. The XPS
measurements are done at SINP by an Oxford Applied Research XPS system with monochromatic Xray source of Mg(kα
) (1253.6eV) and 150mm mean radius hemi spherical analyser. The pressure in the
-10
chamber was 8×10 mbar during irradiation with X-rays.
The XPS measurement of carbon films on Si(100) before and after ion bombardment is consistent with
the AFM data. The Si peaks disappear in case of carbon film deposited on Si(100) and only C(1s) and
O(1s) peaks are visible. The intensity of the C(1s) is found to decrease when the carbon film is
1+
1+
bombarded with C and Ar ions. The faster decrease of carbon intensity is observed for Ar ion
bombardment. Si peaks appears for Ar ion bombarded carbon film, whereas no such Si peaks are
observed for the samples (carbon films) bombarded with C ions. The higher roughness on Ar
bombarded carbon surface and decrease of roughness after fulence 5×1017 ions/cm2 indicate that the
sputtering yield is higher than C ion and after a certain fluence the Si surface is exposed for Ar ion
bombardment. Thus higher sputtering as well as high mass re-distribution by Ar ion beam leads to
faster ripple formation compared to the carbon ions. Due to inert nature of Ar ion and self
bombardment of carbon film by C ion no chemical effect is expected for ripple formation.
ONGOING PROJECTS
Figure 2. AFM images of the (a) virgin Si(100) surface, (b1-b5) ripple pattern formed on Si surface due to C1+ bombardement
at 600. C1and C2 due to Ar1+ bombardement at 600
Figure 3. Shows the Si(2s) and Si(2p) peak respectively for virgin Si, C1+ ion implanted on Si and also Ar1+ ion implanted on
C/Si sample.
Fig 2 (AFM data) and Fig 3 (XPS data) shows the chemical effect on nano structure formation where
1+
1+
the target is changed from carbon film to pure Si(100) keeping the same C and Ar ions as projectiles.
1+
Fig 2 shows the AFM images of the morphology developed on Si surfaces due to bombardment of C
152
+
+
The ripple like pattern is developed on carbon film when bombarded with both the C and Ar ions. As
the grown film is rough enough so the ripple like pattern is formed at a lower fluence. C implantation on
virgin Si developed a chemical phase helps in early pattern formation as compared to the inert
projectile like Ar.
The authors would like to acknowledge the help of Prof S. Bhattacharya for XPS measurements.
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
U. Valbusa, C. Boragno, and F. B. deMongeot, J. Phys.:Condens. Matter 14, 8153 (2002).
G. Carter, J. Phys. D: Appl. Phys. 34, R1 (2001).
K. Tay, X. Shi, and H. S. Tan, et al., Surf. Coat. Technol. 105, 155 (1998).
A. Grill, Surf. Coat. Technol. 507, 94 (1997).
A. Chakrabarti, Nucl. Instr. Meth. Phys. Res. B 261, 1018 (2007).
R. M. Bradley and J. M. E. Harper, J. Vac. Sci. Technol. A 6, 2390 (1988).
P. Sigmund, Phys. Rev. 184, 383 (1969).
H. Yan, R. W. M. Kwok, and S. P. Wong, Appl. Surf. Sci. 92, 61 (1996).
P. R. Poudel, P. P. Poudel, B. Rout, M. E. Bouanani, and F. D. McDaniel, Nucl. Instr. Meth. Phys. Res. B 283, 93
(2012).
[10] S. Bhattacharjee, P. Karmakar, and A. Chakrabarti, Nucl. Inst. Meth. Phys. Res. B 278, 58 (2012).
Interplay of 4f-3d magnetism and ferroelectricity in DyFeO3
B. Rajeswaran1, D. Sanyal, M Chakrabarti2,Y. Sundarayya1, A. Sundaresan1
and C. N. R. Rao1
1
Chemistry and Physics of Materials Unit, JNCASR, Jakkur P. O., Bangalore 560 064, India
2
Department of Physics, University of Calcutta, Kolkata 700 009, India
D
Fe
yFeO3 exhibits a weak ferromagnetism (TN 645K) that disappears below a spin reorientation
Fe
(Morin) transition at TSR 50K. It is also known that applied magnetic field induces
153
ONGOING PROJECTS
and Ar1+ ions. In case of C ion bombardment the surface is roughened and slowly increases the rms
17
2
roughness, at fluence greater than 5×10 ions/cm the ripple structure starts to form and the surface
roughness increase sharply. The wavelength of the ripple structure is also found to increase with the ion
fluence. In case of Ar ion bombardment no ripple is formed in the present ion energy even at very high
fluence 2×1018 ions/cm2. Initial bombardment of C1+ ion generates only the random roughness on the
17
2
surface at fluence less than 5×10 ions/cm , where sputtering induced initial height perturbation is not
enough to form the sufficient instability on the surface to form the ripple structure. At greater fluence
the implanted carbon ions change the chemical nature of the Si surface. The chemical shift of Si 2p peak
towards higher binding energy (E = 1.255) (shown in Fig 2 ) indicates the SiC formation. Binding
energy of the Si 2p signals shifts towards higher binding energies with increasing implanted carbon
content. The charge transfer from the silicon atoms to the more electronegative implanted carbon
atoms leads to the shift of Si 2p peaks towards higher binding energy. H. Yan et.al observed the similar
shift of Si 2p peaks from C1+ implanted Si sample . Poudel et al. reported the SiC formation from XPS
measurement of C ion implanted Si at elevated temperature. Ar1+ ion implanted does not show any
chemical shift of the Si 2p peaks. Therefore ion Ar bombardment does not generate sufficient
instabilities to form the ripple structure on the surface. No structure formation on Si by Ar
bombardment in this energy range also reported earlier .
ferroelectricity at the magnetic ordering temperature of Dy ions (TNDy 4.5K). Here, we show that the
ferroelectricity exists in the weak ferromagnetic state (TSRFe <T <TN,C) without applying a magnetic field
(Fig.1), indicating the crucial role of weak ferromagnetism in inducing ferroelectricity. 57Fe Mossbauer
studies show that a hyperfine field (Bhf ) deviates from the mean-field–like behaviour (Fig.2) that is
observed in the weak ferromagnetic state and decreases below the onset of the spin reorientation
transition (80K), implying that the Bhf above TSR had an additional contribution from Dy ions due to the
induced magnetization by the weak ferromagnetic moment of the Fe sublattice and below TSR this
contribution decreases due to collinear ordering of the Fe sublattice. These results clearly demonstrate
the presence of magnetic interactions between Dy(4f ) and Fe(3d) and their correlation with
ferroelectricity in the weak ferromagnetic state of DyFeO3
ONGOING PROJECTS
Figure 1. Temperature dependence of (a) field cooled magnetization of DyFeO3 and
(b) polarization at various magnetic fields near TNDy
Figure 2. Temperature dependence of Bhf in the range 25 K to 300 K
154
Defects in 6 MeV H+ irradiated hydrothermal ZnO single crystal
D. Sanyal, A. Sarkar1, D. Bhowmick, M Chakrabarti2 and D. Rafaja3
1
Department of Physics, Bangabasi Morning College,
19 Rajkumar Chakraborty Sarani, Kolkata 700 009, India
2
Department of Physics, University of Calcutta, 92 A P C Road, Kolkata 700009, India
3
Institute of Materials Science, TU Bergakademie Freiberg, 09596 Freiberg, Germany
Figure 1. Reciprocal space maps (002) of pristine and irradiated ZnO crystals.
155
ONGOING PROJECTS
T
+
he effect of 6 MeV H irradiations on hydrothermally grown ZnO single crystal has been
investigated using high resolution X-ray diffraction (Fig. 1) and optical absorption (ultravioletvisible) spectroscopy (Fig. 2). The increase of the diffuse scattering in the reciprocal space maps
measured by using X-ray diffraction indicated an increase of the point defect density after the
irradiation. Within the penetration depth of X-rays of several micrometers, the defect density increased
with increasing distance from the surface of the sample. Optical absorption, on the other hand,
becomes sharper near the band gap for irradiated crystal. It is an indication of more band to band
absorption and reduced sub-band gap energy states (energy levels due to defects). Low temperature
photoluminescence spectroscopy on the samples reveals the role of both generated and recovered
defects. Enhancement of near band edge luminescence and reduction of sub-band gap luminescence
have been observed at 10 K for the irradiated crystal. Dominant donor bound exciton in the irradiated
crystal has been identified as HO (hydrogen at oxygen vacancy site) defects. Possible role of hydrogen
to determine irradiation induced final state in ZnO has been pointed out.
The intensities are plotted in logarithmic scale. Black colour was used for high intensity, light gray for
low intensity. The streaks denoted W and M stem from the wavelength dispersion and from the
dispersion on the monochromator, respectively.
ONGOING PROJECTS
Figure 2. Optical absorption at different photon energies for the pristine and H+ irradiated ZnO crystals.
Ferromagnetic ordering in 4 MeV Ar6+ irradiated rutile TiO2
D. Sanyal et al
R
oom temperature ferromagnetic ordering has been observed in rutile “as received” TiO2
6+
polycrystalline sample by 4 MeV Ar ion irradiation. Due to irradiation a huge number of oxygen
vacancy has been created in TiO2 sample, as a result of which the surface resistance of the irradiated
Figure 1. Room temperature ferromagnetic ordering in Ar irradiated TiO2
156
7
3
sample drastically decreases (~10 ohm-cm to ~1.5x10 ohm-cm). Ab initio calculation in the density
functional theory indicate that oxygen vacancy in rutile TiO2 can leads to ferromagnetic ordering in
TiO2.
Study of sintering mechanism in oxide ceramics from
dilatometric measurements
Tapatee Kundu Roy et al.
In the present study, dilatometric shrinkage data was utilized to study the sintering kinetics of the oxide
ceramics. The objective is to determine the activation energy of sintering (Q) and sintering mechanism
(n) relevant to the initial stage of sintering. One approach is to study the sintering kinetics in the
ceramic system under constant rate of heating (CRH) [1]. The difficulty with CRH method is to
determine both the sintering parameters, n and Q, simultaneously from a single CRH experiment. It is
thus necessary to determine the activation energy by using different techniques and use this value to
determine the value of n. Modified Dorn method [2], which is a very effective technique is used to
determine the activation energy of sintering.
Figure 1. Shrinkage plot of powder compacts during CRH experiments
157
ONGOING PROJECTS
S
intering of powder compact at an elevated temperature is a combination of many intermediate
processes that results into pore filling followed by densification. The material transport that occurs
is essentially a diffusion controlled process. However, the practical approaches to understand these
processes in a ceramic system have been still a challenge. It is necessary to determine various rate
controlling parameters of sintering in order to understand the sintering mechanism of a particular
ceramic system.
The product of 'nQ' was calculated from the shrinkage data acquired from the constant rate of heating
(CRH) experiment. In this method, the sample temperature is increased at a constant rate (dT/dt) to
determine the amount of shrinkage that occurs as a function of temperature using a Dilatometer.
o
Dilatometric linear shrinkage measurement under constant rate of heating (300 C/h) was carried out in
a double push rod dilatometer (TD5000SMAC Science, Japan) up to 1500oC. The samples used were
made by compaction to a cylindrical shape of 6 mm dia, 8 mm length and green density ~ 60% TD
(theoretical density). The apparent activation energy of sintering (Q) was calculated using modified
Dorn method. To determine activation energy of sintering by modified Dorn's method, a special
heating schedule in Dilatometer was maintained. In this, the compact mass was hold isothermally at
some predetermined temperature
mostly for a period of 30 minutes for
thermal stability and the sample was
ramped from one isotherm to the next
higher one with a heating rate of
10ºC/min.
ONGOING PROJECTS
Shrinkage of the powder compacts as a
function of temperature during CRH
experiment is shown in Fig. 1. The
onset temperature of shrinkage
corresponds to the initiation of sudden
decrease in sample length that occurs as
a result of bulk sintering process.
From the figure, it is evident that in case
Figure 2. A typical time-temperature schedule followed in Dorn method
of both undoped and silica doped ZnO along with the corresponding shrinkage plotted against time (for ZnO-4
samples, the initiation of shrinkage wt% SiO2 sample)
takes place at a much low temperature
of 450-500K during heating. The nature of the shrinkage plot and overall magnitude further changes
with increase in silica doping level in ZnO powder compacts. There is a decreasing value of shrinkage
with increase in silica level. This may be due to retardation of densification in ZnO ceramics with SiO2
addition. The CRH data analysis is done by using different rate controlling equations [1-2] .
The temperature versus time plot that was specially done to determine the activation energy using
modified Dorn equation along with the shrinkage data is shown in Fig. 2. The activation energy of
sintering can be obtained from the shrinkage data of these two isotherms (point A & B) as shown in the
figure.
The analysis of shrinkage data to determine different values of Q and n along with the interpretation of
results to identify the sintering mechanism is on progress.
References
[1] D. L. Johnson, J. of Appl. Phys, 1969, 40 (1) 192-200.
[2] J.J.Bacmann and G. Cizeron, J. Am.Ceram.Soc., 51 (1968) 209-212.
158
Design and development of a 3 kW RF amplifier for re-buncher
of RIB beam-line
H. K. Pandey, T. K. Mandi, D. P. Dutta, S. Basak, J. Kumar,
N. Madokar and K. P. Ray1
1
SAMEER, IIT campus, Powai, Mumbai, India
Radio Frequency amplifier of 3 kW at 37.8 MHz frequency has been designed and developed for
post buncher of RIB at VECC, Kolkata. It has two stages of amplification, a 100 W Solid State
Amplifier (SSA) as driver followed by a 3 kW triode-tube 3CX5000A7 based amplifier as high power
stage. The solid state amplifier (driver amplifier) has been already developed and tested. The final stage
amplifier is a class AB amplifier designed using triode 3CX5000A7 in grounded grid configuration.
The tube selected from VARIAN is specially made for grounded grid i.e. cathode driven configuration
to provide good stability and wider bandwidth at the cost of gain. The photograph of amplifier cage is
shown in Fig. 1(a). After fixing the biasing condition, the input and output parameters of amplifier
were computed. The input and output matching networks were designed to match this impedance to 50.
The matching networks are single LC networks. The inductance L and capacitance C are variable type.
Figure 1(b) shows the measured S-parameters of input and output matching circuits. Their range are so
chosen that the frequency can be tuned anywhere between 36 MHz to 43MHz.
Figure 1. (a) Amplifier tube cage assembly
(b) S-Parameters of input and output matching
The tube cage and proper forced air cooling arrangement with RF filter blocks has been designed. The
fabrication of this cage has been done by VECC WORK SHOP. The forced air cooling system for the
tube has been arranged as prescribed by the manufacturer. The air flow rate required for plate
dissipation of 2000 watts at inlet air temp of 30oC is more than 40 CFM. The proper air flow and
pressure drop of tube cage has been measured with help of AC division VECC.
159
ONGOING PROJECTS
A
Design and prototype testing of amplitude and phase control of
RF cavity voltage
Subhasish Basak, D. P. Dutta, T. K. Mandi and H. K. Pandey
I
ONGOING PROJECTS
n this work the design of analog amplitude and phase control of RF cavity voltage was
carried out and then tested / verified on dummy RF cavity ( Cold Model RFQ) having resonance
frequency of 72.06 MHz in a lab prototype set up . The amplitude control is made up of the RF
source, PI controller, voltage attenuator, amplifier, RF cavity (with coupler and pick up) and
amplitude detector. Figure 1 shows the schematic diagram of the amplitude and phase control of RF
cavity. The phase control consists of the RF source, PI controller, voltage controlled phase
shifters, amplifier, RF cavity(with coupler and pick up) and phase detector. The feedback control
circuitry is realized with op-amp and discrete components and tested. The performance of the
amplitude control was good ( measured a 1% relative change in the cavity amplitude for 100%
relative change in source power i.e., doubling of the RF source relative power level). The
performance of the phase control was also good ( the cavity phase could be changed accurately to
the phase reference change with a range obtained about 110° ).
Figure 1. Schematic diagram of the amplitude and phase control of RF cavity.
Operation and maintenance of RF systems of RIB project
D. P. Dutta, T. K. Mandi, S. Basak, J. Kumar, N. Madokar, P. Bhattacharjee,
H. K. Pandey, Tanuja Das1 and Saket Kumar1
1
SAMEER, Kolkata campus, Sector-5, Salt Lake, Kolkata, India
T
he RF systems of RIB facility consists of High power RF transmitters for RFQ, LINAC-1,
LINAC-2, LINAC-3, buncher cavity and two Klystron high power amplifier (KHPA). The
transmitters for RFQ, LINAC 1, LINAC 2 and buncher operate at 37.8 MHz. The transmitter for
LINAC 3 operates at 75.6 MHz and the KHPA operate at 6.4 GHz for ECRIS.
160
Figure 1. The high power amplifier systems of the RIB facility
Installation and testing of remote interfacing module of
D-DAC system
T. K. Mandi, H. K. Pandey, D. P. Dutta, S. Basak, J. Kumar, N. Madokar,
A. Bandyopadhyay, A. Chakrabarti, A. Kumar, K. Datta, D.R. Sarkar,
K. P. Ray1, A. Balasubramaniam2, G. Karna2 and K. Mourougayane2
1
SAMEER, Mumbai, 2SAMEER, Chennai
A
Distributed Data Acquisition and Control System (D-DACs) have been developed for remote
control of the systems and sub-systems associated with the RIB Beam Line. Each system has its
own interface for remote controlling system parameters. For reliable and fast operation, the data
161
ONGOING PROJECTS
The RF transmitters for RIB accelerators are operated periodically with closed loop amplitude and
phase control. The transmitters are generally terminated with the RF cavities as complex loads and
operated for beam tests. For troubleshooting, the RF transmitters are operated by terminating them with
dummy 50 ? loads. Presently, the forward and reflected power meters in the RF transmitters are analog
pointer panel meters. For the LINAC 1 and LINAC 2 transmitters, the analog scales for reading the
forward and reverse powers have been calibrated to read the lower power levels with better accuracy.
The power supply unit of the 40 kW transmitters for LINAC 2 has been repaired following the failure of
two 12 uF filter capacitors for the 15 kV plate supplies. The interlocks for the transmitters, cooling
water and vacuum in the accelerator cavities are checked periodically to ensure proper operation and
safety of the RF transmitters and cavities. For remote operation of the RF transmitters, a Remoter
Interface Module (RIM) has been installed in the control racks of the RF transmitters. Through the
RIM, an external controller can monitor the status of the RF transmitter, power levels and interlocks as
well as control the RF transmitter. It is being tested for reliable operation.
acquisition and control system has a 3 layered design as shown in Figure 1, namely: a) Equipment
Interface Layer b) Supervisory Layer and c) Operator Interface Layer.
Figure 1. Schematic diagram of control system
ONGOING PROJECTS
Some components of the RIB facility like RF Transmitters do not have provision for remote control.
Hence, it is aimed to develop all necessary systems, sub-systems and interface circuits to monitor and
control the RIB sub-systems. The Remote Interfacing Module (RIM) is developed for the control and
monitoring of all the parameters for RF transmitters. The control system has to analyze and display the
status of different interlocks (like LCW, Air Flow, high voltage door, Plate Voltage, VSWR, filament
ready, etc) continuously, operate the RF transmitter, power up the RF accelerator and display the
important parameters like forward power, reflected power and phase.
The main controller used in RIM is 32-bit LPC 2478 ARM7TDMI with analog/digital front-end
electronics (ADCs, DACs, Opto-Isolators, and Multiplexers etc.) and RS232 line driver. It also
consists of a touch-screen display from which equipments connected to it, can be locally controlled and
monitored. RIM is directly connected to the different analog and digital input/output signals and the
local controller for the RF transmitters. The local controller of the RF transmitter is equipped with 8-bit
microcontroller, relays, buffers etc. All interlock systems are checked by the local controller and the
status of the interlocks are transmitted to the RIM for display as shown in figure 2. The RIM modules
are connected with Equipment Interface Module (EIM) through RS-232 interface.
Figure 2. RIM control display and interlocks status
162
The control modules are installed at the RF transmitter rack and testing of the modules is in progress. It
has the facility to control the transmitter locally and monitors the Plate voltage, Plate current, RF
power, Phase etc. Screenshot of data read back from the RIM modules is shown in figure 3.
ONGOING PROJECTS
Figure 3. Screenshot of data read-back output from RIM module.
163
4.3
RECOVERY AND ANALYSIS OF HELIUM FROM HOT SPRINGS
Development of sub-Kelvin technology at VECC
Nisith Kr. Das, Jedidiah Pradhan, Zamal Naser, Anindya Roy,
Bidhan Ch. Mandal and Alok Chakraborty
I
ONGOING PROJECTS
n consonance with the emerging technologies involving very low temperature measurement of
semiconducting and superconducting alloys besides nano-materials, we are in the process of
developing an indigenous sub Kelvin system at VECC. Basic objective of the project is to have a
firsthand experience and to cultivate skill by way of overcoming the complex engineering challenges
intrinsic to the sub-Kelvin temperature region. The system has three distinct temperature steps, namely
1.2K, 0.6K and 0.1mK. At the first place, we have successfully attained a temperature somewhat less
than 1.0K and it was found to maintain that temperature over a considerable time period. Cooling
power was measured to be ~17 mW using manganin wire heater.
Achievement of <1.0K by means of 4He evaporation
Recently we have successfully commissioned the 1K pot to facilitate cooling and condensation of the
inflowing helium mixture. Prior to initiate the cool down of the evaporator, leak testing of IVC and
evaporator were performed using mass spectrometer leak detector. As no leak was detected,
impedance, IVC and evaporator was cleansed at relatively higher pressure and evacuated for four
times. This helps to remove the trapped air which could solidify and plug the capillaries. Subsequently,
liquid helium was introduced into the evaporator from the bath through a precision needle valve. The
pressure on the pirani gauge was noted to rise to a steady value and temperature was stable at 4.2K as
the evaporator fills up. Within a few minutes pressure increased suddenly indicating over flowing of the
evaporator. At this point, needle valve was closed and pressure above the liquid was reduced by the
Figure 1. Temperature profile for cooling down
164
RECOVERY AND ANALYSIS OF HELIUM FROM HOT SPRINGS
external pump encouraging evaporation. The energy absorbed by the helium molecules which undergo
phase transition result in cooling of the residual liquid. Evaporation loss in the evaporator was
-12
3
replenished by liquid helium flown through the permanent impedance (10 cm ) at a limited rate.
Figure 1 shows the cool down of the evaporator with time. The lowest temperature achieved was 0.98K
with no load condition with optimized residual heat load. The temperature within the range of 0.98 –
1.2 K was found to maintain over a considerable period. This happens to be quite satisfactory for the
purpose it has been designed.
The continuously filled evaporator (1K pot) designed and tested in the laboratory and found to offer
temperature less than 1.0K by withdrawing vapour from the evaporator. In order to minimize the heat
load and to prevent film creep across the pumping tube, size optimization of the pumping line and
pump out port has been performed. Five numbers thermal baffles are used along the pumping line as
thermal barrier to radiative heat load. To achieve the available cooling power the required steady state
molar flow rate that has to be pumped out by the pump is calculated to be 250 µ mol/sec. For minimum
ultimate evaporator temperature of 1K the vapour pressure at the pot has to be maintained 0.1 torr.
Initially if we consider the pressure drop alone the pumping line be negligible, then from ideal gas
equation PV=nRT, where P is the pressure at the pumping line at the top of the cryostat, T is the room
temperature (300K), n and V are the molar flow rate and the pumping speed at the top of the cryostat.
For P = 0.1 Torr, the pumping speed is calculated as 168 m3/hr. To minimize the vibration arises due to
pump, the pump is placed few meter away from the cryostat. Considering this the pump pumping speed
250 m3/hr is chosen.
Figure 2. Temperature and pressure distribution along the pumping line of the evaporator (1K Pot)
To achieve the second and final temperature steps
3
We have finalized the design of He distillation chamber (Still), counter flow heat exchanger and
mixing chamber, the place for final base temperature. As a way of operating continuously, the
3
circulating gas essentially He needs to re-circulate through a closed circuit. This gas handling system
is presently being fabricated in the laboratory. A prototype Still has been built up and the mixing
chamber is in its final stage of fabrication and polishing. This project will also help us to decipher many
subtle thermo-dynamical features involved in the process.
165
ONGOING PROJECTS
Evaporator pumping system
4.4
ACCELERATOR DRIVEN SUB-CRITICAL SYSTEM
Auto tuned PID controller design using diophantine equation
Saurabh Srivastava, Anuraag Misra and V.S. Pandit
A
ONGOING PROJECTS
Proportional-Integral-Derivative (PID) controller is the most widely used controller in the
industry today due to its simplicity which uses only three parameters to tune. These are: (1)
Proportional (Kp) term which controls the plant or system proportional to the input error, (2) Integral
(Ti) term which gives the change in the control input proportional to the integral of the error signal and
(3) Derivative (Td) term which controls the system by providing control signal proportional to the
derivative of the error signal [1]. Error value is the difference between the set (reference) value and the
output value. This work describes the application of Diophantine equation in auto tuned PID
controllers. The transfer function (TF) identification was carried out by using system identification
toolbox of the MATLAB. The method has been applied to a second order system with no zeroes. The
uniqueness of the approach is that the PID parameters can be found very quickly with less
computational efforts. The proposed method has been validated on the speed control of a DC motor.
The PID controller parameters tuning is done by solving Diophantine equation which emerges by
equating the denominator of the closed loop feedback system of the plant with PID controller with the
desired or known characteristics equation. This can be written as:
AP + BD = Q
(1)
where A and P are the denominator polynomial of the plant and PID controller, whereas B and D are the
Numerator polynomial of the plant and PID controller and Q is the closed loop polynomial of desired
roots. For the second order plant Q can be expressed as:
2
2
Q(s)=(s + P1) (s + 2ξ
ω
s+ω
)
(2)
ξ
,ω
and P1 are the desired damping ratio, natural frequency and real roots (at least 5 times away from
the desired roots) respectively. The transfer function of the PID controller is:
1

C ( s) =
Kp 
1+
+
Td s 
e (s )


T
s
i

(3)
the plant be given by:
K
G (s ) =
2
s +
as +
b
(4)
Finally after solving Eq. 1 the values of the PID parameters can be arrange in matrix form as given in
Eq. 5 below:
2+

Kp
(ω
2ξ
ω
P1 −
b) K 




T
=

(
2
ξ
ω
+
P
−
a
)
KK

d
1
p



2


T
i 
P1



KK p ω

(5)
166
The effectiveness of the proposed tuning method is demonstrated on speed control of the dc motor. The
block diagram of the DC motor is given by,
Figure 1: DC Motor
the original TF of the DC Motor Speed Control is:
2
G ( s) =
2
s +
12 s +
20.02
(6)
And the identified TF is:
&
θ
1 .8
G (s ) =
=
2
V s +
10.8 s +
18
ONGOING PROJECTS
(7)
Figure 2. Step response of DC Motor speed control
Figure 3. Step response of DC motor with different ξ and w.
Reference
[1] Sigurd Skogestad, “Probably the best simple PID tuning rules in the world” Journal of process control July 3, 2001.
Development of bunching system and fast faraday cup
for high current proton beams
Anuraag Misra, Gautam Pal and V. S. Pandit
High Current Bunching System
T
he bunching of 3-5mA of beam current at low energies needs special attention and only attempted
at selected laboratories [1]. To explore the high current bunching phenomenon at low energies we
167
have designed and carried out detailed simulations of a quarter wave resonator to bunch 80KeV, 5mA
TM
TM
dc proton beam. The resonator was designed and optimized in HFSS and CST Microwave Studio
for a gap voltage of 4kV.The resonator has been fabricated and installed at ion source test stand as
shown in figure 1 and off line measurements are being done to improve the loaded Q of the resonator.
The loop coupler to feed power into the cavity was tuned to be -15dB which needs to be optimized
further. Preliminary results show the presence of higher order mode at 112 MHz, which is far away
from our operating frequency. The buncher resonator has been chemically conditioned (HCL + H2SO4)
for the improvement of quality factor.
ONGOING PROJECTS
Figure 1. Assembly of bunching cavity with key components
Fast Faraday Cup
The fabrication of fast faraday cup to characterize the phase width of bunched beam is completed and
its high frequency measurements have been done. The Fast faraday cup was designed and optimized in
TM
HFSS as shown in figure 2. We have fabricated two sets of faraday cups in un-cooled and cooled
configurations to establish the effects of cooling lines and support structures on its high frequency
performance. The un-cooled faraday cup has a bandwidth of 1.2 GHz which can resolve ~600 ps rise
time signal. The cooled fast faraday cup has a bandwidth of 0.5 GHz which can resolve ~1.4ns rise time
signal and needs some improvement. The high frequency measurement results are shown in figure 4.
Figure 2. HFSS model and high frequency characteristics of fast faraday cup
168
Figure 4. Return loss of fast faraday cups
Reference
[1] M.Marki, J.Cherix, A.Scherer, A,Wasser, PSI Annual Report ( 2000), pp.12.
Self-consistent intense beam dynamics in a spiral inflector
A. Goswami, P. Sing Babu and V. S. Pandit
W
e have investigated the dynamics of space charge dominated beam in a spiral inflector selfconsistently by assuming uniform density beam [1]. Starting from the Hamiltonian of the
equations of motion we have first obtained the paraxial ray equations of motion in the applied and selffields. We then obtained the infinitesimal transfer matrix and the beam envelopes by employing the
recursive sigma matrix method. The simulation results are compared with that estimated using uniform
cylindrical beam model. The dependence of the emittance growth at the inflector exit is for different
inflector parameters are also studied. The parameters of the spiral inflector [2] used in the simulations
are A = 8.65 cm, Rm = 7.92 cm and k' = 0.65. The electric field is constant (18.5kV/cm) and the magnetic
field is 5.15 kG.
169
ONGOING PROJECTS
Figure 3. Fabricated cooled (copper) and un-cooled (aluminium) faraday cups
Figure 1 compares the behaviour of beam envelope through the inflector for two values of beam
current. The input beam conditions are um(0) = hm(0) = 4 mm and ε
u(0) = ε
h(0) = 60 mmmrad in h
(horizontal) and u (vertical) planes. We see that the focusing characteristics of spiral inflector are not
similar in u and h planes and the space charge force contributes significantly at this current level. The
simulation result indicates that uniform cylindrical beam model underestimates the space charge
contributions in both the planes.
ONGOING PROJECTS
Figure 1. The evolution of beam sizes through the spiral inflector in u and h planes
Figure 2(a) compares the beam transmission through the inflector as a function of the beam current
with the straight cylindrical beam model. The transmission is almost 99.5 % for 1 mA, reduces faster as
we increase the beam current and becomes ~ 91% for 8 mA beam current. Since the simulations with
uniform cylindrical beam underestimates the space charge contributions, the transmission is, thus,
slightly more compared to that of a self-consistent simulation. In order to study the parametric
dependence of the emittance growth at the inflector exit we have selected ten specific values of
parameter A keeping the injection energy and magnetic field fixed and obtained the value of k' in each
case which produces correct beam centering. The variation of parameter k' as a function of A which
produces correct beam centering is shown by a solid line in Fig. 2(b). We have then estimated the
projected emittances at the inflector exit for each inflector at two values of the beam current. The results
are shown by dashed lines in Fig. 2(b). We found that for each inflector defined by A and k' the initial
beam conditions are different for minimum emittance growth. It is easy to see that the emittance growth
decreases as the height of the inflector increases. We also observe from Fig. 2(b) that as we increase the
170
value of the parameter A the rate of growth of projected emittance decreases. Thus it is always
beneficial to use inflector with parameter A as large (less tilted) as possible considering the available
space in the central region.
ONGOING PROJECTS
Figure 2. Variation of the (a) transmission of the beam through the inflector and (b) projected emittances at the inflector exit as
a function of the inflector height.
References
[1] A. Goswami, P. Sing Babu, V. S. Pandit, Nucl. Instr. and Meth. A 693(2012) 276.
[2] A. Goswami, P. Sing Babu, and V. S. Pandit, Eur. Phys. Jour. Plus 127 (2012) 79.
Optimisation of beam line parameters for space charge
dominated multi species beam using random search method
P. Sing Babu, A. Goswami and V. S. Pandit
W
e have developed a method based on random search optimization technique to transport and
match a particular species of space charge dominated multispecies beam using the recently
developed multispecies beam envelope equations. This technique optimizes the transport of primary
species and maximizes the loss of other unwanted species. To illustrate the utility of the procedure, we
have studied and optimised the transport of proton beam in the presence of H2+ and H3+ in a solenoid
+
based transport line for various values of the total beam current and different fractions of p, H2 , and H3
species.
+
The envelope equations of each species of the beam, in its own Larmor frame, propagating through a
solenoid focussing channel, is given by
2
aj
ε
4 n
j
(
r j″
+
k 2j r j −
−
b
f
(
r
,
r
)
+
g
(
r
,
r
)
−
=
0
)
∑
jk
j
k
j
k
3
rj rj k≠
r
j
j
171
(1)
ONGOING PROJECTS
Figure 1. Plots of unmatched (dotted) and matched (solid) beam envelopes of proton. The initial parameters are: B1=3.97kG,
B2=2.47kG, ld1=97cm, ld2=144cm, ld3=39cm. The optimised parameters are: B1=3.09kG, B2=2.87kG, ld1=59cm, ld2=150cm,
ld3=71cm.
The matched beam envelopes (solid line) and the beam envelope obtained with initial setting (dotted
line) of the proton beam along the transport line for 10mA total beam current are shown in Fig.1. The
initial beam radius and divergence of all the species are same i.e. R(0) = 2.5 mm, R(0)=0 with fractions
+
+
of p, H2 and H3 as 80%, 15% and 5% respectively. It is evident from Fig. 1 that for the initial set of
parameters the trajectory of the proton beam does not satisfy the matching conditions at the final point
and the radius of the proton beam at the slit location is larger than the slit size. The radius of proton
beam is also beyond the allowed set value of Rmax=2cm along the beam line. The beam envelope for H2+
Figure 2. Plots of envelope radii of H2+ beam (dotted), H3+ beam (dashed) before optimisation and H2+ beam (solid), H3+ beam
(dashed dot) after optimisation of the beam line parameters. The initial and optimised parameters are same as in Fig. 1.
172
and H3+ beam before the slit and after the selection by slit is shown in Fig. 2 for both the initial and
optimised beam line parameters. It is readily seen that beam sizes of H2+ and H3+ at the position of the slit
are larger in the case of optimised set of the parameters compared to the beam sizes with initial
parameters. This indicates a loss of large fraction of total beam current due to H2+ and H3+ species at the
the slit.
Reference
[1] P. Sing Babu, A. Goswami and V. S. Pandit, Phys. Lett. A 376 3192 (2012).
Hollow formation of subdominant species in a
multispecies beam
A
self consistent particle-in-cell (PIC) simulation is used to study the transport properties of a
space-charge-dominated multispecies beam propagating through a solenoid-based low energy
beam transport line. The evolution of the beam radius and emittance growth of each species arising due
to the nonlinear space-charge forces has been investigated. The self-consistent PIC simulation shows
the formation of hollow density profiles of subdominant unwanted species around the primary beam,
downstream of the transport line. We have utilized this effect for efficient removal of unwanted species
by making use of a slit at a suitable location in the beam line.
Figure 1. The evolution of rms beam sizes of p, H2+ and H3+ obtained from the envelope model (solid curve) and PIC
simulations (dashed curve) for I = 10 mA.
Results of PIC simulations with a K-V distribution for the beam species, and using circular slits at two
locations, are shown in Figs. 2A (a)-(h). Figures 2A (a) and 2A(c) represent the real space distribution
173
ONGOING PROJECTS
of macroparticles at the slit (s=135 cm) and at the second waist of the proton beam (s=277 cm), whereas
Figs. 2A (b) and 2A (d) show the corresponding phase space plots at the same locations, respectively.
Similar plots of real space and phase space are shown in Figs. 2A (e) to 2A (h), when the slit is placed at
s = 257 cm. The beam selection using a slit of radius 5 mm at s = 135 cm results in further formation of
hollows of unwanted species at the second waist of the proton beam (Fig. 2A (c)), which indicates that
the beam selection is not very efficient. It can be readily seen from Fig. 2A (e) that the unwanted species
+
+
H2 and H3 beams are well separated from the proton beam at s = 257 cm. We have also shown the
results of self-consistent PIC simulations with a Gaussian distribution in Fig. 2B (a)-(h) for
comparison.
ONGOING PROJECTS
Figure 2. Phase space (s, s´) and real space (x, y) distributions of p, H2+ and H3+ at different locations (A) K-V distribution and
(B) Gaussian distribution for all the species.
Reference
[1]
P. Sing Babu, A. Goswami and V. S. Pandit, Phys. Plasmas 19, 113112 (2012).
174
LQR based PID controller for the optimal
design of buck converter
Saurabh Srivastava, Yashwant Kumar, A. Misra, S.K.Thakur and V.S. Pandit
uck converter is a DC-DC converter that is widely used in the industry today, due to its high
efficiency, low cost and more important small size [1]. This small size results due to the use of
high frequency switching, which is accomplished by using high frequency IGBT. For making the DCDC converter more robust one needs to design the pulse width modulator (PWM) controller. The
design methods of PWM controller have been discussed extensively in the literature [2, 3]. In this paper
we have used a linear quadratic regulator approach (LQR) for obtaining an optimal control which is
finally re-arranged to give the parameters of a Proportional-Integral-Derivative (PID) controller.
Although LQR can be directly implemented in the plant, but most of the industry uses PID controller
due to its simplicity which uses only three parameters to tune. Fig.1 shows the optimal tuning of PID
parameters using LQR approach. LQR gives the value of control vector u in an optimum way using the
calculus of variation approach [4] which minimizes the quadratic performance cost function as given
by:
∞
(
)
J(
u (t ))
=
X(t )T QX (t ) +
u(t ) T Ru(t ) dt
∫
(1)
0
(2)
1 T
u=
−
R−
B P
where, X(t) is the state vector; u(t) is the control vector; A is the state transitions matrix; B is the control
matrix; C is the output matrix; Q and R are the state and control weighting matrix operators which can
be optimized to give the necessary weighted to the state and control vectors to give desired closed loop
response [5,6].
Figure 1. Optimal tuning of PID using LQR approach
BUCK CONVERTER
Figure 2. Buck converter with switch ON
Figure 3. Buck converter with switch OFF
175
ONGOING PROJECTS
B
The value of the Riccati coefficient matrix, state weighting matrix, control matrix and the PID
parameters calculated for the Buck Converter of 12V/25mA given as:
4

 
1×
10 6
0
0 
1.761 ×
10 3
0 .9969
6×
10 −



−
7
−
4
−
7 
Q=
0
1×
10
0 
;R =
[
1]
P=
0 .9969
7.5809 ×
10
4 .2501 ×
10 


−
9
−
4
−
7
−
10  

0
0
1×
10 
6×
10
4 .2501 ×
10
3.7141 ×
10  

and,
K
K
[
p
d
]
[
4
Ki =
0. 7083 6.19 ×
10 −
1000
]
ONGOING PROJECTS
Figure 4. Simulated graph of the step response of the Buck converter
Figure 5. Experimented Buck converter and controller response
176
(3)
References
[1] Ned Mohan,”Power Electronics: Converter application and Design”, John wiley & Sons Inc.
[2] W.Stefanutti et.al “Auto tuning of Digitally Controlled Buck Converter based on Relay Feedback” IEEE 2005.
[3] Carlos Otalla et.al “Robust LQR Control for PWM Converters:An LMI Approach” IEEE Transaction on industrial
electronics,Vol 56,No.7,2009.
[4] D.S.Naidu “Otimal Control System”, CRC press 2003.
[5] Saptarishi Das et.al,”Impact of fractional order Integral performance Indices in LQR Based PID Controller Design
via Optimum selection of weighting matrrices” IEEE 2012 International Conference on Computer Communication
and Informatics,jan-10-12,2012,India.
[6] Jian-Bo He et.al”PI/PID controller tuning via LQR aproach”, chemical engineering science,vol 55,no 13. Pp24292439,July 2000.
Optical properties of an elliptical solenoid magnet for intense beam
A
solenoid magnet with elliptical pole face aperture creates unequal focusing forces in the two
transverse planes and can therefore be utilized in making a planer beam as well as transverse
matching to a system with unequal beam sizes in the two transverse planes. In this work the beam
optical properties of an elliptical solenoid magnet have been studied, including the effect of space
charge, and the feasibility of using an elliptical solenoid for transverse matching of a space charge
dominated beam to the acceptance of a spiral inflector has also been discussed. The transverse linear
equations of motion of a particle of rest mass m and charge q in the applied and beam self fields can be
written as [1]
S
S
qB ′
∂
ψ
qB′
∂
ψ
′
′
x′
= y+
Jy +
2K y′
+, y ′
=
− x+
Jx−
2K x′
+ (1)
2mγ
β
c
∂
x
2m γ
β
c
∂
y
S
3
2 2
where K = qB/(2mγβc), J = qD/(2mγβc) and φ
( x, y , s) =
qφ
/( m γ
β
c ) is the normalized space
charge potential (φ
is the usual electrostatic potential). We have obtained the infinitesimal transfer
matrix of an elliptical solenoid and at the same time we have also calculated the beam envelope by
employing the recursive sigma matrix method [1]. The beam matrix σ
(s) at location s is obtained
T
by σ (s ) =
(s0) is the beam matrix at location s0 and M(s, s0) is the
M (s , s0 )σ (s 0 )M (s , s0 ) where σ
infinitesimal transfer matrix for a small portion ds = s-s0 through the elliptical solenoid. The beam sizes
σ 33 (s ) , ε
det(σ x ( s)) , ε
det(σ y ( s))
and emittances are X ( s ) =
.
σ11 (s ) , Y ( s) =
y ( s) =
x ( s) =
In figure 1 the behavior of beam envelope and focusing properties of elliptical solenoid are compared
with the solenoid (J = 0 ) at two values of beam current I = 0 mA (solid) and I = 10 mA (dashed). The
input beam conditions for both cases are X(0) = Y(0) = 0.25 cm, X’(0) = Y’(0) = 0 mrad and ε
x(0) = ε
y (0)
= 60 π
mm mrad. In the case of elliptical solenoid the effect of asymmetric focusing and inter-plane
coupling effect is clearly visible from the envelope behavior. The beam envelopes for I = 0 mA are
different because of the parameter J which causes an extra gain in focusing force in y plane and a
reduction in the x plane. As a result the beam waist in y plane is formed at a shorter distance compared
177
ONGOING PROJECTS
A. Goswami, P. Sing Babu and V. S. Pandit
to that of the x-plane. The effect of space charge, as shown by dashed curve, not only increases the waist
sizes but also the location of the waists in both planes.
ONGOING PROJECTS
Figure 1. Beam envelopes for (a) solenoid (b) elliptical solenoid
magnet.
Figure 2. Transverse beam matching at the input of the
spiral inflector
A detailed simulation study through the spiral inflector indicates that convergent phase ellipses with
different orientations in x and y planes give better beam transmission through the spiral inflector [2].
Figure 2 shows the results of transverse matching of an axisymmetric beam at the entrance of the spiral
inflector by using an elliptical solenoid. The resulting beam envelopes producing a beam of unequal
sizes in x and y planes are shown in Fig. 2(a) and the phase ellipses are shown by solid lines in Fig. 2(b)
and 2(c). The required phase ellipses at the entrance of the spiral inflector for better transmission and
minimum emittance growth are shown by dotted curves in Fig. 2(b) and 2(c). The initial beam
parameters at the waist position (s = 0) of second solenoid are X(0) = Y(0) = 0.25 cm and ε
x (0) = ε
y (0) =
-1
60 π
mm mrad. The optimized parameters of the elliptical solenoid are K = 0.064 cm and J = 0.00014
-2
cm and length L = 25 cm. The location of elliptical solenoid and matching point from the beam waist of
the second solenoid are 20 cm and 65 cm respectively.
References
[1] A. Goswami, P. Sing Babu, and V. S. Pandit, Nucl. Instr. Meth. A 685(2012) 46.
[1] A. Goswami, P. Sing Babu, and V. S. Pandit, Eur. Phys. Jour. Plus 127 (2012) 79.
A Vlasov equilibrium for space charge dominated beam in a
misaligned solenoidal channel
T
he effect of displacement and rotational misalignments of solenoid magnets with respect to the
ideal beam propagation axis on the dynamics of intense charged particle beams have been studied.
178
The equation of motion of the beam centroid has been obtained and found to be independent of any
specific beam distribution. A Vlasov equilibrium distribution for the intense beam propagation through
misaligned focussing channel has been obtained. Self-consistent simulation confirms the analytical
result.
A schematic of beam transport system with misaligned solenoid magnets is shown in figure1. In figure
2(a) we have shown the evolution of beam centroid <x> and <y> as the beam propagates in the
misaligned solenoids. The numerical solution to the beam centroid equations (solid curves) shows a
Figure 2. Plots show the evolution of (a) beam centroid <x> and <y> (b) percentage change in rms beam emittances and (c)
rms beam sizes Xrms and Yrms as a function of drift distance s.
179
ONGOING PROJECTS
Figure 1. A schematic of beam transport system with misaligned solenoid magnets.
good agreement with the self-consistent simulation result (dashed curves). The input parameters are:
beam current I=10mA, normalized emittance ε
n = 0.8 mmmrad, <x>=<y>=0 and <x>'=<y>'=0, the rms
beam sizes Xrms=1.25mm and Yrms= 1.25 mm at s=0. The peak values of the magnetic field of solenoids
S1 and S2 are 3.035kG and 2.883kG respectively. The misaligned parameters of S1 are ∆x= 3mm, ∆y= 3mm, θx= 0mrad, θy= 0mrad and for S2 are ∆x=-5.225mm, ∆y=5.225mm, θx= -0.09deg, θy=0.09deg.
Other important parameters for the numerical simulations used are: Np= 77000, step size along the axial
direction ∆s=1mm, Nx= Ny= 128. Here we have assumed that the beam pipe is of square cross-section
12.8cm × 12.8cm. From Fig. 2(a) we see that initially the beam centroid which is aligned to the beam
propagation axis get deviated from the ideal axis as it enters the dipole field region of the misaligned
solenoid. Figure 2(b) shows the evolution of percentage change of rms beam emittances εx and εy
obtained with PIC simulation for misaligned (dashed curves) and aligned (dotted curves) solenoids. It
can be readily seen that the beam emittances are well conserved in the case of misaligned solenoids and
the evolution of emittances is similar to the aligned solenoids, confirming that the chosen K-V beam
distribution function is the equilibrium distribution. The comparison of the rms beam envelope sizes
shown in figure2(c) indicates that there is hardly any difference in the evolution of the beam envelopes
for the cases of misaligned and aligned solenoids.
Reference
ONGOING PROJECTS
[1] P. Sing Babu, A. Goswami and V. S. Pandit, Phys. Plasmas 19 080702 (2012).
180
4.5
SUPERCONDUCTING CYCLOTRON UTILISATION
PROJECT (SUCCUP)
VECC cryogenic penning ion trap : a status report
A. Ray, A. K. Sikdar, P. Das, A. Reza, Subrata Saha and M. Ahmed
T
he Magnet-Cryostat of VECC Penning Ion Trap [1, 2] that would house the Penning trap assembly
was commissioned on 17/2/2012. The electrode assembly for loading, trapping and ion detection
set up for this cryogenic trap facility is in its advanced stage and the progress made is reported here.
The magnet-cryostat system had been kept at liquid helium temperature (4 K) for quite some time and
cryostat stability was tested for any quenching effect before powering up the magnet. The system was
powered up by inserting a detachable charging wand through the charging port of the system. In order
to send current through the main superconducting coil, a superconducting persistent mode switch was
at first heated up by sending 55mA current through a heater placed close to it. As the persistent switch
became resistive, it allowed us to send current through the main solenoid coil. The current in the main
solenoid coil was raised slowly from zero to 96.9 Amp (corresponding to 5 Tesla magnetic field). This
is the maximum magnetic field that can be obtained from the system as per design specification. After
attaining the maximum current, the heater of the persistent switch for the main coil was turned off and
the switch was allowed to cool off to reach superconducting temperature. As soon as the persistent
switch became superconducting again, 96.9 Amp current started flowing in a closed loop comprising
the main solenoid magnet coil and the switch. At this stage, the current from the power supply was
switched off and the system started running in the persistent mode.
Then seven superconducting shim coils were energized one by one. In order to do that, the persistent
mode switch of each shim coil was first made resistive by sending 90 mA current through a heater
placed close to it. As the switch became resistive, current was sent through the shim coil. The current
through the shim coils varied from 0.67 Amp to 4.1 Amp as per requirement. As the current reached
appropriate value, the heater was turned off and the switch was allowed to cool off and became
superconducting again. Then the current started flowing in a closed loop comprising the shim coil and
the switch, the external current was switched off and the shim coil was put in persistent mode.
After putting the main coil and all the seven shim coils in persistent mode, the external power supply
was switched off and the power cables were disconnected from the magnet. The magnetic field
remained as before. After running the system in persistent mode for 17-18 hours, we reconnected the
power cables to the supply and measuring devices to measure currents through the solenoid main coil
and shim coils. We found all the currents were exactly the same as before showing that the system was
running in persistent mode perfectly well.
Design, Simulation, Fabrication and measurements of electrode assembly for electron trapping
Design of a five electrode cylindrical trap assembly that would provide the quadrupolar potential has
been done taking into account realistic gap effects. Extensive simulation work has been done and a
181
ONGOING PROJECTS
Commissioning of the magnet-cryostat system
careful choice of electrode lengths, voltages applied to various electrodes has been selected that would
not only produce the high quality electrostatic quadrupole potential at the centre of the trap but also
satisfy the orthogonality condition which makes the trapping potential depth independent of
anharmonicity of tuning voltages applied to correction electrodes.
In order to determine the capacitance of the trap electrode assembly under cryogenic condition, an
oscillator circuit has been designed. The complete setup with Field Emission Point (FEP) holder and
accelerating electrode for electron generation and trap assembly is shown in Fig 1 and it is under
fabrication.
Results and Discussion
The magnet-cryostat of VECC Penning Ion Trap facility has been commissioned. The trap electrode
assembly, insertion arrangement and detection setup are in advanced stages of fabrications. Simulation
studies are being pursued with virtual assembly for understanding response of the trapped ions.
ONGOING PROJECTS
Figure 1. TRAP assembly with electron source
182
SUPERCONDUCTING CYCLOTRON UTILISATION PROJECT (SUCCUP)
References
[1] P. Das et al. Proc. Of the National Symp. On Nucl. Inst-2010, 33 (2010)
[2] K. Blaum, Phys. Rep. 425, 1 (2006).
[3] SIMION 8.0 user manual
Design of a dynamic orthogonalized Penning trap with higher
order anharmonicity compensation
A.K. Sikdar , P. Das and A. Ray
Penning trap uses a strong and uniform magnetic field and an electrostatic quadrupole potential
to confine and manipulate charged particles. Penning traps with cylindrical electrodes have the
advantage of machining to better surface finish and also provides the accessibility for particle loading
and rejection, laser beams and microwaves [1]. A set of compensation electrodes can be introduced to
tune out the anharmonicity of a Penning trap to first order. The concept of an orthogonalized Penning
trap was introduced for a trap with special geometries such that the trapping well depth and the trapped
particle axial oscillation frequency were independent of the tuning of anharmonicity. We have been
working on a new design of double compensated cylindrical Penning ion trap including the effect of
realistic gap and trying to reach design parameters to tune out anharmonicity parameters up to C8.
Let V0be the voltage applied between the ring and the endcaps, then the electric potential close to the
centre of the trap can be written as
(1)
In the expression, it
where d is the characteristic dimension of the trap, defined as d=
is assumed that the trapped ions have no effect on the potential field and the centre of the ring electrode
is considered as origin. In order to generate an ideal quadrupole trapping field, it is required that all Ck (k
> 2) should be zero. By varying the lengths of the electrodes, we have been able to make the trap
dynamically orthogonalized and tune out higher order anharmonicities up to C8 term over a wide range
of inner radii of the cylindrical trap and gap lengths between adjacent electrodes. Let Zg, Z1,lc1, lc2 be the
gap between adjacent electrodes, half-length of ring electrodes and lengths of the compensation
electrode 1 and electrode 2 respectively. Let us define Z2=Z1+Zg+ lc1 and Z0=Z2+2Zg+lc2. In Fig. 1, we
show the variation of C8 with Z2/Z0 for different values of Zg/Z0 as obtained by varying the lengths of the
electrodes and the gap between adjacent electrodes for dynamically orthogonalized trap.
Discussion
We have done calculations of the electrostatic potential profiles for doubly compensated, open ended
cylindrical Penning traps including the effect of the gaps between adjacent electrodes. The dynamic
orthogonalization and tuning out of the first and higher order anharmonicities (C4, C6 & C8 ) have been
achieved by proper choice of the lengths of the trap electrodes for a trap of fixed total length. The
183
ONGOING PROJECTS
A
coefficients obtained from the analytical solution match very well with those obtained from the
SIMION8 code [2]. We have provided new information for building Penning traps with a quadrupolar
potential which minimize the unwanted axial frequency shift due to the trap imperfections. This work
can be useful in designing Penning traps for high accuracy mass measurement and several other trap
applications.
ONGOING PROJECTS
Fig. 1a. Variation of C8 as a function of Z2/Z0for different values of Zg/Z0.
References
[1] R.S. Van Dyck Jr., D.L. Farnham, P.B. Schwinberg, IEEE Trans. Instrum. Meas. 44, 546 (1995).
[2] SIMION 8.0 user manual.
Design and development of backward part of CPDA system
S. Roy, S. R. Bajirao, S. Bhakat, S. Manna, C. Nandi, G. Pal, S. Kundu,
C. Bhattacharya and S. Bhattacharya
D
evelopment of backward part of 4π Charged Particle Detector Array (CPDA) has been
undertaken at VECC to understand basic properties equations of state of nuclear matter, liquid
gas phase transition, isoscaling etc using Superconducting cyclotron beam. According to types of
detection system, the array can be divided into three parts. The backward part of the detector system
0
0
0
0
spans over polar angle of θ
= 45 -175 with all arrays having azimuthally coverage of φ
=0 -360 .
Front face of the detectors form a part of sphere of radius 150mm and the spherical surface was
discretized with isosceles trapezoids which represents the functional face of a detector. The shape of the
detectors resemble to frustum of a pyramid. There are 6 arrays with azimuthally symmetry and
different numbers of detectors will be kept in different rings with different angle. A support structure
184
SUPERCONDUCTING CYCLOTRON UTILISATION PROJECT (SUCCUP)
Figure 1. Fitting simulation of CPDA assembly
Figure 2. Forming of sheet metal for detector housing
185
ONGOING PROJECTS
has been designed for mounting the detectors as per required orientation. The detectors are placed
inside shell made of SS plate. Each shell is assembled with a handle which is fitted with an adjustable
fixture to support the detectors. The entire assembly of detector and its housing is mounted on six
support rings each of which is placed in between two consecutive arrays. The simulation for
dismantling a single housing was carried out with fitting simulation module of CATIA software (Fig. 1)
to asses the accessibility of individual detectors for maintenance. Support ring cross sections are
contained outside of the swept volumes generated by imparting radial out ward motion on two adjacent
segments. The support rings are mounted on a base plate through 4pairs of skewed legs.
The detectors are encased within open ended housings of shell thickness 1.6mm. The fabrication of the
detector housings were carried out from 1.6mm thick Stainless Steel 304 sheets. The development of
the sheets was carried out and die-punch were designed for bending the sheets. In order to achieve the
inner corner without any bending radius, 'V' grooves were cut upto two third depth of the sheet along
the bending line. The housings were formed using a customized set up (Fig. 2) within a dimensional
tolerance of 0.1mm. The detector shells were electro-polished to achieve a surface roughness of
0.2micron or better.
The handles, support rings and legs are made from aluminum2024 plates. The profile of the handles and
support rings were laid appropriately to minimize the material wastage. The geometry of support rings
consists of multiple surfaces oriented at specific angle which is required to achieve the specified
detector orientation in final assembly. The three dimensionally oriented surfaces of the support rings
were machined with extreme precision with the CNC machining centre. Special jigs were designed and
fabricated to carry out drilling and tapping of the dowel pin holes and threaded holes on these surfaces
oriented at different angles. The jigs were mounted on the rotary axis of the CNC machine and required
rotation was given to the handles and support rings to align the surfaces normal to tool axis.
ONGOING PROJECTS
Figure 3. Final assembly of the backward part of CPDA
The parts were inspected with the Portable CMM and dimensionally nonconforming parts were
eliminated. The mechanical design, component level fabrication, inspection and final assembly (Fig.
3) of backward part were carried out at the workshop of Accelerator Technology Development Section.
186
4.6
RF SUPERCONDUCTING CAVITY
Multipacting analysis of 650 MHz, β
=0.61 SRF
cavity using 3D CST Code
RF Division, VECC
A
ONGOING PROJECTS
fter the preliminary study of multipacting analysis for 650 MHz, β
=0.61, 5-cell SCRF cavity
using 2D code MultiPac2.1 (Windows version), it is observed that for mid-cells and end-cells,
even after 30 impacts of electrons at the equator region (at the radius of 197 mm.) of the cavity, the final
Figure 1. VECC 650 MHz,β
=0.61 SRF Cavity dimensions
187
impact energy is 28.4364 eV, which is well below 50eV and hence it is unlikely to cross secondary
electron emission yield for producing multipacting. In case of 2D code, only true secondary emission
has been taken into account. Now, multipacting analysis using 3D CST Particle Studio has been
carried out. Unlike 2D codes, three types of scattering particles (true, elastic and rediffused secondary
ONGOING PROJECTS
188
RF SUPERCONDUCTING CAVITY
particles as per "Fuman model of emission") are taken into consideration in the most sophisticated 3D
CST code.
9
In the 3D CST simulation, the whole cavity could not be simulated because it requires around 10 or
more cells, which would take a very long time of calculation for each variant. So, the simulation of
6
particles motion by CST has been carried out with typical mesh cells around 10 and time of calculation
is around 2 hours per variant.
In case of VECC 650 MHZ, β
=0.61 cavity (as shown in Fig.1), 30 mm. of equator region has been
simulated with mesh size 0.37 mm.(minimum) and 0.74 mm. (maximum). It is observed from the
following figures that the multipacting has been found between 5.8 MV/m and 11.5 MV/m electric
field gradient. The multipacting growth rate is very fast at 6.8 MV/m and the rate is very slow at 11.6
MV/m. There is no multipacting at 4.5 MV/m and above 22.5 MV/m.
ONGOING PROJECTS
Unlike true seondary elctrons only in 2D code, the elastic and rediffused electrons change the situation
drastically and have been included in the 3D model. As a result, 3D CST code can see multipacting
inside the cavity equator.
189
4.7
SUPERCONDUCTING MAGNETIC ENERGY
STORAGE (SMES)
4.5 MJ SMES Cryostat
Uttam Bhunia, Javed Akhter, Chinmay Nandi and Gautam Pal
T
ONGOING PROJECTS
he Cryostat for 4.5 MJ SMES is designed in VECC. Large toroidal coil assembly will be housed
inside the cryostat. Due to the large size of the cryostat the diameter of the cryostat is also very
large (2 m approx.). Number and size of support links are optimized to minimize heat loss without
compromising with required mechanical strength. Each sector coil will have a separate helium
container of stainless steel to minimize the helium volume. Sector cryostats are interconnected through
flexible coupling. The entire toroidal coil system along with liquid helium chamber is enclosed in
thermal shield. Layers of multi-layer insulation (MLI) will be wrapped over the thermal shield. The
thermal shield will be maintained at around 60 K using a single-stage Gifford-McMahon (GM) type
refrigerator (capacity of 240 W at 60 K). The surface area of the intermediate thermal shield is
2
2
approximately 9.0 m . The inside surface area of the vacuum tank is 9.55 m . The total cold mass
together with backing plate and backing cylinder is about 1600 kg. The provisional scheme of the
assembly is shown in Fig. 1. The expected steady state heat load is shown in table 1.
Table1 : Expected Steady State Heat Load
Lhe chamber
Intermediate shield
Radiation
5.0
14.5
Conduction: Support link
0.45
7.2
Conduction: Current Lead(HTS)
0.5
105
Instrumentation Ports and others
0.5
2.0
Total
6.0
128.7
The design of the Cryostat is performed in
accordance with ASME boiler and pressure
code Section VIII Division 2. The wall
thickness of the cryostat 15 mm and the flange
is 50 mm thick. The diameter of the cryostat is
around 2.2 mm while its height is
approximately 1.5 m. Detailed Stress Analysis
is also performed on the Helium Vessel and the
on the Cryostat.
Figure 1. SMES cryostat scheme
190
SUPERCONDUCTING MAGNETIC ENERGY STORAGE (SMES)
Development of power conditioning system for 0.6MJ
superconducting magnetic energy storage system
Samit Bandyopadhyay, Anirban De, Yashwant Kumar, Sudhanshu Srivastava, V.K.Khare,
Santwana Kumari, M.L.V.Krishnan, S.S.Pal, A. Bera, A.Sadhukhan, M.K. Ghosh, Lalit
Biranwar, Ranjan Kumar, Mousumi Garai, Anand Kumar, C.S.Prasad, V.K.Meshram,
Amareshwar Patra, Arvind Kumar, S.K.Thakur, Manoranjan Das and Subimal Saha
T
ONGOING PROJECTS
he Power Conditioning System (PCS) with the energy storage capability working as a Dynamic
Voltage Restorer (DVR), which is the most effective and viable solution for improving the voltage
sag of the electrical utility supply, is shown in Fig. 1. The major components of the PCS consists of
rectifier and dc-dc Chopper for charging / discharging of the SMES coil, a voltage source inverter
(VSI) for mitigating the power line sag, passive filters for suppressing unwanted harmonics, injection
transformer and DSP based control and instrumentation for voltage sag detection and mitigation.
Development on all these subsystems is in progress at the centre.
Figure 1. Basic scheme of the integrated power conditioning system using SMES
191
The control system of SMES based DVR has three parts
1. Voltage compensation control, which detects the voltage fluctuation and generates the reference
voltage for compensation.
2. Series converter control, which controls its output voltage according to the reference voltage for
compensations.
3. DC chopper control, which regulates the power transfer of the superconducting magnet in
coordination with the voltage control of the PWM converter.
In the process of voltage compensation using the Dynamic Voltage Restorer (DVR), the DC-DC
chopper is utilized to control the energy transfer to and fro the superconducting magnet. The chopper
has two basic operation modes as follows.
1. Charging: The chopper absorbs active power from AC side and charge the superconducting
magnet to the desired set current.
2. Discharging: The chopper delivers active power to the AC side and discharge the
superconducting magnet.
ONGOING PROJECTS
Figure 2. Front (left) and rear (right) views of the two quadrant DC-DC chopper
A high current two-quadrant dc-dc chopper (Fig. 2) has been designed and developed for charging the
SMES coil to a constant current (ISMES= 400A) for energy storage and for discharging to a constant dc
capacitor voltage (Vdc= 56V). A novel topology of Hysteresis-Band current controller is adopted for the
development of the two-quadrant chopper. The SMES coil was satisfactorily energized by the chopper
upto its rated current.
The NbTi based cryostable and solenoid type 0.6MJ SMES coil with HTS (BSCCO-22237) based
current leads along with related instrumentations, quench detection and protection system, dump
resistors and the data-logging systems are assembled, integrated and connected for energization of the
coil. The coil with 800kg of cold mass and inductance 1.86H underwent rigorous cryogenic tests and
thereafter cooled down to 4.5K. The “Hysteresis Band Current Controller” based two-quadrant dc-dc
192
The control philosophy of the VSI, implemented by DSP based controller with associated
interfacing, is to sense input 3-φ
voltage by a multi-channel 12-bit 12.5MSPS ADC, synchronise its
phase so as to offer the compensation at the correct phase at the injection transformer output and finally
generate the required PWM based gating signal to the IGBT bridge. The high frequency is filtered out
by a LC combination that generates the output wave. Fig. 4 and 5 show recorded result of the VSI with
mains being simulated by a programmable power source and the load being a star connected resistive
network.
Design study of 4.5 MJ sector-toroidal SMES coil
U Bhunia, J Akhter, J Pradhan, B Mondal, C Nandi, V K Khare, U S Panda, A De,
S Bandopadhyay, A Roy, T Bhattacharyya, S K Thakur, M Das, G Pal and S Saha
ONGOING PROJECTS
I
n continuation of SMES technology development in our centre, design study of a 4. 5 MJ (1.25 kW h)
sector-toroidal SMES coil using custom make Rutherford type NbTi cable is reported. The sectortoroid is optimized with six modular type solenoid coils connected in series. The basic module is
considered to be solenoid type because of its easier winding technique though it is not the best choice
from stress considerations. The coil operating current as well as maximum magnetic field at the inner
layer has been determined in order to limit voltage across the coil during discharging mode of its
operation and also to minimize the overall dynamic and static load in the cryostat. Due to asymmetric
field distribution around the coil, each coil experiences a huge radially inward body force that needs to
be arrested with proper support structures. Therefore, extensive magneto-structural stress analysis has
been carried out using commercial finite element code ANSYS to understand the integrity of the
structure. Transient electromagnetic analysis has also been carried out to find out dynamic loss
developed into the cryostat.
Design analysis
The magnet cryostat as shown in Fig.1
primarily includes the coil former, backing
cylinder, backing plate to transfer body force
from coil to backing cylinder, intermediate
copper shield around the helium chamber,
fiber-reinforced plastic (FRP) support
structure, etc. Each sector coil will have a
separate helium container of stainless steel
interconnected through flexible coupling to
minimize the helium volume. The entire
toroidal coil system along with liquid helium
chamber is enclosed in thermal shield. The
thermal shield will be maintained at around
60 K using a single-stage Gifford-McMahon
(GM) type refrigerator.
Figure1. Cryostat assembly
194
SUPERCONDUCTING MAGNETIC ENERGY STORAGE (SMES)
The coils are made of custom make cryo-stable Nb-Ti Rutherford type cable and will be kept in a liquid
helium pool boiling bath cryostat. The detailed design specification of the magnet is as illustrated in
Table 1.
Table 1. Toroidal field coil parameters
4.5 MJ (1.25 kWh)
Output power
1 MW
Maximum current
1225 A
Maximum voltage
1.2 kV
Number of sectors
6
Individual coil module
Solenoid
Number of turns
21×78
Coil ID/OD/Height
380/480/300 mm
Arrangement
Toroid
Conductor
Rutherford type
Insulation
Polymide (~25µm thick & 50 % overlap)
IC of conductor
≥
2200 A (7T, 4.2 K)
Cooling system
Pool boiling in liquid helium
Steady-state Load
1.75 W (at 4.2K)
122 W (at 60 K shield)
During normal operation, the forces on and around the coils are asymmetric and non-uniform that
produces a net centered magnetic force as shown in Fig.2. A net inward radial force on the coils (in our
case at steady state: around 500 kN on each coil) develops as calculated by Maxwell stress tensor
formalism towards the magnet centre.
Figure 2. Nodal magnetic force distribution
Figure 3. von-Mises Stress on assembly
Corresponding to peak magnetic field of 7T on magnetic median plane of winding, coil winding pretension of 20 kgf has been determined to be applied so that under all possible scenario radial stress is
negative.
A sequential coupled analysis utilizing ANSYS finite element has been performed for two main
operating conditions: thermal cool-down to 4.5 K and energisation. The equivalent (von-Mises) stress
distribution developed on the cold assembly during excitation at 4.5 K is as shown in Fig.3. Maximum
von-Mises stress has been found to be 258 MPa on coil former as summarized in Fig.4. The coil former
195
ONGOING PROJECTS
Stored energy
is made of stainless steel 316LN which has high strength at cryogenic temperature and can withstand
the stress developed.
Figure 4. Stress summary
Figure 5. Dynamic heat load
ONGOING PROJECTS
The dynamic heat load developed due to high magnetic field transients in superconducting cable and
the nearby metallic structure is quiet significant as shown in Fig.5. This dynamic load together with
static load, therefore, will develop pressure built-up during each discharge cycle. However, since the
discharge period is only over few seconds, the helium vapor so evaporated can be recondensed back
into the system.
196
Regional Ra diation
Medicine C entre
Activities of the regional radiation medicine centre,
VECC, year-2012
S. Sinha, B.R. Sarkar, C. Nandi, S. Mitra, A. Gupta, S. Ganguly and S. Saha
Introduction
REGIONAL RADIATION MEDICINE CENTRE
T
he Regional Radiation Medicine Centre (VECC), Kolkata was set up by the Department of
Atomic Energy in the year 1989, in collaboration with the CCWHRI, Thakurpukur. This is a part
of the DAE's charter with the same philosophy as Radiation Medicine Centre, BARC, Mumbai, to
bring the benefits of nuclear science to the common man of Eastern India for the diagnosis and
treatment of human diseases.
The present activities of the RRMC include in-vivo nuclear imaging, in-vivo non-imaging studies,
in-vitro diagnostic studies, and radionuclide therapy.
In-vivo nuclear imaging
The most important equipment at the RRMC is the Dual Head Gamma Camera with CT (Infinia
Hawkeye TM) from GE., installed in April 2007.
With this state of art gamma camera, static imaging like Skeletal, Thyroid, Liver, Whole body I131(Large Dose), and dynamic imaging such as, Renal Dynamic, Hepatobiliary, G.I. bleeding, etc. are
being performed regularly.
This camera is also being used occasionally for more sophisticated imaging like SPECT/CT imaging of
skeletal system, cardiac Gated Blood Pool Imaging, Scintimammography(Breast Imaging),
Parathyroid imaging etc.
Around 130 patients under went various type of Nuclear imaging every month during this year.
In vivo non-imaging
The main In-vivo non-imaging studies being performed at the RRMC is Thyroidal Iodine-131 uptake
studies for various diseases of the thyroid gland.
An imported state of the art PC Based Uptake Probe with Well Counter is used for this purpose.
A total number of 165 patients under went I-131 Uptake Study during this year.
In Vitro Diagnostic studies
In-vitro diagnostic studies being performed regularly at present are radioimmunoassay of thyroid
hormones:
Tri-iodothyronine, (T-3) and Thyroxin, (T-4), as well as Thyroid Stimulating Hormone (TSH) and Free
thyroxin (Free T-4).
198
These studies are essential to assess thyroid function in various thyroid diseases.
The imported PC Based Multi detector Automatic RIA Counter is being regularly used for counting
and processing of RIA data and use of this counter has ensured rapid generation of RIA reports and also
high quality of reports.
Around 180 patients under went radioimmunoassay every month during this year.
Radio nuclide therapy
In collaboration with the CCWH&RI, a facility for high dose Iodine – 131 therapy of Cancer of Thyroid
patients (On an Inpatients basis) was started in 2004.
SPECT CT FUSION IMAGES OF LUMBAR SPINE TRACER : TC-99 M MDP
199
This is the only facility of its kind in West Bengal A total number of 49 patients under went I-131
Therapy of Cancer of Thyroid during This year.
In addition, low dose Iodine I-131 Therapy is being administered to patients of Thyrotoxicosis
(Graves's disease) (On an Outpatients basis).
A total number of 48 patients under went I-131 Therapy of Thyrotoxicosis during this Year.
CARDIAC GATED BLOODPOOL IMAGING (MUGA STUDY) TRACER : Tc-99m RBCs
200
Research Activities
Besides its routine activities, RRMC also carries out some research and development activities.
At present, we carry out collaborative research projects with the Indian Institute of Chemical
Biology, Kolkata, and the unit of BRIT at VECC, involving animal imaging using various newly
developed radiopharmaceuticals meant for the imaging of various organs or lesions. 2 no. of research
papers based on these collaborative studies involving the RRMC have been published in international
journals.
Under the program of short duration vocational training to students of different educational
th
institutions undertaken by the VECC, we at the RRMC imparted vocational training to a 4 year student
of B.Pharm (Engineering) from the “Bengal School of Technology” at Sughandha, Hooghly, West
Bengal for a period of around 1 month.
We Also guided and supervised his Project (Dissertation) work.
Percentage of Different Nuclear Scans-2012
201
Academic Activities
Internation al
Collaborati on
Measurement of leakage current for 1 cm2
silicon pad detectors
S. A. Khan, R. N. Singaraju, P. Bhaskar, J. Saini and T. K. Nayak
O
INTERNATIONAL COLLABORATION
ne of the most important performance requirements of any Silicon detector is the dark-state
reverse bias leakage current, i.e. dark current. This sets the limit of noise. Limit of the leakage
current sets an important parameter for acceptance or rejection of a detector. The leakage current for 1
2
cm Si pad detector of 300 µm thickness is measured using Keithley Picoammeter Model 6487 by
interfacing the meter to PC through Rs232.
Figure 1. Measurement setup (left side) along with the variation of leakage current Vs bias Voltage (right side) for a single
element and with two and three elements in series.
The methodology used for this purpose is reverse bias applied to the detector through the Keithley
Model 6487 meter itself which has a facility of sourcing voltage (max 505V) also. The voltage is varied
in steps of 5 volts and the leakage current is measured at each step through a tri-axial cable attached to
the detector. The detector is kept in a light tight arrangement to avoid ambient light entering it. The
leakage current continuously fluctuates over a range at a given value of reverse bias, so an arrangement
is made in the meter itself to average all the fluctuating values of leakage current over few seconds. This
averaged value of leakage current is sent out to a PC via RS 232 for storing, plotting and further
processing as shown in the plot of fig.1. Leakage current is measured for a single element, two elements
and three such elements in series for the verification. All the measurements are done at the room
204
temperature of 25 degree cent. The leakage current of the single element at 100 volts reverse bias is
2
about 10nA/cm , which is in accordance with the specifications of the manufacturer Bharat Electronics
Limited Bangalore.
Beamtest of triple GEM detectors with particle beams
A.K. Dubey, S. Chattopadhyay, J. Saini, R. Singaraju, S. Pal, A. Prakash1, B. Singh1
Department of Physics, BHU, Varanasi
A
Gas Electron Multiplier (GEM) based detector has been envisaged for the Muon Chamber
(MUCH) in the CBM experiment at FAIR. In this regard prototype chambers were built at
VECC and tested with high energy proton and pion/muon beams at Julich, Germany in January
2012 and at CERN SPS in November 2012, respectively. A test with high a intensity Cu-X-ray
source was also conducted in RD51 laboratory at CERN to study the gain stability at high rates.
A triple GEM chamber was tested with 2.6 GeV/c proton beams at the Jessica beamline facility at
COSY accelerator facility in Julich. The main goal in this test beam was to study the response of
the detector by varying the detector parameters such as the drift voltages, the voltage difference
for every GEM, the transfer field and the induction fields. In order to achieve this, each of the
GEM planes and the drift plane was powered separately using independent power supply
channels. Their voltages were accordingly changed and data sets were taken for different field
configurations of the triple GEM chamber. The timing response and change in the detector gain
was studied in order to optimize the operating conditions. A high intensity run was also taken at the
end to study the dependence of gain and efficiency with rate. A typical timing spectra and variation
of efficiency with rate is shown in Fig. 1.
Figure 1. (Left) A typical time difference spectra of the detector hits relative to the trigger time. (Right) Variation of efficiency
per event in a particular time slice.
205
1
Figure 2. Picture of the first “miniMUCH” test setup at CERN SPS.
Figure 3. (Top) picture of the triple GEM chamber under test with Xray
source. (Bottom) Cu X-ray pulse height spectra for varying incident
intensities.
206
In the CERN beamtest conducted
in Oct-Nov. 2012, an almost
complete muon tracking setup
(mini-MUCH) was employed for
the first time. It consisted of 5
GEM detectors, as shown in Fig. 2,
to face the muon and pion beams.
Each of these chambers were
readout via self triggered
electronics, nXYTER. Two sets of
absorbers, one of 20 cm thickness
and other of 70 cm thickness were
inserted at different places. At low
intensity, the tracking has been
demonstrated to work very well.
At an intensity larger than 1
MHz/cm2, where the data rate is
very high, there are some
unresolved issues which are under
investigation.
In order to test the rate capability
of the triple GEM chamber
independent of a self triggered
readout, we performed a test with a
high intensity X-ray source in the
RD51 laboratory at CERN. This
Cu target X-ray source having a
characteristic energy of 8~keV
was incident from a narrow tube
having an aperture of ~2 mm
diameter on a 10 cm x 10 cm
chamber as shown in Fig 3 (top).
The signal was readout via
standard Ortec NIM electronics
and the pulse height spectra using
an MCA is shown in the
Fig.3(bottom). The results clearly
show that the gain of the chamber
remains pretty stable upto the
highest intensity tested of about
1.2 MHz/cm2.
Kolkata Tier-2 @ ALICE Grid
Vikas Singhal and Prasun Singh Roy
n beginning of year 2012, a green and efficient cooling solution for Kolkata Tier-2 site has been
implemented. Solution is based on cold and hot aisle containment concept (reported in VECC
Progress Report
2 0 11 ) . D u e t o
cooling solution
implementation,
performance of the
site with respect to
throughput of
completed jobs has
increased and
failure of hardware
has decreased.
K o l k a t a Ti e r - 2
comprises of 476
core of computing
which is equivalent
Figure 1. Completed jobs during Year 2012
Figure 2. Network traffic chart for Year 2012
207
I
to 6000 HEPSpec 2006. Figure 1 shows that Kolkata Tier-2 successfully completed more than 800000
real ALICE jobs during 2012 which is more than 3 times compared to 2011.
Kolkata Tier-2 comprises 227TB of usable space which is connected with 4 disk servers named
dcache-pool (37.3TB), dcache-client (33.4TB), storage01 (78TB), storage02 (78TB) and one
redirector server named dcache-server.tier2-kol.res.in. Figure 2 shows traffic in and out from these 5
storage servers during year 2012. Kolkata Tier-2 network backbone is 1Gpbs which we are going to
increase to 10Gbps. It has dedicated 1Gbps network connectivity to the CERN, therefore traffic graph
shows that our SE elements were consuming the available network bandwidth and total around 900 TB
of data travelled to and fro to these 5 servers during the entire year.
Multiplicity fluctuations in high-energy heavy-ion collisions
Maitreyee Mukherjee, Sumit Basu, Subikash Chaudhuri and Tapan Nayak
O
ne of the very basic advantages of the heavy ion collisions at very high energies is the production
of large number of particles in every event. This allows for a detailed study of event-by-event
? uctuations in particle multiplicities. Since multiplicity of produced particles is an important quantity
to characterize the evolving system, its ? uctuation from event to event may provide a distinct signal of
the phase transition from hadronic gas to QGP phase. The observed ? uctuations will have contributions
from statistical ? uctuations and those which have dynamical origin. To extract the dynamical part from
the observed ? uctuations, one has to understand the contributions from statistical and other known
sources.
A lot of theoretical interest has been generated on the subject of event-by event ? uctuations, primarily
motivated by the near perfect Gaussian distributions of several observables for a given centrality bin. If
the distribution of a quantity X is Gaussian, then the ? uctuation of the distribution is the variance
squared normalized to the mean of the distribution under consideration. Thus it is very important to
control centrality properly in all ? uctuation studies such that the multiplicity distributions are good
Gaussians. Keeping this aspect in mind we have used a different set of centrality selection by taking 1%
,2% and 5%cross section bins, such as 0-1%, 1-2%, 2-3% or 0-2%, 2-4%, 4-6%, 6-8% and 0-5%, 510%, 10-15% etc. The resulting multiplicity distributions are good Gaussians in nature with χ2/ndf
between 1 and 1.5. The minimum bias distribution is the convolution of such Gaussians. We have
obtained the centrality-dependence and beam-energy dependence (from RHIC to LHC) for
multiplicity fluctuation using event generators AMPT-Default and AMPT-String Melting. Details of
the results will be reported soon.
208
First level event selection for MUCH using GPU
V. Singhal, P. P. Bhaduri, A. Prakash1, S. Chattopadhyay and S. K. Aggarwal2
1
Banares Hindu University, Varanasi, India; 2Indian Institute of Technology, Kanpur, India
Introduction and motivation
t FAIR energies, the cross section for J/ψ production is extremely low, such that a measurement
requires very high interaction rates of up to 10MHz. The corresponding data volume has to be
reduced online by selecting only events potentially containing a J/ψ. Here we report on the
development of an event selection procedure on GPUs, which allow executing thousands of threads in
parallel. The algorithm was implemented on the NVIDIA Tesla C2075 card[1], using the Compute
Unified Device Architecture [CUDA][2]. To achieve a high execution speed of the event selection, the
algorithm developed earlier[3] was modified and implemented in the C language using the CUDA API
on TESLA C2075 Card. The algorithm is designed to select events likely to contain J/ψ. It is based on
searching for the hit triplets which are formed using the spatial information associated with
reconstructed hits. We tested and developed the algorithm on simulated J/ψ decays, generated by
PLUTO, which were embedded into
minimum-bias Au+Au collisions at 35A
GeV from UrQMD.
First Level Event Selection using
GPU
The acceleration of the event selection
was performed in several steps. First,
the original procedure was
implemented in CUDA (Opt-1). It was
then optimized by using coalesced
memory access according to the CUDA
architecture (Opt-2). Further
optimization was achieved by reducing
the number of global reads (Opt-3). Fig. Figure1: Time comparison between different optimization steps as a
function of the number of events processed in parallel
1 shows a comparison of the execution
Table1: Final results for event selection algorithm
# EVENTs
GPU Time (ms)
CPU-GPU Transfer
Time(ms)
CPU Time (ms)
Speed Up
1000
30
1
120
4
2000
30
1
250
8
3000
30
10
370
12
4000
30
10
490
18
5000
40
10
610
15
10000
50
10
1230
25
20000
80
10
2470
31
40000
140
20
4920
35
209
A
time on CPU (entire code running on single core of CPU) and on GPU for the different optimization
steps (Opt-1, Opt-2 and Opt-3), together with the data transfer time from CPU to GPU, as a function of
the number of events processed in parallel. After the optimization of GPU code (Opt-3), the
computation time is significantly reduced compared to execution on CPU, but the CPU to GPU data
transfer time is substantial. After analyzing this problem, we could, with little computation on the CPU,
reduce the data volume which has to be transferred from CPU to GPU. Table1 shows the results after
this last optimization step. For 40000 events, we achieved speed-up by a factor of 35 on the GPU with
respect to a single-core CPU. The data transfer time is reduced to a small fraction of the computation
time.
Conclusion and Future Scope
In summary, we have demonstrated the implementation of an accelerated event selection for the
5
5
MUCH detector based on GPU. Table1 shows that we can process 3×10 to 4×10 events per second
using one GPU Card. The present hardware supports up to four GPU cards on a single motherboard;
6
thus, we can process more than 10 events per second, which is close to the targeted event rate. The
distribution of computation between GPU and CPU remains a subject of research. Our results suggest
that the usage of GPUs can be beneficial for performing first level event selection in the CBM
experiment. Our next step is to develop and implement 4-dimensional event reconstruction algorithms,
with the time as 4th dimension, on GPU.
References
[1] www.nvidia.com/object/workstation-solutions-tesla.html
[2] www.nvidia.com/cuda
[3] P. P. Bhaduri et al., Proc. DAE Symp. on Nucl. Phys. 55 (2010) 640
Baseline study for higher moments of net-charge
distributions at RHIC energies
Nihar Ranjan Sahoo, Sudipan De and Tapan Nayak
U
nderstanding the nature of phase transition from normal hadronic matter to quark-gluon plasma
(QGP) has been a topic of tremendous interest over last decades, both in terms of theoretical
studies and large-scale experiments. The Relativistic Heavy-Ion Collider (RHIC) at Brookhaven
National Laboratory has been the major facility for the search and study of QGP and to explore the
QCD phase transition. Theoretical models, based on lattice QCD, reveal that at vanishing baryon
chemical potentials, the transition from QGP to hadron gas is a simple crossover, whereas at large
chemical potentials, the phase transition is of first order. Therefore, one expects the existence of a
critical point at the end of the first order transition. Locating the QCD critical point has been one of the
major thrusts of the physics program at RHIC. The collider is capable of accelerating heavy-nuclei,
from top center-of-mass (c.m.) energy at 200 GeV, down to as low as 7.7 GeV. Taking advantage of this,
a beam energy scan program has been undertaken to exploit wide region of phase diagram and to search
for the possible location of the QCD critical point.
210
2
closer to HRG prediction. For the top central collisions, κ
σ
values remain constant from 200 GeV to 27
GeV below which a decreasing trend is observed.
Response simulation of the GEM detector
for the CBM experiment
Partha Pratim Bhaduri and Subhasis Chattopadhyay
T
he Compressed Baryonic Matter (CBM) experiment at FAIR, the upcoming accelerator facility at
Darmstadt, Germany endows us with the unique opportunity to investigate the phase structures of
the strongly interacting matter in the region of moderate temperatures and high net baryon densities.
The proposed key observables include the measurement of muon pairs originating from the decay of
low mass vector mesons (lmvm) and charmonia. The experimental groups from India and Russia
jointly hold the responsibility of designing, building and operating a muon detector system to enable
dimuon measurements [1]. An optimized version of the muon detection system (MUCH) has already
been designed through simulations. It includes 6 iron absorbers and 6 tracking stations. Each tracking
station consists of three chambers located in the air gap between two successive absorbers. The total
absorber length in the current design amounts to 2.25 m of iron. For inclusion of a realistic scenario,
modular structure has been implemented in simulation. Each detector layer has been divided in several
trapezoidal sectors and filled with an argon based gas mixture as the active medium. The muon tracking
chambers will be under conditions of high hit density and large event rates (107 events/s) to enable the
muon measurements. Conventional Multi wire proportional chamber (MWPC) like gas detectors
cannot cope with such high rate. Modern micro-pattern gas detectors like Gas Electron Multiplier
(GEM) and micromegas are expected to meet up these requirements. In the present paper we report the
detailed simulation of the GEM response to the minimum ionizing particles in CBM-MUCH
environment.
Figure 1. A schematic view of the primary ionization and secondary multiplication due to the incident radiation in the active
gas gap inside GEM chamber.
213
Introduction
In recent days, GEM based detectors have found wide spread applications in different fields with a
major share in high energy physics experiments. The micropattern detectors of this particular type are
widely used following their reported good time resolutions coupled to an excellent rate handling
capability.
Feasibility study
For simulation of detector response, each detector chamber is filled with argon gas as the active
medium. The gas thickness is set to 8 mm. The process of detection inside a gaseous detector includes
the primary ionization created by the incident ionizing radiation, avalanche multiplication and charge
deposition on the readout pads as shown schematically in Fig. 1. Inside the gas volume, the distribution
of the number of primary electrons is simulated using HEED [2] package and fitted to two parameter
Figure 2. (top) Distribution of primary electron multiplicity for incident muons inside the gas volume; (bottom) distribution
of secondary electron 4 multiplicity. Average gas gain is set to 104 .
Landau function. Thus obtained
parameterizations of expectation
value and variance as functions of
logarithm of kinetic energy of the
ionizing particles are used for the
random simulation of the number
of primary electrons, which
depends on the track length of the
incident particle inside the muon
chamber. The primary electrons are
then distributed according to
Poisson distribution. The gas gain
for each primary electron fluctuates
according to an exponential
distribution with a mean value set
to 104. The distribution of primary
and secondary electrons are shown
in Fig. 2.
Figure 3. Charge distribution from the incident tracks.
214
The transversal diffusion of the avalanche which gives the measure of the spot size is assumed to be
constant. It is tunable parameter and takes different values depending on the exact micro pattern
detector technology (GEM/ micromegas). The spot radius in the present case is set to 600 micron. The
avalanche spot for each primary electron is projected to the pad plane and and the sum of charges at
each pad is calculated. With the currently implemented pad design, typically 1.4 pads are fired by a
primary track, while the highly inclined secondary particles cover relatively larger number of pads.
Final step of detector response simulation includes the analysis of charge distributions collected in the
read-out plane. The reconstructed charge distribution of the incident tracks for 25 GeV Au+Au
collisions is shown in in Fig. 3. As expected the charge distribution shows a Landau spectra.
References
K/π fluctuation in ALICE experiment at LHC
Zubayer Ahammed For the ALICE Collaboration
E
vent wise fluctuation and correlation of global observables have been considered as one of the
signatures of Quark Gluon Plasma (QGP) phase transition. The nature of this phase transition
from hadronic state of matter may also be revealed in the study of fluctuations of global observables.
Fluctuation in K/π ratio on an event-by-event basis has been predicted to reveal nature of QGP phase
transition [1]. STAR experiment at the Relativistic Heavy Ion Collider (RHIC) measured particle ratio
fluctuations, particularly K/π fluctuation as a function of energy and system-system size [2,3] . In the
present study, we have measured K/π fluctuation in Pb+Pb collision at 2.76 TeV in ALICE experiment
at LHC (Large Hadron Collider) using a measure called, νdyn,Kπ . νdyn,Kπ is independent of tracking
efficiencies and was first used in STAR Collaboration for net charge fluctuation study[ 4,5].
Figure 1. The measured dynamical fluctuations in ALICE experiment. The fitted line corresponds to a+b/(dNch/dη) .
215
[1] A. Kiseleva, P. P. Bhaduri et. al., Indian J.Phys.85:211-216,(2011)
[2] http://ismirnov.web.cern.ch/ismirnov/heed.html
The data analyzed were measured using Time Projection Chamber (TPC) detector in ALICE
experiment located inside solenoidal magnetic field. The particle identification is based on specific
energy loss (dE/dx) measured in the TPC. In the present analysis, all tracks within - 0.8 < η < 0.8 and
200 < pt < 600 MeV/c are selected for TPC track selection. We select a particle to be pion if Nσ,π < 2 and
Nσ,K > 2, similarly kaon is selected if Nσ,K< φ
2 and Nσ,π >2 . For removing electron contamination, we
give tighter cuts on electron. A particle is called electron, if Nσ,e < 1.
The Measured dynamical fluctuation has been shown in fig.1 as a function of centrality. The fitted line
corresponds to a+b/(dNch/dη) fit. This analysis is in progress.
References
[1]
[2]
[3]
[4]
[5]
Kpusta and Mekjian, Phys. Rev. D33(1986)1304.
STAR Collaboration, Phys. Rev. 68, 044905(2003).
Z. Ahammed for the STAR Collaboration, J. Phys. G: Nucl. Part. Phys.35(2008)104092
C. Pruneau, S. Gavin and S. Voloshin, Phys. Rev. C 66, 044904(2002).
J. Adams et al. (STAR Collaboration), Phys. Rev. C 68, 044905(2003).
Test of FoCAL-prototype (mini-tower) at PS beam line at CERN
S. Muhuri, T. K. Nayak, J. Saini, S. A. Khan and R. Singaraju
D
evelopment of silicon pad detectors, with pad sizes of 1cm2, has been done in collaboration with
BARC, Mumbai and BEL, bangalore. In order to have preliminary knowledge of the
characteristics of such detectors, a prototype mini-tower was assembled with 4 layers of W+Si pad
modules. Each layer consisted of a 3mm thick W plate and a silicon pad plane with an array of 5×5
2
pads. The silicon pads were of 1cm area, 320um thick, with full depletion voltages of 70-80 Volts and
2
full depletion capacitance of 40pF/cm . Individual detector planes were tested in the laboratory using
radioactive sources. The result of the test using a beta-source of 90Sr was quite satisfactory.
Figure 1. Response of the Mini-Tower to MIP and electromegnetic (produced by electron) shower
216
W+Si detector assembly was tested
using the test beam facility at CERNPS. The response of the W+Si detector
assembly was tested with pion and
electron beams with momentum
between 1-5 GeV/c. MIP signals have
been obtained from pions, whereas
characteristics of electron showers are
studied with electron beams of varying
energies. A voltage scan from 20-70
Volts was performed to test the stability
of the detector. The response was found
to be stable from 40-60 Volts. The
operating voltage was kept as 60 Volts.
As expected only single pad was hit for
MIP which ( ADC) could be fitted well
with a Landau distribution, with a MPV
value 9.7. But with electron beam, all
the 25 pads were hit, although most of
the energy distribution concentrated on
the central 9 pads. To understand the
response of the electron beam, ADC
sum was made from all the 25 pads. The
ADC distribution has a mean at a value
of 318, which is considerably larger
than what is obtained for the pion beam.
Total energy deposition on the silicon
detector planes have been obtained for
varying electron energy and also for
adding W converter in front of the
assembly. Thus we have obtained total
energy loss for electron energies of 1-5
GeV/c and with longitudinal depth of W
from 1-6 X0 in front of the silicon pads.
The results for total energy loss in terms
of ADC as a function of longitudinal Figure 2. Longitudinal shower profile (left) using simulated data, (right)
depth for four beam energies are shown using real data.
in the top panel of Fig.2 longitudinal
profile. With the increase of the depth, there is increase in the total ADC in all cases, after a shower
maximum, the total ADC decreases.
A simulation using GEANT-4 has been performed by implementing the full detector geometry. The
response of the pion and electron beam has been studied. The energy loss obtained in the simulation for
all cases are similar to those observed in the test beam data. The results for longitudinal shower profile
is shown in Fig-2. We observe that the experimental results for the position of the shower maximum is
in agreement with the simulated data.
217
Net-charge fluctuations in PbPb collisions at LHC energies
Satyajit Jena1, Basanta Nandi1 and Tapan Nayak (for ALICE Collaboration)
1
Indian Institute of Technology - Bombay, Mumbai
T
he fluctuations of conserved quantities in a finite phase space window, like the net-charge of the
system, are predicted to be one of the most sensitive signals of the QGP formation and phase
transition and may provide a complementary understanding of strong interactions. In the QGP phase,
the charge carriers are quarks with fractional charges, whereas the particles in a hadron gas (HG) carry
unit charge. The fluctuations in the net charge depend on the squares of the charge states present in the
system. Consequently, the net-charge fluctuations in the QGP phase are significantly smaller compared
to that of a HG. At the same time, if the initial QGP phase is strongly gluon dominated, the fluctuation
per entropy may further be reduced as the hadronization of gluons increases the entropy. Thus, the netcharge fluctuations are strongly dependent on which phase they originate from. However, the netcharge fluctuations may get affected by uncertainties arising from volume fluctuations, so one
considers the fluctuations of the ratio of the numbers of positive and negative particles. The fluctuation
measure, D, is defined as:
δ
Q2
D=
N ch δ
R ≈
4
N ch
2
where R is the ratio of the number of positive and negative particles and Q is the net-charge (difference
between positive and negative charges). D provides a measure of the charge fluctuations per unit
entropy. In a simple picture, by neglecting quark-quark interactions, D is found to be approximately 4
times smaller for a QGP compared to a HG. Lattice calculations, which include the quark-quark
interactions, give a quantitatively different estimate for a QGP phase, still significantly smaller than for
a HG. It has been shown that D=4 for an uncorrelated pion gas, and, after taking resonance yields into
account, the value decreases to D=3. For a QGP, D is significantly lower and has been calculated to be
about 1.0-1.5, where the uncertainty arises from the uncertainty of relating the entropy to the number of
charged particles in the final state. Thus, a measurement of D can be effectively used as a probe for
distinguishing the two
phases, the HG and the
QGP. However, in reality,
these fluctuations may get
diluted in the rapidly
expanding medium due to
the diffusion of particles in
rapidity space. Several
other effects, such as
collision dynamics, radial
flow, resonance decays,
and final state interactions
may also affect the amount
of measured fluctuations.
The D measure has been
computed for PbPb
218
collisions at the nucleon-nucleon center-of-mass energy of 2.76 TeV with the ALICE experiment at the
LHC. This is done using a robust variable called ν
dyn. After all corrections, the extracted D value is
obtained to be 2.24 with statistical error of 0.09 and systematic error of 0.21.
Forward backward multiplicity correlations in proton-proton
collisions at LHC energies
Sudipan De, Tapan Nayak and Brijesh Srivastava1 (ALICE Collaboration)
1
Physics Department, Purdue University, USA
C
orrelations, that are produced across a wide range in rapidity, reflect the earliest stages of a heavy
ion collision, free from final state effects. From the measurements of forward backward (F-B)
correlation at Fermilab and RHIC, several physical interpretations have been made. The correlations
over small range in rapidity are believed to be dominated by short-range correlations, arising out of the
particles produced from cluster decay, resonance decay or jet correlations. Correlations extending over
a wide range in pseudorapidity could be interpreted as due to multiple parton interactions. Recently
STAR experiment has made a comparative study of forward-backward correlation between pp and
AuAu collisions and shows the existence of a large long-range correlation in central AuAu collisions.
The correlations for proton-proton collisions can provide the baseline for the Pb-Pb analysis. Particle
production mechanism can also be highlighted through the comparison of existing event generators
like PYTHIA and PHOJET.
We have studied the forward-backward multiplicity correlations of charged particles in proton-proton
collisions at c.m. energies of 0.9, 2.76 and 7 TeV. This study has been made with minimum bias events
within the acceptance of |η| < 0.8 and 0.3<pT<1.5 (GeV/c). Two separate pseudorapidity windows of
variable width from 0.2 to 0.8 rapidity units have been chosen symmetrically about η = 0. Multiplicity
correlation strength has been studied as a function of η-gap between the two windows as well as the
width of these windows. It is observed that correlation strength decreases with increasing η gap, i.e.,
with increasing distance between two η windows and increases with the width of the each window. The
results have been compared with the MC generator PYTHIA Perugia - 0. Relative correlation has been
studied in terms of the ratio of the correlation strength of 7 TeV and 2.76 TeV with respect to 0.9 TeV
and it is found that the correlation strength significantly increases with beam energy. The final results
are going through ALICE collaboration review and will be reported soon.
219
The adjacent figure shows the beam energy dependence of net-charge fluctuations are shown for RHIC
and LHC energies. A monotonic decrease of the D values has been observed. The fluctuations at LHC
are smaller than the theoretical expectations for a HG. It shows for the first time at the LHC energy a
clear tendency toward expectations from a QGP. We may infer that the fluctuations have their origin in
the QGP phase. For details, please refer to the published version of the paper:
Inclusive photon production at forward rapidities in
proton-proton collisions at LHC energies
Sudipan De, Subhash Singha, Satyajit Jena1, Basanta Nandi1, Bedangadas Mohanty,
and Tapan Nayak (ALICE Collaboration)
1
Indian Institute of Technology-Bombay, Mumbai
M
easurements of multiplicity and pseudorapidity distributions of produced particles in p-p
collisions are important to study the particle production mechanism and provide the base line
for the study of heavy ion collisions. The photon measurements are complementary to those of the
charged particles. Photon measurements provide a signature of the phase transition; provide a measure
of flow and fluctuations. This work highlights the particle production mechanism in forward rapidity
region and provides information about longitudinal scaling of produced particles for proton-proton
collisions at CERN-LHC energies.
The Photon Multiplicity Detector
(PMD) in the ALICE experiment
has been exclusively designed by
the Indian groups in ALICE, to
measure the multiplicity of
inclusive photons in the forward
rapidity region on an event-byevent basis. We measure the
multiplicity and pseudorapidity
distributions of inclusive photons
using the PMD at forward rapidity
(2.3<η<3.9) for proton-proton
collisions at center of mass
energies of 0.9, 2.76 and 7 TeV.
Presently, dedicated efforts on
data analyses are under way.
First results on the system size and energy dependence of the photon multiplicity, their pseudo-rapidity
distributions at forward rapidity have been extracted. The attached figure shows the pseudo-rapidity
distributions of photons as measured by PMD at the center of mass energy of 7 TeV at LHC. This gives
only a glimpse of such results.
From the detailed results, we observe that the photon multiplicity distributions are well described by
the Negative Binomial Distribution (NBD). We see that the average photon multiplicity is compatible
both with a logarithmic and a power law increase as a function of beam energy. Inclusive photon
production for inelastic events are compared with the charged particles production within the same
rapidity interval and Limiting fragmentation behaviour is obtained. The results are compared with the
expectation from different event generators like PYTHIA and PHOJET. The draft of the paper is under
review within the ALICE Collaboration.
220
Beam energy dependence of elliptic and triangular ?ow with the
AMPT model
Dronika Solanki1, Paul Sorensen2, Sumit Basu, Rashmi Raniwala1
and Tapan Kumar Nayak
1
2
Physics Department, University of Rajasthan, Jaipur 302004, India
Brookhaven National Laboratory, Physics Department, Upton, NY 11973, USA
T
he anisotropic flow in heavy ion
collision at ultra-relativistic energies is
expected to provide information about the
early stages of the systems evolution. It is
expected that flow would provide
information about the reaction dynamics and
fluctuations at initial stage. The spatial
anisotropy at the early time collision
converted into momentum anisotropy. The
strength of anisotropic flow is usually written
with a Fourier decomposition of the
azimuthal distribution of observed particles
relative to the reaction plane: Here, v1 is the
directed flow, which measures how much the
reaction is shifted along x direction. The
second harmonics in the Fourier series is
known as elliptic flow (v2), which is most
dominant term for anisotropic flow. The third
term in Fourier series is triangular flow (v3) is
supposed to be zero from symmetry
considerations. But recently it is observed
that initial lumpiness in energy density v3 has
non-zero values. We have made a detailed
study of the elliptic and triangular flow using
the AMPT model.
The AMPT model provides two modes:
Default and String Melting. Here the main
idea is that beyond a critical value of energy
3
density 1Gev/fm coexistence of string and
partons are not possible and hence strings are
melted into partons. By changing the
different parameters of Lund string
fragmentation, screening mass, coupling
constants and with a unique choice for all
parameters in any energy from RHIC to LHC
energies, we have compared the values of v2
with published results.
221
Top figure shows the charge particle density from AMPT, which is well matching to the experimental
data. A detailed study has been made to understand the beam energy dependence of v2 and v3 at different
centralities. Middle figure shows the behavior of the slope of <v3> vs. ε3 as a function of the square root
of the number of participants for four diffrent colliding energies. Bottom figure shows the temperature
dependence of η/s according to shear viscosity to entropy ratio formula (η/s) based on kinetic theory for
different parameter setting.
[1] arXiv : 1210.0512.
Fluctuating glasma initial condition for heavy ion collisions
Prithwish Tribedy, Bjoern Schenke1 and Raju Venugopalan1
1
Brookhaven National Laboratory, Upton, NY, USA
W
e present a new model of fluctuating initial conditions for heavy ion collision based on the ab
initio color glass condensate (CGC) framework. Initial nuclear color charge distributions
are obtained from the IP-Sat parameterization constrained by HERA data. The early time
classical “Glasma” fields are computed by solving Classical Yang-Mills (CYM) equations. The
model includes quantum fluctuations on length scales smaller than the nucleon size, given by the
inverse nuclear saturation scale. Soft modes (kT < Qs ) are treated in a more appropriate way than in
other CGC models based on factorization schemes. The model naturally produces initial energy
densities and gluon multiplicities whose fluctuations are described by convolution of negative
binomial distributions. We present first computations of observable particle spectra and flow
harmonics vn (pT ), obtained by matching the solution to the CYM equations to a relativistic
viscous hydrodynamic model, and compare to results obtained using other models for the initial state.
The resulting ratio of triangular to elliptic flow is compatible with experimental observations, as
opposed to previous CGC based models (KLN).
IP-Glasma Model
The IP-Glasma model introduced in ref. [1] calculates event-by-event initial energy distribution for
heavy ion collision at a time τ by solving CYM equations in 2+1 dimensions. Nucleon positions are
sampled for two colliding nuclei from a Fermi distribution. A Gaussian color chargedensity with
2
2
2(x, b⊥
width g µ (x, b), proportional to the nucleon saturation scale Q
) asobtained from the IP-Sat
model is added for each nucleon. The nuclear color charge distribu-tion g2 µ2 (x, b) is obtained by
2 2
a
summing individual nucleon g µ . The final Gaussian sampledcolor charge distribution ρ (x) gives
ν
ν±
(x±, x
+
rise to the color current J = δ ρ A(B) ⊥) gen-erated by nucleus A(B) moving along the x (x )
direction. The classical gluon fields inside the nuclei due to these color currents are obtained by
µν
ν
solving the classical Yang-Mills equation [Dµ , F ] = J . The components of Glasma fields after
collision can be expressed in terms of individual gluon fields of the colliding nuclei. Energy densities
and initial gluon multiplicities at time τ can be computed by CYM evolution of the components of the
Glasma gluon fields. The event-by-event Glasma distribution can be matched to viscous relativistic
222
References
[1] B. Schenke, P. Tribedy, & R. Venugopalan, Phys. Rev. Lett. 108, 252301 (2012), arXiv:1206.6805.
[2] P. Tribedy and R. Venugopalan, Nucl.Phys. A850 (2011), arXiv:1112.2445
[3] B. Schenke, S. Jeon, and C. Gale, Phys. Rev. Lett. 106, 042301 (2011).
Test of a triple GEM chamber with neutrons using α beam at
VECC cyclotron
A. K. Dubey, J. Saini, R. Ravishankar, T. Bandopadhyay, P.P. Bhaduri, R. Adak1, S. Samanta1,
S. Chattopadhyay, G.S.N. Murthy, Z. Ahammed, S.A. Khan, S. Ramnarayan, S. Muhuri, P.
Ghosh, S.K. Pal, T.K. Nayak and Y.P. Viyogi,
1
Bose Institute, Kolkata, 700064
A
GEM based detector system is being developed at VECC for use as muon tracker in the
Compressed Baryonic Matter (CBM) experiment at the upcoming FAIR facility at
Germany[1][2]. The Muon Chambers(MUCH) consist of alternating layer of six absorbers and
detector stations. A high hadronic environment and the thick iron absorbers of MUCH contribute to a
high neutron background. As per fluka calculations[3], it is estimated that the MUCH detectors will
13
2
have to cope up with a neutron dose of ~10 neq/cm /year. The aim of the neutron tests is: to measure
the neutron hits as recorded by the detector so as to have an idea of the number of background hits per
event on the GEM detector and also to study the response of the detector before and after neutron
irradiation, in terms of relative change in gain, or in terms of any physical damage due to irradiation. In
this direction, we conducted the first such test of a triple GEM chamber in VECC cyclotron. As shown
schematically in Fig.1, a 40 MeV alpha beam on hitting 0.5 cm thick Tantalum target produces neutrons
and gammas as the end product. A Pb shield of 10 cm is placed in front of this target for screening the
gammas. The triple GEM chamber was placed at about 80 cm away from the Tantalum target and was
Figure 1. Left: Schematic of the neutron test setup. Right: Picture of the neutron test setup at VECC. The picture shows the
setup with beam shielding.
224
operated at Vgem ~340 V across each GEM layer. The gas mixture consisted of Ar/CO2 mixed in the
ratio (70/30). The GEM signal was read out using standard Ortec NIM electronics coupled to an MCA.
Data corresponding to different beam currents(which corresponded to different neutron intensities)
were taken with and without the Pb shielding. Neutron flux was estimated by measuring the flux with
BF3 counters for current ranges from 50 – 500 nA for both with and without Pb shield. Fig.2(left) shows
the calibration relation for obtaining the neutron flux for higher beam currents. The BF3 counter was
then replaced by the GEM detector. Fig.
2(Middle) shows the pulse height spectra from
the detector for four different beam
currents(neutron intensities) without Pb
shielding. The highest neutron flux
corresponding to a beam current of 4 uA, as
derived from the calibrated fit was about ~ 105
2
neutrons/cm /s. For every current setting, three
sets of data were taken and the number of GEM
hits for each of these sets were estimated. Fig.
2(Right) shows these hits vs. the beam current.
About 350 hits/sq.cm/s are seen corresponding to
5
a maximum neutron flux of ~ 10 /sq.cm/s. The
expected neutron rate in CBM experiment is
5
6
expected to be 10 /s resulting from 10
collisions/s. The test results indicate that the
background hits per event in the GEM detector
due to neutrons would be insignificant thereby
ruling out any tracking issues due to neutron hits.
The prototype detector was exposed to neutron
radiation for about four days and the integrated
dose of exposure in four days of beamtest was
about 1011 neq. over 100 sq. cm. No visible
damages were observed after this irradiation. It is
planned to conduct more such tests in future at
higher beam intensities and at higher overall dose
of neutron exposure to investigate the detector
response in detail.
Acknowledgements
We acknowledge the help from Anna Senger and
Peter Senger of GSI, Darmstadt, in Fluka
calculations. We also thank the VECC cyclotron
division for excellent beam during the tests.
Figure 2. Top : Neutron fluence vs. beam current as
measured by BF3 counter. Middle: Pulse height spectra from
the triple GEM detector for four different neutron beam
intensities. Bottom : number of GEM_chamber hits/sq.cm/s
vs. beam current.
References
[1] CBM Conceptual Design Report (CDR)
[2] A.K. Dubey, et. al, DAE Symp. On Nucl.Phys. vv,
ppp (2010), Anna Kiseleva, P.P. Bhaduri, et.al. 85,
211-216 (2011)
[3] A. Senger, CBM Progress Report 2012, p26.
225
Photon–hadron discrimination with improved clustering
for a preshower detector in high energy
heavy ion experiments
Susanta Kumar Pal, Subhasis Chattopadhyay and Y.P. Viyogi
T
he present work describes a vastly improved clustering method using the fuzzy c-mean (FCM)
clustering algorithm in combination with the energy deposition of the cells. The present
formulation of the weighted FCM is able to perform clustering even in the high occupancy
environment of the PMD. Compared to the FCM method, the new method is computationally fast,
avoids multiple iterations to find the optimum number of clusters in the data and provides highly
improved performance, with the absolute clustering efficiency going up by ~10% and the percentage of
ghost clusters reducing by similar amount. In addition the profile and the signal strengths of clusters
obtained are found to be close to those of the corresponding particle tracks.
The artificial neural network formalism has been applied for photon–hadron discrimination in the case
of a standalone PMD and for real implementation of the PMD in the ALICE experiment along with
other detectors. The performance of the ANN has been studied with varying combination of cluster
attributes derived from both the preshower and CPV planes of the PMD. It is found that a combination
of only six attributes, consisting of number of cells and the signal strength of the clusters on the two
planes and the kurtosis value of the cluster profile provide the optimum set for the best performance.
Both the efficiency of photon reconstruction and the purity of photon sample have improved
considerably. One can now obtain efficiency values of 70% along with purity values of ~ 73% for the
PMD in the actual environment of the ALICE experiment with all the detectors and associated
structural material. The main difference between the present and earlier investigations seems to be in
the use of improved method of clustering and higher moments of cluster profile as input for
photon–hadron discrimination.
One of the most encouraging results of the present investigation is the near-independence of efficiency
and purity values as a function of centrality even for the large multiplicities expected at the LHC
energy. For minimum bias data these are only weakly dependent on η over the entire region of
acceptance. The acceptance of low pT (<200MeV/c) photon samples after the ANN method of
discrimination is found to be 85%, almost 25% higher than the conventional method of discrimination
[1].
Reference
[1] S.Pal, et. al. Nuclear Instrumentation and Method in Physics Research A, Vol. 693, 285-293(2012)
226
where α
s only. The other parameters, functions
soft is the fraction of “soft” events and is a function of √
of both, the √s and the η
c, have usual meanings as described for Eq. - (1) with suffixes in parameters
indicating respective components.
Figure 1. Primary charged hadron multiplicity distributions for η
< 0.5 to 2.4 for = 7 TeV. The solid lines correspond to
respective fits of single NBD while the dashed lines correspond to Two-NBD.
The Compact Muon Solenoid (CMS) experiment at LHC has measured multiplicity distributions of
primary charged hadrons for all the three LHC energies, √s = 900, 2360 and 7000 GeV in the midrapidity region in five symmetric overlapping η
- intervals |η
| or η
c < 0.5, 1.0, 1.5, 2.0 and 2.4 [4] around
the centre-of-mass pseudo-rapidity (η
cm = 0). We analyse the multiplicity distribution data of the CMS
experiment first with single NBD function and then extend our study with weighted superposition of
two NBD functions [5], for the first time with the LHC data.
√
S (GeV)
ksoft
<n>soft
ksemihard
<n>semihard
900
2.44+0.32
14.78+1.99
8.13+2.34
35.11+3.90
2360
2.57+0.52
15.74+2.98
6.27+2.21
41.92+6.21
7000
2.38+0.34
15.06+1.48
3.25+0.49
46.86+3.45
Our study reveals that the weighted superposition of two NBD functions fits better than a single NBD
with the available multiplicity distribution data of LHC at √s = 0.9, 2.36 and 7 TeV at η
c < 2.4 (Fig. – 1) .
Further, application of the formalism of the weighted superposition of two NBDs in the analysis reveals
significant property of energy invariance of “soft” component of particle productions at LHC in the
largest available pseudo-rapidity interval, η
c< 2.4, as is evident from the values of the NBD-parameters
listed in the given table. The detail of the study is available in ref. [6].
228
References
[1]
[2]
[3]
[4]
[5]
[6]
Evans, L. and Bryant, P.(editors), J. Instrum. 3, S08001 (2008).
Thome, W. et al.Nucl. Phys. B129, 365 (1977).
UA5 Collaboration, Ansorge,R. E. et al., Z.Phys. C43 , 357 (1989).
E735 Collaboration, Turkot,F. et al., Nucl.Phys. A525 , 165 (1991).
Giovannini,A. and Ugoccioni,R. Phys.Rev. D59 , 094020(1999) 094020.
Ghosh, P. Phys. Rev. D85, 054017 (2012).
Spark protection of the DAQ and electronics of the photon
multiplicity detector in ALICE
Introduction
T
he Photon Detector (PMD) [1,2] has been operational in the ALICE experiment since 2009. It has
taken data for proton-proton collisions at 0.9, 2.76, 7 and 8 TeV, Pb-Pb collisions at 2.76 TeV.
PMD comprises of large arrays of hexagonal gas cells, where a honeycomb structure forms the
common cathode and a gold plated tungsten wire at the centre of each honeycomb acting as the anode.
The detector operates at a voltage of -1300V with Ar/CO2 gas mixture in 70:30 proportions by weight.
PMD, being a gas-based detector, is prone to sparks. The generated sparks can get injected in the
electronics, which can cause damages or can cause single event upsets in electronic circuitry, which can
affect the overall data taking of the detector. A spark protection circuitry had been already implemented
for the PMD as reported earlier [3]. Additional measures were taken in this direction for spark
protection which was proven to be very effective.
Address/data loss due to spark
It has been observed that when a spark occurs within the detector, front end electronics and the MARC
ASIC (which is used in the PMD) loses its address and the stored data does not have the required zero
suppression. This results in enormous increase in data volume and data becomes unusable for that
particular electronics chain.
To analyze the effect of spark, a test setup was made at VECC with a PMD module, along with
electronics. Sparks were generated forcibly inside the chamber. Twelve FEE boards with 64 channels
each, were mounted on the section of detector. It can be seen from the ADC vs. channel plot (Fig.1 left),
that first 64 channels show higher ADC values which conveys the configuration data loss in the middle
of the run. Analyses of the oscilloscope waveforms show that reset and trigger lines are changing their
logic state momentarily with spark. Synchronous signals were found to be not affecting the data
integrity in spite of these sparks, while asynchronous reset line was making the MARC to reset
resulting in a configuration data loss.
With the removal of termination resistors and putting a capacitor of 100 nF/10 nF to ground in reset
line, we found that with lots of spark also, no configuration data loss errors were seen. However with
100 nF it was disturbing the normal reset mechanism. There was a detailed study done during PMD
229
Jogender Saini, R.N. Singaraju, Shuaib A. Khan and Tapan K. Nayak
test-beam taken at CERN using CROCUS with 10 nF and it was found that 10nF is the most suitable
value and finally it was installed in all the PMD modules. After this implementation there was no
address/ configuration data loss reported.
TVS diode
Existing fast
fuse
and inductor
Figure 1. Left : Effect of spark on the first 64 channels out of 768 channels. Those have higher ADC values due to address loss
in middle of the run. Right: Additional TVS diode put on FRT
CROCUS Busy/Reset
It is seen that PMD runs very well in standalone and technical runs with HV for long time. However
during data taking with all other ALICE detector, PMD faced frequent problems when run for a long
time. The reason being, interruption from CROCUS (PMD-DAQ) going to error state. Detailed
investigation led us to believe that the sources could be arising mostly from external disturbances. We
took two measures to deal with this problem. Firstly we put the Transient voltage suppressor (TVS)
diode on FRT and CRT of CROCUS to protect the spikes coming from the PMD detector itself as
shown in Fig.1 (right). Secondly, we put the filter circuit and TVS diode at the supply input of the
CROCUS to deal with the spikes coming due to external sources as shown in Fig. 2.
Figure 2. Filter circuit used for spike protection.
230
Figure 3. Performance of PMD in pA run of Jan-Feb, 2013
References
[1] M.M. Aggarwal et al., Nucl. Instr. and Methods, A499 (2003) 751.
[2] T. K. Nayak et al, Proceedings of DAE Symp. On Nucl. Phys. 55(2010) pg 694-695
[3] Jogender Saini et al, Proceedings of DAE Symp. On Nucl. Phys. 55(2010) pg 764-765
Design and development of a low voltage distribution system for
CBM-MUCH experiment
Vikas Jain, Susanta Kumar Pal, Subhasis Chattopadhyay, S.R. Narayan and J.Saini
Introduction
I
ncreasing demands for high position resolution and high rate capabilities of a tracking detector led to
a more complex and densely packed electronics which require more and more power in confined
space. In such systems power consumption and space is always a big issue to address. A GEM-based
tracking system is planned to be used for muon tracking in the proposed CBM experiment at FAIR. This
Muon Chamber will be movable system hence a careful design of low voltage distribution is needed for
optimized performance and less cable count for ease of operation. To minimize the cable load, 48V is
planned to be taken as the input the Low Voltage Distribution System which will be sitting near the
detector
231
This modification was done in the Dec-2012 and after this modification in pA run in Jan-Feb, 2013
there were minimal stop of run due to PMD DAQ reset/busy, as shown in Fig. 3 taken from ALICE
Run-Coordinator.
Functional Description of Low Voltage Distribution System
The (Low Voltage Distribution System) divides a single channel high power low voltage (LV) to
several low power LV channels as per the requirement. The distribution system has mainly 8 channels
with each channel having 3.3V and 1.2A. The distribution system has over-current protection and
monitoring facility of voltage and current for each channel. The block diagram of distribution system is
shown in Fig.1. In this distribution system 48V further stepped down to 5V using a DC to DC SMPS
type converter. Reason for choosing the SMPS here is reduced size and low power loss on the convertor
to avoid excess heat generation and power loss on board. The prototype design has been tested for 2
channels. The number of channels for each distribution system may vary depending on final
requirement.
Figure 1. Block Diagram of Low Voltage Distribution System
Gas electron Multiplier [GEM] is a gaseous detector with operating voltage of around 3.5kV and hence
there is always a possibility of sparks and unwanted glitches in the system. At times these may even
spoil the electronics load. Hence in distribution system all output channels are protected from overcurrent and if anyone electronic channel observes over-current, only that particular channel will be shut
down keeping rest of its channels
in working state. This minimizes
the data loss due to unexpected
glitches in the system. In low
voltage distribution system for
over Current protection using
MAX4373, sense resistors,
control logic and switching
elements. The current sense
resistor is coming in series so the
resistance chosen should be as
Fig.2 Load Current Vs Voltage Regulation
232
low as possible to minimize the
low voltage drops and it has to be
very stable.
Figure 3. Load Current Vs Efficiency
In distribution system we use DC
to DC converter (PTH05010) as
a voltage regulator. The test
results of this voltage regulator
are as shown in Fig. 2 and Fig.3.
In Fig.2 the voltage regulation of
DC to DC converter is
decreasing to increase the load
current. In Fig.4 the efficiency of
DC to DC converter is nearly
constant to increase the load
current.
Vo l t a g e a n d C u r r e n t
Monitoring and control of
Each channel
The Low Voltage distribution
system handles large number of
channels that are required in the actual experiment, so it is essential to monitor the status of each
channel and control them to achieve this purpose. To monitor voltage and current of distribution system
we use FPGA virtex 5 Board. Firstly we select the channel of distribution system using analog
multiplexer (CD4053B), after select channel we convert analog signal into digital signal using ADC
(AD7476). This digital data dump into FPGA board for monitoring application. Fig.4 shows the
experimental setup of Low Voltage Distribution system to monitor voltage and current of each channel.
In Fig. 5 show prototype design of Low Voltage distribution system for 2 Channel.
Figure 4. Experimental Set up Low Voltage Distribution System Monitoring
Figure 5. Proto Type low Voltage Distribution System for 2 Channels
233
Proto type testing and Circuit
performance
To display data on PC of low voltage distribution system we design MATLAB based Graphical user
Interface (GUI). Firstly we connect FPGA virtex 5 board to PC using RS 232 (Serial communication)
cable, then dump the serial data on Com Port and develop GUI to display voltage and current of
distribution system. Fig.7 show GUI result of low voltage distribution system for 2 channels.
Figure 6. GUI Result on PC of Low Voltage Distribution System of channel 1 and channel 2
Design of large aperture dipole magnet
A. Dutta Gupta, P.R.Sarma, S. Saha, S. Ghosh, S. Murali and G. Pal
T
he magnets in the Energy Buncher of the FAIR Super-FRS are wide aperture superferric magnets.
Dipoles, quadrupoles, and sextupole magnets will be used in the beam lines for transporting and
focusing the beam into the experimental area. In most of the applications, especially in high resolution
spectrometric experiments, the beam quality is of utmost importance. The beam quality, on the other
hand, depends on the field quality of the magnets. Since these magnets are wide aperture magnets
having a large component of edge
field, special design features have
been adopted in the design
process.
Figure 1. Magnetic field distribution in dipole magnet.
234
The superferric dipoles will have
radius of curvature of 4.375 m,
magnetic field up to 1.6 T over
elliptical bore of size ± 380 mm ×
± 100 mm and effective length
2.43 m to bend ion beams by an
angle 30°. The main criticallity of
this magnate is to achieve field
Engineering design of dipole
magnets
This dipole magnet system
consists of mainly two subsystems, i.e. cryostat and iron
yoke.
Helium chamber and Vacuum
Chamber of Cryostat
Structural design of the low
temperature helium vessel and
the room temperature vacuum
vessels has been performed.
Figure 3. Equivalent Stress on vacuum chamber
Figure 4. Quench propagation in a coil
235
For helium chamber, nonmagnetic and high strength low
temperature ductile material SS316LN and for vacuum chamber
non magnetic SS-316 has been
selected.
Finite element analyses of helium
chamber have been carried out
considering the thermal load due
to cool-down and the structural
load for the maximum pressure 5
bar. From the analysis it was
found the maximum stress on
vertical and horizontal support
links were 400 MPa and 900 MPa
r e s p e c t i v e l y. T h e r e f o r e ,
adjustments (loosening) of
Figure 2. Total deformation of He chamber due to cool-down.
uniformity better than ± 3 × 10–4
through out this large elliptical
beam path. To analysis the
magnetic field along this path,
3D magneticfield simulastion
was carried out by OPERA
software. After a large number of
itteration with OPERA software,
the desired shape of magnet was
achived to attain the required
field qualitiy. The overall size of
the magnet is 3.51 m X 3.20 m
and 3.08 m height and weigt is
115 ton.
horizontal support links during
cooldown are suggested to protect
the support links from damage.
For the vacuum chamber,
structural analysis has been
carried out for the vacuum load
and thermal load reaction arises
due to support the vertical and
horizontal links. The analysis
shows maximum stress 80 MPa
will be at support link ports
considering horizontal support
link adjustment.
Coil & magnet supports
Figure 5. Quench current and voltage without dump resistor
The helium vessel will be hanged
from the room temperature vessel
by eight vertical and four
horizontal support links. The
links will be made of glass-epoxy
to reduce the conduction heat load
to the liquid helium.
Detail thermo-mechanical
analysis has been carried out to
optimize the support link for the
high mechanical strength and low
heat conduction to the liquid
Helium chamber.
Cooldown analysis
A through analytical analysis was
carried out to predict the different
paramiters during cool-down
process like liquid helium plant
requirement, time required to
cool-down, consumtion of liquid
helium during normal operation
etc.
Figure 6. Cryostat and magnet iron assembly
Quench analysis
To predict the maximum temperature and voltage rise within the coil, a 3D transient coupled field
(electrical, magnetic and tharmal) analysis was carried out by using a finite element softwate, OPERA.
Figure 5 shows after quenching voltage raise and current decay in the coil without dump resister. The
maximum voltage and maximum temperature may rise up to 1.5 kV and 110K respectively. The
voltage rise is of concern and further analysis is being done for finding the way to reduce it.
The 108 T iron with cryostat will be supported and positioned with the help of four rectangular pillars
made of 30 mm thick 316 SS plats.
236
Conclusion
The engineering design of dipole is advanced a quite bit. Further optimization of the iron weight and
reduction of coil voltage is required to be carried out. A detail stress analysis of the coil is also to be
done. Efforts are on for completion of the design in full extent. Search for vendors for fabrication of
these unique magnets are also on.
Design of outer vacuum chamber for long superconducting
quadrupoles for FAIR super FRS Energy Buncher
T
he Superconducting Fragment Separator (Super FRS) of the Facility for Antiproton and Ion
Research (FAIR) at GSI in Darmstadt is a large-acceptance superconducting fragment separator
to efficiently separate rare isotopes. The energy buncher acts as a high-acceptance spectrometer. The
spectrometer consists of large dipole, quadrupole and hexapole superconducting magnets. The
stainless steel helium chamber for quadrupole magnet cryostat contains the magnet iron, NbTi
superconducting coil and stainless steel coil support and weighs about 23 tons. The helium chamber
and thermal shield is enclosed in a vacuum shell using specially designed support links.
Outer Vacuum Chamber Description
The model is shown in the figure 1. The cryostat has 15 mm wall thickness with a flat head thickness of
40 mm. The vessel is kept on saddle support whose span is 1200 .Wear plate has a thickness of 15 mm is
also provided. The Outer Vacuum Chamber design conforms to ASME Boiler and pr4essure Vessel
Code Section VIII Division II. The magnet is supported by two compression supports of G10 fiber
Epoxy.
Figure 1. Von Mises Stress
Figure 2. Total Deformation
237
Javed Akhter, C. Nandi, S. Roy, U. Bhunia, A. Datta and G. Pal
The Helium Vessel is also of 15 mm wall thickness with a flat head thickness of 40 mm . Tri-unions are
provided on the flat head for lifting. A total of four tri-unions are provided (two on each side). A total of
eight locks are provided for the purpose of transportation. Four transportation locks are provided on the
flat heads and 4 on the curved surface on the vacuum chamber.
Figure 3. Von-Mises Stress
Figure 4. Total Deformation
Design Calculations
Outer Vacuum Chamber
Finite element Analysis was performed with the applied loads and the optimal geometry of the cryostat
was determined. Fig. 1 & 2 show the stress distribution and the total deformation of the outer vacuum
chamber with loads namely, external pressure and the magnet weight. Table 1 shows the value of the
primary membrane, membrane + bending and peak stress in the vacuum chamber.
Table 1. Peak Linearized Stresses in the Outer Vacuum Chamber.
Region
Stress Category
Main Shell near the
PL
head and Shell Junction
Head near the HeadShell Junction
Value (MPa)
17.4
Limit (Mpa)
143
PL + P b
62.8
214.5
PL + P b + F
97.8
429
PL
2.93
143
PL + P b
19.8
214.5
PL + P b + F
22.1
429
Box near the Box-
PL
32.9
143
Shell Junction
PL + P b
57.2
214.5
PL + P b + F
67
429
Box Plate near the
PL
10.7
143
Box-Box Plate Junction
PL + P b
59.7
214.5
PL + P b + F
173
429
Shell near the Box-
PL
61.4
143
Shell Junction
PL + P b
130
214.5
PL + P b + F
306
429
238
Buckling Analysis
According to ASME section VII division 2, the buckling factor of safety shall be greater than 2.8. For
different modes shaped the buckling factor of safety is calculated and compared with ASME
requirement. With ANSYS minimum factor obtained is 36.
1. Helium Vessel
Stress Analysis was performed for the internal pressure of 6 atmospheres. Weight of the magnet is
attached as a dead weight to the fat head of the vacuum vessel. Table 2 shows the value of the primary
membrane, membrane + bending and peak stress in the vacuum chamber. Figure 3 and 4 shows the plot
of von-mises and the total deformation.
Table 2: Peak Linearized Stresses in the Helium Vessel.
Stress Category
Value (MPa)
Limit (Mpa)
Shell Near the Shell-Box
PL
176
512
Intersection
PL + Pb
249
768
P L + P b+ F
243
1536
Shell Near the Shell-Head
PL
17.5
512
Intersection
P L + Pb
97.8
768
P L + P b+ F
104
1536
Head Near the Shell-Head
PL
22.3
512
Intersection
PL + Pb
63.9
768
P L + P b+ F
104
1536
Structural design and trial for fabrication of 650 MHz β=0.6
superconducting radio-frequency cavity
Pranab Bhattacharyya, Bishwanath Manna, Kanchan Majumdar, Sundeep Ghosh
S. Sur and A. Dutta Gupta
T
he cavity is subjected to external pressure during operation at 2K. The structural analysis of SCRF
cavity has been carried out to find the model predictions for stresses and deflections under
external pressure load and operating temperature. The important part of the simulation is devoted to the
determination of membrane stress, bending stress, secondary stress, etc.
Two separate cases for primary loading alone and primary loading combined with secondary loading
has been considered. During cool-down, the cavity may be subjected to a 2.2 atm external pressure
while still near room temperature. In first case, a scenario of 2.2 atm external pressure at room
temperature has been considered thinking of initial cool down. In a second case, 3 atms. external
pressure at 2K has been considered for a situation of loss of insulation vacuum.
239
Region
Mechanical modal analysis has been carried out for unstiffened cavity for different end conditions to
find out lowest natural frequency. Analysis has also been carried out for addition of stiffener to find out
the optimum position of placing it to ensure that the lowest natural frequency lies well above the
100Hz. It ensures any surrounding noise and vibration does not affect cavity performance.
Figure A. FEM Model for analysis
Figure B. Deformation due to 2K Temperature & 3atm Pressure
Figure C. Die-Punch for deep drawing trial
240
Limit load analysis has also been done to establish and compare the collapse pressure for stiffened &
un-stiffened cavity.
Cavity Fabrication
Half cell Cavity first trial is over. After Inspection small variations of dimensions found near the central
zone. Subsequent work on re-striking tool for second trial is over and the trial cavity is accepted for
further welding and RF tests.
Pranab Bhattacharyya, Sutripta Sur and Anjan Dutta Gupta
I
n IIFC, VECC is working for the design of SSR1 cryomodule. Part of the design, the thermal
analysis of the strong back support, has already been done
All of the cavities of SSR1 will be mounted on individual support posts which are in turn mounted to a
full-length strong back located between the vacuum vessel and thermal shield. This enables the entire
cavity string to be assembled and aligned as a unit and then inserted into the vacuum vessel during final
assembly. The strong back is envisioned to be aluminum, but stainless steel is an option. Maintaining
the strong back near room temperature helps minimize axial movement of the cold elements during
Figure 1. Temperature distribution along the length of strong back of different material
241
Thermo-structural design of strong back for
SSR1 cryomodule
cooldown, reducing displacement of couplers, current leads, and many of the internal piping
components.
Detail calculation has been carried for determination of steady state temperature of passively cooled
strong back for 2D & 3D cases. Further comparison of temperature distribution of strong back for
different construction material has been done. During operation the strong back will be taking the load
of SSR1 cavities & solenoids. Hence, combination of thermal load & dead load has been considered to
do the stress analysis for different material of construction.
242
Publicatio ns
Colloquia
Theses Etc
7.1
PUBLICATIONS
IN
JOURNALS
1.
J. Akhter, G. Pal, A. Datta, P. R. Sarma, U. Bhunia, S. Roy, S. Bhattacharyya, C. Nandi, C.
Mallik and R. K. Bhandari, “Preliminary Design of the Vacuum System for FAIR Super
FRS Quadrupole Magnet Cryostat”, Journal of Physics: Conference Series 390, 012043,
(2012).
2.
ALICE Collaboration, "Measurement of electrons from semileptonic heavy-flavour hadron
decays in pp collisions at s = 7 TeV" Phys. Rev. D 86, 112007 (2012)
3.
ALICE Collaboration, "Measurement of the Cross Section for Electromagnetic Dissociation
with Neutron Emission in Pb-Pb Collisions at
252302 (2012)
4.
= 2.76 TeV"Phys. Rev. Lett. 109,
ALICE Collaboration, "Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at
= 2.76 TeV" Phys. Rev. Lett. 109, 252301 (2012)
5.
ALICE Collaboration, "Inclusive J/ production in pp collisions at
B718, 295 (2012)
=2.76 TeV" Phys.Lett.
6.
ALICE Collaboration, "Ds meson production at central rapidity in proton--proton collisions
at
= 7 TeV" Physics Letters B 718 (2012)
7.
ALICE Collaboration, "Measurement of prompt and beauty hadron production cross sections
at mid-rapidity in pp collisions at
= 7 TeV" JHEP 11, 506 (2012).
8.
ALICE Collaboration, "Rapidity and transverse momentum dependence of inclusive J/
production in pp collisions at
= 7 TeV" Physics Letters B 718, 692-698 (2012)
9.
ALICE Collaboration, "Production of K*(892)0 and (1020) in pp collisions at
Eur. Phys. J. C72, 2183 (2012).
= 7TeV"
10.
ALICE Collaboration, "K0s-K0s correlations in 7 TeV pp collisions from the LHC ALICE
experiment" Physics Letters B 717 (2012).
11.
ALICE Collaboration, "Neutral pion and ? meson production in proton-proton collisions at
= 0.9 TeV and 7 TeV" Physics Letters B 717 (2012).
12.
ALICE Collaboration, "Suppression of high transverse momentum prompt D mesons in
central Pb--Pb collisions at
13.
ALICE Collaboration, "Production of muons from heavy flavour decays at forward rapidity
in pp and Pb--Pb collisions at
14.
= 2.76 TeV" JHEP 9 112 (2012).
= 2.76 TeV" Phys. Rev. Lett. 109, 112301 (2012).
ALICE Collaboration, "Transverse sphericity of primary charged particles in minimum bias
proton-proton collisions at
= 0.9, 2.76 and 7 TeV" Eur. Phys. J. C 72, 2124 (2012).
244
PUBLICATIONS IN JOURNALS
15.
ALICE Collaboration, "J/ suppression at forward rapidity in Pb-Pb collisions at
2.76 TeV" Phys. Rev. Lett. 109, 072301 (2012).
16.
ALICE Collaboration, "Measurement of charm production at central rapidity in proton proton
collisions at
=2.76 TeV" JHEP 1207, 191 (2012).
17.
ALICE Collaboration, "Underlying Event measurements in pp collisions at
TeV with the ALICE experiment at the LHC" JHEP 1207, 116 (2012).
18.
ALICE Collaboration, "Multi-strange baryon production in pp collisions at
ALICE" Phys. Lett. B 712, 309 (2012).
19.
ALICE Collaboration, "J/ Production as a Function of Charged Particle Multiplicity in pp
Collisions at
= 7 TeV" Phys. Lett. B712, 165-175 (2012).
20.
ALICE Collaboration, "Light vector meson production in pp collisions at
Physics Letters B 710 (2012).
21.
ALICE Collaboration, "Measurement of Event Background Fluctuations for Charged Particle
Jet Reconstruction in Pb-Pb collisions at
22.
=
= 0.9 and 7
= 7 TeV with
= 7 TeV"
= 2.76 TeV" JHEP 03, 053 (2012).
ALICE Collaboration, "Particle-yield modification in jet-like azimuthal di-hadron correlations
in Pb-Pb collisions at
= 2.76 TeV" Phys. Rev. Lett. 108, 092301 (2012).
23.
ALICE Collaboration, "Heavy flavour decay muon production at forward rapidity in proton-proton collisions at
= 7 TeV" Phys. Lett. B 708, 265 (2012).
24.
ALICE Collaboration, "Harmonic decomposition of two-particle angular correlations in PbPb collisions at
= 2.76 TeV" Phys. Lett. B708, 249-264 (2012).
25.
ALICE Collaboration, "J/ polarization in pp collisions at
108, 082001 (2012).
26.
ALICE Collaboration, "Measurement of charm production at central rapidity in proton-proton
collisions at
= 7 TeV", JHEP 01, 128 (2012).
27.
D. Banerjee, P. Das, R. Guin, S. K. Das, “Nuclear quadrupole interaction at 181Ta in
hafnium dioxide fiber: Time differential perturbed angular correlation measurements
and ab initio calculations’’, J Phys. Chem. Solids 73, 1090, (2012).
28.
K. Banerjee, S. Bhattacharya, C. Bhattacharya, M. Gohil, S. Kundu, T. K. Rana, G.
Mukherjee, R. Pandey, P. Roy, H. Pai, A. Dey, T. K. Ghosh, J. K. Meena, S. Mukhopadhyay,
D. Pandit, S. Pal, and S. R. Banerjee “Variation of nuclear level density with angular
momentum”, Phys. Rev. C 85, 064310 (2012).
29.
K. S. Banerjee, R. Guin, J. L. Gutierrez-Villanueva, M. E. Charro, D. Sengupta, “Variation
in U-238 and Th-232 enrichment in U-mineralized zone and geological controls on
their spatial distribution, Singhbhum Shear Zone of India”, Environmental Earth Science:
65, 2103, (2012).
30.
D. N. Basu, “Four Pedagogic Exercises”, Lat. Am. J. Phys. Educ. 6, 27, (2012).
245
= 7 TeV", Phys. Rev. Lett.
31.
D. N. Basu, “On the E-L Equation and Snell’s Law for Massive Particles: A
Mathematical Revisit”, Phys. Educ. 28, 02, (2012).
32.
Partha Pratim Bhaduri, A. K. Chaudhuri and Subhasis Chattopadhyay, “J/ suppression
in a dense baryonic matter”, Phys. Rev. C85, 064911, (2012).
33.
Sumantra Bhattacharya, Chinmoy Nandi, Subhasis Gayen, Suvadeep Roy, Santosh Kumar
Mishra, Sanjay Ramrao Bajirao, Gautam Pal and C Mallik, “Design of Large Vacuum
Chamber for VEC Superconducting Cyclotron Beam Line Switching Magnet”, Journal
of Physics: Conference Series 390, 012017, (2012).
34.
U Bhunia, J Pradhan, A Roy, V Khare, U S Panda, A De, S Bandopadhaya, T Bhattacharyya,
S K Thakur, M Das, S Saha, C Mallik, R K Bhandari, “Design, Fabrication and Cryogenic
Testing of 0.6 MJ SMES Coil”, Cryogenics, June, (2012).
35.
U. Bhunia, J Pradhan, S Saha, C Mallik, R K Bhandari, “Optimization of Solenoid type
Superconducting Magnetic Energy Storage Coil”, Indian Journal of Cryogenics, 37, 6166, (2012).
36.
Kumar Brajesh, A.K.Himanshu, Himanshu Sharma, Kiran Kumari, Rajeev Ranjan,
S.K.Bandyopadhyay and T.P.Sinha, “Structural, dielectric relaxation and piezoelectric
characterization of Sr2+ substituted modified PMS-PZT ceramic”; Physica B 407, 635,
(2012).
37.
S. Chatterjee & T. Bandyopadhyay, “Estimation of induced activity in superconductiong
cyclotron at VECC:Monte Carlo Calculations” Indian Journal of Pure & Applied Physics,
Vol. 50, 498, (2012).
38.
S. Chattopadhyay, M. Ghosh, S. Sett, M. K. Das, S. Chandra, K. De, M. Mishra, S. Sinha,
B. R. Sarkar and S. Ganguly : “Preparation and evaluation of 99mTc-cefuroxime, a
potential infection specific imaging agent: A reliable thin layer chromatographic system
to delineate impurities from the 99mTc-antibiotic”. Appl. Radiat. Isot. 70, 2384, (2012).
39.
Sankha Chattopadhyay, Luna Barua, Anirban De, Sujata Saha Das, Remashan Kuniyil,
Partha Bhaskar, Sasanka Shekhar Pal, Sishir Kumar Sarkar, Malay Kanti Das, “A
computerized compact module for separation of 99mTc-radionuclide from molybdenum”,
Applied Radiation and Isotopes, 70, 2631, (2012).
40.
A. K. Chaudhuri, “Temperature dependence of QGP viscosity over entropy ratio from
hydrodynamical analysis of ALICE data in
Phys. G39, 125102, (2012).
=2.76 TeV Pb+Pb collisions”, J.
41.
A. K. Chaudhuri, “Influence of shear viscosity on the correlation between the triangular
flow and initial spatial triangularity”, Phys. Lett. B713, 91, (2012).
42.
A. K. Chaudhuri, “Fluctuating initial conditions and fluctuations in elliptic and
triangular flow”, Phys. Lett. B710, 339, (2012).
43.
N. K. Das, J. Pradhan, Md. Z. A. Naser, A. Roy, B. Ch. Mandal, C. Mallik and R. K.
Bhandari, “Design and performance of a 4He-evaporator at <1.0K”, Cryogenics. 52,
679, (2012).
246
44.
N. K. Das, P. Kumar C. Mallik and Rakesh K. Bhandari, “Development of a helium
purification system using pressure swing adsorption’’, Current Science. 103, 6, 631
(2012).
45.
Jagannath Datta, Nihar R. Ray, Pintu Sen, Hari S. Biswas, Erwin A. Vogler; “Structure of
hydrogenated diamond like carbon by Micro-Raman Spectroscopy”; Materials Letters
71, 131, (2012).
46.
J. Datta, D.P. Chowdhury, R. Verma, A.V.R. Reddy; “Determination of elemental
concentrations in environmental plant samples by instrumental neutron activation
analysis”; Journal of Radioanalytical and Nuclear Chemistry 294, 261, (2012).
47.
A. Dey, S. Kundu, T. K. Rana, K. Banerjee, C. Bhattacharya, M. Biswas, T. K. Ghosh,
H.Pai, G. Mukherjee, J.K.Meena, D.Gupta, S.Bhattacharya, S.Mukhopadhyay, D.Pandit,
S.R.Banerjee, S.Kumar, A.Chatterjee, K.Ramachandran, K.Mahata, S.Santra, S.Pandit,
“Study of the 1p transfer channel in the 12C + 27Al reaction at 6-7 MeV per nucleon’,
Phys.Scr. T150, 014011, (2012).
48.
A. K. Dubey, A. Prakash, S.Chattopadhyay, M. S. Ganti, R.Singaraju, J. Saini, B. K. Singh,
Y.P.Viyogi, “GEM Detector Development for CBM experiment at FAIR”, Nuclear
Instruments and Methods A, 718, 418 (2012).
49.
A. Dutta, M. Bhattacharya, N. Gayathri, G. C. Das and P. Barat “The mechanism of climb
in dislocation–nanovoid interaction”, Acta Mater. 60, 3789 (2012).
50.
A. Dutta, M. Bhattacharya, N. Gayathri, G. C. Das and P. Barat, “In silico determination
of surface entropy of 1-D copper nanostructures’’, Appl. Nanosci 2, 319, (2012).
51.
M. Ganguly, S. Parida, E. Sinha, S. K. Rout, A. K. Himanshu, A. Hussain, I. M. Kim.
“Structral, dielectric and electrical properties of BaFe0.5Nb0.5O3 ceramic prepared by
solid-state reaction technique”, Material Chemistry & Physics, 132, 1125, (2012).
52.
Premomoy Ghosh, “Negative binomial multiplicity distribution in proton-proton collisions
in limited pseudorapidity intervals at LHC up to
Physical Review D 85, 054017 (2012).
= 7TeV and the clan model”
53.
M. Gohil, K.Banerjee, S. Bhattacharya, C. Bhattacharya, S. Kundu, T. K. Rana, G.
Mukherjee, J. K. Meena, R. Pandey, H. Pai, T. K. Ghosh, A. Dey, S. Mukhopadhyay, D.
Pandit, S. Pal, S. R. Banerjee, T. Bandopadhyay, “Measurement and simulation of neutron
response function of organic liquid scintillator detector”, Nucl. Instr. and Meth. A 664,
304 (2012).
54.
A. Goswami, P. Sing Babu, V. S. Pandit, “Transfer matrix of a Glaser magnet to study
the dynamics of non-axisymmetric beam”, Nucl. Instrum. Methods Phy. Res. A 678, 14
(2012).
55.
A. Goswami, P. Sing Babu, V. S. Pandit, “Investigation on beam envelope oscillations
and amplitude growth in a high current compact cyclotron”, Eur. Phys. J. Plus 127, 47
(2012).
247
56.
A. Goswami, P. Sing Babu, V. S. Pandit, “Beam focusing characteristic of an elliptical
solenoid magnet in the presence of space charge”, Nucl. Instrum. Methods Phy. Res. A
685, 46 (2012).
57.
A. Goswami, P. Sing Babu, V. S. Pandit, “Space charge dominated beam dynamics in a
spiral inflector for a compact cyclotron”, Eur. Phys. J. Plus 127, 79, (2012).
58.
A. Goswami, P. Sing Babu, and V. S. Pandit, “Self-consistent space charge dominated
beam dynamics in a spiral inflector”, Nucl. Instrum. Methods Phys. Res. A 693, 276
(2012).
59.
A. Goswami, P. Sing Babu and V. S. Pandit, “Transport characteristics of a glaser
magnet for an axisymmetric and non-axisymmetric space charge dominated beam”,
Phys. Plasmas 19, 123105 (2012).
60.
Md. Rihan Haque, Victor Roy, A. K. Chaudhuri, “Fluctuating initial condition and
smoothening effect on elliptic and triangular flow”, Phys. Rev. C86, 037901, (2012).
61.
S. Kundu, C. Bhattacharya, K. Banerjee, T. K. Rana, S. Bhattacharya, A. Dey, T. K.
Ghosh, G. Mukherjee, J. K. Meena, P. Mali, S. Mukhopadhyay, D. Pandit, H. Pai, S. R.
Banerjee, and D. Gupta, P. Banerjee, Suresh Kumar, A. Shrivastava, A. Chatterjee, K.
Ramachandran, K. Mahata, S. K. Pandit, and S. Santra, “Complex-fragment emission in
low-energy light-ion reactions”, Phys. Rev. C 85, 064607, (2012).
62.
S. Kundu, S. Bhattacharya, J. K. Meena, T. K. Ghosh, T. Bhattacharjee, P. Mukhopadhyay,
C. Bhattacharya, T. K. Rana, K. Banerjee, G. Mukherjee, S. R. Banerjee, D. L.
Bandyopadhyay, M. Ahammed and P. Bhattacharya, “A Large High Vacuum Reaction
Chamber for Nuclear Physics Research at VECC, Kolkata”, J. Phys.: Conf. Ser. 390,
012075, (2012).
63.
Swagata Mallik and Gargi Chaudhuri, “Conditions for equivalence of statistical ensembles
in nuclear multifragmentation’’, Phys. Lett. B 718, 189, (2012).
64.
Bidhan Chandra Mandal, S Saha, S C Sarkar, D Adak, T Viswanathan, B Hemram, P S
Chakraborty, R C Yadav, C Mallik and R K Bhandari, “Design, Installation and
Commissioning of new Vacuum chamber for Analysing Magnet of K-130 Cyclotron”,
Journal of Physics: Conference Series 390, 012021, (2012).
65.
Abhishek Mishra, Partha Roy Chowdhury, D. N. Basu, “Rapidly Rotating Axisymmetric
Neutron Stars with Quark Cores”, Astropart. Phys. 36, 42 (2012).
66.
Abhishek Mishra, D. N. Basu, “Nuclear Reaction Rates and the Primordial
Nucleosynthesis’’, Rom. J. Phys. 57, 1317 (2012).
67.
S. Mitra, S. Ghosh and S. Sarkar, “Effect of Spectral Modification of  on Shear
Viscosity of a Pion Gas’’, Phys. Rev. C85, 064917, (2012).
68.
Payal Mohanty, Victor Roy, Sabyasachi Ghosh, Santosh K. Das, Bedangadas Mohanty,
Sourav Sarkar, Jane Alam, A. K. Chaudhuri, “Elliptic flow of thermal dileptons as a
probe of QCD matter”, Phys. Rev. C85, 031903 (2012).
69.
M. Mondal, P. Roy, S. Mitra and S. Sarkar, “Effect of Running Coupling on Photon
Emission from Quark Gluon Plasma’’, Phys. Rev. C85, 067901 (2012).
248
70.
S. Mukhopadhyay, Deepak Pandit , Surajit Pal, Srijit Bhattacharya, A. De, S. Bhattacharya,
C. Bhattacharya, Banerjee, S. Kundu, T. K. Rana, G. Mukherjee, R. Pandey, M. Gohil, H.
Pai, J. K. Meena and S. R. Banerjee, “Measurement of giant dipole resonance width at
low temperature: A new experimental perspective”, Phys. Lett. B 709, 9 (2012).
71.
Dipak Kumar Nayak, Rinku Baishya,Kamal Krishna Halder, Tuhinadri Sen Bharat R.Sarkar,
Shantanu Ganguly, M.K.Das , and Mita Chatterjee Debnath, “Evaluation of 99mTc (I)tricarbonyl complexes of fluoroquinolones for targeting bacterial infection”,
Metallomics, 4, 1197, (2012).
72.
J. K. Nayak, J. Alam, T. Hirano, S. Sarkar and B. Sinha, “Muon pairs from In+In
Collisions at Energies Available at the CERN Super proton Synchrotron”, Phys. Rev.
C 85, 064906, (2012).
73.
H. Pai, G. Mukherjee, R. Raut, S. K. Basu, A. Goswami, S. Chanda, T. Bhattacharjee, S.
Bhattacharyya, C. Bhattacharya, S. Bhattacharya, S. R. Banerjee, S. Kundu, K. Banerjee,
A. Dey, T. K. Rana, J. K. Meena, D. Gupta, S. Mukhopadhyay, Srijit Bhattacharya, Sudeb
Bhattacharya, S. Ganguly, R. Kshetri, and M. K. Pradhan, “Onset of deformation at N =
112 in Bi nuclei”, Phys. Rev. C 85, 064317 (2012).
74.
H. Pai, G. Mukherjee, S. Bhattacharyya, M. R. Gohil, T. Bhattacharjee, C. Bhattacharya,
R. Palit, S. Saha, J. Sethi, T. Trivedi, Shital Thakur, B. S. Naidu, S. K. Jadav, R. Donthi, A.
Goswami, and S. Chanda, “High spin band structures in doubly odd 194Tl’’, Phys. Rev.
C85, 064313, (2012).
75.
Susanta Kumar Pal, Subhasis Chattopadhyay, Y. P. Viyogi, “Photon–hadron discrimination
with improved clustering for a preshower detector in high energy heavy ion
experiments”, Nuclear Instruments and Methods in Physics Research A 693, 285, (2012).
76.
G. Pal, C. Mallik, R.C. Yadav, J. Akhter, A. Datta Gupta, B. Mandal, A. Roy, A. Polley, M.
Datta, C. Nandi, A. Sarkar, Srimantra Bhattacharyya, Sarbajit Pal, and R.K. Bhandari,
“Vacuum System of the Large Cyclotrons at VECC”, Journal of Physics: Conference
Series 390, 012001, (2012).
77.
G. Pal, J. Akhter, R.C. Yadav, C. Mallik and R.K. Bhandari, “Removal of water from
unbaked vacuum system”, Journal of Physics: Conference Series 390, 012045, (2012).
78.
G. Pal, C. Nandi, S. Roy, U. Bhunia, J. Akhter, S. Bhattacharyya, A. Datta, T.K.
Bhattacharyya, M.K. Dey, C. Mallik, S. Saha and R.K. Bhandari, “Superferric
Quadrupoles for FAIR SUPER FRS Energy Buncher”, Cryogenics, 52, 730-738, (2012).
79.
Deepak Pandit, S. Mukhopadhyay, Surajit Pal, A. De, S.R. Banerjee. “Critical behavior
in the variation of GDR width at low temperature”, Phys. Lett. B 713, 434 (2012).
80.
J Pradhan et. al., “Design and Development of HTS Magnet Insert to produce 12T of
Magnetic field” published in Indian Journal of Cryogenics 37, 1-4, (2012).
81.
Y. N. Rao, S. K. Das, A. Saha, “Room Temperature Aqueous Synthesis of Bipyramidal
Silver Nanostructures”, J. Nanosci. Nanotechnol. 12, 2014, (2012).
82.
T. R. Routray, Abhishek Mishra, S. K. Tripathy, B. Behera, D. N. Basu, “Proton
Radioactivity Half Lives with Skyrme interactions”, Eur. Phys. J. A 48, 77, (2012).
249
83.
P. Roy, K.Banerjee, S. Bhattacharya, C. Bhattacharya, S. Kundu, T. K. Rana, T. K.Ghosh,
G. Mukherjee, R. Pandey, J. K. Meena, M. Gohil, H. Pai, V. Srivastava, A. Dey, D. Pandit,
S. Mukhopadhyay, S. Pal, S. R. Banerjee, “Angular-momentum-gated light-particle
evaporation spectra from 97Tc* and 62Zn* systems.”, Phys. Rev. C86, 044622, (2012).
84.
Victor Roy, A. K. Chaudhuri and Bedangadas Mohanty, “Comparison of results from a
2+1D relativistic viscous hydrodynamic model to elliptic and hexadecapole flow of
charged hadrons measured in Au-Au collisions at
014902 (2012).
= 200 GeV”, Phys. Rev. C86,
85.
Victor Roy, A. K. Chaudhuri, “2+1 dimensional hydrodynamics including bulk viscosity:
A Systematics study”, Phys.Rev. C85, 024909 (2012).
86.
S. Saha Das, S. Chattopadhyay, L. Barua and M. K. Das : “Production of 61Cu using
natural cobalt target and its separation using ascorbic acid and common anion
exchange resin”, Appl. Radiat. Isot. 70, 365, (2012).
87.
S. Saha, R. Palit, J. Sethi, T. Trivedi, P. C. Srivastava, S. Kumar, B. S. Naidu, R. Donthi, S.
Jadhav, D. C. Biswas, U. Garg, A. Goswami, H. C. Jain, P. K. Joshi, G. Mukherjee, Z.
Naik, S. Nag, V. Nanal, R. G. Pillay, S. Saha, A. K. Singh, “Experimental investigation of
shell-model excitations of 89Zr up to high spin”, Phys. Rev. C86, 034315, (2012).
88.
Radha Pyari Sandhir, Sanjib Muhuri, Tapan K. Nayak “Dynamic fuzzy c-means (dFCM)
clustering and its application to calorimetric data reconstruction in high-energy
physics’’, Nuclear Instruments and Methods in Physics Research A 681, 34–43 (2012).
89.
K. Sanyal, S. Chattopadhyay and M. Chatterjee Debnath : “Synthesis of S-thiomethyl
MAG3, radiolabelling with technetium-99m and biological evaluation”. Label. Compd.
Radiopharm. 55, 377-382 (2012).
90.
Björn Schenke, Prithwish Tribedy and Raju Venugopalan1, “Fluctuating Glasma Initial
Conditions and Flow in Heavy Ion Collisions”, Physical Review Letters 108, 252301
(2012).
91.
Pintu Sen, Arjun Dey, Anoop Kumar Mukhopadhyay, S.K.Bandyopadhyay and
A.K.Himanshu, Nanoindentation Behaviour of Nano BiFeO3, Ceramics International 38,
1347, (2012).
92.
P. Setua, C. Ghatak, V. Govind Rao, S. K. Das, N. Sarkar, “Dynamics of Solvation and
Rotational Relaxation of Coumarin 480 in Pure Aqueous-AOT Reverse Micelle and
Reverse Micelle Containing Different-Sized Silver Nanoparticles Inside Its Core: A
Comparative Study”, J. Phys. Chem. B, 116, 3704, (2012).
93.
P. Sing Babu, A. Goswami, V. S. Pandit, “A Vlasov Equilibrium for Space Charge
Dominated Beam in a Misaligned Solenoidal Channel”, Physics of Plasmas 19, 080702
(2012).
94.
P. Sing Babu, A. Goswami, V. S. Pandit, “Optimisation of beam line parameters for
space charge dominated multi species beam using random search method”, Physics
Letter A 376, 3192 (2012).
250
95.
P. Sing Babu, A. Goswami, V. S. Pandit, “Self consistent study of space charge dominated
beam in a misaligned transport system”, Physics of Plasmas 19, 113112 (2012).
96.
D. Singh, R. Ali, M. Afzal Ansari, B.S. Tomar, M.H. Rashid, R. Guin, S.K. Das,
“Observation of entrance channel mass-asymmetry effect on incomplete fusion reaction
for 20Ne+165Ho system”, Nucl. Phy. A 879, 107, (2012).
97.
STAR Collaboration, "Inclusive charged hadron elliptic flow in Au + Au collisions at
= 7.7 - 39 GeV", Phys. Rev. C 86, 54908 (2012).
98.
STAR Collaboration, "Single Spin Asymmetry AN in Polarized Proton-Proton Elastic
Scattering at
99.
= 200 GeV", Phys. Lett. B 719, 62 (2013).
STAR Collaboration, "Transverse Single-Spin Asymmetry and Cross-Section for 0 and
 Mesons at Large Feynman-x in Polarized p+p Collisions at
Rev. D 86, 51101 (2012).
100.
STAR Collaboration, "Longitudinal and transverse spin asymmetries for inclusive jet
production at mid-rapidity in polarized p+p collisions at
D 86, 32006 (2012).
101.
= 200 GeV", Phys.
= 200 GeV", Phys. Rev.
STAR Collaboration, "Measurements of D0 and D* Production in p + p Collisions at
= 200 GeV", Phys. Rev. D 86, 72013 (2012).
=
102.
STAR Collaboration, "Di-electron spectrum at mid-rapidity in p+p collisions at
200 GeV", Phys. Rev. C 86, 24906 (2012).
103.
STAR Collaboration, "Hadronic Trigger using electromagnetic calorimeter and particle
identification at high-pT with STAR Detector", e-Print Archives (1112.2946)
104.
STAR Collaboration, "Directed Flow of Identified Particles in Au + Au Collisions at
s
= 200 GeV at RHIC" Phys. Rev. Lett. 108, 202301 (2012).
105.
STAR Collaboration, "Measurement of the W  e and z/*  e+e– Production Cross
Sections at Mid-rapidity in Proton-Proton Collisions at
92010 (2012).
= 500 GeV", Phys. Rev. D 85,
106.
STAR Collaboration, "Energy and system-size dependence of two- and four-particle v2
measurements in heavy-ion collisions at 62.4 and 200 GeV and their implications on flow
fluctuations and nonflow" , Phys. Rev. C 86 (2012).
107.
D. Trivedi, M. C. Raicy, K. Devi, D. Kumar, I. Buynevich, P. Srinivasan, N. R. Iyer, R.
Guin, D. Sengupta and R. R. Nair, “Sediment Characteristics of Tidal Deposits at Mandvi,
Gulf of Kuchchh, Gujarat, India: Geophysical, Textural and Mineralogical Attributes”,
Int. J. Geosciences 3, 515, (2012).
251
7.2
PUBLICATIONS IN SYMPOSIA,
CONFERENCES AND REPORTS
1.
M. Ahammed, S. Ghosh, S.Saha, S. Singh, B. Hembram etc “Design of 4K-2K cryoinsert
test setup for validating the cryogenic circuitries to produce and deliver 2K liquid He
for superconducting e-linac”, 24th National Symposium on Cryogenics, January 21-24,
2013, Ahmedabad, India.
2.
M. Ahammed, S. Ghosh, S.Saha, A. Duttagupta, M. Mandal etc, “Design and development
of injector cryomodule for superconducting electron linac”, 24th National Symposium
on Cryogenics, January 21-24, 2013, Ahmedabad, India.
3.
M. Ahammed, S.Ghosh, A. DuttaGupta, M.K. Dey, M. Mondal etc “Thermal stability
analysis of the niobium made elliptical cavity for superconducting electron linac
project”, 24th National Symposium on Cryogenics, January 21-24, 2013, Ahmedabad, India.
4.
M. Bhattacharya, A. Dutta, A. Giri, N. Gayathri, and P. Barat, “Study of dislocation climb
at nanovoids in bcc metal”, Proceedings: Vol 2: Materials Properties, Characterization,
and Modeling TMS (The Minerals, Metals & Materials Society), p683 (2012).
5.
D. Banerjee, S. K. Das, “Nano-phase Hindered Evolution of HfO2 Thin Film on Si
(111) Surface: A Nuclear Quadrupole Interaction Study”, 4th Joint International
Conference on Hyperfine Interactions and International Symposium on Nuclear Quadrupole
Interactions, September 10-14, (2012).
6.
D. Banerjee, T. Bhattacharjee, S. K. Das, R. Guin, A. Chowdhury, P. Das, S. Dasgupta, S.
Bhattacharyya, P. Mukhopadhyay, H. Pai, S. K. Basu, “Decay Spectroscopy of neutron
rich odd-odd Pm isotope”, Proc. of DAE-BRNS Symposium on Nuclear Physics, 57, 186
(2012).
7.
I. Banerjee, A. Behera, K. De, S. Chattopadhayay and M. Misra : “Radiolabelling, stability
study and biodistribution of paclitaxel”. Presented at 44th Annual Conference of Indian
Soc. of Nuclear Medicine on 29th Nov-2nd Dec. 2012.
8.
A. Behera, I. Banerjee, K. De, S. Chattopadhayay and M. Misra : “Radiosynthesis, quality
control and biological evaluation of hynic-his3-octreotate”. Presented at 44th Annual
Conference of Indian Soc. of Nuclear Medicine on 29th Nov-2nd Dec. 2012.
9.
A. Behera, I. Banerjee, K. De, S. Chattopadhayay, A. Samanta and M. Misra : “Synthesis,
radiolabelling and biological evaluation of hynic-met3-octreotate as a new somatostatin
receptor positive tumour imaging agent”. Presented at 44th Annual Conference of Indian
Soc. of Nuclear Medicine on 29th Nov-2nd Dec. 2012.
10.
Partha Pratim Bhaduri, Subhasis Chattopadhyay, “Response simulation of the GEM
detector for the CBM experiment”, Page No: 848, Proceedings of the DAE SYMPOSIUM
ON NUCLEAR PHYSICS, Volume 57 (2012).
252
PUBLICATIONS IN SYMPOSIA, CONFERENCES AND REPORTS
11.
Tanushyam Bhattacharjee, Rajendra Balkrishna Bhole, Kaushik Datta, Sarbajit Pal, Anindya
Roy, Tapas Samanta, Debranjan Sarkar, Gaurav Saxena, “Facility Monitoring System using
Storage Area Network for VEC and SCC”, Proceedings of 9th International workshop on
Personal Computers and Particle Accelerator Controls (PCaPAC-2012), VECC, Kolkata,
December 4-7 (2012).
12.
T. Bhattacharjee, A. Chowdhury, D. Banerjee, P. Das, S. K. Das, D. Pandit, S. Pal, S.
Mukhopadhyay , H. Pai, R. Guin, S. R. Banerjee, “Measurement of - end point energies
with LEPS detector”, DAE Symposium on Nuclear Physics, December 3-7 (2012).
13.
H. S. Biswas, J. Datta, N.R. Ray, S Datta, and U.C. Ghosh; “Formation of Continuous
Thin Film of Nanocrytalline Graphite Clusters”; International Conference on Nanoscience
and Technology (ICONSAT - 2012), January 20 - 23, 2012; Hyderabad, India.
14.
Niraj Chaddha, Shantonu Sahoo, Rajendra Balkrishna Bhole, Partha Pratim Nandy, Sarbajit
Pal, “Modular Beam Diagnostics Instrument Design For Cyclotrons”, Proceedings of
9th International workshop on Personal Computers and Particle Accelerator Controls
(PCaPAC-2012), VECC, Kolkata, December 4-7 (2012).
15.
P. S. Chakraborty, C. Mallik and R.K. Bhandari, “Improved performance of Variable
Energy Cyclotron(VEC)’’, Invited talk in Theme Meeting on Unveiling Future with
Cyclotrons, 28-29 June, 2012, at VECC.
16.
P. S. Chakraborty, C. Mallik, “Low energy light ion beam development and Status of
Variable Energy Cyclotron at Kolkata’’, Proceedings of the DAE Symp. on Nucl. Phys.
57 (2012), pp- 878-879, Delhi University, Dec 03-07, 2012.
17.
Gargi Chaudhuri, Swagata Mallik and Subal Das Gupta, “University of projectile
fragmentation model”, DAE Symposium on Nuclear Physics, Volume 57, 746 (2012).
University of Delhi, New Delhi.
18.
M. K. Das, Madhusmita, S. Chattopadhyay, S. Saha Das, Md. Nayer Alam and L. Barua :
“Direct production of 99mTc in VEC cyclotron from natMo target and separation of
99m
Tc from Mo by solvent extraction technique”, Presented at 44th Annual Conference
of Indian Soc. of Nuclear Medicine on 29th Nov-2nd Dec. 2012.
19.
N. K. Das, J. Pradhan, Md. Z. A. Naser, B. Ch. Mandal, A. Roy, P. Kumar C. Mallik and
R. K. Bhandari, “Three Stage Vacuum System for ultralow temperature installation”,
International Symposium on Vacuum Science & Technology and its application for
Accelerators, 390, 012055 (2012).
20.
S. Das Gupta, S. Bhattacharyya, H. Pai, G. Mukherjee, R. Palit, A. Srivastava, S. Chanda,
A. Chatterjee, V. Nanal, S.K. Pandit, S. Saha and S. Thakur, “Spectroscopy of 201Tl
isotope”, Proc. of DAE-BRNS Symposium for Nuclear Physics, 57, 344 (2012).
21.
S. Dasgupta, A. Dutta, S. Bhattacharyya, P. Das, A. Reja, U. Bhuia, S. Saha, S. Murali and
M. H. Rashid, “Study of Field Profile of a Mini Orange Spectrometer Magnet”, Proc.
of DAE-BRNS Symposium on Nuclear Physics, 57, 950 (2012).
22.
Aparajita Dey, S. Ganguly, V. Srivastava, T. K. Rana, S. Kundu, K. Banerjee, H. Pai, C.
hattacharya, T. K. Ghosh, R. Pandey, G. Mukherjee, J. K. Meena, M. R. Gohil, and S.
253
Bhattacharya, ‘Elastic scattering of alpha particles from 27Al target’, Proceedings of the
DAE Symp. on Nucl. Phys. 57, 438, (2012).
23.
Anirban De, S.S. Pal, P. Bhaskar, S. Kumari, V.K. Khare, A. Duttaroy, M. Garai, S.K.
Thakur, S. Saha, Sankha Chattopadhyay, Luna Barua, Sujata Saha Das, U. Kumar, M.K.
Das, “An Embedded System based Computer Controlled Process Automation for
Recovery and Purification of 99mTc from (n,v) 99Mo”, Proceeding of the 9th International
Workshop on Personal Computers and Particle Accelerator Controls (PCaPAC2012), VECC,
Kolkata, Dec 4-7, 2012.
24.
Anirban De, Santwana Kumari, V.K. Khare, S.S. Pal, Anindya Sadhukhan, V. K. Meshram,
S.K. Thakur, Subimal Saha, “Design, Development and Testing of a DSP based Dynamic
Voltage Restorer”, Proceeding of the 3rd International Symposium on Electronic System
Design (ISED2012), BESU, Shibpur, Howrah, Dec 19-22, 2012.
25.
Balaram Dey, Deepak Pandit, S. Mukhopadhyay, Surajit Pal, K. Banerjee, and S. R.
Banerjee, “Neutron response of the LAMBDA spectrometer”, DAE-BRNS Symp on NP,
57, 868 (2012).
26.
Madhusudan Dey, Abhishek Singh, Amitava Roy “SEU mitigation technique by Dynamic
Reconfiguration method in FPGA based DSP application”, DAE Symposium on Nuclear
Physics, 57, 912 (2012).
27.
Madhusudan Dey, Abhishek Singh, Aditya Mondal, Surajit Ghosh, Sumit Som, “FPGA based
amplitude control system for accelerating cavities”, PcAPAC 2012.
28.
Madhusudan Dey, Amitava Roy, Subhasish Chattopadhyay, “Development & Production
of ROC SysCore Board V2.2”, GSI Annual Report, 2012.
29.
P. Dhara, Amitava Roy, P. Maity, P. S. Roy, “The Multi-crate VME Data Acquisition
System”,DAE Symposium on Nuclear Physics, 57, 916 (2012).
30.
P. Dhara, Amitava Roy, P. Maity, P. Singhai, and P. S. Roy, “Design of the Data Acquisition
System for the Nuclear Physics Experiments at VECC”, 9th International Workshop On
Personal Computers and Particle Accelerator Controls, VECC, Oral presentation, 2012.
31.
Neha Dokania, V. Nanal, V. Singh, N. Katyan, S. Mathimalar, R.G. Pillay, D.R.Chakrabarty,
V. M. Datar, Suresh Kumar, G. Mishra, M. S. Pose, S. Mishra, Deepak Pandit, and
S.Mukhopadhyay. “Characterisation of a LaBr3(Ce)-NaI(Tl) Phoswich detector for high
energy gamma rays”, DAE-BRNS Symp on NP, 57, 874 (2012).
32.
A.K. Dubey, J, Saini, R. N. Singaraju, Z. Ahammad, S. Chattopadhyay, G. S. N. Murthy, Y.
P. Viyogi, A. Prakash, B. K. Singh, “Testing of Triple-GEM Chamber with muon beams
at CERN SP “, Proceedings of the DAE Symp. on Nucl. Phys. 57, 860 (2012).
33.
Anand K. Dubey, “A GEM based Muon Tracker for CBM experiment at FAIR”,
Proceedings of DAE symposium on Nuclear Physics 2012, 57, 132 (2012).
34.
Nabanita Dutta, S.K.Bandyopadhyay, A.K.Himanshu, Abhishek Kumar Das and Sangam
Banerjee, “Atypical Magnetic and Dielectric properties of agglomerated nanostructured
BFO”; Proceedings on International Conference on Nanoscience and Technology
(ICONSAT-2012) p. 122.
254
35.
N. Dutta, S. K. Bandyopadhyay, P. Sen, A. K. Himanshu, P. Y. Naviraj, R. Menon, P. K.
Mukhopadhyay, and P. Ray, “A simple novel method of developing BFO nanostructures”;
Proceedings of the 57th DAE Solid State Physics Symposium 2012, Indian Institute of
Technology, Bombay, Mumbai, India 3 – 7 December 2012, Pages: 234-236.
36.
S. Ganguly, “Nuclear Medicine-its uses in Diagnosis and Therapy of Cancer”,
International Conference on Radiation, Cancer and Society, NGB University, Allahabad,
India, November 26-28, (2012)
37.
S. Ghosh, M. Ahammed, S. Saha, M.Mondal, A. Duttagupta, etc, “Design and development
of recuperative shell & tube type helium heat exchanger”, 24th National Symposium on
Cryogenics, January 21-24, 2013, Ahmedabad, India.
38.
S. Ghosh, M. Ahammed, A. Duttagupta, M.K.Dey, etc, “Design of helium thermo-siphon
circuit for injector cryomodule of superconducting electron linac”, 24th National
Symposium on Cryogenics, January 21-24, 2013, Ahmedabad, India.
39.
M. Gohil1, K. Banerjee, C. Bhattacharya, S. Kundu, T. K. Rana, G. Mukherjee, J. K.
Meena, R. Pandey, H. Pai, M. Biswas, A. Dey, T. Bandhopadhyay, and S. Bhattacharya,
‘Study of nuclear level density parameter using neutron’, Proceedings of the DAE Symp.
on Nucl. Phys. 57, 494 (2012).
40.
A.K. Himanshu, S. K. Bandyopadhayay,Rajni Bahuguna, D. K. Ray, T.P. Sinha, “Synthesis
and Dielectric Studies of Polyorthotoluidine – Polyacrylamide Conducting Polymer
Composites”, AIP Conf. Proc. of 56th DAE, Solid State Symposium, 1447, 149-150 (2012).
41.
P. Kumar, N. K. Das, C. Mallik and R. K. Bhandari, “Development of a high vacuum
sample preparation system for helium mass spectrometer”, International Symposium on
Vacuum Science & Technology and its application for Accelerators, 390, 012056 (2012).
42.
S. Kundu, C. Bhattacharya, T. K. Rana, K. Banerjee, S. Bhattacharya, J. K. Meena, R.
Saha, G. Mukherjee, T. K. Ghosh, R. Pandey, P. Roy, M. Gohil, V. Srivastava, A. Dey, G.
Pal, S. Roy, S. R. Bajirao, C. Nandi, ‘Charged particle detector array: 45 0-1750’,
Proceedings of the DAE Symp. on Nucl. Phys. 57, 864 (2012).
43.
Swagata Mallik, Gargi Chaudhuri and Subal Das Gupta, “Study of symmetry energy to
temperature ratio in projectile fragmentation reaction”, DAE Symposium on Nuclear
Physics, Volume 57, 744 (2012). University of Delhi, New Delhi.
44.
Swagata Mallik and Gargi Chaudhuri “Isoscaling parameter in nuclear
multifragmentation”, DAE Symposium on Nuclear Physics, Volume 57, 748 (2012).
University of Delhi, New Delhi.
45.
Aditya Mandal, Sumit Som, S.K. Manna, Surajit Ghosh, Sudeshna Seth, S.K Thakur, S.
Saha, Uma Shankar Panda, “Testing of inductive output tube based RF amplifier for
650 MHz SRF cavities” 9th International Workshop on Personal Computers and Particle
Accelerator Controls (PCaPAC2012) held at VECC during December 4-7, 2012.
46.
B.C. Mandal, P. S. Chakraborty, R. K. Bhandari, “Design, Installation and commissioning
of new vacuum chamber for Analysing magnet of K-130 cyclotron’’, Proc. of the Vacuum
255
Science & Technology and its application for Accelerators, IVS- 2012, Feb 15-17, 2012,
VECC, Kolkata.
47.
Debasish Mondal and B. K. Nayak, “Superconducting Solenoid Spectrometer as fragment
analyser”, DAE-BRNS Symp on NP. 57, 870 (2012).
48.
S. Muhuri, T. K. Nayak, “Simulation and design studies of ALICE Forward Calorimeter”,
Proceedings of the DAE Symp. on Nucl. Phys. 57 (2012).
49.
G Mukherjee, Balaram Dey, S Mukhopadhyay, Deepak Pandit, Surajit Pal, H Pai, S. R
Banerjee, “A modular TAS Setup at VECC using BaF2detectors”, Proc. of DAE-BRNS
Symposium on Nuclear Physics, 57, 872 (2012).
50.
S.R. Narayan, S.A. Khan, J. Saini, P. Bhaskar, S. Muhuri, T.K. Nayak, Y.P. Viyogi, Y.P.
Prabhakara Rao, Y. Rejeena Rani, S. Mukhopadhyay ,V.B.Chandratre, M. Sukhwani and
C.K.Pithawa, “Silicon Pad Detectors for ALICE Forward Calorimeter” Proceedings of
the DAE Symp. on Nucl. Phys. 57, 954 (2012).
51.
Tapan K. Nayak, “Heavy-Ions: Results from the Large Hadron Collider”, Pramana: Vol.
79, No. 4, Oct 2012, pp: 719 (2012)
52.
Tapan K. Nayak, “Phases of Nuclear Matter”, Current Science, Vol. 103, Issue 8, page:
888 (2012) .
53.
Tapan K. Nayak, “LHC in a Nutshell”, Science Horizon, May 2012
54.
Tapan K. Nayak, “India in ALICE – A journey to the beginning of the Universe”,
Science Reporter 49, 11, (2012).
55.
R Pandey, A Dey, T. K Rana, M Biswas, T. K Ghosh, C Bhattacharya, S Kundu, K Banerjee,
G Mukherjee, P Roy, J. K Meena, H Pai, M Gohil, S Bhattacharya, ‘[a, 3He] and [a, 3H]
transfer reaction studies at Ea =60 MeV’, Proceedings of the DAE Symp. on Nucl.
Phys. 57, 526 (2012).
56.
R Pandey, T. K Ghosh, J. K Meena, K Banerjee, C Bhattacharya, S Bhattacharya, M
Gohil, G Mukherjee, S Kundu, T. K Rana, P Roy, H Pai, V Srivastava, “Development of a
low pressure PPAC for detection of heavy charged particles”, Proceedings of the DAE
Symp. on Nucl. Phys. 57, 930 (2012).
57.
Deepak Pandit, S. Mukhopadhyay, Surajit Pal, A. De and S. R. Banerjee, “The effect of
GDR - GQR couplings on the GDR width at low temperature “, DAE-BRNS Symp on
NP, 57, 188 (2012).
58.
J Pradhan et. al., “Conductively Cooled HTS Magnet and Cryo-cooler based Cryogenic
Test Set- up” presented in the 24th National symposium on Cryogenics (2013) in IPR Gandhi
Nagar, Ahemadabad India.
59.
S. Rajbanshi, A. Bisoi, S. Nag, S. Saha, J. Sethi, T. Trivedi, T. Bhattacharjee, S. Bhattacharyya,
S. Chattopadhyay, G. Gangopadhyay, G. Mukherjee, R. Palit, M. Saha Sarkar, A. K. Singh
and A. Goswami, “Determination of nuclear life time from time stamped decay data”,
Proc. of DAE-BRNS Symposium on Nuclear Physics, 57, 244 (2012).
60.
S. Rajbanshi, A. Bisoi, S. Nag, S. Saha, J. Sethi, T. Trivedi, T. Bhattacharjee, S. Bhattacharyya,
S. Chattopadhyay, G. Gangopadhyay, G. Mukherjee, R. Palit, M. Saha Sarkar, A. K. Singh
256
and A. Goswami,, “Search for Shears Mechanism in
Symposium on Nuclear Physics, 57, 208 (2012).
142
Sm”, Proc. of DAE-BRNS
61.
T. K. Rana, S. Bhattacharya, C. Bhattacharya, S. Kundu, K. Banerjee, T. K. Ghosh, G.
Mukherjee, R. Pandey, M. Gohil, A. Dey, J. K. Meena, G. Prajapati, P. Roy, H. Pai, M.
Biswas, “Search of 22+ state of Hoyle state of 12C”, Proceedings of the DAE Symp. on
Nucl. Phys. 57, 422, (2012).
62.
Anindya Roy, Rajendra Balkrishna Bhole, Sarbajit Pal, “Development of EPICS Channel
Access Embedded ActiveX Components for GUI Development”, Proceedings of 9th
International workshop on Personal Computers and Particle Accelerator Controls (PCaPAC2012), VECC, Kolkata, December 4-7 (2012).
63.
Anindya Roy, Rajendra Balkrishna Bhole, Sarbajit Pal, Debranjan Sarkar, “EPICS
MySQLArchiver - Integration Between EPICS and MySQL”, Proceedings of 9th
International workshop on Personal Computers and Particle Accelerator Controls (PCaPAC2012), VECC, Kolkata, December 4-7 (2012).
64.
Anindya Roy, Tomohiro Okazaki (EJIT, Hitachi, Ibaraki), Kazuro Furukawa, Naoko Iida
(KEK, Ibaraki), “Development of Fast Controls for Beam Wire Scanner for SuperKEKB”,
Proceedings of 9th International workshop on Personal Computers and Particle Accelerator
Controls (PCaPAC-2012), VECC, Kolkata, December 4-7 (2012).
65.
Pratap Roy, K. Banerjee, S. Kundu, T. K. Rana, T.K. Ghosh, C. Bhattacharya, G. Mukherjee,
R. Pandey, J. K. Meena, M. Gohil, H. Pai, V. Srivastava, A. Dey, S. Mukhopadhyay, D.
Pandit, S. Pal, S. R. Banerjee, and S. Bhattacharya , ‘Study of angular momentum gated
light-particle evaporation spectra in 4He + 93Nb and 4He + 58Ni reactions’, Proceedings
of the DAE Symp. on Nucl. Phys. 57, 420 (2012).
66.
S. Saha, R. Palit, J. Sethi, T. Trivedi, P. C. Srivastava, S. Kumar, B. S. Naidu, R. Donthi, S.
Jadhav, D. C. Biswas, U. Garg, A. Goswami, H. C. Jain, P. K. Joshi, G. Mukherjee, Z.
Naik, S. Nag, V. Nanal, R. G. Pillay, S. Saha, A. K. Singh, “Experimental Investigation
Shell Model Excitations of 89Zr up to High Spin and its Comparison with 88,90Zr”, Proc.
of DAE-BRNS Symposium on Nuclear Physics, 57, 360 (2012).
67.
Shantonu Sahoo, Sarbajit Pal, Tanushyam Bhattacharjee, “Development and Performance
analysis of EPICS Channel Access Server on FPGA based Soft-core Processor”,
Proceedings of 9th International workshop on Personal Computers and Particle Accelerator
Controls (PCaPAC-2012), VECC, Kolkata, December 4-7 (2012).
68.
S. Sarkar and S. Ghosh, “In-medium Vector Mesons and Low Mass Lepton Pairs from
Heavy Ion Collisions”, 5th DAE-BRNS Workshop on Hadron Physics (Hadron 2011) Journal
of Physics: Conference Series 374, 012010 (2012).
69.
S.K.Sarkar, S.Chattopadhyay, L. Barua, A. De, S. Saha Das, S. Joshi, P. Kale, Tara Pillai,
M.K.Das, S.S.Sachdev and N.Sivaprasad : “Performance evaluation of SOL-COL
generator system and comparison of labeling efficiency of Tc-cold kits with 99mTc
obtained from different types of generators”. Presented at 44th Annual Conference of
Indian Soc. of Nuclear Medicine on 29th Nov-2nd Dec. 2012.
257
70.
R. N. Sinde, A. K. Pandey, R. Acharya, R. Guin, S. K. Das, N. S. Rajurkar, P. K. Pujari,
“Arsenic speciation in water using iron-complexed chitosan membrane : application
of radiotracer and NAA”, SESTEC-2012, Mumbai (2012).
71.
S. Singh, M. Ahammed, B. Hembram, A. Dutta Gupta, etc, “Design and fabrication of
the cryoshocking test facility for the inhouse development of the 4K-2K cryo-insert”,
24th National Symposium on Cryogenics, January 21-24, 2013, Ahmedabad, India.
72.
P. Singhai, Amitava Roy, P. Dhara and S. Chatterjee, “Digital Pulse Processing Techniques
for High Resolution Amplitude Measurement of Radiation Detector”, 9th International
Workshop on Personal Computers and Particle Accelerator Controls, VECC, Oral
presentation, 2012.
73.
S. Srivastava, A. Misra, V. S. Pandit, “Auto tuned PID Controller design Using
Diophantine Equation”, IEEE, International Conference on communication devices and
intelligent systems Dec, 28-29, 2012, India.
74.
S. Srivastava, V. S. Pandit, “A New Scheme for Direct Estimation of PID Controller”,
International Workshop on Personal Computers and Particle Accelerator Controls. Dec, 0407, 2012, India.
75.
A. Shrivastava, A. Navin, A. Diaz-Torres, V. Nanal, K. Ramachandran, M. Rejmund, S.
Bhattacharyya, A. Chatterjee, S. Kailas, R. Palit, V.V. Parkar, R.G. Pillay, P.C. Rout, and Y.
Sawant,, “Dynamics of fragment capture in 7Li + 198Pt”, Proc. of DAE-BRNS Symposium
on Nuclear Physics, 57, 950 (2012).
76.
V. Singhal, P. P. Bhaduri, S. Chattopadhyay, and S. K. Aggarwal, “Real time data analysis
using GPU for High energy physics experiments”, Proceedings of the DAE Symp. on
Nucl. Phys. 57, 972 (2012).
77.
Prithwish Tribedy, Bjoern Schenke, Raju Venugopalan, “Fluctuating Glasma initial
condition for heavy ion collisions”, Proceedings of the DAE Symp. on Nucl. Phys. 57
(2012).
258
7.3
1.
THESES
Prasun Sharma Chowdhury, “Characterization of Microstructure of Nuclear Structural
Materials by XRD”. Doctor of Philosophy in Science, 2012. Homi Bhabha National Institute
(HBNI)
Supervisor: Dr. P. Barat, VECC, Kolkata
2.
Jhilam Sadhukhan, “The Statistical and Dynamical Models of Nuclear Fission”. Doctor
of Philosophy in Science, 2012. Homi Bhabha National Institute (HBNI)
Supervisor: Dr. Santanu Pal
3.
Joydev Lahiri, “Theoretical Aspects of Cosmological Inflation”. Doctor of Philosophy in
Science, 2012, Jadavpur University, Kolkata
Supervisor: Prof. Gautam Bhattacharya, SINP, Kolkata
4.
Santosh Kumar Das, “Heavy Flavor Production and Propagation in Heavy Ion
Collision”. Doctor of Philosophy in Science, 2012. Homi Bhabha National Institute (HBNI)
Supervisor: Dr. Jane Alam, VECC, Kolkata
5.
Payal Mohanty, “Electromagnetic radiations from partons and hadrons”. Doctor of
Philosophy in Science, 2012. Homi Bhabha National Institute (HBNI)
Supervisor: Dr. Jane Alam, VECC, Kolkata
6.
Victor Roy, “Dissipative fluid dynamics for ultra-relativistic nuclear collisions” . Doctor
of Philosophy in Science, 2012. Homi Bhabha National Institute (HBNI)
Supervisor: Dr. Asis Kumar Chaudhuri, VECC, Kolkata
7.
Sabyasachi Ghosh, “Probing Spectral Properties of Hadrons in Hot and Dense
Hadronic Matter”, Doctor of Philosophy in Science, 2012. Homi Bhabha National Institute
(HBNI)
Supervisor: Dr. Sourav Sarkar, VECC, Kolkata
8.
Haridas Pai, “Study of nuclear structure near the Z=82 and N=82 shell closures”.
Doctor of Philosophy in Science, 2012. Homi Bhabha National Institute (HBNI)
Supervisors: Dr. Chandana Bhattacharya & Dr. Gopal Mukherjee, VECC, Kolkata
9.
Susanta Kumar Pal, “Recognition of Photon and Hadron clusters in High Energy Heavy
Ion Collisions” Doctor of Philosophy in Science, 2012, Jadavpur University, Kolkata
Supervisor: Dr. Subhasis Chattopadhyay, VECC, Kolkata
10.
Shantonu Sahoo, “Development of Embedded EPICS for ARM Microcontroller and FPGA
based soft-core processor”, M. Tech., 2012, Homi Bhabha National Institute (HBNI)
Supervisor: Dr. Sarbajit Pal, VECC, Kolkata
259
11.
Vikas Singhal, “Real time data analysis using GPU for High energy physics experiments”,
M. Tech., 2012, Indian Institute of Technology, Kanpur
Supervisor: Dr. Sanjeev K. Aggarwal, IITK, Kanpur.
260
7.4
COLLOQUIUM
1.
Dr. T.S. Radhakrishnan, Formerly, Head, Materials Science Division, IGCAR. Presently,
a DST supported Scientist, “Biomagnetism with SQUIDs”, February 2, 2012.
2.
Prof. Ritabrata Munshi, School of mathematics, TIFR, Mumbai, “Revisiting the legacy
of Ramanujan”, June 12, 2012.
3.
Prof. Abhay L. Deshpande, Deparment of Physics and Astronomy, Stony Brook
University, USA, “Exploring the glue that binds us all: The science of the Electro Ion
Collider”, July 23, 2012.
261
7.5
EVENTS & OTHER ACTIVITIES
1.
Academic activities of HBNI at VECC: For the doctoral research (Ph.D.) in physical
science under HBNI at VECC few research scholars were admitted in 2012 (through
JEST Examination and selection interview) and one year pre-doctoral course work was
organized on completion of which they joined various research groups for doctoral research.
Three engineers, who joined after successful completion of BARC training school at Mumbai
and CAT training school at Indore, were registered for M.Tech programme. .
2.
Training programme: About one twenty under graduate students of Electronics &
Communication, Electronics & Instrumentation, computer Science, Information Technology,
Electrical and mechanical Engineering disciplines from Indian Institute of Technology, National
Institute of Technology and colleges under other universities of India have taken their
vocational training at this centre during summer and puja vacation in the year 2012.
3.
Participated in 15th national science exhibition: VECC participated as a unit of DAE
in the 15th National Science Exhibition organized by Central Calcutta Science & Cultural
Organization for the youth from 7 to 11 September 2012, at Bhairabh Ganguly College
Maidan, Kolkata. Poster displaying activities of the various units of DAE were exhibited by
DAE personnel. Main contribution of VECC was Superconducting cyclotron model along
with sample superconductor coil and cables.
4.
Public awareness program at Apeejay School, Salt Lake: VECC and Apeejay School,
Salt Lake arranged a programme for public awareness on the theme of “Japan and its
Aftermath” on January 16, 2012 at the school campus. Dr. R.K Bhandari, Former Director,
VECC chaired the entire session convened by Ms. Reeta Chatterjee, Principal, Apeejay
School, Salt Lake. The key note address on Nuclear Power: its need, the public perceptions
and the realities, was delivered by Shri S K Malhotra, Head, Public Awareness Division,
DAE, Mumbai.
5.
Scientists and engineers of VECC deliver lectures on the activities of the centre:
Dr. Subhasis Chattopadhyay, Dr. Gopal Mukherjee, Shri Malay Kanti Dey and Shri Tanushyam
Bhattacharyay presented the R&D activities at VECC in the field of high energy physics
experiments, nuclear physics experiments, detector technology and accelerator developments
in the University Grant Commission sponsored “National Conference on Developments of
Modern Physics and Electronics: 2012” based on the theme of ‘Modern trend in Physics
and electronics’ and arranged by the Physics Department of J. K. College, Purulia during
February 3-4, 2012.
Mr. Niraj Chaddha of C&I group, VECC delivered a lecture on “Control and Monitoring
System for Beam Diagnostics”, detailing the accelerator control activities of VECC, at
Bengal Institute of Technology, Kolkata on March 5, 2012 during the institute’s annual
technical fest, “Bits-to Bytes”. Around 150 students of Electronics and Communication
Engineering and several faculty members, including Mr. Samaresh Goswami, Chairman
262
Tech-fest and former Director, Birla Industrial & Technological Museum attended the lecture.
6.
XXVII all India DAE Chess Tournament: The XXVII all INDIADAE chess tournament
was hosted by VECC from March 15-20, 2012. 40 participants, representing 8 teams (Ajanta,
Ellora, Dwaraka, Golconda, Nagarjuna, Rameshwaram, Pushkar and Konark) from all the
units of Department of Atomic Energy in India participated in the tournament with great
zeal and enthusiasm.
7.
National Science Day celebration: National Science Day at VECC has been celebrated
this year on March 16, 2012 along with a month long program of visits to cyclotrons of the
centre for the students from various colleges and schools of West Bengal. The main theme
of the National Science Day celebration was “Clean Energy Options and Nuclear Safety”.
A talk on “Nuclear Energy : Clean, Green and Safe Power” was delivered by Dr. S.K.
Malhotra, Head, Public Awareness Division, Department of Atomic Energy, Mumbai
elaborating the various implications of nuclear energy in India and its safety features. The
program included a visit to cyclotrons and other experimental laboratories. The visit was
followed by a science quiz and debate contest on the topic “Nuclear Energy: a better option
for clean energy”.
Convener: Dr. Sarmistha Bhattacharyya.
8.
National safety week celebration 2012: Fire Safety Week was observed at VECC
during April 16-20, 2012. On April 16, 2012 the programme was inaugurated by Dr. R.
K.Bhandari, Former Director, VECC. Mr Gopal Bhattacharya, Director, West Bengal Fire
& Emergency Services attended the function as Chief Guest and delivered an elaborate
lecture on Fire Safety, highlighting recent major fire incidence in the city. Shri Subimal Saha,
Chairman VECC Safety Committee delivered the welcome address and Shri D.
Bandyopadhyay, Deputy Chief Security Officer proposed the vote of thanks as convener of
the organizing committee.
9.
Educational Visits:
i. The following school / colleges visited the institute during science day programme

Bethun college

Kanchrapara college

Krishnanagar Govt. College

Ramakrishna Mission, Narendrapur

Ramakrishna Mission Vivekananda Centenary College

S. A. Jaipuria College

Scottish Church College

Vivekananda College

Vidyamandira Ramakrishna Mission

South Point School

Garden High School
263

Presidency University
ii. The following school / colleges visited the institute in a special day visit programme

St. Paul’s Cathedral Mission College, Kolkata (May 1, 2012).

Sushila Birla Girls’ School, Kolkata (July 2, 2012).

Barasat Govt. College (September 21, 2012).

Kathamandu University (October 29, 2012).

Jadavpur University, MSc. Instrumentation (November 20, 2012).

Indira Gandhi Memorial High School, (December 13, 2012).
10.
Asian Forum for Accelerators and Detectors Workshop (AFAD-2012): Asian Forum
for Accelerators and Detectors Workshop (AFAD-2012) and Asian Committee for Future
Accelerators (ACFA) meeting hosted by Variable Energy Cyclotron Centre, Kolkata, from
February 6-8, 2012. The AFAD workshop held on February 6th & 7th followed by the 19th
ACFA meeting on February 8, 2012.
11.
International Symposium on Vacuum Science & technology (IVS – 2012): International
Symposium on Vacuum Science & Technology and its Applications for Accelerators (IVS2012) was organized by VECC during February 15-17, 2012 in collaboration with Indian
Vacuum Society (IVS). The main areas covered under this symposium were production &
management of vacuum, large vacuum systems, leak detections, vacuum metallurgy and
application of high vacuum in cyclotron, LINAC’S, synchrotron storage ring, plasma devices
(TOKAMAK), ion source, high energy particle accelerators, vacuum tubes, thin films etc.
More than 250 registered delegates from various DAE units, CEERI, ISRO, DRDO, CSIR
and R&D institutions participated in the symposium. Besides national laboratories, there
were good number of presentations by experts from international laboratories viz TRIUMF,
Canada, RIKEN, Japan, CERN, Geneva, Jefferson Lab, USA, Karlsruhe Institute of
Technology, Germany, ITER, France, MIT, USA and also from industries viz SAES Getters,
Italy, Edwards, UK, Pfeiffer , Germany etc.
12.
Theme Meeting on Unveiling Future with Cyclotrons: Two days “Theme Meeting on
Unveiling Future with Cyclotrons” sponsored by Board of Research in Nuclear Sciences
held at Variable Energy Cyclotron Centre, Kolkata during June 28-29, 2012. Around 230
delegates participated in this meet.
13.
QGP Meet-2012: The 5th National workshop on Ultra – relativistic Heavy ion collisions,
QGP (Quark-Gluon Plasma) meet-2012 held on July 3-6, 2012 at VECC. Being a premier
institute in the field, it brought together researchers, experts and scholars to discuss physics
Quark-Gluon Plasma and its early connection with universe. Large number of Ph.D students
and research scholars was participated in this workshop.
14.
International Collaboration Meeting of The CBM Experiment and School On
computing in CBM: The 20th International collaboration meeting of the Compressed
Baryonic Matter (CBM) experiment collaboration was held at VECC during September 2428, 2012. About 120 collaborators including 60 from abroad attended the meeting. Dr. T.
Ramasami, Secretary, Department of Science and Technology, Government of India
264
inaugurated the meeting. Dr. D. K. Srivastava, Director, VECC introduced VECC in his
welcome address. CBM is scheduled to take data in 2018 at the upcoming Facility for
Antiproton and Ion Research (FAIR) in Germany.
15.
NUSTAR WEEK 2012: NUSTAR is a collaboration of scientists from all over the world,
devoted to the study of NUclear STructure, Astrophysics, and Reactions at the upcoming
FAIR (Facility for Antiproton and Ion Research) facility at GSI, Darmstadt in Germany.
The collaboration holds its 4th annual “NUSTAR week 2012” meeting at VECC during
October 8-12, 2012. The aim of the meeting was to exchange views about the collaboration
in general, hold working group meetings of all NUSTAR projects, presentation of new
technical results and discuss perspective ideas together. More than 150 scientists from
India and abroad participated in this meeting.
16.
Science with Rare Ion Beams-2012 (SCRIBE-2012): VECC with support from Board
of Research in Nuclear Sciences (BRNS), Department of Atomic Energy, organized an
international workshop on Science with Rare-Ion Beams – SCRIBE2001 during November
7-9, 2012 at Kolkata. Rare-isotope science experts from across Asia, Europe and North
America came together to discuss and fine tune the physics programme and accelerator
scheme of ANURIB (Advanced National facility for Unstable and Rare Ion Beams) - the
upcoming national facility for basic research at VECC.
17.
Evaluation of Nuclear Structure and Decay Data (ENSDD-2012) Workshop and
NDPCI Meeting: A BRNS sponsored workshop on the Evaluation of Nuclear Structure
and Decay Data (ENSDD-2012) was held at VECC during November 26 – 29, 2012. This
event, organized under the aegis of the Nuclear Data Physics Centre of India (NDPCI), is
the first of its kind in India. The aim of the workshop was to provide detailed information
and training on the evaluation of nuclear structure and decay data in the ENSDF (Evaluated
Nuclear Structure Data File) format.
18.
Ninth International Workshop on Personal Computers and Particle Accelerator
Controls (PCaPAC 2012): The Ninth International Workshop on Personal Computers
and Particle Accelerator Controls (PCaPAC-2012) was organized by VECC during
December 04-07, 2012. It covered varieties of modern aspects of control system design,
implementation and technologies used in the scientific fields including particle accelerators
fusion reactors, and telescopes available worldwide. A total of 139 registered participants
from 13 different countries across the globe took part in this international event, presented
their works and experienced a valuable interaction with each other on the recent trends of
control system and its future. Participants from various national institutes like VECC, BARC,
RRCAT, IPR, IUAC, SAMEER etc. found a great opportunity to share knowledge with the
internationally acclaimed control system experts.
19.
VISITS
i. Canadian High Commissioner visits VECC: His Excellency Mr. Stewart Beck,
Canadian high commissioner to India visited VECC on January 18, 2013 to discuss
research collaboration between Canada and India. VECC and TRIUMF – Canada’s
national laboratory for particle and nuclear physics, have a very active collaboration on
superconducting radiofrequency accelerator development running for the past three
years.
265
ii. Director General of CERN visits VECC: Prof. Rolf Heuer, Director General of
CERN, Geneva visited VECC on January 4, 2013. In a meeting organized in his honour,
he had given an overview of the activities of VECC and the centre’s participation in
the ALICE experiment at CERN.
iii. Visit of GSI Director at VECC: Prof. Horst Stoecker, Director, GSI-Darmstadt,
Germany visited VECC recently while he was in the city on occasion of attending the
centenary year of Indian Science Congress. Prof. Stoecker had detailed discussions
on VECC’s involvement in activities related to the FAIR (Facility for Antiproton and
Ion Research) project.
266
7.6
AWARDS & HONOURS
1.
Most valued reviewer 2012: Dr. Sankha Chattopadhyay, Dy. General Manager, Board
of Radiation & Isotope Technology, Regional Centre Kolkata has been named one of the
most valued reviewers of 2012 by the editors of Applied Radiation and Isotopes, Elsevier,
appreciating his commitment to the journal. The honour is conferred upon reviewers
acknowledging their contributions to efficient editorial procedures and maintaining high journal
standards.
2.
Fellow of IAS, Bangalore: Dr. Tapan K. Nayak, Head High Energy Physics Section I,
Experimental High Energy Physics & Application Group has recently been elected as a
Fellow of the Indian Academy of Sciences, Bangalore, following a long-standing career in
the field of heavy-ion physics.
3.
Dr. Rakesh Kumar Bhandari,Director VECC and Senior Professor, Homi Bhabha National
Institute has been felicitated by the Anusuya Sharma Medical Education Foundation, Kolkata
on March 18, 2012 for his lifetime contributions in the field of nuclear science research and
accelerator technology developments in India.
4.
Dr. Dinesh Kumar Srivastava, distinguished scientist and director of VECC , senior
professor of Homi Bhabha national Institute has been selected the fellow of The National
Academy of science, Allahabad, India in 2012.
5.
PGDLIM best student award 2011-12: Shri S. Balabharathi, scientific assistant/E,
(Library), computer informatics group, received the best student award in Post Graduate
Diploma in Digital Library and Information Management (PGDLIM) 2011-12 from Tata
institute of Social Science (TISS) Mumbai.
6.
Gold Medal for securing the first class first position in M. Tech in Applied Physics in 1996
in Calcutta University by Susanta Kumar Pal.
7.
Isamu Abe Award: Shri Shantonu Sahoo has received the ‘Isamu Abe Award’ at PCaPAC
2012 for best oral presentation in the conference.
DAE Awards
DAE Group Achievement Award Winners 2012:

R&D activities on production, acceleration and use of Radioactive Ion beams at VECC.
Group leader Dr. Alok Chakrabarti (Total 24 persons)

Development of different types of Neutron Detectors at VECC.
Group leader Dr. Sailajananda Bhattacharya (Total 14 persons)
267

Improvement of Vacuum System for K130 Room Temperature Cyclotron.
Group leader Shri Gautam Pal (Total 31 persons)
DAE SCIENTIFIC & TECHNICAL EXCELLENCE AWARD WINNERS 2012

Shri Chinmay Nandi, SO/F, ATD(M), MEG, VECC.

Dr. Sarmishtha Bhattacharyya, SO/F, ENPD, PG, VECC.
DAE YOUNG SCIENTIST AWARD WINNER 2012

Shri Jhilam Sadhukhan, SO/D, TPD, PG, VECC.
DAE Young Engineer Award Winner 2012

Shri Jogender Saini, SO/E, EHEPA Group, VECC
268
Personnel
Personnel
1. Retired Employees in the year 2012
GO
PERSONNEL
1
Shri Tapan Kumar Bhattacharjee
801/074
SO/H
31.01.2012
2
Shri A.S. Banerjee
801/165
SO/G
30.04.2012
3
Dr. Santanu Pal
801/057
O.S.
31.05.2012
4
Dr. Rakesh Kumar Bhandari
801/027
D.S.
30.06.2012
5
Shri Raj Nath Sharma
801/173
SO/F
30.06.2012
6
Dr. Y.P. Viyogi
801/061
O.S.
31.10.2012
7
Shri C. Mallik
801/093
O.S.
31.10.2012
8
Dr. G.S. Taki
801/166
SO/H
31.10.2012
9
Shri Chamelidhar Datta
801/251
SO/H
31.12.2012
NGO
1
Shri S.N. Das
807/282
Sr. T/H
31.01.2012
2
Shri Ajoy Kumar Kar
807/248
T/G
31.01.2012
3
Shri Samir Kumar Mitra
807/219
T/J
31.01.2012
4
Shri Tinu Chandra Das
807/556
5
Shri Kuniyil Remashan
807/303
6
Shri Kishan Hari
807/273
7
Shri C.S. Prasad
807/302
Foreman/C
30.04.2012
8
Shri Amit Kumar Hazra
807/321
SA/G
30.04.2012
9
Shri Subrata Mukherjee
807/387
Technician/G
30.04.2012
10
Shri Paran Chndra Dey
807/499
Technician/D
30.04.2012
11
Shri Achintya Kumar Jana
807/501
Technician/D
31.05.2012
12
Shri Bipul Kumar Bose
807/313
Foreman/B
30.06.2012
13
Shri Ajay Kumar Sadhukhan
807/476
SCD Grade-I
31.07.2012
14
Shri P.G. Dey Sarkar
807/441
Technician/F1
31.08.2012
15
Shri Shiba Pada Ghosh
807/477
SCD Grade-II
30.09.2012
16
Shri T. Viswanathan
807/228
Foreman/D
31.10.2012
270
Sr. Security Guard 29.02.2012
Foreman/D
29.02.2012
Sr. Work Assistnat/A 29.02.2012
PERSONNEL
17
Shri Prasanta Kumar Mondal
807/249
Technician/G
30.11.2012
18
Shri Banamali Nayak
807/642
Sr. Work Assistnat/A
30.11.2012
19
Shri Harendra Nath Samanta
807/449
Technician/F1
31.12.2012
20
Shri Arup Kumar Biswas
807/205
SA/G
31.12.2012
1
Shri Rakesh Ming
807/839
SA/B
12.01.2012
2
Shri Anwar Ali
807/840
SA/B
03.03.2012
3
Shri Sunil Kumar
807/841
SA/B
03.03.2012
4
Shri Lakshman Chandra Saren
807/842
SA/B
03.03.2012
5
Shri Sanjeet Kumar Yadav
807/843
SA/B
03.03.2012
6
Shri Avijit Roy
807/844
SA/B
03.03.2012
7
Kum. Mousumi Garai
807/845
SA/B
03.03.2012
8
Shri Ritesh Karmakar
807/846
SA/B
03.03.2012
9
Shri Sourav Shit
807/847
SA/B
03.03.2012
10
Shri Amar Nath
807/848
SA/B
03.03.2012
11
Shri Swarnendu Thakurta
807/849
SA/B
03.03.2012
12
Shri Rintu Bhar
807/850
SA/B
03.03.2012
13
Shri Vikas Tiwari
807/851
SA/B
03.03.2012
14
Shri Rakesh Kumar Keshri
807/852
SA/B
03.03.2012
15
Shri Santu Ghosh
807/853
SA/B
03.03.2012
16
Shri Malayshree Dash
807/854
SA/B
03.03.2012
17
Shri Sanjay Bhakat
807/855
SA/B
03.03.2012
18
Shri Rakesh Kumar
807/856
SA/B
03.03.2012
19
Shri Doddi Lavanya Kumar
807/857
SA/B
04.03.2012
20
Shri Arpan Kumar Das
807/858
SA/B
04.03.2012
21
Shri Dibyendu Koley
807/859
SA/B
04.03.2012
22
Shri Anand Kumar Kushwaha
807/860
SA/B
04.03.2012
23
Shri Amiya Kumar Saha
807/864
SA/B
12.04.2012
24
Shri Debasish Mondal
801/450
SO/C
01.08.2012
25
Shri Chiranjib Das
801/451
SO/C
01.08.2012
26
Shri Soumik Bhattacharya
801/452
SO/C
01.08.2012
27
Shri Vishal Lilhare
801/453
SO/C
01.08.2012
28
Dr. Arindam Chatterjee
801/455
SO/C (Medical)
26.09.2012
271
PERSONNEL
2. Officers/Employees Joining in VECC in the year 2012
3. Officers/employees joined on transfer from other unit to VECC in the year 2012
1
Shri Sukumar Manna
807/865
SA/D
24.04.2012
IGCAR,
Kalpakkam
2
Shri Debasish Gain
807/866
SA/C
13.07.2012
IGCAR,
Kalpakkam
3
Shri Alok Kumar
807/867
Work Asst./B
01.10.2012
BARC, Mumbai
4
Shri Ashish Kumar Tiwary
807/868
Work Asst./B
01.10.2012
BARC, Mumbai
5
Shri Aroop Banerjee
801/456
Administrative
Officer-III
01.11.2012
BARC, Mumbai
4. Officer Transfered from VECC to other unit in the year 2012
1
Shri N.V.S.V. Prasad
801/434
Administrative
Officer-III
PERSONNEL
272
29.10.2012
VECC to DAE
Secretariat
Obituary
PERSONNEL
Late Raj Mangal Singh
Security Guard
807/719
21.04.2012
273
Author Index
Author Index
A
AUTHOR INDEX
Adak, D.
Adak, Debabrata
Adak, R.
Aggarwal, S. K.
Ahammed, M.
Ahammed, Z.
Ahammed, Zubayer
Ahmed, M.
Ahmed, Manir
Akhter, J.
Akhter, Javed
Alam, Md. Nayer
Ali, Md. Sabir
Amaral, V. S.
Ames, Freidhelm
Basu, Sumit
208
Basu, Sumit
221
Behera, Ashok
44,45
Bera, A.
191
Bera, Arbinda
92
Bhaduri, P. P.
209,224
Bhaduri, Partha Pratim
213
Bhakat, S.
184
Bhaskar, P.
80,204
Bhattacharjee, P.
160
Bhattacharjee, S.
150
Bhattacharjee, T.
2,4.6
Bhattacharjee, Tanushyam
108,110,112
Bhattacharya, C.
8,10,12,17,184
Bhattacharya, M.
52,56
Bhattacharya, S.
8,10,12,17,21,184
Bhattacharya, Sailajananda
103
Bhattacharya, Srijit
15
Bhattacharya, Sumantra
99,137
Bhattacharya, T. K.
139
Bhattacharyya, Pranab
239,241
Bhattacharyya, S.
6,19,21
Bhattacharyya, T. K.
98,137
Bhattacharyya, T.
194
Bhaumik, Tapas Kumar
103
Bhole, R.
95,134
Bhole, Rajendra Balakrishna
108,110
Bhowmick, D.
155
Bhuia, U.
19
Bhunia, U.
194,237
Bhunia, Uttam
190
Biranwar, Lalit
191
Bishwanadh, B.
66
Biswas, D. J.
35
Biswas, S.
139
Butz, T.
32
C
Chaddah, N.
95,134
Chaddha, Niraj
110
Chakrabarti, A.
150,161
Chakrabarti, Alok
108,132,141,146,
147,149
Chakrabarti, M.
153,155
Chakraborty, A.
86,139
86
103
224
209
139
224
215
181
147
194
190,237
49
149
32
147
B
B. Behera
27
Bahuguna, Rajni
59
Bajirao, S. R.
184
Balasubramaniam, A.
161
Bandopadhyay, A.
139
Bandopadhyay, S.
194
Bandopadhyay, T.
224
Bandyopadhyay, A.
161
Bandyopadhyay, S. K.
56,57,58,59,60
Bandyopadhyay, Amal Kumar
44
Bandyopadhyay, Arup
145,149
Bandyopadhyay, Samit
191
Bandyopadhyay, T.
71,81
Bandyopadhyay, Tapas
68,70
Banerjee, D.
2,4,6,32,38,40
Banerjee, Indranil
44,45
Banerjee, K.
8,10,12,17
Banerjee, P.
17
Banerjee, S. R.
2,8,10,15,17,80
Barat, P.
52,53,54,56
Barat, Partha
116
Barbosa, M. B.
32
Barua, Luna
41,42,47,49
Basak, S.
159
Basak, Subhasish
160,161
Basu, D. N.
26,27
Basu, S. K.
6
276
AUTHOR INDEX
Dey, Madhusudan
Dey, Malay Kanti
Dey, R.
Dey, S.
Dey, Santu
Dey, Sounak
Dhara, Asish Kumar
Dhara, Partha
Dubey, A. K.
Durgaprasad, P. V.
Dutta Gupta, A.
Dutta Gupta, Anjan
Dutta, A.
Dutta, Atanu
Dutta, B. K.
Dutta, C. D.
Dutta, D. P.
Dutta, Nabanita
Duttagupta, Anjan
Chakraborty, Alok
Chakraborty, P. S.
Chakravartty, J. K.
Chanda, S.
Chatterjee, A.
Chatterjee, S.
Chatterjee, Soham
Chatterjee, Sujoy
Chattopadhyay, S.
Chattopadhyay, Sankha
Chattopadhyay, Subhasis
Chattopadhyay, Subhasish
Chaudhuri, A.
Chaudhuri, G.
Chaudhuri, Subikash
Chaudhuri. A. K.
Choudhary, B. K.
Chowdhury, A.
Chowdhury, D. P.
Chowdhury, P.S.
Correia, J. G.
164
76
60
21
17,21,60
81
124
127
205,209,224
41,42,44,45,47,49
213,226,231
121
12
28,29
208
24,25,26
59,60
2,4,6
34,35,36
65
32
D
Das, M.
194
Das, Malay Kanti
41,42,47,49
Das, Manoranjan
191
Das, Nilangshu K.
53
Das, Nilangshu Kumar
116
Das, Nisith Kr.
164
Das, P.
2,6,19,32,181,183
Das, S. K.
2,4,6,32,38,40
Das, S. N.
78,103
Das, T.
98,137
Das, Tanuja
160
Dasgupta, S.
6,19,21
Datta, A.
237
Datta, J.
34,35,36
Datta, K.
161
Datta, Kaushik
126,127
De, A.
15,194
De, Anirban
41,42,47,88,90,92,
191
De, Kakali
44,45
De, Sudipan
210,219,220
Debnath, Jayanta
108
Debnath, T.
86
Dechoudhury, Siddhartha
146,147
Dey, A.
10,17
Dey, Balaram
8
Dey, G. K.
63,66
Dey, M. K.
135
117,119,121
108
96
56
54
53
29
108,122,124
205,224
63
139,234,239
241
19,52
108
63
126
147,159,160,161
56,57
147
113
G
Ganguly, S.
Ganguly, Santanu
Gantayet, L. M.
Garai, Mousumi
Gayathri, N.
Gayen, Subhasis
Ghosh, Arup
Ghosh, J.
Ghosh, M. K.
Ghosh, P.
Ghosh, Premomoy
Ghosh, S.
Ghosh, Sabyasachi
Ghosh, Santu
Ghosh, Sujit
Ghosh, Sundeep
Ghosh, T. K.
Ghosh, Tamal
Ghosh, U.
Gohil, M.
Goswami, A.
Guin, R.
Gupta, A.
Gupta, D.
Haque, Md. Rihan
277
198
44,45
35
42,191
54,56,60,63,65,66
99,137
58
54,96
88,90,191
224
227
139,234
30
119
42
239
8,10,12,17
84,93
58
8,10,12
169,171,173,177,178
6,32,38,40
198
17
H
25
AUTHOR INDEX
F
Furukawa, Kazuro
Hareesh, K.
Hembram, B.
Hemram, B.
Himanshu, A. K.
58
139
86
56,57,58,59,60
L
Laxdal, R. E.
Laxdal, Robert
Lilhare, Vishal
M
I
Iida, Naoko
Madhusmita
Madokar, N.
Majumdar, K.
Majumdar, Kanchan
Mali, P.
Malick, Tapas
Mallik, S.
Mandal, Bidhan Ch
Mandal, N.
Mandi, T. K.
Manna, Bishwanath
Manna, S.
Mayer, N.
Mazumdar, K.
Meena, J. K.
Merminga, Lia
Meshram, V. K.
Mishra, A.
Mishra, Abhishek
Mishra, S. K.
Mishra, Santosh Kumar
Misra, A.
Misra, Anuraag
Misra, J.
Misra, Joydeep
Misra, Mridula
Mitra, A. K.
Mitra, M. K.
Mitra, M. Sengupta
Mitra, S.
Mitra, Sukanya
Mohanty, Bedangadas
Mondal, B.
Mondal, M.
Mondal, Manas
Mourougayane, K.
Muhuri, S.
Mukherjee, A.
Mukherjee, G.
Mukherjee, Maitreyee
Mukherjee, P.
Mukhopadhyay, P.
Mukhopadhyay, S.
Munda, Rudra Narayan
113
J
Jain, Vikas
Jayakumar, T.
Jena, Satyajit
Johnston, K.
Johny, T.
Joshi, Sangita
231
53
218,220
32
56
41
K
AUTHOR INDEX
Kale, P.
Karanjkar, Sanjay
Karmakar, P.
Karmakar, R.
Karmakar, Ritesh
Karna, G.
Keshri, Rakesh Kumar
Khan, S. A.
Khan, Shuaib A.
Khare, V. K.
Kovesnikov, A.
Krishna, J. B. M.
Krishna, P. S. R.
Krishnan, M. L. V.
Kumar, A.
Kumar, Anand
Kumar, Arbind
Kumar, Arvind
Kumar, Brajesh
Kumar, J.
Kumar, Naveen
Kumar, R. Ajay
Kumar, Ranjan
Kumar, Saket
Kumar, Suresh
Kumar, Uday
Kumar, Umesh
Kumar, Yashwant
Kumari, Kiran
Kumari, S.
Kumari, Santwana
Kundu Roy, Tapatee
Kundu, S.
Kushwaha, Anand Kumar
139
147
92
41
99
150
103
78
161
127
204,216,224
229
90,92,191,194
139
63
59
191
161
191
92
191
59
159,160,161
63
63
191
160
17
59,60
42
59,88,92,175,191
59
88
42,90,92,191
157
8,10,12,17,184
92
278
49
159,160,161
86
239
17
42
28,29
86,103,164
139
159,160,161
239
184
139
96
8,10,12,17
147
191
27
26,27
70,71
99,137
175
132,166,167
103
78,79
44,45
147
65
71
198
30
24,220
194
139
147
161
216,224
139
8,10,12,17,21
208
60,63,65,66
6
2,8,10,15,17
45
AUTHOR INDEX
19,234
224
56
92,191
84
41
194
108,164
205,209
191
103
Patra, Amareshwar
Patra, Suparna
Pillai, Tara
Pradhan, J.
Pradhan, Jedidiah
Prakash, A.
Prasad, C. S.
Purkait, Monirul
N
Nabhiraj, P. Y.
Naik, V.
Nair, K. G.M.
Nanal, V.
Nandi, Basanta
Nandi, C.
132
139,150
56
21
218,220
95,134,135,184,194,
198,237
Nandi, Chinmay
84,86,93,99,137,190
Nandy, Partha Pratim
110
Narain, S. R.
80
Narayan, S. R.
231
Naser, Zamal
164
Nayak, T. K.
204,224, 229
Nayak, Tapan Kumar
221
Nayak, Tapan
208,210,212,216,218,
219,220
Neogy, S.
66
Nilaya, J. P.
35
P
Pai, H.
6,8,10,12,21
Pal, G.
95,98,134,135,137,139,
184,194,234,237
Pal, Gautam
84,86,99,108,132,137,
147,167,190
Pal, S. K.
224
Pal, S. S.
92,191
Pal, S.
2,10,95,134,139,205
Pal, Sandip
147
Pal, Sarbajit
108,110,112,116
Pal, Sasanka Shekhar
42
Pal, Surajit
8,15
Pal, Susanta Kumar
226,231
Palit, R.
21
Panda, U. S.
194
Panda, U.
96
Pandey, H. K.
159,160,161
Pandey, R.
8,10,12
Pandit, D.
2,10,17
Pandit, Deepak
8,15
Pandit, S. K.
21
Pandit, V. S.
166,167,169,171,173,
175,177,178
Pant, P.
63
Pariwal, K.
38
Patel, U.
96
R
Rafaja, D.
155
Rai, U.
86
Rajeswaran, B.
153
Rakshit, R.
98,137
Ramachandran, K.
17
Ramnarayan, S.
224
Ramrao Bajirao, Sanjay
99,137
Rana, T. K.
8,10,12,17
Raniwala, Rashmi
221
Ranjan, Rajeev
59
Rao, C. N. R.
153
Rashid, M. H.
19
Ravishankar, R.
68,70,71,224
Ray, A.
181,183
Ray, Ayan
149
Ray, D. K.
59
Ray, K. P.
159,161
Ray, N. R.
36
Reddy, A. V. R.
34
Reja, A.
19
Reza, A.
181
RF Division, ATG, VECC
130
RF Division, VECC
187
Roy Chowdhury, Aruni
122
Roy Chowdhury, Partha
26
Roy, A.
194
Roy, Amitava
90,108,117,119,121,
122,124
Roy, Anindya
110,113,164
Roy, P.
12
Roy, Pratap
10
Roy, S.
95,134,135,184,237
Roy, Suvadeep
99,108,137
Roy, Victor
24,25
S
Sachdev, S. S.
41
Sadhukhan, A.
191
Saha Das, Sujata
41,42,47,49
Saha, Amiya Kumar
103
Saha, S. C.
96
279
AUTHOR INDEX
Murali, S.
Murthy, G. S. N.
Murugan, S.
Saha, S.
AUTHOR INDEX
Saha, Subimal
Saha, Subrata
Saha, Surojit
Sahoo, B. B.
Sahoo, Nihar Ranjan
Sahoo, R. K.
Sahoo, Shantonu
Saini, J.
Saini, Jogender
Samanta, Amlesh
Samanta, S.
Santra, G. C.
Sanyal, D.
Sanyal, N.
Sarkar, A.
Sarkar, B. R.
Sarkar, Bharat
Sarkar, Biswajit
Sarkar, D. R.
Sarkar, Debranjan
Sarkar, Kalyan
Sarkar, S.
Sarkar, Sishir Kumar
Sarkar, Sourav
Sarma, P. R.
Schenke, Bjoern
Selvaraj, P.
Sen, Pintu
Sengupta, D.
Sharma, Garima
Shinde, A. B.
Shrivastava, A.
Siddiqui, Md. I.
Siddiqui, Md. Islam
Siddiqui, Md. Waseem
Sikdar, A. K.
Sing Babu, P.
Singaraju, R. N.
Singaraju, R.
Singh Roy, Prasun
Singh, Abhishek
Singh, B. K.
Singh, B.
Singh, N. K.
Singh, S. N.
Singh, S.
Singha Roy, Pranab
Singha, Subhash
Singhai, Payal
Singhal, V.
Singhal, Vikas
Sinha, A. K.
Sinha, A.
Sinha, S.
Sinha, T. P.
Sivaprasad, N.
Solanki, Dronika
Sorensen, Paul
Srihari, K.
Srivastava, A.
Srivastava, Brijesh
Srivastava, D.
Srivastava, Saurabh
Srivastava, Sudhanshu
Srivastava, V.
Sundarayya, Y.
Sundaresan, A.
Sur, S.
Sur, Sutripta
19,21,88,139,194,
198,234
90,92,96,191
147,181
125
96
210,212
96
110,112
204,205,216,224,231
229
45
224
80
153,155,156
96
60,155
198
44,45
125,126
161
125,126,127
42
86
41
30
234
222
56
56,57,58,59,60
38
60
59
17
103
78,79
96
181,183
169,171,173,177,178
204,229
205,216
207
117
59
205
59
60
139
122,124
220
124
209
207
150
63
198
59,60
41
221
221
68,71
21,66
219
66
166,175
191
8,10,12
153
153
139,239
241
T
T. R. Routray
Taki, G. S.
Tewari, R.
Thakur, S. K.
Thakur, S.
Tiwari, T. P.
Tribedy, Prithwish
Tripathy, S. K.
Vaishali Naik
Venugopalan, Raju
Verma, R.
Verma, Rakesh
Viyogi, Y. P.
Xaxa, P.
Yadav, R. C.
280
27
63
63,66
88,90,92,175,191,194
21
88,92
222
27
V
143,147,149
222
34
35
224,226
X
86
Y
139
Website : http:// www. vecc.gov.in/

2012 - Variable Energy Cyclotron Centre

Transcription

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