water-based liquid scintillator light yield and time profile

water-based liquid scintillator light yield and time profile

WATER-BASED LIQUID SCINTILLATOR LIGHT
YIELD AND TIME PROFILE MEASUREMENTS
Sean Grullon
Wb-LS LBNE Workshop
Berkeley
May 17th, 2014
OVERVIEW
Broad physics potential for a Water-based liquid scintillator Physics reach affected by the light yield, the scintillation timing, and relative
scintillation/Cherenkov timing
Gauge possible light yields and timing profiles which are achievable at this
early stage
Four candidate water-based liquid scintillator solvents (labeled wbLS1-wbLS4)
from Minfang et al. at BNL in 2012. Updated sample (wbLS5) in 2014.
Light output and timing profiles of five candidate solvents measured at Penn
SOURCE
•One 0.1 μCi Sr90
Hollowed out
cavity
source mounted
below hollowed
out SNO acrylic (~
5 mL volume)
•Optically
coupled to 2’’
HQE PMT trigger
Sr90 Source
DARK BOX MEASUREMENT SETUP
12’’ R11780 High Quantum
Efficiency
Details of PMTs
and DAQ
available in NIM
A 712, 162-173
(2013)
WATER-BASED LIQUID SCINTILLATOR
- TOTAL LIGHT OUTPUT
wbLS 1
wbLS 2
wbLS 3
wbLS 4
500,000
waveform
traces
!
Gain 107 :
1.6 pC / p.e.
WATER-BASED LIQUID SCINTILLATOR
- TOTAL LIGHT OUTPUT
wbLS 1
wbLS 2
wbLS 3
wbLS 4
wbLS 5: New 2014
sample
500,000
waveform
traces
!
Gain 107 :
1.6 pC / p.e.
COMPARISON - “TRADITIONAL”
LIQUID SCINTILLATOR
Light Yield = 10800 ± 574
Photons/MeV
500,000
waveform
traces
1.6 pC / p.e.
Linear Alkyl Beznene
(LAB) + 2g/L fluor
(PPO): Scintillator
solvent for SNO+
~10,000 photons/
MeV typical for pure
liquid scintillators.
WATER-BASED LIQUID SCINTILLATOR
- MEASURED LIGHT YIELDS
SAMPLE
MEASURED P.E. : WBLS/WATER
SCINTILLATION LIGHT YIELD
WbLS1
4.00 ± 0.06
~300 photons/MeV
WbLS2
2.71 ± 0.07
~200 photons/MeV
WbLS3
1.68 ± 0.09
~110 photons/MeV
WbLS4
1.52 ± 0.08
~100 photons/MeV
WbLS5
1.9 ± 0.09
~125 photons/MeV
Scintillation Light yields a rough estimate. Derived by scaling down well-measured LAB + 2g/L PPO intrinsic
light yield and subtracting off Cherenkov component.
TIMING PROFILES - CHERENKOV/
SCINTILLATION SEPARATION
Scintillation later than
Cherenkov light ANT 2013
Is the timing resolution of
current-gen PMTs good
enough to discriminate
between the two?
TIMING PROFILE - WB-LS, SAMPLE 5
Python module
incorporating
TSpectrum to
extract photon
arrival times
125 photons/
MeV
Late Pulsing
~4-5 ns
separation
TIMING PROFILE - WB-LS, SAMPLE 4
Python module
incorporating
TSpectrum to
extract photon
arrival times
100 photons/
MeV
Late Pulsing
~4-5 ns
separation
TIMING PROFILE - WB-LS, SAMPLE 3
110 photons/
MeV
Late Pulsing
~4-5 ns
separation
TIMING PROFILE - WB-LS, SAMPLE 2
200 photons/
MeV
Late Pulsing
~4 ns separation
TIMING PROFILE - WB-LS, SAMPLE 1
~2 ns separation
300 photons/
MeV
CONCLUSIONS & OUTLOOK
water-based liquid scintillator solvent can give a factor 1.5 - 4 more light
than a
Corresponds to a scintillation light yield between ~100-300 photons/MeV
Cherenkov/Scintillation light discrimination based on timing possible.
Components separated by ~4 ns on average for prototype samples.
Determine light yield and timing requirements for different physics topics.
Could perform a detailed study of what % of Cherenkov light gets
converted to scintillation light…
WATER-BASED LIQUID SCINTILLATOR
- TOTAL LIGHT OUTPUT
wbLS 1
wbLS 2
wbLS 3
wbLS 4
500,000
waveform
traces
!
Gain 107 :
1.6 pC / p.e.