Work Progress for FLASH2 HGHG Simulation

Work Progress for FLASH2 HGHG Simulation

Work Progress for
FLASH2 HGHG Simulation
Guangyao Feng
S2E Meeting
DESY
17.04.2014
1.Single stage HGHG simulation for
FLASH 2 with high peak current
using the previous models of
undulator, chicane and seeding laser
(from Velizar).
2.Preparing for the new simulation with
the models from Joern.
Descriptions for the undulator and the seeding laser
λ/k
λ
λ
Modulator 1
Seed Laser
Electron Beam
Radiator 1
Dispersive Chicane
𝜆𝑢 = 6.5 cm
L = 0.65m
λ = 233 nm
𝜆𝑢 = 3.14 cm
L = 5.56 m
λ/7 = 33.3 nm
Seeding Laser
Chicane defined in Genesis input file
9
1.6x10
trama= 1
itram11= -0.9924
itram12= -0.0037
itram13= 0.000000D+00
.
.
.
itram66= 1.000000D+00
Input power of the radiation field [W]
9
1.4x10
9
1.2x10
9
1.0x10
8
8.0x10
8
6.0x10
8
4.0x10
8
2.0x10
0.0
0.00000
0.00002
0.00004
0.00006
z [m]
0.00008
0.00010
R56 for full compression and beam current estimation
𝐸0 𝐸𝑚𝑜𝑑 𝜎𝐿𝑎𝑠𝑒𝑟
9
𝑃𝐿 = 8.7 × 10 ×
5110002 𝐿𝑢 ∙ 𝐾𝑢𝑡
2
𝑬𝒎𝒐𝒅 = 𝟑. 𝟐𝟓MeV
𝑃𝐿 = 1.42 GW
𝐸0 = 1.0 GeV
𝑹𝟓𝟔 = 𝟏𝟏. 𝟒𝟑 μm
Bunching factor
𝑏𝑚 = 𝐽𝑚
For full compression
𝐸𝑚𝑜𝑑
𝐸𝑠
𝑚 ∙ 𝑘 ∙ 𝑟56 ∙
∙ 𝐸𝑥𝑝 −0.5 𝑚 ∙ 𝑘 ∙ 𝑟56 ∙
𝐸0
𝐸0
𝑏𝑚 ∙ 𝐼 = 𝑀𝑎𝑥𝑖𝑚𝑎𝑙 𝑣𝑎𝑙𝑢𝑒
For getting high radiation power
𝐼=
𝐸0
𝑑𝐸𝑠
𝑑𝐼
𝑑𝐸𝑠 3𝑘𝑒𝑉
≈
𝑑𝐼
50𝐴
m=7
𝑚 ∙ 𝑘 ∙ 𝑟56
I=7728 A
2
Energy modulation, microbunching and bunching factor
𝑏𝑚 = 𝐽𝑚
𝐸𝑚𝑜𝑑
𝐸𝑠
𝑚 ∙ 𝑘 ∙ 𝑟56 ∙
∙ 𝐸𝑥𝑝 −0.5 𝑚 ∙ 𝑘 ∙ 𝑟56 ∙
𝐸0
𝐸0
1
𝐾𝑚 =
𝑁
𝐸𝑥𝑝 𝑖 ∙ 𝑚 ∙ 𝑘 ∙ 𝑧𝑛
𝑛
𝐸𝑠 = 250 𝑘𝑒𝑉
N=1000000
2
bm
Km
HGHG simulation with high peak current (Q=0.5nC)
Beam bunch properties at the
entrance of undulator system
5% bad particles are removed
HGHG simulation with high peak current
* R56 of the dispersive chicane has not been adjusted for full
compression because of the original transfer matrix description.
R56=8 μm
under-compression
With formulas
bm
Km
With particle distribution
generated from beam
dynamics simulation
HGHG simulation with high peak current
Radiator, Ip=1.2kA
Radiator, Ip=2.5kA
9
1.4x10
9
1.2x10
9
Radiation Power
1.0x10
9
P [W]
7x10
8.0x10
8
6.0x10
8
4.0x10
8
2.0x10
8
9
6x10
9
5x10
9
P [W]
4x10
9
3x10
9
2x10
9
1x10
0.0
0
0
20
40
60
80
100
0
120
20
40
60
80
100
120
s [m]
s [m]
100
Q=0.5nC
Ip=2.5kA
Radiator 1
1
Radiation energy [ J]
Radiation Energy [ J]
Radiation energy
10
10
0.1
0.01
0
1
2
3
z [m]
4
5
6
Eend=154 μJ
Q= 0.5 nC
Ip=1.2 kA
Radiator1
1
0.1
0.01
0
1
2
3
z [m]
4
5
6
Eend=31μJ
Preparation for HGHG simulation with new models of
modulator and seeding laser
Modulator length: L = 2 m
Number of periods: N = 30
Period length: L_u = 0.067 m
Laser peak power P_laser = 125 MW
with Rayleigh length z_R = 4.2 m
laser pulse duration of τ =30 fs (FWHM)
Wavelength λ= 235 nm
8
Input power of the seeding laser [W]
1.4x10
8
1.2x10
8
1.0x10
E0= 1.0 GeV
λ= 235 nm
PL = 125 MW
Keff= 5.0858
7
8.0x10
7
6.0x10
7
4.0x10
7
2.0x10
0.0
0.00000
0.00001
0.00002
0.00003
s [m]
0.00004
0.00005
0.00006
Preparation for HGHG simulation with new models of
modulator and seeding laser
𝑹𝟓𝟔 = 𝟓𝟖. 𝟐𝟖μm
For full compression
uncorrelated energy spread: 150keV (1.2 kA) uncorrelated energy spread: 250keV (2.5kA)
Bunching factor
Bunching factor