-
Beam Energy Spread for HGHG
in FLASH2
Igor Zagorodnov DESY, Hamburg, Germany
22.04.2010
S2E Meeting
-
Technical constraints and beam parameters
I > 1kA
∆ > 200 fs 0.2nCQ I
ACC39 ACC4/5/6/7ACC39 ACC4/5/6/7
Energy spread < 120keV
ASTRA+CSRtrack
-
Energy spread vs. charge?
Charge
Q,
nC
Energy
in BC2
E1,
[MeV]
Energy
in BC3
E2,
[MeV]
Deflecting
radius in BC2
teta1,
[grad]
Deflecting
radius in BC3
r2,
[m]
Compression
in BC2
C1
Total
compression
C
First
derivative
Z2',
[m-1]
Second
derivative
Z2'',
[m-2]
1
130
450
15
4.78 2.84 48 1 2e3
0.5 4.14 4.63 90 1 3.5e3
0.25 3.68 6.57 150 0.7 4e3
Igor Zagorodnov and Martin Dohlus,
Beam Dynamics and FEL Simulations for FLASH,
08.02.2010,Beam Dynamics Meeting, DESY
http://www.desy.de/fel-beam/data/talks/files/IZ_2010_February.pdf
-
-3000 -2000 -1000 0 1000 2000 30000
0.5
1
1.5
2
2.5
-30 -20 -10 0 10 20 3050
100
150
200
250
300
Energy spread vs. charge?
[μm]s[μm]s
Slice emittance [um] Slice energy spread [keV]
1nCQ 0.5nCQ 0.25nCQ
-
-4000 -2000 0 2000 40000
0.5
1
1.5
2
2.5
3
3.5
-4000 -2000 0 2000 4000
0.6
0.8
1
1.2
1.4
1.6
1.8
E in BC 2 = 130 MeV, ACC1(40%, 60 %)
E in BC 2 = 145 MeV, ACC1 (50%, 50 %)
E in BC 2 = 145 MeV, ACC1 (37.5%, 62.5 %)
Energy spread after ACC1 (z=14.61 m) for Q=1nC
Slice emittance [um] Slice energy spread [keV]
[μm]s [μm]s
-
Charge
Q,
nC
Energy
in BC2
E1,
[MeV]
Energy
in BC3
E2,
[MeV]
Deflecting
radius in BC2
teta1,
[grad]
Deflecting
radius in BC3
teta2,
[grad]
Compression
in BC2
C1
Total
compression
C
First
derivative
Z2',
[m-1]
Second
derivative
Z2'',
[m-2]
1 130 450 18 4.5 4 26 0 0
S2E (up z = 152 m ) for Q=1nC
-
-150 -100 -50 0 50 100 1500
50
100
150
-150 -100 -50 0 50 100 1500
20
40
60
80
100
-150 -100 -50 0 50 100 1500
20
40
60
80
100
ACC39 ACC4/5/6/7ACC39 ACC4/5/6/7
Energy spread after ACC7 (z=152 m) for Q=1nC
[μm]
26
s
26 [keV]E26 [keV]E
[μm]
26
s
6.5 [keV]E
[μm]
6.5
s
6.5 [keV]E
[μm]
6.5
s
-
-150 -100 -50 0 50 100 1500
20
40
60
80
100
120
140
160
180
-150 -100 -50 0 50 100 1500
50
100
150
ACC39 ACC4/5/6/7ACC39 ACC4/5/6/7
6.5 [keV]E
[keV]E
[μm]
6.5
s[μm]s
[keV]E
[μm]s
Energy spread after ACC7 (z=152 m) for Q=1nC
-
-150 -100 -50 0 50 100 1500
50
100
150
6.5 [keV]E
[μm]
6.5
s25.3[m]z
26 28 30 32 34 36 38 400
2
4
6
8
10
12
[m]z
[m]y
3D(MATLAB)
2D(ASTRA)
3D(ASTRA)
-
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
S2E (up z = 152 m ) for Q=1nC
[kA]I
[μm]y
[keV]
100
E
[μm]s
[μm]x
330fs
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
660fs
2D(ASTRA)3D(ASTRA)
[μm]s
-
S2E for FLASH2 line (Q=1nC)
-100 -50 0 50 100 150994
996
998
1000
1002
1004
ASTRA+CSRtrack
Elegant
?
-
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
S2E for FLASH2 line at z=194 m (Q=1nC)
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
[kA]I
[μm]y
[keV]
100
E
[μm]s
[μm]x
360fs
200k particles (3D ASTRA) 1000k particles (3D ASTRA)
-
S2E for FLASH2 line at z=194 m (Q=1nC)
-100 -50 0 50 100 150994
996
998
1000
1002
1004
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
[kA]I
[μm]y
[keV]
100
E
[μm]s
[μm]x
360fs
1) the global slice length: ~15 um slice = 50 fs
- Slippage in Modulator ~ 4 um
- Slippage in Radiator ~10 um
* Within this slice, the energy spread should be smaller
than 100 keV
2) min current along the global slice: Should exceed at
least 0.5 kA
3) how large can be the variation of the current along the
global slice:
most important to assure min. 0.5 kA.
4) maximal local slice emittance along the global slice?:
1.5 um
5) maximal local (uncorrelated) energy spread: ~100 keV
6) maximal energy chirp (correlated energy spread) along
the global
slice? ~150 keV
-
S2E for FLASH2 line at z=194 m (Q=1nC)
-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
[kA]I
[keV]
100
uncorr
E
[μm]s-150 -100 -50 0 50 100 1500
0.5
1
1.5
2
2.5
slice 15um[keV]
100
E
slice 10um[keV]
100
E
[μm]s
energy spread in slice of length 10 um
and 15 um uncorreleted energy spread