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-2 -1 0 1 2
13.995
14
14.005
Compression Scenarios for the European XFEL
Charge and Bunch Length Scope
Igor Zagorodnov
1st Meeting of the European XFEL Accelerator Consortium
DESY, MPY14. April 2012
[GeV]E
[μm]s
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 2
Inhalt
Analytical and Numerical Approaches
Compression Scenarios for Different Charges
Strong Compression
Summary
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 3
Analytical and Numerical Approaches
Layout
1 130MeVE 1,1M
Gun
1,3M
2M 3M 4M
LH
DL 1BC 2BC 3BC2 700MeVE 3 2400MeVE 4 14 /17.5GeVE
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 4
Analytical and Numerical Approaches
1
56,1
1
130MeV
?
?
E
R
C
2
56,2
2
700MeV
?
?
E
R
C
3
56,3
2400MeV
?
E
R
Working points (11 macro-parameters)
What is the optimal choice?
1,1M
Gun
1,3M
2M 3M 4M
LH
DL 1BC 2BC 3BC
, ,C C C
Zagorodnov I., Dohlus M., A Semi-Analytical Modelling of Multistage Bunch Compression with Collective Effects, Phys. Rev. ST Accel. Beams, 2011.
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 5
-100 -50 0 50 1000
1
2
3
4
-5 0 50
0.01
0.02
0.03
0.04
[mm]s
1
( )C s
3 [μm]s
[kA]I
(0) 0C
Analytical and Numerical Approaches
Choosing of machine parameters
very strong compression at the bunch head (spike)
(0) 0C
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 6
Analytical and Numerical Approaches
ACC39 ACC4/5/6/7ACC39 ACC4/5/6/7
~ 1.5 kA
~2.5 kA
slice emittance > 2mm
slice emittance ~ 0.3 - 1mm
Q=1 nC
Q=0.5 nC
Rollover Compression vs. Linearized (FLASH)
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 7
Analytical and Numerical Approaches
[MeV]E
[μm]s
[kA]I
[μm]s
[μm]s[μm]s
[MeV]E
[kA]I
0C 0C
Q=1 nC
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 8
Analytical and Numerical ApproachesAnalytical solution without self-fields
10 0 0( )x A f
Solution with self-fields
0( ) A x f
10 ( )n nx A g
nonlinear operator (tracking with self-fields)
1 1n n n g g f
10 0 0( ) ( ) x A A x f A x
10 0 1 0 1( ) ( )n n n
x A A x f A x
numerical tracking
analytical correction of RF parameters
1 1( )n n f A x
1 0 1n n f f fresidual inmacroscopic parameters
1,1
1,1
1,3
1,3
2
2
3
3
V
V
V
V
x
1
2
3
10
2
E
E
E
C
C
C
C
C
f
Zagorodnov I., Dohlus M., A Semi-Analytical Modelling of Multistage Bunch Compression with Collective Effects, Phys. Rev. ST Accel. Beams, 2011.
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 9
Analytical and Numerical Approaches
1 130MeVE
Beam dynamics simulation
1,1M
Gun
1,3M
2M 3M 4M
LH
DL 1BC 2BC 3BC2 700MeVE 3 2400MeVE 4 14GeVE
ASTRA ( tracking with 3D space charge, DESY, K. Flötmann)
W1 -TESLA cryomodule wake (TESLA Report 2003-19, DESY, 2003)
W3 - ACC39 wake (TESLA Report 2004-01, DESY, 2004)TM - transverse matching to the design optics
W
3
W1
TM4W1
TM64W
1
12W1
TM
Full 3D simulation method (200 CPU, ~10 hours)
CSRtrack (tracking through dipoles, DESY, M. Dohlus, T. Limberg)
1.6 kmz
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 10
Compression for Different Charges
-40 -20 0 20 40 600
1
2
3
4
5
Q=1 nC
E
[kA]I
Phase space
[MeV]E
0.9 [μm]projx
3.5 [μm]projy
Current, emittance, energy spread
[μm]x[μm]y
[μm]s [μm]s
178fs
bunch head
-40 -20 0 20 40 60
13.998
14
14.002
14.004
14.006
14.008
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 11
Compression for Different Charges
-20 -10 0 10 200
0.2
0.4
0.6
0.8
1
EPhase space
[MeV]E
0.45 [μm]projx
1.5[μm]projy
Current, emittance, energy spread
[μm]x
[μm]y
[μm]s [μm]s
39fs
bunch head
5kA
I
-10 0 10 20
13.995
14
14.005
14.01
Q=250 pC
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 12
Compression for Different Charges
-2 -1 0 1 20
0.2
0.4
0.6
0.8
1
[MeV]E
0.14 [μm]projx
0.26 [μm]projy
Current, emittance, energy spread
[μm]x[μm]y
[μm]s
2fs
5kA
I
E
[μm]s
-2 -1 0 1 2
13.995
14
14.005
Phase space
Q=20 pC
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 13
Compression for Different Charges
Parameter Unit
Bunch charge nC 1 0.5 0.25 0.1 0.02
Peak current (gun) A 43 24 13.5 5.7 1.2
Bunch length (gun, FWHM) ps 25 22 20 17 17
Slice emittance (gun) mm 0.8 0.5 0.3 0.21 0.09
Projected emittance (gun) mm 1 0.7 0.6 0.3 0.1
Compression 114 233 363 877 3833
Peak current kA 4.9 5.6 4.9 5 4.6
Bunch length (FWHM) fs 178 72 39 12 2.2
Slice emittance mm 1 0.7 0.5 0.3 0.17
Projected emittance mm 3.5 2.2 1.5 0.84 0.26
Slice energy spread (laser heater off)
MeV 0.45 0.44 0.6 0.6 0.8
Beam parameters from S2E simulations
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 14
Compression for Different Charges
-30 -20 -10 0 10 200
5
10
15
20
25
30
35
0 50 100 1500
0.5
1
1.5
2
Radiation Q=1nC. SASE[GW]P
[μm]s
[mJ]W
[m]z
Genesis
ALICE
Genesis
ALICE
Zagorodnov I., Dohlus M., Numerical FEL studies with a new code ALICE, in Proceedings of FEL09, Liverpool, 2009.
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 15
Compression for Different Charges
0 50 100 1500
5
10
15
20
25
30
0 50 100 150
10-4
10-2
100
Radiation energy statistics (1-25-120 runs) mJE
[m]z
250 pC
1 nC
Mean energy
20 pC
fsz
Radiation pulse width (RMS)
Charge, nC 1 0.25 0.02
Mean radiation energy, mJ 1-4 1-2 0.1-0.4
Pulse radiation width (FWHM), fs 25-50 10-20 1-2
250 pC
1 nC
20 pC
[m]z
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 16
Compression for Different Charges
Bunch charge, nC 1 0.25 0.02
Wavelength, nm 0.1
Beam energy, GeV 14
Peak current, kA ~ 5
Slice emmitance,mm-mrad 1 0.5 0.2
Saturation length, m 85 60 45
Energy in the rad. pulse, mJ 1-4 1-2 0.1-0.4
Radiation pulse duration FWHM, fs 25-50 10-20 1-2
Averaged peak power, GW 10-50 10-100 50-150
Spectrum width, % 0.15-0.3 0.18-0.5
Radiation Properties from S2E
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 17
Strong Compression
-40 -20 0 20 40 600
1
2
3
4
5
6
7
8
9
10
Q=1 nC, I=10kAPhase space
[MeV]E
0.9 [μm]projx
8 [μm]projy
Current, emittance, energy spread
[μm]x
[μm]y
[μm]s [μm]s
85fs
[kA]I
-20 0 20 40
14.002
14.004
14.006
14.008
14.01
14.012
14.014E
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 18
Strong Compression
Parameter Unit
Bunch charge nC 1
Peak current (gun) A 43
Compression 116 228
Peak current kA 5 9.8
Bunch length (FWHM) fs 178 75
Slice emittance mm 1 1
Projected emittance mm 3.5 8
Slice energy spread (laser heater off)
MeV 0.45 1
Q=1 nC
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 19
Strong Compression for 250 pC
[MeV]E
[kA]I
[μm]s
[μm]s [μm]s
[μm]s
[MeV]E
[kA]I
R56,3= -20 mm R56,3= -23.8 mm
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 20
Strong Compression for 250 pC
Momentum compaction
factor in BC1
R56,1,
[mm]
Compr.in BC1
C1
Momentum compaction
factor in BC2
R56,2,
[mm]
Compr.in BC2
C2
Momentum compaction
factor in BC3
R56,3,
[mm]
Totalcompr.
C
Second derivative
(C-1)'',[m-2]
-78 3.5 -50 8 -20,…,-24 385 1000
Macro-parameters
1 130 MeVE 2 700MeVE 3 2400MeVE
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 21
Strong Compression for 250 pC
-10 0 10 20
13.995
14
14.005
14.01
-20 -10 0 10 20 300
0.5
1
1.5
R56,3=-20mm
5kA
I
Phase space
[MeV]E
Current, emittance, energy spread
[μm]x
[μm]y
[μm]s [μm]s
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 22
Strong Compression for 250 pC
-20 -10 0 10 20 300
1
2
3
-10 0 10 20
13.935
13.94
13.945
13.95
13.955
R56,3 =-21 mm
5kA
I
Phase space
[MeV]E
Current, emittance, energy spread
[μm]x
[μm]y
[μm]s [μm]s
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 23
Strong Compression for 250 pC
-10 0 10 200
2
4
6
8
10
[MeV]E-5 0 5 10 15
13.9
13.92
13.94
13.96
13.98
5kA
I
[MeV]E
[μm]x
[μm]y
[μm]s [μm]s
R56,3 =-21.9 mmPhase space Current, emittance, energy spread
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 24
Strong Compression for 250 pC
-5 0 5 10 150
2
4
6
8
0 5 10
13.92
13.93
13.94
13.95
13.96
13.97
5kA
I
[MeV]E
[μm]x
[μm]y
[μm]s [μm]s
R56,3 =-22.6 mmPhase space Current, emittance, energy spread
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 25
Strong Compression for 250 pC
-4 -2 0 2 40
1
2
3
4
5
-2 -1 0 1 2
13.92
13.93
13.94
13.95
13.96
13.97
5kA
I
[MeV]E
[μm]x
[μm]y
[μm]s [μm]s
R56,3 =-22.6 mm (70% of particles)Phase space Current, emittance, energy spread
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 26
Strong Compression for 250 pC
-10 -5 0 5 100
0.5
1
1.5
2
2.5
-4 -2 0 2 413.98
13.99
14
14.01
14.02
5kA
I
[MeV]E
[μm]x
[μm]y
[μm]s [μm]s
R56,3 =-23.2 mm (70% of particles)Phase space Current, emittance, energy spread
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 27
Strong Compression for 250 pC
Beam core parameters vs. R56
20 21 22 23 240
10
20
30
40
50
20 21 22 23 240
5
10
15
20
25
20 21 22 23 240.2
0.3
0.4
0.5
0.6
20 21 22 23 240
1
2
3
4
[kA]I
[μm]slicex [μm]slice
y
[fs]t
56,3 [mm]R56,3 [mm]R
56,3 [mm]R56,3 [mm]R
70% of particles
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 28
Strong Compression for 250 pC
20 21 22 23 240
2
4
6
8
20 21 22 23 24
0.35
0.4
0.45
0.5
0.55
0.6
0.65
20 21 22 23 240
2
4
6
8
20 21 22 23 240
10
20
30
40
50
[kA]I [MeV]E
[μm]y[μm]x
56,3 [mm]R
56,3 [mm]R
56,3 [mm]R
56,3 [mm]R
70% of particles
Beam core parameters vs. R56
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 29
Strong Compression for 250 pC
0 50 100 1500
0.5
1
1.5
2
2.5
3
[mJ]E
[m]z
56.3 20mmR
56.3 21.6mmR
Radiation energy vs. R56 (with und. wake and taper)
20 21 22 23 240
0.2
0.4
0.6
0.8
1
1.2
1.4
60mz
[mJ]E
[a.u.]I
56,3 [mm]R
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 30
Strong Compression (SLAC)
0.155
0.03
Q=20 pC
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 31
Strong Compression for 250 pC
Radiation energy vs. compression rate
20 21 22 23 240
0.2
0.4
0.6
0.8
1
1.2
1.4
60mz
[mJ]E
[a.u.]I
56,3 [mm]R
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 32
Strong Compression for 250 pC
20 21 22 23 240
0.2
0.4
0.6
0.8
1
1.2
1.4
60mz
[mJ]E
[a.u.]I
56,3 [mm]R
0.155
0.03
16
0.16
Radiation energy vs. compression rate
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 33
Strong Compression for 250 pC
20 21 22 23 240
100
200
300
400
500
600
700175mz
[a.u.]I
56,3 [mm]R20 21 22 23 24
0
50
100
150
200
60mz
max[GW]P
[a.u.]I
max[GW]P
56,3 [mm]R
Radiation power vs. compression rate
Igor Zagorodnov| 1st Meeting of EXFEL Accelerator Consortium | 17. April 2012 | Seite 34
Summary
Bunches with charge 20-1000 pC can be compressed to 5 kA and higher
Radiation energy drops down at “full” compression
Overcompression scenario can be used
Acknowledgements to M.Dohlus and T.Limberg for many useful discussions