LCLS Accelerator

1
LCLS Accelerator
6 MeV ?z ? 0.83 mm ?? ? 0.05
250 MeV ?z ? 0.19 mm ?? ? 1.6
4.30 GeV ?z ? 0.022 mm ?? ? 0.71
13.6 GeV ?z ? 0.022 mm ?? ? 0.01
135 MeV ?z ? 0.83 mm ?? ? 0.10
Linac-X L 0.6 m ?rf -160?
Linac-0 L 6 m
rf gun
L0-a,b
Linac-3 L ?550 m ?rf ? 0
Linac-1 L ?9 m ?rf ? -25
Linac-2 L ?330 m ?rf ? -41
25-1a 30-8c
21-3b 24-6d
...existing linac
21-1 b,c,d
undulator L 130 m
X
BC1 L ?6 m R56? -39 mm
BC2 L ?22 m R56? -25 mm
DL1 L ?12 m R56 ?0
DL2 L 275 m R56 ? 0
SLAC linac tunnel
research yard
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LCLS Installation and Commissioning Time-Line
Drive-Laser Commissioning
undulator hall ready
LTU/und. Install
First FEL Light
Drive-Laser Install
linac/BC2 Install
First Spont. Light
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
J
J
2006
2007
2008
May 2006
Gun/Inj./BC1 Commissioning
Gun/Inj./BC1 Install
linac/BC2 Commissioning
FEL Comm.
LTU/undulator Commissioning
3
RF Photo-Cathode Gun

• Q 1 nC
• f 120 Hz
• G 120 MV/m
• gex,y 1 mm
• Dt 10 ps
• I 100 A

4
Slice emittance gt1.8 mm will not saturate
electron beam must meet brightness requirements
5
Complete Detailed Design (cathode to dump)
L3
BC2
LTU
L2
cathode
undulator
Full MAD deck at http//www-ssrl.slac.stanford.e
du/lcls/linac/optics/lcls.txt
6
Bunch Compression Progression
time profile
energy profile
phase space
sz 830 mm
sz 190 mm
sz 830 mm
sz 23 mm
sz 830 mm
sz 23 mm
sz 190 mm
sz 23 mm
7
Location of Main Linac Diagnostics

• 5 energy spread meas. stations (optimized with
  small b)

• 5 emittance meas. stations designed into optics
  (Dyx,y)

• BPMs at or near most quadrupoles and in each bend
  syst.
• RF deflectors for slice e and sE measurements (L0
  L3)

T-cav.
rf gun
T-cav.
gex,y
gex,y
gex,y
gex,y
L0
gex,y
L3
L1
X
L2
...existing linac
sE
sE
sE
sE
?E?
?E?
?E?
sE
?E?
?E?
8
Slice-Emittance Measurement Simulation
sy ? bunch length
RF-deflector at 1 MV
slice OTR 10 times
135 MeV
quad scanned
9
Slice-Emittance Measurement Simulation
(slice-y-emittance also simulated in BC1-center)
Injector (135 MeV) with S-band RF-deflector
at 1 MV
(same SLAC slice-e code used at BNL/SDL)
DL1 slice-emit on WS02
slice-5
10
Gun/Injector Diagnostics

• trajectory (BPMs)
• emittance ( slice)
• energy spread ( slice)
• bunch length ( dist.)
• charge ( dark current)

YAG screen
RF Gun
YAG screen
YAG screen
YAG screen
YAG screen
gun spectrometer
Transverse RF deflector
OTR screen wire
OTR screen wire
OTR screen wire
OTR screen wire
main SLAC Linac
injector spectrometer
YAG screen
YAG OTR
11
Injector Through BC1 Commissioning
no laser-heater until 2007
sE
gex,y and slice
RF deflector
?E?
12
Injector Through BC1 Commissioning (2)
relative bunch length monitors
BC1
sE
stopper
X-band RF
gex,y
?E? slice gey
13
Linac-To-Undulator (LTU)
vertical bends
energy centroid spread meas. (OTR) (3?10-5
10-4) collimation
4 e-wires, 6 collimators, 1 OTR

• vertical bend 4.7 mr
• horizontal jog 1.25 m
• energy diagnostics
• emit. diagnostics
• bunch length diag.
• collimators
• CSR cancellation
• branch points for future undulators
• spontaneous undulator possible

14
Enhanced CSR in BC1
15
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• Emittance of RF Photo-Cathode Gun
• Micro-Bunching Instability
• Bunch Length Monitors
• CSR in BC1 and BC2
• Impedance in BC2 Vacuum Chambers
• Space-Charge Effects in BC1 Region
• Chromatic Correction for Highly Chirped Beams
• Improved LTU Lattice
• Undulator Wakefields
• FEL Commissioning and Tuning
• Start-to-end Simulations and Integration with
  LCLS Controls
• ESASE/Replicator
• Optical Klystron Gain Enhancement
• Seeded and Self-Seeded FEL for Next Phase of LCLS
• Development of an X-band Transverse RF Deflector
• Multi-bunch LCLS and Regenerative Amplifier FEL
• Harmonic Afterburner