1. LCLS Commissioning P. Emma, et al
LCLS Commissioning P. Emma, et al. LCLS Operations Lectures June 7, 2006
LCLS

2. LCLS Accelerator Schematic
6 MeV
z  0.83 mm
  0.05 %
135 MeV
z  0.83 mm
  0.10 %
250 MeV
z  0.19 mm
  1.6 %
4.30 GeV
z  mm
  0.71 %
13.6 GeV
z  mm
  0.01 %
Linac-X
L =0.6 m
rf= -160
Linac-0
L =6 m rf
gun
L0-a,b
Linac-1
L 9 m
rf  -25°
Linac-2
L 330 m
rf  -41°
Linac-3
L 550 m
rf  0°
25-1a
30-8c
...existing
linac
21-3b
24-6d
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
Commission in Jan. 2007
Commission in Jan. 2008
SLAC linac tunnel
research yard

3. Complete & Detailed Optics (cathode to dump)
BC2 L3
LTU
undulator
muon plug wall
sec-21
sec-30
Full MAD files at:

4. 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
June
2006
Gun/Inj./BC1 Install
(8/21 – 1/5)
Gun/Inj./BC1 Commissioning
linac/BC2 Commissioning
FEL Comm.
LTU/undulator Commissioning

5. Injector Layout RF Gun L0a RF section L0b RF section gun spectrometer
6 MeV
L0b RF section
62 MeV
gun spectrometer
Transverse RF deflector
135 MeV
L1 RF section
(21-1b)
main SLAC Linac
injector spectrometer
sector 20
sector 21

6. LCLS Injector Commissioning Dates (’06 - ’07)
July 24: Sector-20 ready for laser installation
Aug. 29: Laser installation complete
Dec. 18: Virtual cathode fully characterized (ready to install gun)
Dec. 19: RF gun installation starts (10 days) + pre-beam checkout
Dec. 20-Jan. 1: Holidays
Jan. 2: VVS’s switched on (RF power available)
Jan. 12: First laser UV-light on cathode!
Jan. 12-Feb. 4: Electrons in GTL and gun-spect. (RF processing L0a,b, L1, LX)
Feb. 5: Beam into L0a, L0b and down to 135-MeV spect.
Feb. 20: Beam into main linac (to TD11 dump)
~June: Take beam down full linac (to BSY SL2 stopper)

7. Microsoft Project Commissioning Schedule
OUT OF DATE
Microsoft Project Commissioning Schedule
2006 DOWN
2007 DOWN

8. pass-1
OUT OF DATE
pass-2
pass-3
pass-1
2006 DOWN
2007 DOWN
pass-2...

9. pass-1
pass-2...
pass-3
2006 DOWN
2007 DOWN
OUT OF DATE

10. Commissioning Definition and Strategy
All components have been installed, aligned, connected, and initially verified by the system engineer, then commissioning starts.
Commissioning Sequence (1-4)
Pre-Beam Checkout (tunnel and MCC)
Controls/software testing, check cameras, ‘snail’ hunt, etc
Magnet polarities, cable connections, verify motion-control, etc
Beam-based Hardware and Software Checkout
Establish beam transport, RF setup, MPS/BCS tests, etc
Checkout of all wires, screens, BPMs, toroids, magnets, etc
First-Order Optics: Measurement and Correction
Steering, transmission, oscillation data, feedback setup, etc
Beta and dispersion matching, beam-base align key quads, etc
Full Beam Characterization: Measurement and Correction
Measure emittance, energy spread, distributions - correct
Measure beam sensitivities, optimize tuning, beam experiments
No (serious) emittance measurements until all hardware/software checked out!

11. Electron Commissioning Organization
Project Director
J. Galayda
Commissioning Don
P. Emma
Alternating Weekly
Run Coordinator
One Lead Physicist
per shift
Shift Physicists
Controls & System
Engineers
MCC & Laser
Operators

12. LCLS Injector Commissioning Day
24-Hour Cycle (7 days/week, 1/2/07 to 9/1/07, 32 total weeks)
DAY SHIFT (8:00-16:00)
1 lead physicist, 1 physicist,
1 controls eng., 1 sys. engineer,
1 LCLS operator, 1 laser operator
SWING SHIFT (16:00-24:00)
1 lead physicist, 1 physicist,
1 LCLS operator, 1 laser operator
OWL SHIFT (0:00-8:00)
1 LCLS operator,
1 laser operator ?

13. LCLS Commissioning Parameters
Value
Comments
RF rate
30 Hz
30 Hz in linac (possible short-term 120-Hz rate in L0-BC1 for feedback tests, etc) Hz in gun for short time to verify full rate
Beam rate
≤30 Hz
30 Hz e- beam as baseline – possible short term 120-Hz tests in L0-BC1 for feedback tests, etc
Drive-laser rate
120 Hz
120-Hz at all times – shutters provide e- rate as required above
Bunch charge pC
depends on QE and diagnostics – some short spans at 10 pC – later in ’07 we explore 1-nC
Drive-laser pulse length
10 ps fwhm
10-ps fwhm startup with possibility of 6-ps at 0.2 nC later – early laser tests may provide path to more convenient pulse-length changes
Gun gradient
120 MV/m
Set as goal, although 110 MV/m is adequate in ‘07

14. Issues
Controls will be mixed (SLC & epics) and capabilities may be limited initially
Most High-Level Applications (emittance, bunch length, feedback) must done through MATLAB as a temporary solution
Most LCLS physicists not yet experienced in SLAC control room with SLC controls
Help from operations group will be needed
LCLS Lecture Series + Workshop in Oct.?

15. RF Photo-Cathode Gun Q = 1 nC f = 120 Hz e- G = 120 MV/m gex,y = 1 mm
Dt = 10 ps
I = 100 A
E = 6 MeV e-
spec. dipole e-
UV laser
solenoid
YAG screens
RF gun
cathode

16. Injector Diagnostics YAG screen RF Gun trajectory (BPMs)
emittance (+ slice)
energy spread (+ slice)
bunch length (+ dist.)
charge (+ dark current)
YAG screen
YAG screen
YAG
screen
YAG screen
gun spectrometer
Transverse RF deflector
OTR & wire
Injector Diagnostics
OTR & wire
OTR & wire
OTR & wire
main SLAC Linac
injector spectrometer
YAG
YAG & OTR

17. Injector Through BC1 Commissioning
no laser-heater until ‘08 sE
gex,y
and slice
RF deflector
E

18. Injector Through BC1 Commissioning (2)
relative bunch length monitors
BC1 sE
stopper
X-band RF
gex,y
E
slice gey

19. Setup of Linac-1, X-band RF Phases
20-mm res. BC1 BPM
20-mm res. BC1 BPM
LX RF phase
L1 RF phase
Linac-1 RF phase scan
(X-band off, BC1 bends at 295 MeV)
Linac-X RF phase scan
(BC1 bends at 250 MeV)
set phase to -25˚0.5˚
set phase to -160˚0.5˚
Linac-1
new rf
gun
21-1b
21-1d X
Turn on BC1 energy feedback
Switch off BC2 chicane
Use sec-25 RF-deflector to meas. bunch length (sz1)
Adjust S-band RF phase (0.5˚) to set sz1  195 10 mm

20. Setup of Linac-2 RF 40-mm res. BC2 BPM 5-mm res. LTU BPM
wake-loss scan
L2 RF phase
L2 phase
Linac-2 RF phase scan
(BC2 bends at 5.9 GeV, or…)
Scan Linac-2 phase & use LTU BPM to find max. wake-induced energy loss across Linac-3
set phase to -41˚0.5˚
Turn on BC2 energy feedback
Use sec-25 RF-deflector to measure length (sz2)
Adjust L2 RF phase (0.5˚) to set sz2  20  2 mm
Linac-3 phasing is trivial (5˚) L2 L3

21. Longitudinal Beam-Based Feedback
gun L3 L2 X
DL1
BC1
BC2
DL2 L1
sz1 d1 1 V1
sz2 d2 2 V2 d3 V3 d0 V0

22. 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) rf
gun
T-cav.
gex,y
T-cav. L0
gex,y
gex,y
gex,y
gex,y
...existing linac L1 X L2 L3 sE sE sE
E
E
E sE sE
E
E

23. Slice-Emittance Measurement Simulation
RF-deflector at 1 MV
sy  bunch length
slice OTR 10 times
135 MeV
quad scanned

24. Slice-Emittance Measurement Simulation
(slice-y-emittance also simulated in BC1-center)
Injector (135 MeV) with S-band RF-deflector at 1 MV
= meas. sim.
= calc.
= y distribution
= actual
(same SLAC slice-e code used at BNL/SDL)
DL1 slice-emit on WS02
slice-5

25. y-slice-Emittance Measurement in BC1
“Q21201” scanned ±20%
0.1 mm
3.9 mm

26. Slice ey Measurements at BNL
weak quad setting
Slice ey Measurements at BNL
undulators
linac (off)
linac
75 MeV
75 MeV
5 MeV
dump
dump
200 pC, 100 A, 75 MeV
medium quad setting
strong quad setting
Data from DUVFEL at BNL: W. Graves, et al.

27. Linac-To-Undulator (LTU)
vertical bends
energy centroid & spread meas. (OTR) (310-5 & 10-4) + collimation
4 e-wires, collimators, 1 OTR
vertical bends
horiz. jog 1.25 m
energy diagnostics
emit. diagnostics
collimators
branch points for future undulators

28. Slice Energy Spread Measurements in LTU
LTU at 14 GeV with S-band RF-deflector at 24 MV
sE/E  10-4
sx  12 mm
FEL goal

29. Summary
Injector commissioning starts very soon (Laser: Aug. ‘06, Electrons: Jan. ‘07)
Phase-II of commissioning comes in Jan. ‘08
LCLS group will need continual help from operations group
LCLS is a 30-year machine – this is just the start