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

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  0.022 mm   0.71 % 13.6 GeV z  0.022 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

Complete & Detailed Optics (cathode to dump) BC2 L3 LTU undulator muon plug wall sec-21 sec-30 Full MAD files at: http://www-ssrl.slac.stanford.edu/lcls/linac/optics/

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

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

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)

Microsoft Project Commissioning Schedule OUT OF DATE Microsoft Project Commissioning Schedule 2006 DOWN 2007 DOWN

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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!

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

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 ?

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) - 120 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 200-500 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

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.?

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

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

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

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

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

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

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

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

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

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

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

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.

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 bends horiz. jog 1.25 m energy diagnostics emit. diagnostics collimators branch points for future undulators

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

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