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LCLS

Initial Experience with Injector Commissioning P. Emma, et al. Facilities Advisory Committee Meeting April 16, 2007. LCLS. http://www-ssrl.slac.stanford.edu/lcls/internals/commissioning/index.html. LCLS Injector Through BC1. RF Gun & Solenoid + YAG screens. 6 MeV. L0a&L0b S-Band Linacs.

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LCLS

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  1. Initial Experience with Injector CommissioningP. Emma, et al.Facilities Advisory Committee MeetingApril 16, 2007 LCLS http://www-ssrl.slac.stanford.edu/lcls/internals/commissioning/index.html

  2. LCLS Injector Through BC1 RF Gun & Solenoid + YAG screens 6 MeV L0a&L0b S-Band Linacs Transverse RF Cavity Bunch-Compressor-1 (BPM, OTR, collimator) OTR & Wire Scanners Gun Spectrometer Wire Scanners + OTR L1 S-Band Linac 135 MeV 250 MeV TD11 stopper X-Band RF Straight Ahead Spectrometer Bunch Length Diagnostics ~45 m (150 ft)

  3. Electron Beam Transported to All Injector Areas • April 5: First photo-electrons from gun (6 MeV) • April 5: First e- to gun spectrometer (6 MeV) • April 8: First e- to inj-spectrometer (127 MeV) • April 9: First e- in linac to TD11 dump (127 MeV) • April 14: First 250-MeV beam through BC1 • Up to ~330 pC of charge (370 µJ laser energy) • 10 Hz beam & 30 Hz RF (30 Hz e- also tested) • Gun RF feedback running well (+ water)

  4. Pre-Beam Tunnel Check List Almost Complete 40 pages, ~2000 checks – all DONE (except a few missing screens) Polarity conventions Field type (quad, dipole) Serial numbers Installation orientation etc. etc.

  5. RF Processing of L0b (20-8) March 25 March 10 Thanks to R. Akre & AMRF

  6. Gun Temperature Feedback Loop Gun Temperature Gun RF Probes RF On RF Off RF On Thanks Phil Cutino, Claudio Rivetta, Joe Frisch

  7. Gun RF Power (30 Hz) Time laser here with diode Gun RF probe (cavity power) Gun RF coupler (input power) 11 MW (~120 MV/m) Gun Reflected Power 1.2 µsec Thanks Arnold Vlieks

  8. Virtual Cathode (optical image of laser spot on cathode)

  9. Beam on YAG02 (80 cm from gun) 20 mm

  10. Laser Phase (Shottky) Scan 50 µJ laser energy 30º

  11. Beam on Gun Spectrometer 5.7 MeV

  12. Beam to Injector Spectrometer 135 MeV Steering was easy with few correctors on strong energy BPMs worked almost immediately! GUN SDMP

  13. Trajectory to TD11 (in main linac) BC1 energy BPM DL1 energy BPM BPMs worked almost immediately! GUN TD11 BC1 BPM old BPM old BPM

  14. L0a RF Phase Scan on Dispersed BPM X high energy Spect. BPM X Reading after Bend (mm) L0a RF phase (deg-S)

  15. Bunch Charge vs. Laser Energy 330 pC 370 µJ at cathode • calibrations need confirmation • Iris cut clips laser energy

  16. EPICS Controls - Vacuum Manual valve

  17. EPICS Controls - Magnets

  18. EPICS Controls – Profile Monitors

  19. Long Ion Chamber Along Full Accelerator YAGS2 inserted YAG03 inserted

  20. Charge and Position Jitter – Shot to Shot X-position jitter is 10 µm rms Charge jitter is 2.6% rms 2% 20 µm 100 shots at 10 Hz using BPM immediately after gun

  21. BC1 Chicane Control and Compression Ceramic Gap Bunch Length Monitor Slope = 1 BC1 BPM X (mm) RF phase: +40º 250 MeV when X = 0 BC1 X-Mover (mm) BPM offset checked using BC1 collimator jaws to locate beam in X RF phase: 0º RF phase: -40º OTR screen still needs camera

  22. Problems/Issues • Gun Faraday cup broken (pneumatic error) • Gun toroid shorted during installation • Gun z-position not right yet (7.5-mm interference) • YAG screens not setup before installation (hard-stops) • Still need to install cameras and air lines for 7 screens • No toroids working yet (1 shorted, 3 left to install) • BC1 motion control limited (300 mm  260 mm) • QE about 4-times lower than design (to be verified) • Some controls tools late (orbit displays & fitting) • MCOR power supply ADC readback noise (~1%)

  23. 2007 Injector Commissioning Goals DONE DONE DONE DONE http://www-ssrl.slac.stanford.edu/lcls/internals/commissioning/documents/lclsinjector-commissioninggoals.doc STARTED ~DONE STARTED NOT STARTED

  24. Summary • Beam transported to all areas (no trouble) • No obstructions or ‘backwards’ components, etc (but no systematic checkout yet) • Controls still developing, but working well and improving fast – great cooperation and effort • Communication with laser group excellent • Screens and toroids late, but installation continues • Some quality control issues with a few components • Thanks to all – First indications are very positive

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