1. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 1 Beam Losses During LCLS Injector Phase-1 Operation Scope of phase 1 operation Operating modes Operating plan for phase 1 Beam power and losses during nominal operation Maximum credible beam Summary of maximum credible beam in injector and linac

2. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 2 RF Gun & Solenoid Gun Energy Spectrometer L0a&L0b S-Band Linacs Laser-Heater OTRs & Wire Scanners Straight Ahead Spectrometer Transverse RF Cavity L1 S-Band Linacs Bunch Compressor 1 Wire Scanners Bunch Length Diagnostics X-Band Linac Commissioning of Injector thru BC1 ending at TD-11 will Begin in March 2007 TD-11 Scope of LCLS Phase-1 Operation

3. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 3 1. Beam operation from the LCLS injector gun to dump SDMP during LINAC operation, which is located in Sector 21-1. Magnets BX01/BX02 will be locked off. 2. Beam operation from the LCLS injector gun to dump TD11, which is located in sector 21-3. Dump TD11 will be disabled “in”. The following modes of operation for phase-1 of LCLS injector commissioning have been approved: Modes for LCLS Injector Phase-1 Operation

4. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 4 http://www-ssrl.slac.stanford.edu/lcls/internals/commissioning/documents/commissioning-dates-2006-2007.ppt Dec 22:PPS Certified Dec 20-Jan 1:Holidays Jan 2:VVS’s switched on for PEP-II (RF power available) Jan 15:L0a, L0b, L1 RF processing begins Feb. 1:X-band RF processing begins Feb 20:GTL beamline installation complete Mar 6:Virtual cathode fully characterized (ready to install gun) Mar 7:RF gun installation begins – laser rate to 30 Hz Mar 16:First laser UV-light on cathode! Mar 17:Electrons in GTL and gun-spectrometer Apr 9:Beam through L0a, L0b and down to 135-MeV spectrometer Apr 24:Beam into main linac (to TD11 dump) ~July:Take beam down full linac (to BSY SL2 stopper) LCLS Injector Commissioning Dates (2006 - 2007)

5. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 5 LCLS Phase 1 Operation DateLCLS ProgramTest Beam Program Administrative Controls Jan 4 – Jan 29 RF Processing, no beam Linac set-up and SABER BX01/02 locked off Jan 30 – Feb 12 RF Processing, no beam ESA for ILCBX01/02 locked off Feb 12 – Mar 25 Beam to 7 MeV Gun Spectrometer OFFTD11 disabled IN Mar 26 – Apr 8 Beam to 7 MeV Gun Spectrometer SABERBX01/02 locked off Apr 9 – Jul 9 Beam to TD11 (and 52SL2 ?) OFFTD11 disabled IN Jul 9 – Jul 22 Off or Beam to 135 MeV Inj. Spect. ESA for ILC and test beams BX01/02 locked off Jul 23 – Aug 20 Beam to TD11 (and 52SL2 ?) OFFTD11 disabled IN Aug 20 – Aug 31 Off or Beam to 135 MeV Inj. Spect. SABERBX01/02 locked off

6. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 6 Penetration to Drive Laser Rm. Nominal beam loss locations in the gun-to-linac region, not including dark current L0-a RF Gun Nominal Beam: Losses in the Gun-to-Linac (GTL) Region

7. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 7 Gun: 6 MeV, 0.7 W TD11: 250 MeV, 30 W 135 MeV, 16 W SDMP: 135 MeV, 16 W 250 MeV, 30 W Nominal Beam Power Along Injector

8. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 8 3-nC initial gun dark current based on worst-case GTF operations Dark current energy sources and power estimates for the LCLS injector at 120 Hz

9. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 9 Estimated average beam power loss and location along the LCLS in nominal and special tune-up conditions. Power levels set in bold type occur in normal operating conditions. Non-bold entries are special configurations as described in the “note” column. Table Notes: aa. This loss occurs only when this Faraday cup is inserted (6 MeV, 120 Hz). a. This loss occurs only with beam on the gun spectrometer (6 MeV, 120 Hz). b. This loss occurs only with beam on the injector spectrometer (135 MeV, 120 Hz). c. This is a normal loss due primarily to dark current from gun and injector. d. This loss occurs only with beam on this tune-up dump (120 Hz). Nominal and Tune-up Beam Losses from Gun through BC1 ending at TD11

10. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 10 Explosive electron emission occurs from the photocathode if the drive laser intensity exceeds the threshold for plasma production. This emission persists until it has depleted the gun of all its stored energy. Source in a RF Photocathode Gun is Explosive Electron Emission Maximum Credible Beam

11. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 11 The quads between L0-a and L0-b transport 64 MeV electrons so will over-focus MCB electrons causing lost in the L0-b structure. Max power deposited in L0-b is assumed to be the full beam power of 2.2 kW. The macro pulse 1.2 A is accelerated by L0-a, with beam loading it will have energies between 21 to 76 MeV, with 48 MeV average energy. Average beam power at L0-a exit: (48 MeV)  (0.38  C)  (120 Hz)  2.2 kW. The maximum stored energy in the gun is 10 J at 140 MV/m. Beam loading gives 4 MeV energy, therefore the max charge/pulse is (10 J)/(4 MeV) = 2.5microC, at 120 Hz, current is 0.30mA. Studies show 85% lost in GTL, average loss is (4 MeV)  (0.30mA)  (85%)  1.0 kW. Quads OFF: this beam could be accelerated by L0-b, with range of 56 to 160 MeV, for the max 62 MW RF power and beam loading. The average energy is (160 MeV+56 MeV)/2  110 MeV, average power is (110 MeV)  (0.38  C)  (120 Hz)  5.0 kW after L0-b. DL1 bend off: 5.0 kW lost in and after the spectrometer dipole. Max energy is 160 MeV and DL1 energy acceptance is  5%, the highest energy with max transmission is (1 - 5%)  (160 MeV)  150 MeV. Worst case MCB to main linac is 150 MeV with average power of (13%)  (0.38  C)  (150 MeV)  (120 Hz)  0.9 kW. Acceleration to 250MeV, MCB ~ 6  A*250MeV=1.5kW after L1 MCB in TD11 ~ 1.5 kW Estimate for Maximum Credible Beam

12. Injector Accelerator Readiness Review, 10/31/06 Henrik Loos 12 LCLS GRD 1.1-001 at: http://www-ssrl.slac.stanford.edu/lcls/prd/1.1-001-r0.pdf.http://www-ssrl.slac.stanford.edu/lcls/prd/1.1-001-r0.pdf Summary of Maximum Credible Beam Power Along the Injector and into the Linac