1. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 1 Injector Physics C.Limborg-Deprey GTL final design Wakefield budget Final Modifications Commissioning Readiness Schedule Feedback systems An example of tuning procedure Steering in L0a

2. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 2 Injector  Gun installation Nov. 2006  Gun Region July 2006  Accel Region June 2006  Heater Region June 2006  Wall Region October 2005  Waveguide October 2005  Injection Region Aug-Nov 2006  Spect Region Aug-Nov 2006 Injector Commissioning Start December 2006

3. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 3 Gun to Linac Region

4. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 4 GTL Design Normal incidence Mirror size (14mm x 10 mm) No second Valve in GTL All wakefield computed (see next slides) Diagnostics units finalized accommodate 20 mm screens wakefield mitigation Gun Solenoid moved as close as possible to cathode Bucking Coil added (PRD written) cancels the 55 Gauss Bz field on cathode Compatibility with gun bake + cathode removal

5. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 5 GTL Design Pending issues <1.05 permeability of VV01 Impact on B solenoid falling edge to be measured Choice of material for injector mirror Optical path for CRG1 light Finalization of GTL BPMs to meet 20  m resolution Alignment laser specifications Final GTL design review next week Courtesy J.Langton

6. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 6 Wakefield Budget  projected <1.2 mm-mrad with no error simulations show 1.0 mm-mrad Stability of electro- magnetic components to meet less than 10% increase <10 % increased from total wakefield effects over the whole beamline GTL area is critical region Injection mirror with 1mm beam offset

7. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 7 CasedLWake (1)6 mm10 mm0.247 V/pC on axis (2)6 mm10 mm146 V/pC/m (3)6mm15 mm171 V/pC/m (1) (2)(3) MAFIA Simulations, Courtesy Cho-Kuen Ng Wakefield from Injection Mirror d L

8. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 8 Wakefield Mitigation in GTL Pumping slots 0.24 V/pC/m per unit 3 units at 0.6 m 3 units at 1.2 m Negligible emittance growth Combined Diagnostics chambers Wakefield Mitigated ~small gaps Courtesy J.Langton Courtesy Cho-Kuen Ng Pumping slot

9. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 9 Wakefield Mitigation in GTL Spectrometer bend chamber Wakefield mitigation movable plug Eliminates any wakefield Small gap Bellows Sleeve on each 7 Small step transition instead of 25V/pC/m Gaps 1mm gap ~ 3V/pC/m Beam to Spectrometer Straight beam Courtesy J.Langton Plug out Sleeve Bellows

10. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 10 Wakefield in Radiation Stopper Radiation Stopper not an issue LCLS-TN-05-15 "Wakefield Calculations for Radiation Stopper 1 (RST1)“ W rms < 0.077V/pC on axis  /  < 0.1% due to small  =1.5 m MAFIA computations Courtesy Cho-Kuen Ng

11. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 11 Final changes in Accelerator Region Courtesy P.Stephens

12. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 12 Beamline Modifications L0a moved downstream by 8 cm Ok with emittance compensation Solenoid 2 reduced to 20 cm effective length magnet (Req. sent out) higher B field for same focal length higher B field is not an issue Suppressed one out of 2 BPMs in L0a-L0b drift 4 inch Phase monitor fits in Valve moved from L0a entrance to L0a-L0b drift Mu-shield metal wrapped around all possible location PRD 1.1-009 Unfortunately not possible in GTL

13. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 13 Diagnostics Critical decisions Specifications for screens and resolution finalized (PRD out) CR material: 1mm thick, quartz, to be replaced with aerogel later OTR cameras orientation to increase depth of field Streak camera ordered Choice of CCD cameras finalized Remaining issues Optical path for CRG1 light 2nd pick-up on toroid for BCS Alignment laser spec. to be finalized Finalization (Resolution) of BPM design for large aperture pipe

14. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 14 Commissioning Schedule Discussed every 5 th week with LCLS physicists/operators group To be incorporated into large *.mpp document for links Discussed weekly inside Injector group (Bong, Dowell, Limborg, Loos, Schmerge …) Based on 2 shifts per day Resource loading to be refined 2 physicists per shift + 1 control person + 1 operator guests Meeting will evolve in high level application discussion Schedule Outline Starts with RF Gun cold and hot test (summer 06) First beam at 135MeV dump (Nov.22-06  Dec.06) 8 months of characterization and optimization Deliver most stable beam for acceptable charge for BC1 commissioning at end of June07

15. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 15 Schedule December 06

16. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 16 Commissioning Readiness Pending issues Hot test schedule Finalize start date, detailed schedule Feedback Systems Calibrations procedure Magnetic calibration procedure drafted Screen calibration procedure High Level Applications

17. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 17 High Level Applications Cathode characterization (QE, uniformity, Thermal emittance) Steering in L0a Longitudinal phase space measurements at BXG Bunch length measurement with transverse RF deflector(s) Emittance meas. (multi-wire, multi-OTR, quad-scan, slice) Power-steering through beamlines, with corrector weights Difference orbit fitting, including internal kick Longitudinal phase space measurement at BXS Tomography (Longitudinal and Transverse) …

18. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 18 Feedback Systems Pointing Stability (see Laser) Tolerance Slow (f<1Hz) : <200  m (or slice emittance degraded) Fast (1Hz<f<120 Hz): <10  m (1% of “10%  x,undulator budget”) Slow feedback : Sensor/ actuator Virtual cathode / mirrors Status : preliminary tests at bldg 407 Fast stability Design constraint (Gun + injection mirror + vacuum chamber “rigidly” linked to optical launch table,i.e. less than 10  m fast motion ) Charge Stability (see Laser) Tolerance Fast (shot-to shot) < 2%rms Sensor/Actuator first toroid IM01/ polarizer

19. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 19 Feedback Systems Timing Stability Tolerance Fast stability (120Hz), laser phase w.r.t master clock < 0.5 ps rms feedback system sensor : phase monitor signal actuator: locking electronics from Thales system Slow stability (<1Hz), laser phase w.r.t gun phase < +/-3 ps to maintain emittance within 5% of optimal

20. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 20 Steering in L0a Solenoid SC0SC1SC2 BPM2BPM3BPM5 GunL0a Solenoid mispositioning 250  m, 250  rad Earth Magnetic field 2mrad/m vert. No space for mu-metal shielding in GTL By ~ 0.35 G Bx ~ 0.12 G Offset as large as 3mm without steering

21. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 21 Simulations of steering Solenoid SC0SC1SC2 BPM2BPM3BPM5 GunL0a Procedure L0a solenoid off Orthogonal knobs at SC0 SC0 and SC1 adjusted to steer in L0a Scaling of SC0 orthogonal knobs with solenoid to be implemented in software when

22. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 22 Conclusions GTL Design finalized L0a-L0b space issue solved “Laser Heater” region to be detailed Commissioning schedule under completion Feedback systems under completion High Level Applications to be written

23. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 23 Response to the April FAC Recommendations Wakefield in Gun Large Energy spread in gun identified to be related to 0-mode ACD group will perform more simulations 3D-ellipsoidal laser pulses Presented at major conferences, in particular at FEL05 with good interest shown from many laser experts

24. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 24 BACK-UP

25. C.Limborg-Deprey LCLS FAC, Oct 2005limborg@slac.stanford.edu Oct 27th 2005 25 Hot test schedule Objectives Task1 : RF Conditioning Task2 : Verification of thermal design (  f vs Power,  f vs T) Task3 : Close LLRF feedback loop LLRF feedback loop can only be closed if availability of Chiller, Instrumentation of detection of phase from reflected power signal, Drive Amplifier Four scenarios discussed Klystron lab. (PEP bunker) Aug. 06 S20 July 06 S20 Sep 06 S20 Dec06 + Early start, possible retrofit No impact on S20 work Early start No special PPS Single installation No (-) from previous 2 All (+) from previous 2 “Special PPS” forced in (*) Early commissioning All systems ready No special PPS No impact on S20 work - Dvt Local Control Shielding work, add parts Long WG to be found Task 3 cannot be completed PPS finished unlikely Access Timing cables Impact laser work Task 3 cannot be completed “Special PPS” difficult to obtain High Technical risk Delays Commissioning with beam (*) “Special PPS” == run klystron + e beam to spectrometer during linac downtime