1. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 LCLS Injector/Linac Systems Update E. Bong LCLS FAC April 7, 2005 LCLS

2. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 LCLS Injector/Linac Systems Update Plan Changes Since Last FAC FY05 Schedule & LLP Activity Shutdown Strategy Design & Fabrication Status Response to Last FAC Comments

3. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Nominal LCLS Linac Parameters for 1.5-Å FEL Single bunch, 1-nC charge, 1.2-  m slice emittance, 120-Hz repetition rate… (RF phase:  rf = 0 is at accelerating crest) SLAC linac tunnel research yard Linac-1 L  9 m  rf   25° Linac-2 L  330 m  rf   41° Linac-3 L  550 m  rf   10° BC-1 L  6 m R 56   39 mm BC-2 L  22 m R 56   25 mm LTU L =275 m R 56  0 DL-1 L  12 m R 56  0 undulator L =130 m 135 MeV  z  0.83 mm    0.10 % 250 MeV  z  0.19 mm    1.6 % 4.54 GeV  z  0.022 mm    0.71 % 14.1 GeV  z  0.022 mm    0.01 % SLAC linac 21-1b21-1d X Linac-X L =0.6 m  rf =  21-3b24-6d25-1a30-8c E-Dump Linac-0 L =6 m 6 MeV  z  0.83 mm    0.05 % new rfgun Drive Laser not shownThanks Paul Emma

4. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 System Changes Since Last FAC Continuing resolution delayed project funding October electrical accident halted accelerator operations Review of SLAC Safety Management Plan Halt of program prompts revision of FY05 run and down schedules FY05 down moved to October ’06, shortened to one month Injector and Linac System Management Combined Injector and Linac Systems engineering and design staff combined eliminating duplication of effort Injector WBS converted from geographical to product based. Manpower loaded schedule revised to condense structure into products rather than individual components. Schedule changed to better track cost performance.

5. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Plan Changes Since Last FAC Design, fabrication and installation schedule updated to reflect change in Linac down dates. RF Gun design and fabrication moved in-house to mitigate schedule and technical risk. Added LLNL and ANL collaborations on drive laser temporal, spatial and THG studies. Added UCLA collaboration to develop single shot bunch length measurement device. Formed agreement with Klystron department for RF component design support including gun design. Utilizing ILC personnel for dual-feed structure design.

6. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 FY05 Schedule & LLP Activity The change in ‘05 down time reduced the scope of the planned installation in the Injector and changed the design emphasis from the Linac to the Injector side of the shielding wall. LLP consists of fabrication activities in the Injector which can be started in FY05, the X-Band system components and BC1 & BC2 dipoles $2M bulk vacuum purchase agreement – June 05 The portion of the Injector system in the Linac Housing can not be fabricated in FY05. The Linac L1 segment design is complete and could be installed during the October 2005 down.

7. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector-Linac Installation Strategy Laser System June 2006 Gun Region April 2006 Accel Region March 2006 Heater Region January 2006 Wall Region October 2005 Injection Region August 2006 Spect Region August 2006 Waveguide through wall and up penetration October 2005 Installation schedule sets design and fabrications deadlines

8. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector-Linac Installation Strategy Quad + BPM, YCOR,XCOR, QE, Toroid Treaty Point LCLS Injector/LCLS Linac LCLS InjectorLCLS Linac Emittance Diagnostics. Bunch Compressor & Diagnostics Two short accelerator structures, refurbished Quads+BPMs,X&YCOR X-Band Structure (NLC) Linac 1 (L1) Electrons Bunch Compressor 1 (BC1) L1 Fabrication could be complete for October 2005 Installation X-Band Fabrication started – Installation FY06 Down BC1 Articulation ready for fabrication now BC1 installation FY06 Down Remainder of Linac installation FY07 Remove 5 S-Band Structures

9. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Drive Laser Progress Proposals received from vendors, evaluation in process. Pulse shaping and THG most difficult issues. As a result of BNL/DUVFEL pulse shaping studies, further collaboration set up with LLNL and ANL to study temporal, spatial and THG. Require studies to mitigate technical risk. Laser transport penetration tube design complete, earthquake safety approved, ready for fabrication. Integration and alignment of laser launch, RF gun and solenoid being investigated. 3-D ellipsoidal distribution studies – C. LImborg

10. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector RF Design Progress RF Gun Solenoid design complete. Relative alignment details under study. RF design altered due to review recommendations Increased Mode separation Z-Coupling from Theta-Coupling RF design complete mechanical design started (in –house) Monolithic dual feed Unresolved issues: Final design for bulk cooling system Load lock deferred L0 Accelerator structures Dual feed RF design pieced-together for solenoid assembly Both L0A and L0B dual feed on input Mechanical design in process Removed T-Cav from Li-11 Injector waveguide routing through wall in design

11. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Linac RF Design Progress X-Band System X-Band System layout reviewed. Waveguide components maximizing use of available components and designs. ILC cold decision X-Band system components available from NLC Two partially completed XL4 Klystrons – fabrication resumed Available waveguide components selected and requested X-Band structures selected L1 Short accelerating structures Structures available from spares, under evaluation for use. L1 design complete, drawings available. Can be installed 10-05 Support agreement made with Klystron Department for Injector and Linac RF work

12. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 1 nC 2.8 kA 0.2 nC 2.0 kA Need 20% smaller emittance (0.8  m), but with 1/5 charge & 1/3 gun current (30 A) No more transverse wakes in linac Almost no CSR in BC’s 2-times less peak-current jitter No undulator wakes 3-times shorter X-ray pulse 1-nC still OK, but only ~twice the photons, and a much more challenging machine no resistive wake Low Charge Operations 1.1  10 12 photons W. Fawley, LBNL no spikes Z. Huang

13. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 1 -Do gun tests as early as possible, at vendor maybe Gun will be designed and built in-house to use strength of SLAC RF design and to control technical risk. RF tests will proceed along with fabrication process including cold tests during cold fit-up through to 120 Hz hot-tests of final assembly. -Consider creation of a gun test facility Over the past eight years the GTF has revealed several problems with the prototype gun including correlated energy spread, tilt (transverse position to time correlation) on the beam and asymmetric beam at the gun exit to name just a few. These issues have been addressed in the LCLS design by increasing the 0 and pi mode separation, adding a dual feed coupler with racetrack geometry to both the gun and linac sections and adding a dipole and quadrupole corrector in the solenoid. In addition several diagnostic techniques for determining the beam correlations have been developed over the years that will be used in the LCLS injector to improve the overall beam quality. A new gun test facility will be proposed. However, the facility is beyond the financial scope of the LCLS project. It is suggested that future SLAC funds be allocated to a new gun test facility which could have more benefit to SLAC than LCLS gun testing alone.

14. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 2 -Order 2 guns Parts for two guns will be machined. Tests performed on the first set of parts will be used to dimensionally adjust the second set. The second set will be fully assembled. Hot tests on the second set will be used to dimensionally adjust the first set for final assembly. -Recommend continued testing of laser pulse shaping at DUVFEL Additional pulse shaping, third-harmonic-generation and launch optics testing will be conducted in collaboration LLNL and ANL. -Consider doing electron beam tests at DUVFEL Electron beam bunch length measurement tests will be performed at SPPS in collaboration with UCLA. Additional beamline component and controls tests are also planned in SPPS.

15. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 3 -Consider collaboration with LLNL on gun laser development We are collaborating with LLNL on drive laser development. -Recommend a hot spare laser A hot spare laser is not in the project baseline. However, it is planned to use contingency money, if available, will be used to purchase a second drive laser in FY08. The second laser may be a new design. -Recommend the formation of a laser group An LCLS laser group will be formed. A requisition is in place for a laser group leader. -Consider doing tests of "lock-in" detection of low gain at DUVFEL -Consider x-band waveform modulation as the input modulation for lock-in detection Lock-in low gain FEL signal detection using X-Band waveform modulation was not investigated. The XTOD System investigated other low gain detection schemes.

16. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 4 -Show analysis and simulations of collimator performance at the next review, including shower computations Collimator simulations will be presented at the FAC. The simulations include dark current from the gun and various RF structures, linac and LTU collimation, and undulator protection. Shower calculations will be done soon, but may not be ready for the April 2005 FAC. -Continue work on ESASE ESASE work continues. LBNL is taking the lead on this study. -Recommend x-y scanners for wire monitor, rather than diagonal Performing modal analysis on existing design to determine if there is any real benefit to tripling the number of wire scanners in the project budget.

17. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 5 -Consider the design of a feedback loop that adjusts the laser based on electron beam measurements Signal sources for laser feedback have been defined including bunch charge and bunch timing signals. -Consider options for the ULTIMATE LCLS Master Oscillator A reliable oscillator of proven technology will be installed for LCLS. Development work for the ULTIMATE master oscillator may be done in the future as an upgrade. -Continue tests of THz measurement techniques at SPPS THz bunch length measurements in SPPS will continue once the SLAC Linac resumes operations.

18. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 6 -Consider schemes to modulate X-band phase for optimal set-up -Place appropriate emphasis on challenging phase/amplitude control of X-band system Absolute phase and amplitude control of the X-Band system is not as demanding as was understood. The shot-to-shot (fast) jitter tolerances are fairly tight (0.5 deg-X and 0.25% amplitude, rms). This does not mean that the absolute X-band phase and amplitude need to be held at their design values to this level. The bunch length and energy feedback, described by Juhao Wu, will also compensate for X-band phase and amplitude changes of up to 10 degrees and 5%, as long as these variations occur slowly compared with 120 Hz. The compensation is implemented by Linac-1 S-band phase and amplitude corrections, but the net effect is to maintain a constant post- BC1 bunch length and beam energy. A “dither” feedback, suggested by the FAC, is therefore not as effective since it takes many pulses to dither the system, and variations on this time scale will already be compensated by the bunch length and energy feedback system. Perhaps a dither feedback can be implemented for very slow time scales of more than one minute, but the absolute regulation demands will then be quite loose (e.g., 2 degrees and 2%).

19. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 7 -Consider schemes to modulate X-band phase for optimal set-up -Place appropriate emphasis on challenging phase/amplitude control of X-band system Absolute phase and amplitude control of the X-Band system is not as demanding as was understood. The shot-to-shot (fast) jitter tolerances are fairly tight (0.5 deg-X and 0.25% amplitude, rms). This does not mean that the absolute X-band phase and amplitude need to be held at their design values to this level. The bunch length and energy feedback, described by Juhao Wu, will also compensate for X-band phase and amplitude changes of up to 10 degrees and 5%, as long as these variations occur slowly compared with 120 Hz. The compensation is implemented by Linac-1 S-band phase and amplitude corrections, but the net effect is to maintain a constant post- BC1 bunch length and beam energy. A “dither” feedback, suggested by the FAC, is therefore not as effective since it takes many pulses to dither the system, and variations on this time scale will already be compensated by the bunch length and energy feedback system. Perhaps a dither feedback can be implemented for very slow time scales of more than one minute, but the absolute regulation demands will then be quite loose (e.g., 2 degrees and 2%).

20. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Response to October 2004 FAC 8 -By 1/2005, force a decision on undulator design changes for AC wake field- Resistive wall wakefield studies were performed (SLAC/ANL.) A low charge machine configuration now looks like a very attractive operating point where resistive- wall wakefields are not a problem. In addition, a semi- elliptical undulator vacuum chamber with aluminum coating reduces the wakes to an acceptable level even at the 1-nC charge level. No other large changes to the undulator design have been necessary to further mitigate the wakes.

21. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector/Linac Summary Progress Made On Laser Purchase, Laser Study Collaborations RF Gun & Structure Design X-Band System Design & Klystron Fabrication Collimator Studies Mechanical Design – Area Integration, Components Magnet and Vacuum Procurement Injector and Linac Design Staff Integrated BCR to Modify Injector Manpower Loaded Schedule Incorporating Linac Down Schedule Changes, Better Cost-Performance Tracking Added staff for magnet procurement and diagnostics design

22. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 End

23. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 LCLS Injector/Linac Organizational Chart RF engineering, design and fabrication matrixed from Klystron Department ILC engineering & design matrixed for dual feed structure design Mechanical Design matrixed from SLAC Mechanical Design Department Recent additions: J Langton, Roger Carr

24. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector Launch Feedback Model Ron Akre, D. Kotturi

25. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector L0 Feedback Model Ron Akre, D. Kotturi

26. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 feedback off feedback on (Integral gain:0.5) Juhao Wu (SLAC) LCLS Longitudinal Feedback Simulation Details in Breakout J. Wu LCLS Longitudinal Feedback Simulation Details in Breakout J. Wu

27. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector Wall Region Design Beamline segment piercing Injector vault shielding wall. Includes valves, quadrupoles, OTRs, wire scanners, BPMs, pumps, gages, support stands, vacuum chambers. Beamline layout assembled into wall assembly model. Design effort broken into diagnostics, magnets, vacuum and integration. Quadrupole order April 1, 2005 OTR body ready for vendor bid. Wire scanner in design evaluation. Installation scheduled October 2005

28. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector Heater Region Design Beamline segment Between Accelerators and Shielding Wall Includes laser heater, transverse structure, dipoles, quads, correctors otrs. Installation scheduled January 2006

29. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Injector Waveguide Design Waveguide network feeds gun, Structures L0a & L0b, and T-Cav Gun and structures fed from Li-20-6, 7 & 8 klystrons, T-Cav fed from Li-20-5d structure exhaust. 3-D Layout integrated into Injector system assembly Design effort broken into penetration- wall runs, Gallery and Vault runs. Installation penetration-wall October ’05 Installation Vault & Gallery Spring ’06

30. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 L1 Region Design Beamline segment in Sector 21 Between Injector insertion and X-Band structure. Includes two shortened accelerator structures, quads, correctors and Bethe hole couplers. 3-D Layout integrated into Linac Girder model. Design complete. Drawings complete except couplers. Fabrication could begin April 2005 Installation-early October ‘05

31. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 BC1 Region Design Beamline segment in Sector 21 From X- Band system, through compressor to emittance diagnostics section. Includes articulated compressor, inter- bend diagnostics, emittance wire scanners, OTRs, quadrupoles and vacuum components. 3-D Layout integrated into Linac Girder model. Design effort broken into chicane articulation, diagnostics, magnets, vacuum and integration. Fabrication and testing of articulation could begin April 2005 Installation – August 2006

32. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 X-Band System Design XL4 Klystron in fab Selected NLC waveguide components designed for 8-Pack 60cm structure from Fermi X-Band Layout Integrated into beamline layout

33. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Linac L2, BC2, L3 Mechanical Design System schematics complete 3-D models of area backgrounds complete File management structure for 3-D models complete L2 and L3 modification ready to begin BC2 design scheduled for FY06

34. Eric Bong LCLS FAC Injector-Linac UpdateBONG@slac.stanford.edu April 7, 2005 Main Dump and Safety Dump Main dump electromagnets allow energy and energy spread measurements Safety dump permanent magnets deflect e-beam on BYD failure Ray traces show no beam transported through wall in any failure condition Working with SLAC Radiation Safety for approval of design