Next Meeting
Agenda for Next Meeting
Item Person Responsible Time ---- ------------------ -------- Status of Open Action Items All 5 min Commissioning Schedule Bohn 10 min Status of RF Procedures Merminga 20 min Status of Diagnostic Procedures Piot 20 min New Issues All 5 min
This Week's Attendees
J. Bennett, J. Bisognano, C. Bohn, J. Boyce, D. Douglas, F. Dylla, J. Fugitt, A. Grippo, K. Jordan, G. Krafft, R. Li, L. Merminga, G. Neil, D. Oepts, J. Preble, R. Walker, B. Yunn
Closed Action Items
Items of Discussion
On Monday T. Siggins pulled the cathode from the gun. Visual inspection of the wafer revealed no debris, a observation that is favorable as compared to early February. A new wafer has been cleaned, anodized, and its outer periphery masked to cut down on beam halo. The new cathode is being installed today. We are generally on track for resuming beam operations on 1 Jun 98, give or take a day.
There have been some hardware checks of the drive-laser rf system to ascertain phase drifts and amplitude noise. Nothing dominant has been found to date, but the process is continuing. L. Merminga and C. Hovater have put together a plan do model the drive-laser rf system and expect to complete the modeling in about a month.
G. Neil and M. Shinn advised that the FEL systems are coming to closure. The CaF first-light mirrors are being installed in the optical cavity today, and at the end of the day the FEL systems in the vault (notwithstanding that the wiggler is not installed there) will be ready for lasing. Diagnostics in the Optical Control Room are nearly finished, and the supporting Laser Safety System will be installed imminently. In short, the Optical Control Room will be ready in two weeks or less. In parallel, both Labs 1 (Polymers) and 3 (Metals) are in process of being set up. Most likely the first user experiment will involve lasing on a polymer, but there will also be other options.
C. Bohn reminded everyone that 1 Jun 98 is the day beam operations should resume, most likely with Douglas/Benson on day shift, Siggins on swing shift, and Walker/Piot on owl shift. The general pattern of daily commissioning activities will begin as before: nominally day shift working through the metaprocedure, swing shift exercising the machine, and owl shift measuring beam quality. To expedite progress in establishing lasing-quality electron beam, we hope to evolve quickly to two shifts working through the metaprocedure, with both of these shifts involving a diagnostics expert. The thrust will be to refine continually the Golden (Save/Restore) File without back-tracking. Bohn, G. Neil, and J. Fugitt met this morning to discuss this philosophy, and general agreement was reached. The details will be decided as we progress, and Bohn intends to solicit much input to the process. J. Bisognano recommended a daily meeting be held to discuss technical progress and questions, and Bohn will likely hold such a meeting once commissioning resumes.
Bohn presented a cursory schedule that would take us all the way to high-power lasing with energy recovery. F. Dylla pointed out that it is unlikely we would support any significant level of user experiments during this calendar year, which means we can commission the recirculation arc and take the first CSR data in the Fall. Thus, at top level, the schedule looks something like what follows; it will of course be revised and augmented as we progress technically and programmatically through the coming months:
6/1-6/30: Configure first-light electron beam (set up phase space). 7/1: Install wiggler. 7/2-7/31: Lase at >100 W. 8/1-8/15: Do first user experiment (in time for Williamsburg FEL Conference!). 8/16-8/31: Do additional user experiments. 9/1: Remove wiggler (to protect it from radiation). 9/2-9/30: Commission recirculation loop with beam; take first CSR data. 10/1-11/31: Demonstrate energy recovery with high cw current. 12/1: Reinstall wiggler. 12/2-1/31: Lase with energy recovery at >100 W. 2/1-3/31: Increase average current; lase at higher power.Bohn went over the task list supporting the Phase Space Setup Metaprocedure that was discussed last week. Some slight changes were discussed and adopted. The list is provided at the end of these minutes, and the nominal due date for all draft procedures is next Friday, 29 May, i.e., before beam operations resume. Of course, in most cases, the procedures (and the Metaprocedure itself) will be continually revised as commissioning progresses.
Status of the remaining top-level MUST-priority prerequisites to lasing is:
New Issues
None.
New Action Items
Old Action Items
Procedures in Work
Metaprocedure for Phase Space Setup Douglas, finalize 29 May 98 Emittance Growth from CSR
Procedures Needed for Recirculation
Subsidiary Tasks for Phase Space Metaprocedure
Task Principal ---- --------- I. Stabilize Drifts in Drive-Laser RF Phase Walker/Fugitt II. Calibrate RF Gradients A. Buncher Yunn B. Cryounit Cavities Merminga/Krafft/Yunn C. Cryomodule Cavities Merminga/Krafft/Yunn III. Reconcile Methods for Setting RF Phase Merminga/Krafft/Yunn A. Buncher Cavities 1. Energy fixed point 2. Minimum bunch length/time of flight 3. Transient phasing B. Cryounit Cavities 1. Transient phasing 2. Cresting 3. Time of flight IV. Finalize "Cryounit Cresting" Procedure Merminga V. Finalize "Injector Setup" Procedure Yunn/Biallas VI. Establish Tolerances on Phase/Steering Drifts A. Drive Laser Yunn/Walker B. Buncher Yunn C. Tolerances on RF Phase Drifts 1. Cryounit Yunn 2. Cryomodule Douglas D. Tolerances on Steering 1. Injector Yunn 2. Linac Douglas VII. Develop "Resteer After Rephase" Procedure 1. Injector Yunn 2. Linac Douglas VIII. Establish Expected Beam Quality Yunn A. Multislit #1, #2 B. Happek #1, #2 C. M_55 #1, #2 D. Bunch Length at Cryomodule Center E. Bunch Length at Exit of First Optical Chicane (with Li) E. Emittance at Wiggler, 2G02 (with Li) F. Momentum Spread at Wiggler, 2G02 (with Li) IX. Complete Diagnostics Procedures and Training Krafft/Piot A. M_55 #1, #2 B. Happek #1, #2 C. BPMs 1. button calibration factors 2. rotated MEDM spike charts 3. difference orbit data acquisition script D. Multislit #1, #2 E. Quad/Viewer (at Wiggler, after Wiggler) F. Multimonitor (at Wiggler) G. SLM/CSR H. Zero Phasing I. Momentum Spread (Injector, Linac Pre-Wiggler, Linac Post-Wiggler) J. Energy X. Develop "Injector Rematch" Procedure Biallas/(Unk. Physicist) XI. Revise "CW Setup" Procedure (to 2G02) Douglas A. Minimize Bunch Length with Happek #2 B. Establish Clean Beam Transport to Dump XII. Develop "Energy Rematch to Wiggler, Dump" Procedures Douglas XIII. Update "Difference Orbit Measurement" Procedure Douglas XIV. Update (as appropriate) "First Light" Procedure Benson