Next Meeting

Date: 29 May 98 (back to Friday!)

Time: "0845"-0945

Place: FEL Facility Break Room

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

• Boyce: Set up FEL ARR Review dry-run session for Wednesday, 20 May 98.
  Status: Dry run was held.

  All: Carefully go through Douglas's Phase Space Setup Metaprocedure. Send comments by e- mail to Douglas with copy to Bohn.

  Status: Those who had comments made them.

  Bohn: Go through tasks associated with Douglas's Phase Space Setup Metaprocedure and assign them to appropriate principals.

  Status: List discussed at today's commissioning meeting.

  All: E-mail your requirements for the AMS to Jordan.

  Status: Those who had requirements so advised Jordan.

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.

Status of the remaining top-level MUST-priority prerequisites to lasing is:

1. Stable, easily recoverable 1.1 mA, 38 MeV beam with sufficiently good beam quality.
   Status: Will evolve from the Metaprocedure.

   Working diagnostics:

   Status: Happek and crew are now slated to be here from 25-27 May 98.
   Diagnostic work comprises many of the tasks supporting the Metaprocedure.

   Adequate injector setup.

   Status: Will evolve from the Metaprocedure.

   Detailed procedures and test plans well communicated to MCC staff.

   Status: In work. See tasks supporting the Metaprocedure at end of these minutes.

   Working optical transport, including Laser Safety System for the Optical Control Room.

   Status: See summary above.

New Issues

None.

New Action Items

Old Action Items

• Walker: Prepare glossary of FEL terms as an aid to CEBAF operators.
  Status: Walker sent e- mail asking for comment before finalizing. (due 29 May 98)

  Walker: Work with Operations Department to develop requirements for an FEL Alarms Handler software page for use in monitoring the FEL from the MCC Control Room.

  Status: Meeting is set up for this afternoon to go through the rf alarms and decide how to configure alarms for other subsystems. (due 29 May 98)

  Piot: Establish off-normal setting of quadrupole MQJ0F03 to enable routine measurements with Multislit #1.

  Status: Some empirical attempts were made, but now this is delayed due to halt in machine operation. (due 5 Jun 98)

  Douglas/Bohn/Fugitt: Establish Draconian back-out procedure for cases where Restore files fail to recover the electron beam.

  Status: No progress. Bohn will call a meeting to go through similar procedures for CEBAF, expecting that they will provide a good starting point. (due 29 May 98)

 
Measure Beam Stability                     Benson, 15 May 98
    (dE/E, dx, dy, dx', dy')

Procedures in Work

Metaprocedure for Phase Space Setup             Douglas, finalize 29 May 98
Emittance Growth from CSR

Tomographic Phase-Space Map                 Piot, 30 June 98
Back Leg Thread                             Douglas, 30 June 98




Procedures Needed for Recirculation


Thread Beam around Machine, Top-Level           Douglas, finalize 30 June 98
RF Stability during Energy Recovery             Merminga, 30 June 98

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