Next Meeting

Date: 9 Jan 98 (next year!)

Time: 0830-0930

Place: FEL Facility Break Room

Agenda for Next Meeting

                Item                             Person Responsible     Time
                ----                             ------------------  --------
Progress Report on Commissioning                        Legg/Bohn      10 min
Discussions of Lessons Learned                          Bohn/All       30 min
Punch List for January Setup                            Bohn/All       10 min
New Issues                                              All             5 min
Agenda for next week                                    All             5 min

This Week's Attendees

J. Bennett, G. Biallas, C. Bohn, D. Douglas, A. Grippo, A. Hofler, K. Jordan, R. Li, P. Piot, J. Preble, Q.-S. Shu

Closed Action Items

The following actions from last meeting's report were closed out:

• Musson: Correct the gradient readings of the cryounit cavities on the control screen. Status: M. Drury traced the problem to forgetting to recalibrate attenuation through a VCO circuit after the VCO had been inserted as a replacement for another faulty VCO. Consequently a 2.7 dB power attenuation had been overlooked. The GMES discrepancy on the control screen was subsequently corrected.
• Douglas: Resolve role of magnet probes for DUs. Status: In view of uncertainty in the reliability of the probes, K. Mahoney plans to implement the MPS system without the rotating coils but will leave hooks in the system to allow testing with them. Consequently the role of the probes is to aid in zeroing their respective dipole magnets.
• Bohn: Decide when to make the FEL vault a Radiologically Controlled Area. Status: During the December run, the vault is designated a temporary RCA. The implications are delineated in a memo from K. Welch that has been e-mailed to the FEL Commissioning Team. Highlights are:

1. The general access RWP is basically the same thing that exists for the CEBAF tunnel - with some FEL specific provisions. ALL PERSONS WHO ACCESS THE VAULT NEED TO READ THE GENERAL ACCESS RWP AND SIGN ON THE BRIEFING SHEET. It is in a binder in the FEL Control Room.
2. The vault is posted as an RCA, and all personnel entering must be radworkers with TLDs.
3. Post-operation surveys by ARM or RCG are required. There are survey forms and a Bicron survey instrument kept in the FEL Control Room. Presently R. Legg, T. Siggins, and R. Hill are certified ARMs. When none of them are available, ask for support from an ARM-certified CEBAF operator (x7047). Failing that, call RadCon.
4. Any beamline-related item must be surveyed prior to release from the vault. If it came from the section of the machine where there has been no beam, and it's a new component, no survey is required. In early January we will need to set up a staging area for items requiring RadCon survey.
5. Upon shutdown for the holiday/January down, the vault will be deposted and no longer be an RCA. When we resume running (nominally 26 Jan 98), RadCon will reestablish the RCA status permanently.

Items of Discussion

We now have software in the FEL Control Room for recording shift summaries, and henceforth crews are asked to prepare a summary at the end of their shifts. This process began last night. A. Hofler suggested that we use the shift logs at daily FEL meetings in parallel with what is done for CEBAF. The Commissioning Coordinator (CC) received the suggestion well and will consider doing so once we turn back on in late January to start going after first light.

Commissioning status is that we locked up yesterday at 1430, not surprisingly went through a few hiccups in the process of turning on the injector, and by 0800 had beam at the viewer immediately preceding the cryomodule after running it through the injection line with both cavities crested. Beamline parameters from the November runs seemed to work well, indicating consistent machine performance.

This morning, checkout of the vacuum-interlock system through the cryomodule down to the straight-ahead dump is proceeding. Open questions at this writing (1100 Friday) include whether to reset the vacuum-valve trip limits in the vicinity of the optical cavity, and if so, to what values, and how to configure software controlling the rf interlock to the drive laser so it does not needlessly shut down. Both are being worked this morning.

Plans are to take beam through the cryomodule today and do transient phasing tonight. Then tomorrow we take beam through the optical chicane and crest the cryomodule cavities. D. Douglas suggested we consider taking the beam all the way to the straight-ahead-dump viewer and then crest, a process that he thought would be straightforward based on experience with CEBAF. We will consider this idea.

J. Preble reported that the cryomodule's performance after thermal cycling for replacement of the troublesome valves appears unchanged. Gradients for all of the cavities are consistent with earlier measurements, as are the unloaded Q's of the entrance and exit cavities. On the other hand, the static heat load rose, raising the error bars in the Q measurements. The source of the increased heat load is not yet identified. Bottom line is that all indications are that we still have a 47 MV cryomodule.

D. Douglas gave an overview and demonstration of his Excel version of DIMAD. It is comparable in structure and capability to the FEL model server developed by the Software Group, but it runs slower. (Incidentally, P. Piot reported that the FEL model server is up and running.) The essential advantages of Dave's code is that it is implemented on a well-known user interface, and it is conveniently transportable. Other interfaces that would perhaps be better adapted to this application are mathematics packages like MathCad and Mathematica. Dave will probably spend a bit of time looking at possibilities like these. Bottom line here is that Dave is now well prepared to sit shifts, a resource we look forward to using come January turn-on!

CC advised the Commissioning Team to have a great holiday season after getting beam to the straight-ahead dump. He would like to achieve a stable profile on the dump viewer and be able to shut down a day early, mainly as a Christmas present for Deputy CC (who can then finalize the CW Setup Procedure by 24 Dec 97 as indicated below!!).

New Issues

New Action Items

Old Action Items

Procedures in Work

First Light Setup

CW Setup                                    Legg, finalize 24 Dec 97 

Emittance Growth from CSR

Tomographic Phase-Space Map                 Piot, 15 May 98
Back Leg Thread                             Douglas, 31 Jan 98

Thread Beam around Machine, Top-Level           Douglas, finalize 31 Jan 98
RF Stability during Energy Recovery             Merminga, 23 Jan 98