Next Meeting

Date: 19 Dec 97

Time: 0830-0930

Place: FEL Facility Break Room

Agenda for Next Meeting

                Item                             Person Responsible     Time
                ----                             ------------------  --------
Status of Action Items                                  All             5 min
Progress Report on Commissioning                        Legg/Bohn       5 min
Scheduling Update                                       Bohn           10 min
Summary of SRF/RF Limits                                Merminga       15 min
Beam Optics Spread Sheet                                Douglas        15 min
New Issues                                              All             5 min
Agenda for next week                                    All             5 min

This Week's Attendees

J. Bennett, S. Benson, C. Bohn, J. Boyce, D. Douglas, D. Engwall, G. Krafft, R. Legg, R. Li, R. May, L. Merminga, P. Piot, Q.-S. Shu, A. Todd (Northrop-Grumman), B. Yunn

Closed Action Items

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

• Krafft: In conjunction with P. Piot and J. Song, decide whether phase-space tomography should be pursued, and if so, on what schedule. Status: Capability to do phase-space tomography in conjunction with CSR experiments is scheduled for 15 May 98, i.e., coincident with first light, after which there is a reasonable chance we will do some CSR measurements in parallel with setting up a user experiment. Stay tuned -- the crystal ball is foggy

Items of Discussion

All "operators" need to visit the FEL Control Room and view B. Legg's movie on how to set up the injector preparatory to running beam. The wise operator will do so early next week, at latest, because...

The two replacement vacuum valves that protect the cryomodule were shipped from VAT in Switzerland on Wednesday, not last Friday as had been hoped. According to J. Preble, as reported late this morning, they were still in Customs in Memphis, TN, and are to come directly to us from there. We now anticipate receipt Monday morning, with installation slated for late Tuesday, followed by cryomodule cooldown. Commissioning activities with beam would then resume Wednesday.

Projected shift assignments and tasks up to Christmas break are written on the scheduling board in the FEL Facility Break Room. Affected parties also got an e-mail from R. Walker. The Commissioning Coordinator thanks you in advance, on behalf of the Lab, for getting tuneup beam to the straight-ahead dump before Christmas (and he especially thanks you for your dedication).

There has been considerable commissioning activity not involving electron beam. S. Benson and L. Merminga provided the following highlights since last meeting:

• The optical transport system leading from the wiggler area to the optical control room was pumped down and taken through its first tests with a surrogate laser beam. The pipe was found to be leak-tight, but the beam was seen to wander. The bellows leading into the mirror cans were stiffened, and a retest is scheduled for this evening.
• Further rf commissioning is continuing on the cryounit to enhance the stability of its operation.
• The source of the 2.7 dB miscalibration discussed in preceding minutes was identified and confirmed to be only a matter of downloading to the control screen, meaning the gradients measured in both the cryounit and cryomodule during srf commissioning stand as reported earlier. New corrected kappa coefficients are being downloaded in the rf control modules of all 10 FEL cavities, an activity slated to be completed today.

C. Bohn summarized the post-Christmas commissioning strategy, which is as follows:

Resume beam commissioning 26 Jan 98
Groundrules:

• no installation prior to 17 Feb 98
• no Operations Department operators prior to 1 Mar 98

• run 3 shifts from 26 Jan 98 to 17 Feb 98
  focus is 1.1 mA cw straight ahead

  install GEN and west arc 17-18 Feb 98, no commissioning with beam

  run GEN irradiation swings/owls 19-21 Feb 98; install days

  remove GEN 22 Feb 98

  run 3 shifts to first light

  first-arc CSR, energy recovery are backups

R. May led an extensive discussion about when to make the FEL vault an RCA. His proposal is to do it next week when we go into 3-shift operation. Arguments pro and con were heard. The Commissioning Coordinator considers it his responsibility to make the decision, and he will do so on Monday after soliciting a bit more advice. For the record, May acknowledged that we have been complying with an existing OSP, treating the FEL vault in the same manner as a CEBAF vault during entry after running beam, and this satisfies regulations. The idea to impose RCA is basically one of reasonable conservatism for safety, and overall convenience from the standpoint of reducing the rope count in the vault.

D. Douglas presented his draft top-level procedure for threading the electron beam around the whole machine in preparation for energy recovery. In essence it ties together the various procedures for setting up sections of the machine. But there some additional aspects, chief of which is phasing the beam for deceleration. Douglas's plan calls for using a diagnostic downstream of the x-chamber to measure and adjust the beam's rf phase and M_56. This idea needs fleshing out, especially because the diagnostic is presently undefined. It could conceivably be the current loop, but the loop is not yet installed, nor is its performance well understood at this point. Dave agreed and will further ponder it next month.

B. Yunn has supplied "lots of pictures from PARMELA" that should be helpful in properly setting up the injector for first light.

New Issues

New Action Items

• Bohn: Decide when to make the FEL vault a Radiologically Controlled Area. (due 15 Dec 97)

Old Action Items

• Musson: Correct the gradient readings of the cryounit cavities on the control screen. Status: Slated to be accomplished today. (due 12 Dec 97)
• Douglas: Resolve role of magnet probes for DUs. Status: As revealed after this morning's meeting, K. Mahoney envisions the rotating-coil probes to be used in the MPS to increase its reliability, i.e., as backup diagnostics, not primary diagnostics. He has been authorized to proceed accordingly. However, there are still some residual discussions going on between knowledgeable parties, so there is a chance that this decision will change. Ergo, this action is not quite closed. (due 16 Dec 97)

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