Free Electron Laser Commissioning Meeting

Friday, 5 Dec 97
Recorder: C. Bohn

Next Meeting


Date: 12 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 15 min Top-Level Threading Procedure (Whole Machine) Douglas 15 min RadCon of FEL Vault May 10 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, F. Dylla, K. Jordan, G. Krafft, R. Legg, R. Li, L. Merminga, J. Musson, G. Neil, P. Piot, J. Preble, Q.-S. Shu, R. Walker, B. Yunn

Closed Action Items


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

Items of Discussion


As discussed below, commissioning with beam is suspended pending replacement of the stuck valve upstream of the cryomodule. This means our shift schedule needs to be redone. We must get tune-up beam to the straight-ahead dump before Christmas break, and we must also have B. Yunn's help setting up the injector per PARMELA simulations prior to his departure 15 Dec for vacation. The Commissioning Coordinator (CC) greatly appreciates the cheerful attitudes of those involved with commissioning, and he will try to preserve those attitudes, BUT clearly people will have to be patient and flexible, especially over the next 2-3 weeks. (No -- you'll not be here during Christmas through New Year! No shifts will be scheduled for 24 Dec 97 or 2 Jan 98, either. This means whatever we get done by 24 Dec 97 will be "it" until we can turn on after the CHL shutdown, which according to CC's notes will be 24 Jan 98. So, let's push together to get to the 2G dump, and get 60 pC bunches in the injector for diagnostics checkout!)

Projected shift assignments and tasks for 12-23 Dec 97 were worked out late this morning and are written on the scheduling board in the FEL Facility Break Room. Please saunter by.

Vacation plans are being accommodated in the shift schedule. Vacation plans known to CC are the following:

        Bohn            12/23/97 - 1/4/98
        Douglas         12/20/97 - 1/4/98
        Engwall         12/23/97 - 1/1/98
        Jordan          12/23/97 - 1/4/98
        Krafft          12/20/97 - 1/4/98
        Legg            12/8/97 (Is that all?)
        Merminga        12/17-18/97 and 12/22/97 (will be here on 12/23-24/97)
        Neil            now through 1/6/98
        Shu             12/23/97 - 1/4/98
        Yunn            12/15/97 - 1/21/98
Please advise CC of omissions.

R. Legg and C. Bohn presented commissioning highlights since last meeting:

Subsequent to the Commissioning Meeting, J. Preble updated us on the status of the valve replacement. Two new valves are on order from VAT in Switzerland, and they are likely to be shipped today (but a small possibility exists that they would not be shipped until next Friday). Once we receive them, probably next Wednesday, we'll need to dismantle them, clean them, reassemble them, and put them through several cycles prior to installation, now projected for next Friday, 12 Dec 97. Cryomodule warmup requires care and ideally should be done slowly, so plans are to begin warmup after finishing the unloaded Q measurements tonight. Cooldown will be rapid, projected to start the evening of 12 Dec 97 and be complete to 2K 12-16 hours later, making the cryomodule ready to accept beam next Saturday.

R. Legg presented a synopsis of the procedure for setting up cw beam to the straight-ahead dump. It is similar in principle to that for setting up the CEBAF injector, and in turn no major difficulties are foreseen. However, some discussion ensued concerning the status of software for the SEE BPMs. The software is being extensively rewritten, and the final version will be structured to accept improved calibration constants. The software will be available by Mar 98, in time for setting up the electron beam for first-light lasing.

People were reminded that all commissioning procedures and test plans are to be posted on the Web's FEL Documentation Page. Formally, CC is keeper of these documents, but he requested cooperation in getting them posted. All Accelerator Division secretaries are trained to post documents on the Web. Questions should be addressed to CC.

Tests of the OTR monitors have thus far been favorable, indicating a linear response over their specified operating range. P. Piot and G. Krafft have plots of the data.

We are loaning our external 10 MHz reference for the FEL's MO to CEBAF to cover a temporary need there. J. Musson advised that it is projected to be returned to the FEL by the middle of next week.

New Issues


Disagreement surfaced concerning the role of the magnet probe for the wedge dipoles (DUs). Is it to be used strictly for zeroing the magnets, or is it to contribute to the MPS by providing an indication of the beam operating mode? D. Douglas will resolve the issue, with CC's help if needed.

New Action Items


Old Action Items


Procedures in Work


First Light Setup

Emittance Growth from CSR

Thread Beam around Machine, Top-Level           Douglas, finalize 31 Jan 98