Next Meeting
Agenda for Next Meeting
Item Person Responsible Time ---- ------------------ -------- Status of Open Action Items All 5 min Status of Commissioning Preparations Bohn/All 15 min HOM and Microphonics Measurements Merminga 25 min New Issues All 5 min Agenda for next week All 5 min
This Week's Attendees
J. Bennett, S. Benson, G. Biallas, J. Bisognano, C. Bohn, D. Douglas, F. Dylla, A. Grippo, K. Jordan, C. Leemann, L. Merminga, G. Neil, D. Oepts, P. Piot, J. Preble, R. Walker, B. Yunn
Closed Action Items
Items of Discussion
C. Leemann gave a motivational talk to the attendees. He acknowledged that it will be tough turning on the FEL, as is generally true for any new machine. He also intimated that having less money this year, and possibly next year also, than had been anticipated is an exacerbating factor that understandably would cause people to be concerned about whether the Lab has the resolve to complete the FEL. In contrast, Leemann also pointed out that the FEL carries enormous interest in the outside world, e.g., within DOE and other government sponsors, making the Program commensurately valuable to the Lab's overall image. Consequently, Lab management is sticking to its decision that "lasing @ >100 W" and "first FEL user experiment" carry MUST priority. Logically, the Lab would benefit more if they were completed prior to the August 1998 International FEL Conference slated to be held in Williamsburg. We are working to get the job done.
Leemann also heard about significant FEL needs, foremost of which is the need to be able to schedule operators into the shift plans. Bohn advised that to date there is only an informal agreement with the Operations Department, and that agreement is to commission ASAP from the MCC Control Room and "pull over" a CEBAF operator on each shift providing there is no overriding problem on CEBAF itself. Bohn feels the agreement is problematic in that it does not permit him to schedule CEBAF operators, but rather he must always schedule two scientists/engineers from the sparse "FEL Commissioning Team". Thus, in principle, these people will quickly burn out. Moreover, almost all of them lack operator-level experience in that they do not run machines every day. Plus, it is generally not an efficient use of their time because they are occupied with other responsibilities, such as resolving technical difficulties on the FEL as they arise. The issue is difficult to put to rest because the Lab has a paucity of operators, and the FEL cannot afford to hire its own. Per today's meeting, discussions about this matter will continue until it is resolved. Bohn remains optimistic that it will be resolved in the near term, though he also acknowledges discomfort with the lingering problem. He asks the FEL Commissioning Team to bear with him and the Division. Successful lasing will be sweet.
B. Legg and T. Siggins missed this meeting because they were busily preparing the gun for baking. We are still on track for turning on at swing shift Sunday, 15 Mar 98. The scheduling board in the FEL Facility Break Room has been updated to reflect tasks and manpower for the period 13-27 Mar 98, during which irradiation of the three GEN targets should be completed. C. Bohn outlined the strategy for setting up the machine and for the manpower plan, and he invited affected people to communicate with him and/or R. Walker if they have difficulties. As discussed under "New Issues" below, a question came up concerning what bunch charge to use for irradiating the targets.
Bohn renewed discussion about configuration control. He presented a chart that A. Hutton composed for him. It reflects the general methodology used for CEBAF, and it is represented below:
SNAP GOLDEN** ACTUAL**
(theory) (BURT file # xxx) (real-time)
**CMPQ code (get from Ops Dept) -- Run each shift to compare ACTUAL to
GOLDEN; FEL CC or FEL EC can rename ACTUAL as GOLDEN via BURT label.
New Issues
The question arose as to what bunch charge will be used to do the GEN target irradiation. The desired average current for an 8-hour run is 2 ľA. If we run at 18.7125 MHz, the associated charge per bunch would be 0.1 pC. If, on the other hand, we ran at 60 pC, the repetition rate would be 33 kHz. After some discussion, it was generally felt that we should operate at high rep rate with low bunch charge because to do so would provide an optimal raster pattern across the target. The plan is to use the 60 pC settings that B. Yunn has generated with PARMELA, but then run with "zero" bunch charge. Consequently, we will need viewer images for "zero" bunch charge to aid in setting up the beam (see "New Action Items"). D. Douglas likewise will update his spreadsheet code to propagate the "zero" bunch charge (to be obtained from Yunn) through the linac to the straight-ahead dump assuming the 60 pC PARMELA settings are in place.
New Action Items
Old Action Items
Procedures in Work
Emittance Growth from CSR