Next Meeting
Agenda for Next Meeting
Item Person Responsible Time ---- ------------------ -------- Status of Open Action Items All 5 min Status of Commissioning Bohn 15 min Commissioning Schedule Bohn 10 min Overview of BCM Cavity Circuit Jordan 10 min New Issues All 5 min
This Week's Attendees
S. Benson, G. Biallas, C. Bohn, J. Boyce, D. Douglas, F. Dylla, J. Fugitt, A. Grippo, K. Jordan, R. Lauze, L. Merminga, G. Neil, D. Oepts, M. Shinn, R. Walker, B. Yunn
Closed Action Items
Items of Discussion
F. Dylla presented a synopsis of yesterday's closeout of the Lab's Science and Technology Review, with special focus on the Review Committee's favorable impressions of the FEL Project. The quest for additional FY99 funds continues unabated, both for the FEL and NP programs. By rights something ought to break from this quest, for there is ample motivation given the Lab's accomplishments. But we've got to beware because life isn't fair.
The gun was baked this week. This morning it is being configured for high-voltage processing, which should start at about 1400 and last through the weekend. Plans are carefully to ramp up the voltage to 420 kV and let the gun soak for many hours at that voltage. Initial processing will be done by T. Siggins, G. Biallas, and J. Fugitt. After a stable 420 kV is reached, the gun will be passed to CEBAF operators with written instructions for monitoring the "high- voltage soak". Hot system checks will also begin this afternoon once the vault is in Beam Permit.
As presently envisioned, on Monday Day Shift the cathode will undergo heat treatment and cesiation, the drive laser will be aligned, and final hot system checks will be done. Injector setup and checkout will follow over the next three shifts. Straight-ahead cw lasing is slated for Tuesday Swing Shift to check the setup and to calibrate losses in the optical transport system. Subsequent activities will focus on systematically working through the augmented High-Power Setup Procedure that D. Douglas finalized this week. The Procedure can be accessed via www from http://www.cebaf.gov/~douglas/FEL/FELmasterindex.html. Everyone on the FEL commissioning team needs to read it.
As mentioned, beam operations will begin in earnest next week. The two-week commissioning plan is posted on the white board in the FEL Facility Break Room and soon will be available on www via the FLOG page. Please refer to these sources to check staffing plans.
Much of today's discussion centered on hardware and software updates that affect commissioning. C. Bohn has already hand-updated the Engwall map of the whole machine to reflect the latest hardware and asked a student-secretary to make copies for the control rooms. They will be ready and in place Monday. After we have run awhile and the hardware has reached a steady state, Bohn will have Engwall's CAD file updated so we'll have "professional-looking" maps. They seem to be easier to use than the song sheets, but the latest song sheets will also be on hand in the control rooms.
The principal hardware updates consist of: working viewers in the 180-degree dipole magnets; two new viewers in the second recirculation arc; the beam scraper in the first recirculation arc; modifications to various drive-laser subsystems for increased power and better stability of low- power rf; adjustments of the 60 Hz raster magnets in the injector and energy-recovery dump lines (the raster currents will need to be reset prior to going cw); and gun upgrades for increased pumping speed, faster baking, improved heating of the cesiator, and faster exchange of the conditioning and running resistors.
A. Grippo presented a list of software updates:
Grippo also pointed out that J. Song's last day at JLab is 30 Sep 98. He did an enormous amount of FEL software as well as served as DataCube focal point, and he will be sorely missed.
Douglas's augmented High-Power Setup Procedure was discussed at top-level. As written, it centers on use of cryomodule GASK signals to assure energy recovery without lasing, and does not mention the BCM signal used in early August. A technical question arose as to the nature of the BCM signal, specifically whether it is a voltage signal or a power signal. K. Jordan intimated that it was the former, but he will review the circuit and discuss it at next week's meeting.
As an aside: a meeting was held yesterday to discuss plans for a beam-breakup experiment that will benchmark the code TDBBU so we can have more confidence about designs of future FEL upgrades for higher-power light. Plans were made to check the compatibility of available beam- kicker and pickup hardware with the existing beamline configuration. Based on the findings, a more detailed plan of the experiment will be formulated, and eventually the effort will be presented to M7 for formal approval as a task. As envisioned at this early time, the experiment will likely be conducted on Owl Shifts next May, and it cannot interfere with lasing activities.
New Issues
None.
New Action Items
Old Action Items
Procedures in Work
Procedures Needed for Recirculation
Unfinished 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 (fix control screen) Merminga/Krafft/Yunn
C. Cryomodule Cavities Merminga/Krafft/Yunn
III. Reconcile Methods for Setting RF Phase Merminga/Krafft/Yunn
A. Buncher Cavities
2. Minimum bunch length/time of flight
B. Cryounit Cavities
1. Transient phasing
2. Cresting
3. Time of flight
IX. Complete Diagnostics Procedures and Users' Guide 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
XIV. Laser Turn-On Procedure Benson