Next Meeting
Agenda for Next Meeting
This Week's Attendees
J. Bennett, G. Biallas, C. Bohn, J. Boyce, I. Campisi, D. Douglas, F. Dylla, K. Jordan, A. Grippo, J. Gubeli, L. Merminga, M. Shinn, T. Siggins, B. Yunn
Closed Action Items
New Action Items
Old Action Items
Items of Discussion
C. Bohn briefly summarized the status of the machine. The gun is up and running; its voltage is being kept at a conservative 320 kV to mitigate dark current, to take stress off of its performance/availability, and to enable immediate use of the machine settings from the last run. The reserve is there (up to ~340-350 kV) should we ever wish to push up its voltage, e.g., in an effort to improve beam quality. G. Biallas is in process of setting up the injector with pulsed beam. Plans are to run Day Shift today to complete the injector setup and run some cw beam. The machine would then be ready for next week's program. At present, the one persistent difficulty is frequent trips of the waveguide IR interlocks to the cryomodule cavities. L. Merminga is working with J. Preble to rectify the matter. During the down, screens were installed in each waveguide to block rf radiation thought to be causing the trips, but preliminary indications are that they are not helpful.
Bohn then went over the plans for the next two weeks. Because the new sapphire (3 micron) mirrors are not yet ready, plans are to install them Tuesday of next week. On Monday, plans are to push the average current (without lasing) to ~5 mA, and after the mirrors are in place, we will try again for kW lasing. CSR studies begin next week and continue through the first three weeks of Owl Shifts. BBU studies will begin on or about 19 Jul 99 and will occupy two weeks of Day Shifts. L. Merminga still needs to write the test plans, and she will turn to that after the aforementioned rf trips are rectified. Lasing studies (laser diagnostics and high-priority user tests) will also begin 19 Jul and occupy two weeks of Swing Shifts. As presently envisioned, the fourth (and last) week of the run will be dedicated exclusively to injector studies. Of course, depending on how things progress, there could be adjustments to the program later, but ideally things will proceed in the manner described.
K. Jordan summarized hardware changes made during the down. In addition to installing a new cathode ball and wafer in the gun (after which resurrection of the gun proceeded smoothly), we installed red filters on the CCD cameras used for quad/viewer emittance measurements (they should cut down the background from ghost pulses and provide more accurate data), and we installed three more synchrotron light monitors, one in the first optical chicane, and one in each recirculation arc, to be used to monitor stability of the electron beam. Otherwise, much work was done in further configuring User Labs 1, 3, and 4. An interesting addition is a remote-controlled "turnstile" that will be used to insert new samples rapidly into the laser beamline.
A. Grippo summarized software changes made during the down. The only one of direct interest to an operator is the addition of an FEL RF Alarm Page.
F. Dylla closed the meeting with a brief overview of the latest marketing strategy for the FEL Upgrade. He encouraged people to be thinking about ways to cut the current cost projections. Immediately following today's Commissioning Meeting, D. Douglas presented his latest thinking on the beam transport for the Upgrade, the basic idea of which is to use new Bates bends for recirculation, thereby cutting both cost and risk by building on what we know from the present machine. His biggest uncertainty is in achieving a full 10% acceptance; third-order effects enter into consideration, and existing codes are inaccurate beyond second order.
New Items
None.