Log entry time 22:13:18 on March 30, 2004

Entry number 80920

Run Coordinator's Report for 29 March Swing to 30 March Day

Summary

Had kind of a rough 24 hours. Lost several hours on swing to a quad retune in Hall C (more on that in a minute). Took a lot of data on owl shift and suffered through the normal beam studies and recovery period on day shift.

Significant News

• There will be an extended hall access tomorrow in support of the Hall C AC unit repair. Let me know if there is work you need to do, or have done, in the hall or electronics cage.
• On Swing shift, after coming back from beam studies, we discovered that we could not keep the feedback devices, specifically the PZT voltages from going to the rail the first time a correction was applied. The initial IA/PZT calibration revealed small slopes with big errors (80789). Kaz' solution was to adjust quad settings in Hall C to reduce the noise in the position measurement so we would have a better determination over the 30 minute period between feedback updates (80802). The slopes also changed slightly (80803). We spent about 2.5 hours performing this quad adjustment and afterwards the beam feedback ran very well (no railing).
• In accordance with our ABU policy, the time spent performing the quad scan was billed as BNA (beam not acceptable). This caused some angst and woe in the MCC and the 8:00 AM meeting since we actually were taking 40 ľA and were not having the MCC really doing anything to correct the problem. The primary complaint that I heard was that the MCC did not feel they had been informed properly that the beam was not acceptable until after the fact. After discussions with our shift crew, I do not think this was actually the case. In the future, if we are forced to embark on another one of these quad tuning adventures, we should make it a point to tell the MCC explicitly upfront that we are billing the time as BNA.
• Coming back up from beam studies today we ran into some trouble with the measured halo rates (80871). Rates have been very flat and stable for days until they suddenly began oscillating and running high at 13:00 this afternoon. Eventually, the rates wound up in some kind of oscillatory mode with a period of about 30 minutes (80892, 80896). Things had calmed down somewhat by end day/start of swing but the rates are still higher than previously. MCC has no idea what is causing it.
• Brian Quinn has been working on the NA electronics trying to reduce the LTD error rate (80870). He has bravely sacrificed his olfactory cells to G0 by resoldering many connectors on LTD and SDB boards. There should be more of the same tomorrow during beam studies.
• Thanks to new CRL code from Orsay we were able to swap the order of DMCHs 1-4 today (80869, 80866). To early to tell yet if this has improved the various situations with the French electronics. The spare interface box arrived today; we will try swapping that in tomorrow.
• There is now a better understanding of the discrepancy between the MPS BCM and the BCMs that G0 cares about. First, it appears that the calibration of the MPS BCM changed in the middle of owl shift on the 23rd (80874). Second, it appears that the gains and pedestals of the BCMs have moved around a little more actively than normal this past week (80905). This might have been exacerbated by the AC problems in Hall C. We will perform another calibration after the AC situation has been resolved.

Plans

1. Asymmetry runs on LH₂ with 40 ľA of longitudinally polarized electrons.
2. The Hall C AC unit repair will occur during the extended beam studies time tomorrow. We will take the hall to controlled access for anyone who wants to get in and do some work.
3. Daily beam studies:
   • Wednesday: 09:00 to 14:00
   • Thursday to Friday: 09:00 to 11:00
4. Moller, IHWP change, and RIP calibrations on Wednesday and Friday.
5. BCM calibration on Thursday (after Hall C AC repairs complete).
6. Short Wells plot deadtime study (2.5 hours) - Half hour asymmetry runs at IA settings of 1, 3, 5, 7, and 9 - Friday (?)
7. Fastbus phototube gain calibration (6 hrs) - early next week (?)

Concerns

• AC in hall
• Non-statistical widths in detectors 13 and 14 of octants 4 and 8
• Elevated Silviu ratio in detectors 1 and 2 of octants 2 and 6
• Spikes in French electronics
• Apparent increasing frequency of NA LTD errors
• Crosstalk with target IOC and target FSD box when the Musson box is rebooted remotely
• Changed behavior of BPM 3H00C Y position with respect to other hall BPMs
• Discrepancy in beam current measured by BCM1/2 and the MPS BCM

Shift Summaries and BTA Reports

• Monday Swing: Summary and BTA
• Tuesday Owl: Summary and BTA
• Tuesday Day: Summary and BTA