Log entry time 01:02:09 on March 05, 2004

Entry number 78698

RC Summary

Wednesday, 2 Mar. 2004 day through Thursday, 4 Mar. day

• Data taking on LH2 target with 40 ľA and with 6 mm hole target.
• IHWP is IN Next change on Saturday 6 March.
• LH2 target parity quality
  • 20 hours for this 32 hr period (runs 20438-20477)
  • Overall efficiency: 45.3% (14.5/32) (so-so)
  • Beam (no trip) efficiency: 80.6% (15.8/19.6)
  • Parity efficiency: 91.8% (14.5/15.8)
  • Total parity hours: 210.5 (runs 19815-20477)
  • Overall IN/OUT charge ratio: 1.14

Achievements and events

• Production running at 40 ľA and running with 6 mm halo target.
• Change the ABU hold-off doctrine. We used to hold off 70 seconds from 5ľA, now holding off 20 seconds from 10 ľA.
• Switch to running with automatic coil modulation on Thursday day shift. After a scary start it seems to be working.
• 120 Hz runs taken during
  • Wednesday day shift: run #20445 analyzed
  • Thursday owl shift: run #20462 (mislabels as production data) analyzed
• Coil modulation runs taken during
  • Wednesday swing shift: run #20452
  • Thursday owl shift: run #20457 run #20463
  These may be the last, as we have switched to automatic coil modulation.
• Energy modulation runs taken during
  • Wednesday swing shift: run #20452
• G0Integrity results recorded during the
  • Wednesday day shift
  • Wednesday swing shift
  • Thursday owl shift
  • Thursday day shift
• Convergence of beam parameter asymmetries checked
  • Wednesday day shift
  • Wednesday swing shift
  • Thursday owl shift
  • Thursday day shift
• We received important information about nutritional safety on shift.

Plans

• The bulk of the time remaining before the maintenance period should be devoted to LH2 production running.
• We will stop at roughly 9:00 AM every day for 1/2 hour to perform Chow's fOps test plan until further notice.
• The next polarization sequence (Moller measurement, followed by IHWP reversal (to OUT), followed by another Moller measurement, and then a RIP scan) will take place, on Saturday March 6th.
• We would like to do one energy modulation run per day. Permission has been obtained from the Hall B Run Coordinator, but the shift leader should inform the Hall B shift crew before beginning the modulation. (We don't think that they will be able to see anything.)
• We may do some test to characterize the BPM misbehaviors we're been chasing. A tentative plan for a study is available, but nothing is scheduled pending more input from experts and other interested parties. A pretest, to see if we can profitably analyze the results of the proposed test, may be done first, and can probably be undertaken without a pre-pre-test.

Concerns and Their Resolution

• Spikes in the French timing spectra appear from time to time. Louis is here and will be investigating (Log Book Link).

  After a hiatus, the spikes are back with a vengeance. Five runs in a row(!) right after turning on the automatic coil modulation on Thursday. They didn't go away when we turned the auto modulation off, and did not resume when we turned it back on, so the timing may have been a coincidence...

  So Louis has more data to look at, and has provided a scheme (see logbook entry #78667) for trying to learn more from the next run that shows them.

• More North American electronics errors have occurred (Log Book Link). One of the offending LTDs was replaced. It had a lose connector, possibly due to the currently practiced method of eliminating errors (cable wiggling). The error rate seems to be somewhat improved now.
  
• The issue of variation of BPM response with current has been investigated by looking at the replay and the EPICS archive (Log Book Link). Indeed, for the Y coordinate of the girder BPMs there appears to be a problem when using the 20 uA pulsed beam. We need to find a way to run the harps at higher current to find the proper BPM readings when we are doing real data collection. It is also possible that the BPMs behave differently with and without the raster. A test of this idea will await a convenient point in the schedule. Steve Williamson has been contacted by Richard Dixon, who had some useful information. Testes may be forthcoming.
• A couple of runs (20246 and 20291) showed a large reduction in rates on both French and North American detectors. Paul traced this problem to a brief shift in the Musson box timing shift by about 0.5 ns. It is not clear what caused the change in timing. There has been a slow trend toward lower elastic proton rates also seen on both detector packages, perhaps this can be explained by Musson box shifts at a low level. The data that we have acquired so far should be checked to determine how often Musson box shifts happen. We also need a way to determine in real time that there has been a shift (Realtime monitor plot? EPICS alarm on the control voltage? StripTool plot of the control voltage?)<
• We should spend some time during the 4-day maintenance period to try to find a way to turn the magnet power supply off at full power without causing a fast dump and without compromising our quench protection.
• IOCSE20 seems to be needing more trips. A older, slower (but hopefully more robust) replacement is available. Time to install ~2 hours. No guarantee of that it will help. We probably want to have it put in during the maintenance period, but don't want to use beam time unless the problem becomes worse.

Accumulated Data for the RC's Weekly report

ABU:

	Owl	Day	Swing	Daily Total
Tuesday	5.15	3.47	6.13	14.75
Wednesday	5.99	3.78	5.67	10.44
Thursday	6.48	3.70
Friday
Saturday
Sunday
Monday

Total: 35.37

Non-trivial BANUs: (with causes)

	Owl	Day	Swing	Daily Total
Tuesday
Wednesday
Thursday		0.17[1]
Friday
Saturday
Sunday
Monday

Total: 0.17 BANU notes:

1. Related to spikes in the French detectors. Probably under-reported.

Raw data: List of shift summaries

• Wednesday day shift: Summary and ABU report
• Wednesday swing shift: Summary and ABU report
• Thursday owl shift: Summary and ABU report
• Thursday day shift: Summary and ABU report