Log entry time 01:25:30 on February 28, 2004

Entry number 78052

• Data taking on LH2 target with 40 uA with 6 mm hole target and beam positioning study.
  
• IHWP is now IN (changed on Wednesday 02/25, next change on Sunday 02/29).
• LH2 target parity quality
• 5.5 hours for this 2-day period (runs 20160-20287)
• Overall efficiency: 22.9% (5.5/24) (dismal)
  
• Beam (no trip) efficiency: 80% (6.3/7.9)
  
• Parity efficiency: 88% (5.5/6.3)
• Total parity hours: 143.3 (runs 19815-20287)
• Overall IN/OUT charge ratio: 0.918
  

• Production running during the swing and owl shifts at 40 uA and running with 6 mm halo target.
• 120 Hz data taken during Swing Shift and Owl Shift.
  
• Coil modulation data taken during the Swing Shift and Owl Shift.
  
• G0Integrity results recorded during the Owl Shift and Day Shift.
  
• The accelerator was down for the entire Day Shift due to vacuum maintenance and numerous other parasitic repairs (Accelerator Log Entry).  During that time:
• IOCSE20 was re-mounted in a different orientation (Accelerator Log Entry).
• The dummy Pockels cell was turned on (it was installed during yesterday's down time) (Log Book Link).
  
• French electronics optimization was checked (no changes made) due to the lower electronics cage temperatures that we now enjoy (Log Book Entry).
• The French electronics DNL was checked again (Log Book Link).
• The SMS experienced a fast dump at about 5:00 AM.  The cause of the fast dump was probably PLC radiation damage.  There were no recovery problems (Log Book Entry).
  

• The rather large "Other" region on February 17, was mostly associated with 5.5 hr of high voltage calibration.
• The large "Other" band on February 18, includes time spent on harp scans (one hour) and BCM/BPM calibrations (3 hours).
• The "Other" on February 24 was associated with  a long study of beam positioning. By agreement with the PD, we split the time for this study with the accelerator (1/2 of the time was counted as Beam Not Available, 1/2 of the time was counted as Available Beam in Use).
  
• On February 25, the BCM/BPM calibrations were re-measured and the Lumi response to the "frame" target was measured as a function of current.

120 Hz running has not appeared in this plot since 02/24 due to a problem with the reporting of that data by Julie's abu program.

The last 24 hour period has been characterized by very low overall efficiency (only 22.9%) due to the long periods of accelerator maintenance and the associated long recovery times.  We lost a block of a few hours (most of the BANU on 02/27) due to the magnet dump.  Short periods of beam tuning for Hall B have also had an impact.

• A test of coil modulation with the halo target in will take place in preparation for "auto-coil-modulation" at the beginning of each run.  Should that test be successful (i.e. show that the modulation pattern is not accompanied by halo signal at the extremes), we will turn on auto-coil-modulation.
• The Swing shift of Friday and the rest of the weekend will 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.
• Due to the huge amount of down time that we have experienced, we have skipped the Moller measurements and associated IHWP switch that would normally have been done on Friday.  The next polarization procedure (Moller measurement, followed by IHWP reversal (to OUT), followed by another Moller measurement, and then a RIP scan) will take place, as normally scheduled, on Sunday 02/29.
• We would like to do energy modulation (in addition to coil modulation).  Permission from Hall B must be obtained.  If they are agreeable, we will start this on Saturday 02/28.
  

• There has been a slow trend toward lower elastic proton rates also seen on both detector packages.  No good explanation yet.

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

•  More North American electronics errors have occurred (Log Book Link and Log Book Link).  Disconnecting and re-connecting the "Sync" output of the KGB (at the back of the KGB) seems sometimes to be effective in stopping persistent errors.  The continued wiggling of the cables is eventually going to break the connectors on the LTDs (some already seem lose to me).
  

• The issue of variation of BPM response with current is being investigated by looking at the replay and the EPICS archive.  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.

• One run (20246) showed a large reduction in rates on both French and North American detectors.  Paul traced this 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.  A similar reduction in rates occurred for run 20291 (this should be checked for timing instability).
  

• A quick look at the effects of the 70-sec trip delay on asymmetries indicates that we may be able to shorten this delay.  More checking needs to be done. This would be good for us (more data) and good for our relations with MCC.

• 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.

Wednesday 02/26 Swing and ABUs
Thursday 02/27 Owl and  ABUs
Thursday 02/27 Day and ABUs