Log entry time 20:42:07 on February 22, 2004

Entry number 77446

• Data taking on LH2 target with 40 uA with 6 mm hole target
  
• IHWP is now Out (since this Saturday morning)
• LH2 target parity quality
• 14.4 hours for this period (runs 20082-20114)
• Overall efficiency: 60% (14.4/24)
  
• Beam (no trip) efficiency: 85% (15.9/18.8)
  
• Parity efficiency: 90% (14.4/15.9)
• Total parity hours: 93.8 (runs 19815-20103)
• Overall IN/OUT charge ratio: 1.29
  

• High quality data collection (see above) with beam at 40 uA and running with 6 mm halo target
• 120 Hz data taken during Swing Shift and Day Shift.
• G0Integrity results recorded by the workers during Swing Shift, Owl Shift, and  Day Shift.
  
• Integrated helicity correlated differences were checked during the Owl Shift.
  

• We lose significant beam time due to trips.
• We are not yet at the 45% overall efficiency that will give us the statistics that we want to achieve.  That would imply a green "parity quality" bar that reaches to 10.8 hours on average.
• We may want to reduce the time we spend on studies of systematics (coil pulsing, Moller measurements, BPM/BCM calibrations, etc.)
• The beam available but not in use (BANU) bars (red) are really quite small which is a tribute to our shift crews.

• We expect to perform essentially 100% production LH2 running for the remainder of Sunday and owl shift of Monday. It is possible that, during the day shift, following the meeting on beam positioning (still not confirmed), we will want to do some tests of beam steering and/or harp scans.
  
• We have been efficient about collecting data during the last few days.  As a result the IN/OUT charge ratio has dropped to 1.3.  I think we should continue to take "OUT" data for another day at least -- possibly changing the IHWP on Tuesday, 2/24 (and as usual we will have to perform a Moller measurement and RIP scan at that time too).
• The next BCM calibration will take place next Wednesday.  At the same time, a BCM calibration will be done with the "frame target" (requested by Silviu and Jianglai).
  
• Need target expert around
  
• Need to change administrative limit on beam current
• Al frame target at 20 uA
• We will stop at roughly 9:00 AM  every day for 1/2 hour to perform Chow's fOps test plan until further notice.
• A meeting is planned for Monday afternoon to discuss the current state of the beam positioning and steering and strategies for ensuring that the beam is correctly positioned and oriented at the target.  The invitations have been sent, but as yet no RSVPs
  

• Nothing has been done about the slowly diverging PITA voltages as yet.  Kaz has e-mailed Matt Poelker to find out what can be done to reduce the voltage difference.  At the same time we have noticed that the IA control voltage is slowly decreasing.  Could these trends be correlated?

• Laser phase noise (Log Book Link) continues to come and go.  The result of this is a wide charge asymmetry which is, for the moment narrower than our spec.

• We have also been seeing increased non-statistical widths of the elastic proton asymmetries lately.  The cause of this is not clear.  Presumably this could come from some noise in our electronics (for example oscillations in the gain).  The analyis team is also investigating the possibility that the problem is software related.

• There has been a slow trend toward lower elastic proton rates.  The adjustment of the high voltage may have improved the situation, but some analysis detective work needs to be done to be sure it is gone or to verify that the trend is continuing.
  

• Spikes in the French timing spectra (Log Entry Link and followup) continue to be detected by the G0Integrety checks.  A list of effected runs will be accumulated and forwarded (at their request) to the French experts to help with the investigation of this problem.
  

• Alerts also appear from time to time.  This became a serious problem this morning when the rate of alerts when up dramatically (see for example Log Entry Link).  We contacted Dominique who pointed out that the high rate on detector 16, octant 2, back-left, was probably responsible.  The associated CAEN channel, we discovered, was experiencing an overvoltage error (actual voltage greater than set point) by a couple of hundred volts!  Resetting the channel cleared the problem, but sometime later, the channel turned itself off (overcurrent trip?).  The overvoltage problem is likely due to a known "feature" of the CAEN supplies associated with channel 16 of a CAEN board.  A fix would be to re-cable the high voltage to avoid using the channel  16 outputs, using instead spare channels on another supply.  We should order the cables and consider this for the March maintenance period.  Note that the rate is still too high on detector 16, octant 2, back-left.  Perhaps the high voltage needs to be checked following the recent detector 16 gain adjustment.  The rate is also too high on one of the PMTS for detector 8, Octant 2 (Log Entry Link). 
  

• We have, again, seen a change in the beam position (Log Entry Link).  This appeared to follow a reboot of IOCSE20 which has something to do with the BPM readout.  MCC was unable to steer back to the old positions.    According to the PD the parameter restore problem has been fixed.  But I think this must be revisited.  Our meeting with the experts tomorrow afternoon should help to clarify things (assuming that it takes place).

• The target IOC experienced a couple of crashes (crash 1, crash 2).  There is some sense that these are becoming more frequent. The last crash was differnt in that the control system did not detect it.  Instead, the readouts just stopped and displayed constant values (as though communications had failed).  Target operators need to be aware of this failure mode.

• For the second time, the air conditioning for the electronics cage failed (Log Entry Link).  A chiller apparently stopped.  The new alarm and diagnostics on the target computer warned of the failure.  The alarm limits have since been set lower (Log Entry Link) and a "StripTool" chart of cage temperature has been started to permit an early warning of temperature increases.  Luckily, the chiller was repaired before we had to shut down the electronics.  This must be fixed permanently, or, if that is not possible, we will need to find some kind of back-up system (perhaps a window air conditioner exhausting into the cubicles?)
  

Saturday Swing and ABUs
Sunday Owl and  ABUs
Sunday Day and ABUs