RC report for 7 April Swing through 8 April Day

Log entry time 16:46:23 on April 08, 2004

Entry number 81796

keyword=RC report for 7 April Swing through 8 April Day

Run Coordinator's Report for 7 April Swing to 8 April Swing

Summary

Laser spot moved on crystal, and some injector retuning. Encouraging news is that the PZT/IA feedback parameters did not change significantly despite these rather drastic injector changes, or at least feedback is still operational after these changes. The Hall A IA Pockel's cell has been realigned, and generates injector charge asymmetries large enough such that both Hall C and Hall A charge asymmetries can be nulled. We should now be on cruise control to take LH2 production running through the remainder of the weekend until the maintenance period Monday and Tuesday.

Significant News

IHWP now OUT. Laser spot moved.
Lumi 7 still not working properly. Still not clear what the cause is, but some ideas should be floated around, and next Monday's maintainance day would be a good opportunity to implement them.
DMCH Interface box is the "new" box, and 120 Hz mode still does not work for French electronics. A new procedure for 120 Hz running will be to set acquisition mode to TS_Scaler rather than TS2_full.
Analysis and worker shift personnel seeing many crashes in cdaql1. Paul has requested that these positions generate a shiftly log of how oftern and when these crashes occur. These do not have to be log entries the moment the crash occurs, but at the end of your shift, make one log entry which summarizes the crashes.
Source of "freezing" of cdaql3 traced to routing of G0 cage machines through a Hall A router, which was disconnected for tests. Computing center has been informed and will address the issue during the maintenance next week.
A Damon analysis for all of the data since the change to 4 pass running shows that the BCM monitors in the hall are showing charge asymmetries that are not zero at about the 3 sigma level. We should resurrect the Injector DAQ and measure the charge asymmetries there during the same time as we are running in the hall to see if the same effect is present in the injector, or these are caused by some differential scraping down stream of the injector entrance to the accelerator. (Volunteers?)
We will be down for all day Monday, and through Day shift on Tuesday. This means that worker and leader shifts will not need to be manned from 8:00 Monday through 16:00 Tuesday. We will need one target expert on Monday morning to boil away the target and put it in a safe state at 30 K. When to fill the target again (either Tuesday Swing or Wednesday morning) will be determined by the promise of beam and when we can expect it back in the hall. This decision will be made Tuesday afternoon. We will also need a SMS expert on Monday morning to ramp down the magnet and put it in a safe state for the shutdown.

Plans

Continue with LH2 production running through Saturday morning.

Run Moller/IHWP insertion/Moller sometime Saturday morning (Damon will set the time, and come in to make the measurements).

After Moller measurements, BUT BEFORE PUTTING THE LH2 TARGET BACK IN, we want to run some short test runs to investigate various things.

1) A 1 hour run with detectors and SMS on, but LH2 target out (effectively a "green block" run, with the YO signal in the data stream, checking for helicity correlated YO effects).

- if no signals are present in the detectors, we may have to go to the HIGH GAIN HV settings to mimic the "green block" runs.

2) The Halo monitors are showing some strange behavior, in that they measure a relatively large asymmetry (~50 ppm) in one helicity state but not the other. We would like to address the impact of this on what the FPD's are seeing. Mark and Sarah have outlined a program to investigate this, and some of this can be performed with the LH2 target out immediately after the "green block with YO" run described above.

Continue with LH2 production running until Monday at 7:00 when the maintenance period begins.

We are now on our official 3 day cycle for Moller measurements/IHWP state changes.

Concerns

Spikes in French electronics
Non-statistical widths in detectors 13 and 14 of octants 4 and 8.
Non-understood influence of Interface Box to DMCH's. Spare does not work in 120 Hz mode.
NA LTD errors still occurring at a smaller rate. Brian has generated a "HowTo" document (located on the G0 web page under http://g0web.jlab.org/manual/Electronics_manuals.html) for trouble shooting.
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.
Lumi 7 issues.
cdaql1 also crashing at a pretty regular rate.