[BLAST_SHIFTS] A-Shift

From: Peter Karpius (karpiusp@einstein.unh.edu)
Date: Wed May 28 2003 - 08:02:47 EDT


Shift started with the continuing ion polarimeter work.

Plan was to run unpol D2 at 0.07 sccm, with the compton, flipping beam
helicity every fill. The 0.07 sccm flow rate gave a ligit reading of
about 3E-7 Torr.

This began at 0130 and run 585 was taken with no issue except that the HV
had to be started manually even though we were in auto ring fill mode -
this only occurred once all shift.

Current cutoff for the auto ring fill was 62mA. With an est dead time of
4 min, a lifetime of 20 min, we calculated a DAQ (live) time of 13 min and
a cutoff current of about 50mA. We asked CCR to change the chime to
reflect this.

Part way through run 586 the CODA ER rate dropped to epics level while the
physics trigger was at 30Hz. We had also lost the inhibit. Restarting
coda from the setup level seemed to cure this, but the problem returned
and running setup did not fix it again. We saw the message:

"error writing events, cancel ET read loop"

We tried deleting some junk runs (marked as junk in the logbook) but this
did not cure the problem. (the junk runs were mainly empty but we thought
that maybe the number of files became unmanageable) We decided to call
Karen at this point.

Indeed /scratch/dblast07 was full and we needed to delete some runs of
significant size. Because we took data the other night with terrible WC
sig:noise and the ABS valve was shut we had a few garbage runs which we
could delete. We deleted runs 551-556. This provided enough room to take
some new data.

WC signal:noise looked relatively good for run 585 (on the order of 4:1
for the worst case) Degredation of this ratio was negligible over the
shift.

WC HV did not trip until late in the shift and then only intermittently.

At 0645 we noticed the current dropped to 38mA but there was no autofill,
we called CCR and they reactivated the auto fill but there was no
explanation as to why this happened. This happened again and this time
when we called CCR we did nothing at first and watched the current drop.
Then we set the HV to STBY and immediately the injection sequence began.
This was not a show stopping problem so we did not call anybody but it
should be corrected.

In the end we had good unpol D2 runs: 585, 586, 595, and 596.
Started crunching ntuples for 585, 586, 595.

                                        Pete & Adrian

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Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1220
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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