From: Hironori Ito (hito@rcf.rhic.bnl.gov)
Date: Tue Jan 14 2003 - 18:19:55 EST
Hello. Today (1/14), Bob and I tried to fix H2 HV problem during a short controled access. Making a short story short, we fixed 2 channels, H2T05 and H2T07 are fixed. But at same time, we managed to completely kill H2T01 and H2T03 HV. Anyway, we have a opening tomorrow and will fix them. For more detail, read a BRAHMS E-log. If you still do not know where is our On-Line log book, it is located at http://pii3.brahms.bnl.gov/cgi-bin/elog.pl you can view a previous shift by clicking by Prev icon. Hiro Ian Bearden wrote: > Hi Jens Ivar, others... > This on--again, off--again problem with H2 smells like a bad connection > somewhere. > If it affects all channels, you should probably check the start signal to > the H2 TDCs. There is one START which is daisy chained, so it might be > worthwhile to check the box where the signal originates as well as the cable > itself. It would not be the first time a bad LIMO gave problems. > Also, the drifting HV needs to be checked ASAP, as the PMTs *CANNOT* take > more than > -1800V. > Hope this helps > Ian > -------------------------------------------------------------------- > | I.G. Bearden | > | Niels Bohr Institute Tb 3 email: bearden@nbi.dk | > | Blegdamsvej 17 phone: (+45) 35 32 53 23 | > | København Ø FAX: (+45) 31 42 10 16 | > | Danmark Www: http://www.nbi.dk/~bearden | > -------------------------------------------------------------------- > > -----Original Message----- > From: owner-brahms-l@bnl.gov [mailto:owner-brahms-l@bnl.gov]On Behalf Of > Apache > Sent: 13. januar 2003 14:49 > To: brahms-l@bnl.gov; olchansk@bnl.gov; videbaek@bnl.gov > Subject: Shift report 20030113 00:00-08:00 > > > > ------------------------------------------------------------ > Date: Mon Jan 13 08:48:50 2003, Shift: 00:00-08:00 > Supervisor: JIJ, with: > Log book#13 pages 56 - 57 > > Shift Summary: > ------------------------------------------------------------ > 1. > The machine had low luminosity for deutrons. Most of the time while beam the > blue luminosity was below 18e11. At times the background was low, down below > 20k/s in the H1 and H2 scalers. There were, however, sudden changes in the > background when MCR was steering, sending the H1 and H2 scalers up to 150 > and 200k/s. In summary, overall better background level but not stable. > > 2. > Run 7350 - 117k trigger 6 > Run 7351 - 39k trigger 6 (aborted by IOserver error, incomplete in > database) > Run 7352 - 0.1k trigger 6 > > At this point we are at 167k trigger 6 with FS @ 1/4 A-pol and MRS @ 3kG > A-pol. > > Run 7353 - pedestal run > Run 7354 - TPC pedestal run > Run 7355 - DVM run > > 3. > During a significant increase in background the DAQ reported IO Server > error. Also cathode 3 on T5 tripped, but came up again without a problem. > > Top channels 1, 3, 5 and 7 on H2 have been geetting higher and higher actual > voltage the past shifts, while the demand voltage has been kept constant > at -1600V. Passing -1800V I turned demand voltage down to -1400V, which put > actual voltage around -1600V. > > Also, the H2 problem reported during the Saturday night shift has returned > for unknown reason. This is a problem that shows up in the time average > distribution. > > ------------------------------------------------------------ > > >
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