From: Ian Bearden (bearden@nbi.dk)
Date: Mon Jan 13 2003 - 09:02:58 EST
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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