[BLAST_SHIFTS] 10/08/2002 day shift

From: Adrian T Sindile (asindile@cisunix.unh.edu)
Date: Fri Nov 08 2002 - 17:03:22 EST


Last night people reported problems with first 8 left TOF signals.
We have been taking cosmics data all day and no problem was found with
those TOFs (except that LTOF 9 seems to give a little less events than its
neighbors). However, we could see a lot of problems with the right sector
TOF signals.

Taking runs 2665, 2666, 2667 with cosmicTOF_CC.settings we saw lots of TDC
and ADC spectra missing (for the same detectors).
RTOF4 was traced to an unplugged cable - that is not plugged all the way
at the PMT after the mu-metal job, we think... we fixed it.

Next, we changed the trigger to cosmicTOF.settings (putting Cerenkovs in
X-mode): RTOF0,1 and 2, missing before completely were back now! The
number of events was also improved for other detectors (run 2668).

We were still missing completely RTOF14 and 15, and were still having low
number of counts in others...

We went to the D-tunnel and started troubleshooting; we went through all
the trigger, nothing was wrong, we could trace all the signals and all
were making sense from the BNC cables to the TDC inputs...

The only significant thing we did after two hours of plugging and
unplugging cables was to disconnect the twisted pair cable that seemed to
come from the back of the NC retiming unit into the input of the trigger
supervisor (the orange wire). It was not being used anyway, but nothing
else was looking weird...

We took run 2670 and all spectra were back now!!!

Conclusions:
- plugging and unplugging cables changes things completely (unless that
unused wire created somehow all the trouble, which is unlikely);
- the Cerenkovs seemed to have been denying lots of events again - see the
difference between runs 2667 and 2668;
- the TOFs should be now ready to take data - if there is something wrong,
it is probably because of the trigger settings (beam etc.)

Jason and Adrian

-------------------------------
Adrian Sindile
Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1691
FAX: (603)862-2998
email: asindile@alberti.unh.edu
http://einstein.unh.edu/~adrian/



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