shift summary 7.18.2 A Shift

From: jason seely (seely@MIT.EDU)
Date: Thu Jul 18 2002 - 08:27:10 EDT


GOALS: track down remaining TOF problems, Get Left Cerenkovs working

7.17.2 4-12 shift had a problem with right TOF #6, but this paddle appears
to be working fine as of run 712 on. (???) LTOF #10 looks reasonable,
but LTOF 12 and RTOF 11 are still causing problems.

Spent the night working on the cerenkovs. It looks like now we are seeing
more than just pedestals on the left sector cerenkov adcs. First
we adjusted
the hv on the left boxes. the voltages on boxes 0 and 1 were increased by
10%, and the voltages on boxes 2 and 3 were increased by 20%. Tavi
switched the output from box 3 to cable #7 from cable #4 (the limo that
goes from the crate to the fastbus crate). So this cerenkov box is now
read out at crate 31, slot 7, pin #54. none of the other cerenkov
readouts were altered. the file 'electronics.map' reflects this update.
with all these changes, it appears that there may be some signal above the
pedestals for leftCC 0 and 1. leftCC 3 looks like just pedestals.

Also, as of run 713, all cerenkov thresholds were changed to 30 mV.

We took data most of the night (runs 710-713) but it was slow going
because the hv would
download fresh each time we typed 'run' from 'standby' (is this a
problem or a 'feature'?) This would take about 1 1/2 minutes, so we
missed most of the beam (if the fill was at 60 mA, the hv wouldn't come
back on until the beam had decayed to about 45 mA), so rates were quite
low.

jason and tavi

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jason seely
26.650b
massachusetts institute of technology
77 massachusetts avenue
cambridge, ma 02139-4307

email: seely@mit.edu
phone: 617.253.4772/6734
 html: web.mit.edu/seely/www
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