Gain modification for 6W04 and about 3C04,3T12


Subject: Gain modification for 6W04 and about 3C04,3T12
Roberto.Giuliani@lngs.infn.it
Date: Wed Apr 19 2000 - 13:21:53 EDT


  Hi All,

Today during wed maintenance we looked for 3 Tank (3c04-0,6W04-1,3T12):
So we stopped Run 19425 (PHRASE ONLY on SMs 3,4,5,6) in order to exclude
  those counters fro acquisition.

3C04-0 It seamed to be a light leek, actually we applied a piece of tape to
         prevent light leak obtaining a better PMT signal.

6W04-1 The gain for this box was at ~4.5 mV, we had to swap LE-CROY
         HV channel (we supposed an HV problem), but the gain remained
         the same, so we decided to put 6W04-1 back to its HV channel and
         then put the gain at 4 mV.
         So we have changed the voltage value for this box.
         OLD VALUE=-1410 V , NEW VALUE=-1390 V.

3T12-0 This Box have a L/R asimmetry.
         Side zero is less efficient than side one, the gain for the side zero
         PMT is at @3.5 mV.
         The bottom line for this box is that PHRASE present a L/R ratio=5
         (PRASE 'point of view') and for the other side (size one).
         Today we checked for PHRASE connections and all the connections
         seams OK. The problem seam to be a PHRASE module problem.

Today we checked also for 1BD7-7 the classic LE-CROY channel that appares on
every EMILYs mail.
We noticed that this channel have a fluctuation of about 50 V and it is not
possible to turn it off.

Ciao, Roberto.
         
   



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