Hi Doug-
Here is the TOF update for the Tues meeting.
1) Adrian and I looked at the suspected broken TOF RT3. We physically
inspected it with a ladder and indeed it is broken. However, the scaler
cosmic rates were comparable (and even superior to) the adjacent foward
angle TOFs. Looking at the RT3 and RB3 in tandem on the scope while
alternating the triggering channel we found a peak signal of 750-800mV for
both channels. We repeated this procedure on the adjacent TOFs and found
similar results. Therefore, because of the difficulty in extracting the
TOF group with the crane etc, and the fact that we are indeed seeing a
good signal from RT3. It may be in our best interest to not repair the
joint and run as is.
2) We next examined the RT6 flasher signal while triggering the scope on
the photodiode. Initially seeing a 50-70mV signal for RT6 while the
adjacent TOFs see ~100mV+ led us to follow Michael's suggestion to swap
RT5 (which had a signal ~150mV) and RT6. We did this and then had to
adjust the shimming at the splitter box a bit, but the result was a
flasher signal for RT6 (and RT5) that was ~100mV.
3) We also looked at LT15. The signal in the D-tunnel had a normal peak
but often noisy abnormal behaviour, that we eventually isolated to be at
the PMT. The next step is to replace the base and or PMT (we plan on doing
this Wed after the meeting)
4) As mentioned in previous emails, the LT9 problem was found by Michael
and I to be at the CFD. We will work to resolve this asap.
Pete & Adrian
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Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)978-6152
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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