Generalities about the Cerenkov Detectors:
- There are 4 Cerenkov detectors per Sector
- From forward to backward angles (0-3) each Cerenkov detector contains 6, 8, 12, and 12 PMTS respectively.
- The above pattern is clear when you look at the HV on the PMTs. For example, the HV on the first tube of the most forward LEFT Cerenkov (c0l) is -2006 V.
- Typically, these PMTs have about 3k counts/s of noise, so readings of 20-30kHz per detector with no beam are OK. Much lower readings might indicate very low gains.
- At the initial time of commissioning we found that the four PMT (-1951V) on the Left second Cerenkov (c1l) was very noisy and we needed to turn it off.
- From looking at the HVs it appears that c2l and c3l have low voltages, and perhaps c1r.
- Tavi determined the present voltages so he should verify these comments.
- The MAXIMUM voltage on any given PMT is -2700 V.
Ricardo Alarcon
ralarcon@asu.edu
617-253-9508 (phone)
617-253-9599 (fax)
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