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User name V. Sulkosky
Log entry time 23:17:18 on August 21, 2008
Entry number 242400
keyword=Pion Rejector HV Turned On and Adjusted
Today we turned on the Pion Rejector HV's. We reset the values from the
June 9, 2008 Halog entry 241762.
When we checked the ADC spectra, we found PRL1 Channel 22 was empty and
that PRL2 channels 31-34 only had pedestals. The cable for PRL1 # 22 is
labeled PIRR 5. The cables for PRL2 # 31-34 are labeled PIRR 31-34.
We found that all five channels have a signal coming from the PMT, but it
seems the signals were weak and mostly attenuated away after going
through the delay cables. This was especially true for channel 22. We
switched delay cables at the patch panel, but found that the signal was
still weak. Hence I think the delay cable is fine.
I increased the HV as follows:
PR Channel Old HV (V) New HV (V)
=======================================
PIRR 5 -990 -1070
PIRR 31 -860 -890
PIRR 32 -1030 -1050
PIRR 33 -910 -955
PIRR 34 -880 -900
After the HV increase, there are now signals for all Pion Rejector
channels.
Next we will check the pedestals.
A copy of this log entry has been emailed to: gen@jlab.org,ycwang@jlab.org