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User name yez
Log entry time 19:50:51 on February 20, 2011
Entry number 347852
Followups:
keyword=L-HRS: S2m-13R ADC is getting worse, might need to reduce the HVI noticed that the S2m-13R ADC channels has a huge pedestal which is getting wider. When I saw the plot for the first time, it was about 100channels. but now it became a 400 channels wide big peak. I am worried about that this PMT is working under an extramely anormal condition, for example, the HV is too high, or the PMT itself is dying. A loose connection might course the some issue but it can not growing the peak.
I redueced the HV from -1729V to -1679V to see if it is getting better or not. If not, I am going to reduce another 50V. I will check the signal with a scope when the hall is open.
Figure 1
