User name R. Michaels
Log entry time 22:24:37 on June24,2004
Entry number 126728
This entry is a followup to: 126708
keyword=prof. scan., part 21165 -- Another profile scanner run, better prescales.
UMass/Smith folks (USm) are moving the scanner in the meanwhile.
Run 1166. Turned off pedestal suppression on 1st 6 channels
of roc1, slot 25 and roc3 slot 25 (ADCs for HAPPEX detectors).
This will work until someone does a pedestal run (so, don't).
Based on the the low ADC amplitudes, we bump up the HVs.
Now run 1167 :
HV are 1800 on all 4 HAPPEX PMTs and 1620 on 2 profile scanners.
The T5 and T6 rates are massively bigger
T5 = 345 kHz
T6 = 32 kHz
Other rates not too much different from before.
Now run 1168 (new prescales)
Profile scanner is parked at X = 17, Y = 33 (in USm units).
Based on looking at ADC we will increase HV on profile scanner
to max = 1650.
Meanwhile (fig 1) the 4 PMTs of HAPPEX detector are satisfactory,
although "R2" is smallish, but we decide to leave 1800 V.
David Lhuillier says its ok.
FIGURE 1
