Test on RO: PMT basis, mixer, amplifier
We started by calibrating the lead module, which had been centered in the beam using previous runs not listed here (see logbook), using an 80 GeV e- beam. We used CAEN ADCs to read out the signals and moved the table to point the beam to the center of the different towers. We then followed with a repeat of these measurements wit the beam centered in tower 3 only at different electron beam energies. The table gives the online analysis of these runs.
Moving back to tower 3 (note run 6929 matches these conditions), we took data at additonal energies:
These results show significant non-linearity in the ADC response. There followed an extensive set of runs in which HV variations, capacitive coupling, and different ADC's were tried. The results were not significantly different, so we switched to using oscilloscope readout for the remainder of the studies. Online results will not be repeated here, since they require more extensive analysis, but the settings for the oscilloscope scales are recorded here for convenience.
Energy scan with different PMT Bases
Electron beam, centered in tower 3
S3, C3 only low gain channel;
Tapered PMT bases
HV settings: C3 = 830 V; S3 = 635 V
logbook pages 60-68
HV settings: C3 = 715 V; S3 = 610 V
logbook pages 60-68
Standard PMT bases
HV settings: C3= 570 V ; S3 = 480 V
logbook pages 69 - 71
Tapered PMT bases with independed last dynode
Configuration with polarization of last dynode which maximize the signal output
HV settings: C3 = 715 V ; S3 = 620 V; Dy_C3 = 35.5 V; Dy_S3 = 31 V
Configuration with polarization of last dynode which reproduce the tapered base
HV settings: C3 = 715 V ; S3 = 620 V; Dy_C3 = 77.5 V; Dy_S3 = 67 V
LIght Mixer test
Analyzing data in T3; tapered bases; No veto
HV settings: C3 = 715 V ; S3= 610 V
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AlanSill - 21-Jul-2012