User name Bob/Alex
Log entry time 00:28:02 on January28,2008
Entry number 227611
Followups:
keyword=thin PREX det, part 1We have thin lead target and 60 uA for lumi studies.
We are also studying the thin PREX detector.
S0 is removed. The trigger T4 has prescale 1, and
all other ps are infinite. T4 is stack det. trigger.
We note the rates with threshold on stack detector
Thresh .... Rate
100 mV .... 1520 Hz
300 mV .... 1000 Hz
500 mV .... 880 Hz
Try run 3506 with thresh=500 mV to see where we are.
This gives an enhanced peak in the stack detector ADC
(fig 1, top right), but no signal in thin detector.
At first I worried maybe the two detectors are misaligned,
so I checked a run 3396 from last night -- cutting on stack
detector ADC still leaves a peak in thin detector with reasonable
efficiency, therefore the alignment is ok.
Conclusion for now is the thin detector is busted.
Will take access to check.
FIGURE 1
FIGURE 2
