Dear Flemming,
Concerning the last runs I got a following results:
run 5266, Th=3.2, HV=HVnom+20, T3: 59% +- 3%
T4: 96% +-
6%
T5: 89% +-
5%
run 5276, Th=3.2,HV=HVnom+20, T3: 17% +-1%
T4: 97% +-6%
T5: 87% +-5%
run 5274, Th=3.2,HV=HVnom+20, T3: 19%
T4: 95%
T5: 90%
The errors are only a statistical. For runs 5266 and 5276 I run through
about 150k events
and for run 5274 only through 100k (errors are larger).
run 5264, Th=3.5, HV=HVnom, T3: 35%
T4: 96%
T5: 48%
Conclusions:
T5:
It looks like at Th=3.2 and HV = HVnom+20 T5 has an efficiency slightly
below 90%.
There is large increase observe as compare to Th=3.5 and HV=HVnom (by
40%) but we
still have to improve the efficiency. Keeping also in mind a currents
values from run (5265 HV=HVnom+20)
I would suggest to set HV to:
all X and U views to HVnom+30,
all Y views HVnom+25
all V views HVnom+20,
and Th=3.0V.
T4:
It looks like we are already in the plateau region. The settings
HV=HVnom and Th=3.5 seems
to be OK, but I would suggest to make a very minor correction, namely:
all X and U views HVnom+5
all Y views HVnom
all V views HVnom
and Th=3.4V-3.5V
T3: I don't know what's happened with T3 efficiency for runs 5274 and
5276 (~20%) it was much larger for
5266(~60%) at the same settings?, but any way, I think that we should
make a look at T3 at
settings:
A1: 1180
A2: 1180
A3: 1180,
A threshold should be set as low as possible that means: slights above a
value when lots of extra hits start coming into the
spectra. In case of the T3 we measure a signal width (some how related
to a signal ADC), so we have
a possibility to set a software threshold on the data proceeding level
(like for TPC or Tof).
I have also efficiencies for T1 and T2 which are 92% and 96%-97%,
respectively.
Regards Pawel.
--
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| Pawel Staszel |
| Niels Bohr Institute Tb 8 email: staszel@nbi.dk |
| Blegdamsvej 17 phone: (+45) 35 32 53 51 |
| København Ø FAX: (+45) 35 32 50 16 |
| Danmark |
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