I would like to request a few hours of beam to check and fine tune
the pair counter.
Ideally, it would be nice to do 5 x 3 = 15 short runs,
to check that my thresholds and gain matching
(normally done before with a source) are correct:
TRIGGER = PC
HV:
MAIN LeftTOP RightBottom RightTop LeftBottom
(LeftTop check)
HV Nominal nominal-50 OFF nominal nominal
HV Nominal nominal OFF nominal nominal
HV Nominal nominal+50 OFF nominal nominal
(RightBottom check)
HV Nominal OFF nominal-50 nominal nominal
HV Nominal OFF nominal nominal nominal
HV Nominal OFF nominal+50 nominal nominal
(RightTop check)
HV Nominal nominal nominal nominal-50 OFF
HV Nominal nominal nominal nominal OFF
HV Nominal nominal nominal nominal+50 OFF
(LeftBottom check)
HV Nominal nominal nominal OFF nominal-50
HV Nominal nominal nominal OFF nominal
HV Nominal nominal nominal OFF nominal+50
(main paddle check)
HV Nominal-50 nominal nominal nominal nominal
HV Nominal nominal nominal nominal nominal
HV Nominal+50 nominal nominal nominal nominal
This should be enough to determine thresholds positions on ADC spectra,
(signal amplitude)/(threshold) at the discriminators,
(signals are here the peaks for 1 electron and 2 electrons energy
deposit)
and the signal amplitude vs HV slope.
(pedestral being determined by ADC spectra with any trigger other than
PC.
If we are running out of time, I can compress those measurements into 5
runs:
MAIN LeftTOP RightBottom RightTop LeftBottom
(Main & LeftTop & RightTop threshold check)
HV Nominal nominal OFF nominal OFF
(Main & LeftBottom & RighBottom threshold check)
HV Nominal OFF nominal OFF nominal
(LeftTop & RightTop gain check)
HV Nominal nominal+50 OFF nominal+50 OFF
(LeftBottom & RighTop gain check)
HV Nominal OFF nominal+50 OFF nominal+50
(Main gain check)
HV Nominal+50 nominal nominal nominal nominal
to have ~100,000 events for each run, assuming a trigger DAQ rate of 250
Hz,
I need for each run 400s -> 10 min (let's square to 15 min),
so ~ 4h of beam to be conservative for the full scheme.
2h for the short scheme.
Part or all of the runs could be done at the same time as the
commissioning of the pair spectrometer,
using 2 trigger inputs in the TS.
My plan would be to do the short scheme first, and then extra
measurements if time/beam is available.
eric
--
----- Eric Anciant ------------
DAPNIA/SPhN - Bat 703 - Orme des merisiers
CE-SACLAY - 91191 GIF-SUR-YVETTE Cedex - FRANCE
Office: (33 - 1) 69 08 22 47 fax: (33-1) 69 08 75 84