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User name V. Sulkosky
Log entry time 16:11:03 on March 31, 2011
Entry number 353918
keyword=Deadtime from Current Scan
I have analyzed the deadtime from the current scan data that was taken
near the end of last week as a first attempt to get access to the
deadtime. The table below provides the relevant numbers.
deadtime was calculated using the formalism from E97-111
via the indirect method.
Run BCM [uA] BBEDTMsc BBEDTMtdc CDT [%] ECDT [%] EDT[%]
3056 2 5546 5327 4.4 (0.8) 4.0 (1.3) -0.4 (1)
3044 4 7799 7361 5.6 (0.6) 5.6 (1.1) 0.0 (1)
3068 5 7562 7078 6.6 (0.6) 6.4 (1.1) -0.2 (1)
3055 8 6064 5632 7.6 (0.6) 7.1 (1.2) -0.5 (1)
The values in parentheses are the estimated statistical uncertainty.
the electronic deadtime appears to be small compared to the
and consistent with zero.
CDT: computer deadtime (averaged over all trigger types)
ECDT: combined electronic and computer deadtime
EDT: electronic deadtime
where EDT = (ECDT - CDT)/(1 - CDT) and
ECDT = 1 - Npul/Spul:
Npul = BBEDTMtdc or the number of EDTM counts in the TDC
Spul = BBEDTMsc or the number of EDTM counts in the scaler
1. One caveat is that the EDTM pulser rate in BigBite and HAND is only
It is possible that that rate might be too low to
adequately measure the EDT,
since the CDT is at least 5x higher.
2. From the 2001 Hall A annual report, the scaler measurement of EDT was
also found to be zero. This is suspected, since the EDT effect is a
condition and not a loss.
A copy of this log entry has been emailed to: doug,eip,orchen,igorko,rshneor,nmuangma,sgilad,brads,rom,camsonne