Deadtime from Current Scan

NEXT
Make New Entry, Make Followup Entry

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 electronic
deadtime. The table below provides the relevant numbers. The electronic
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. Hence,
the electronic deadtime appears to be small compared to the computer deadtime
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

Notes:
1. One caveat is that the EDTM pulser rate in BigBite and HAND is only 1.5 Hz.
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 pileup
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