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User name V. Sulkosky
Log entry time 18:17:14 on February 10, 2011
Entry number 346317
This entry is a followup to: 346302
keyword=Re: L-HRS: T3 double pulse issue is because of EDTM signal
The cause of the double pulse appears to be isolated the S1 EDTM module.
The second set of outputs 3 and 4 appear to be the cause of the pulse. At
least when these are removed from the trigger, T3 no longer double pulses.
With Brad, we found that there was about a 15-20 mV DC offset from the
output of the module. It's not clear how to adjust this offset without
further investigation.
The S1 discriminator threshold was set to -40 mV. The pulse from these
channels appears to have a small second pulse about 30-40 mV in amplitude.
As a stop gap measure, Brad suggested increasing the threshold to see if
the second pulse would vanish. We found that increasing the threshold to
-41 mV removes the double pulse. To avoid being close to the edge of the
threshold, we made the S1 discriminator threshold to be -45 mV.
We should investigate this further to eliminate the problem, but the
coincidence timing is more important at this point.
A copy of this log entry has been emailed to: brads,danez,yez,rom