Right HRS DAQ Checks

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User name V. Sulkosky/B. Zhao/R. Subedi

Log entry time 22:42:08 on May 07, 2009

Entry number 271600

keyword=Right HRS DAQ Checks

Ramesh, Bo and I did some checks on the R-HRS. We unplugged all the
triggers to the trigger supervisor, with only T1 plugged but we still saw
the deadtime problem. We went as far as plugging a single twisted pair
with only T1 into the different trigger channels in the TS. This also
resulted in no apparent changes in the deadtime.

My conclusion is that the PVDIS triggers appear to have no impact on the
deadtime of the main experiment.

I did the same check with T8 and saw that datamon and the scaler counts
show that T8 has no deadtime. But for some yet unknown reason the
analysis software shows T8 has deadtime. I think there is a bug in the
software that needs to be tracked down. There were three separate
copies of the clock in the online scaler display, and the counts from
all three copies matched exactly with the level-one-accept counts when
running with only T8.

Finally I looked at the busies from the different crates, but I didn't
see any problems here. They were the same as they were yesterday. I
also do not see any missing gates from ROC 1 or 2, which would definitely
show up as dead time. The fact that the busies are only 12 to 40
microseconds long,
means that the the DAQ isn't just hanging up for long periods of time.

The fact that T1 and T2 show after-pulsing going into the normalization
scalers is probably a good source for the deadtime. I was coming to
this same conclusion around the time Bob showed up.

A copy of this log entry has been emailed to: yqiang,rsubedi,zhaobo,doug,jpchen,jiang,tdaver@wm.edu