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User name V. Sulkosky
Log entry time 10:56:54 on November 20, 2008
Entry number 249956
This entry is a followup to: 249746
keyword=Re: U10 Double Pulsing Checked
During the access, I went to the left HRS to check the double-pulsing of
BCM U10 signal. The signal comes to the upper level of the HRS
electronics racks via patch panel 'Betty B' channel 14. Then this
signal goes to a LeCroy 4616 module that gathers the trigger and BCM
signals for the HRS normalization scalers.
Prior to the experiment, I fanned-out a copy to a level translator before
going down to the BigBite weldment.
I found that the BCM signal coming from the patch panel has a second
pulse about 800 ns after the main pulse. The level translator cuts the
second pulse off so the BigBite scaler does not see the second pulse and
was not double counting.
As a temporary solution, I sent the signal from the patch panel through
a logic module that will remove the second pulse. Ideally we would want
to find why the signal is double-pulsing, but this will require more time
to trouble shoot, since we need to trace the signal from downstairs
up through the left HRS patch panel.
A copy of this log entry has been emailed to: rom,kalyan,jiang,moffit,jinhuang,xqian