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User name sawatzky
Log entry time 12:47:03 on June 16, 2007
Entry number 205625
This entry is a followup to: 205562
Followups:
keyword=Right S2 left PMT comment
Note the loss in resolution at low channel numbers in the ADC too. I
think the most probable explanation is that there is a bunch of noise on
the S2 analog signal. You should see this same effect showing up as a
(very) wide pedestal for this channel too. (Might need to take peds with
beam to get 'true' results if there's a beam loading effect.)
If this is noise is introduced on a line independent of the TDC then your
trigger is unaffected. If the noise is upstream of the split/fan-out to
the ADC and TDC "branches" then your timing could be degraded. Since the
trigger is based on a L+R PMT coincidence your efficiency is probably
unchanged (slightly higher randoms), but the timing resolution could
still be affected if the left PMT sets the timing.
A copy of this log entry has been emailed to: camsonne@jlab.org