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    User name paschke

    Log entry time 11:02:56 on October 21, 2009

    Entry number 295963

    keyword=backgrounds vs rates vs PMT current

    It isn't clear that bad sum0 backgrounds are always correlated to PMT current. We have poor record keeping on Compton rates for some reason, but I was able to find one Compton rate stripchart entry from the period we were discussing in last night's meeting.

    http://www.jlab.org/~adaq/halog/html/0910_archive/091020032631.html

    which coincided with a Compton run #20535

    https://hallaweb.jlab.org/compton/Logbook/Run_list/more_run.php?id_run=20535

    Other Compton rate info in the Halog either covered earlier times, or referred to the time around 7:30-8:30am... and there is no Compton run in the logbook corresponding to that time. Run 20540 is missing from the logbook, should it be there?

    The point here is that 20535 (2-4am) shows significant noise on sum0, which is an indication of background instability (attachment 1) But the rates and phototube current from that time don't show much (attachment 2).

    So... do we understand backgrounds in the FADC analysis?



    A copy of this log entry has been emailed to: camsonne@jlab.org, souder@physics.syr.edu, dwang@jlab.org, mfriend@jlab.org, bquinn@cmu.edu



    sum0 vs MPS for Run 20535



    Compton rate stripchart 2:30-3:30