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    User name brads

    Log entry time 13:42:20 on April 23, 2009

    Entry number 267542

    This entry is a followup to: 267540

    Followups:

    keyword=Re: Strange raster current readback for run 1254

    It seems that there is some strange readout of the raster currents with the BigBite trigger. For run 1257, which only had L-HRS triggers, the raster pattern looks normal.

    This is very worrisome. The raster current signal doesn't know what the trigger type is, nor does the ADC hardware. The only thing left is having the gate width vary as a function of the trigger type -- bizarre and really bad for the BigBite DAQ. I would think we should get a uniform sample of the raster current no matter what trigger we use (including pulser, but for the small(?) chance of some beat frequency issue).

    (You mention raster pattern in the first paragraph and raster current in the quoted (2nd) paragraph. I'm pretty confident that the wierd raster pattern (ie. BPM data) is just due to a screwball beam tune. The weird raster current histo is an unsolved problem. I'm assume that's the issue you're refering to.)



    A copy of this log entry has been emailed to: vasulk, rom, moffit, miham