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    User name Armstrong

    Log entry time 20:23:17 on June22,2001

    Entry number 64174

    keyword=Charge asymmetry

    During the present run (1720/20720/900) I chase the charge asymmetry by
    hand, as it starts out large (+300 ppm); using both the MCC-supplied GUI
    "Hall A Charge Asymmetry" and by running apar on subsets of the data,
    I adjust to get near zero ppm by end of the run, and will then turn the feedback
    on again, after the next run starts (why after? well, otherwise it will adjust the
    plate rotation angle to compensate for the average asymmetry over the entire
    present run, when it was changing in response to my adjustments).

    The apar analysis suggests that there are significant drifts (several 100 ppm)
    over time scales of order 20 minutes, so a feedback based only on the result at
    the end of an hour long run may not be ideal.