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    User name R. Michaels

    Log entry time 18:45:39 on October 10, 2006

    Entry number 186755

    This entry is a followup to: 186711

    keyword=Qasy feedback turned OFF

    Hall A charge asymmetry feedback turned off. It seems that G0 is running their own
    feedback on Hall A Qasy, as they care about this a lot more than Hall A does. I doubt
    that anyone in Hall A except me monitors this.

    Theory of dueling feedbacks: Each being presumably optimized to apply feedback on a
    timescale T -- if longer than this you do no good and if shorter you inject noise -- then if
    T1 << T2 for the 2 systems, the one with T1 does all the work and the other does nothing.
    That appears to be the case since last night. Hall A has T = 12 min for our "noisy" scaler
    measurements, probably G0 does it faster. BTW, if T1 = T2, the "duel" increases the noise
    by some factor [sqrt(2) ?] -- the RMS being typically 200 ppm for our scalers.