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    User name paschke

    Log entry time 13:02:15 on June19,2004

    Entry number 126313


    keyword=Bit resolution of Hall C bcm

    Hall C turned on, so started using their BCM signal to measure (and
    then zero) their charge asymmetry.  They were running only 1 uA, so
    we were somewhat limited by the bit resolution.
    Figure one shows the raw bcm10 signal. The end of the run shows the
    beam off in Hall C, the beginning is about 1 uA.  This is 140 channels
    over pedestal, which gives us a bit resolution of 1/(2*140) ~ 3500 ppm.
    If this is a linear region of the bcm, at 20 uA (were they expect to 
    run this weekend) we will see only about 2800 channels over pedestal.
    This is a bit resolution of 200 ppm, which is probably ok.

    FIGURE 1

    FIGURE 2