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    User name paschke

    Log entry time 22:58:24 on January15,2003

    Entry number 92041

    keyword=IA slope has been changed


    When we returned to production data taking, a large charge asymmetry was seen... approx. -800 ppm, with the IA cell railed at zero. (Previous zero point was 1 V)
    The halfwave plate state was changed, and the charge asymmetry went to 300 ppm, with the IA cell railed at 10 (previous zero point was 7 V). The problem? Matt Poelker studied the effect of the S2 picomotor, which tunes the IA slope, on the Hall B beam today during beam studies (there had been an insane rumor around MCC that we couldn't touch this knob without screwing up Hall B, which wouldn't make any sense so thank goodness it isn't true). Unfortunately, there is an enormous amount of backlash is S2, so the IA slope isn't repeatable with position.

    So, we need to retune our IA slope. We'll start this right away.