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    User name jpchen

    Log entry time 19:42:44 on July20,2001

    Entry number 66921

    keyword=Helicity false charge asymmetry

    Short summary of what Ron Gilman did (with help from Wolfgang
    and with JP watching) during access to study the helicity asymmery
    problem(all on left arm):

    Checked helicity asymmetry with a 1MHz pulser and regular DAQ scaler.
    With Toggle mode, asymmetry (scaler count in H+ gate vs H- gate)
    is small (at 100 ppm level). With random mode, it is at 1000 ppm
    level (just as we observed with data taking).

    Since people were suspecting the problem was from the DAQ scalers (
    left arm use FIFO, which is different from the right arm), so checked
    with a vision scaler. It also shows 1000 ppm asymmetry.

    Checked time gate width: the trailing edge varies by about +- 15 micro-sec.
    Checked the gate generator response to the glitch signal, it responded
    the way as expected.

    Will need to further check what caused the 1000 ppm asymmetry.