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    User name R. Michaels

    Log entry time 01:02:23 on June25,2004

    Entry number 126751

    Followups:

    keyword=alignment checks

    While waiting for magnets to settle I analyzed the full 380K
    events of run 1174 and saw no correlation of VDCs to the
    profile scanner PMT. Note, T5 was 700 kHz for this run which
    far exceeds what was on scint, so something was clearly wrong
    with that detector. T6 was 80 kHz which also seems high.
    Later we realized (see below):
    These rates same with no beam !

    Alignment check: Put the field at +2% (3.035 GeV) (run plan said +1)
    I_beam = 0.15 uA (but how accurate is anyone's guess).
    HAPPEX det HV = 1800 V. Prof. det HV = 1650 V.

    Rates
    T1 = 160 kHz
    T2 = 180 Hz
    T3 = 150 kHz
    T4 = 420 Hz
    T5 = 740 kHz (Piotr's test: it stays this way even with no beam !)
    T6 = 93 kHz (ditto)

    Profile detector is parked.
    Run 1175 is our 1st HAPPEX detector alignment run.

    Urgh. We really wanted -2 % (not +2%) Going for -2%.
    If we had done -2 we would be finished.

    Anyway, the edge of the momentum spectrum is at -46 and -42 MeV
    for L and R-HRS resp. (This was judged accurately on a zoomed
    graph, and is shown crudely in fig 1 as the red line). Spectra
    are for T1 and T3 only.


    FIGURE 1