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    User name R. Michaels

    Log entry time 20:38:26 on July20,2005

    Entry number 148765

    Followups:

    keyword=Runs with new beam shot.

    Beam was adjusted to give a supposedly better entry angle
    and bisect the angle between spectrometers.

    BPM4A at (X,Y) = (1.55, 0.03)
    BPM4B at (X,Y) = (-1.26, 0.07)

    Start run 2178. We've been on C12 target since run 2176
    and this run is also with C12.

    The raster has been off.

    Rates now (this is read online from xscaler):
    T1 = 54 kHz
    T2 = 5.3 kHz
    T3 = 50 kHz
    T4 = 4.8 kHz
    T5 = T6 = 0
    T7 = 88 kHz
    T8 = 58 kHz

    From T1-T4 rates, there is a small hint that the rates became
    more equal -- but the comparison needs to be made carefully offline.
    But ... see below for a first attempt !

    Next step:
    Turn on raster 2x2 (set point 3.8x4.75) and ask for 0.5 uA.
    Have not changed momentum yet.

    Run 2179 : spot++ check.

    Insert He4 target.

    Run 2180 : He4 target at nominal momentum setting.

    While waiting and bored, here are rates for run 2177 vs 2178
    before/after the beam movement. This is based on the ~100
    scaler events and the precision as rather good (probably < 0.1%)
    using scaler package of Podd analyzer.

    Run 2177
    T1 = 58.83 kHz
    T2 = 5.937 kHz
    T3 = 45.63 kHz
    T4 = 4.222 kHz
    Note: T1/T3 = 1.29 and T2/T4 = 1.41 (i.e. R-arm higher rate by
    29 to 41 %).

    Run 2178
    T1 = 53.93 kHz
    T2 = 5.237 kHz
    T3 = 49.56 kHz
    T4 = 4.841 kHz
    Note: T1/T3 = 1.09 and T2/T4 = 1.08 (so, R-arm higher by 8 to 9%).
    Therefore the two spectrometers became more equal in rate,
    as we expected/desired.

    And ... here are rates for run 2180 (Helium run)
    T1 = 293 kHz
    T2 = 50.6 kHz
    T3 = 280 kHz
    T4 = 53.2 kHz
    T1/T3 = 1.05 T2/T4 = 0.95 -- i.e. the same within 5%.