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    User name R. Michaels

    Log entry time 02:56:36 on August16,2005

    Entry number 152121

    This entry is a followup to: 151477

    keyword=Aluminum background, integrating

    02:28 Put in 20 cm Alum dummy target.
    Raster remains same size.

    Ask for 20 uA, got 19.5. The spec says this target can run
    at 40 uA but we don't want to get too close to that.

    Alum 20cm dummy target HAPPEX run 4451. 15K events.

    Background is judged from det1/bcm1 for bcm1 "on" cut and
    similarly det3/bcm1 by comparing to recent Helium production.

    For a Helium production run 4450
    L-arm det1/bcm1 = 3.556
    R-arm det3/bcm1 = 3.558

    For the Alum dummy run 4451
    L-arm det1/bcm1 = 0.222
    R-arm det3/bcm1 = 0.234

    Using the "xt" factor 0.278 we get background fractions
    L-arm 1.74 % (Integrating)
    R-arm 1.83 %

    These may be compared to the spectrometer DAQ results in
    halog 151477, which I confirmed :
    L-arm 1.62 % (Counting)
    R-arm 1.64 %

    The agreement is not too bad.