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    User name Jixie, Min, Chao

    Log entry time 22:33:39 on March30,2012

    Entry number 368443

    keyword=beam position dependence

    Ryan showed a figure that the nu (nu=E-E') distribution of current g2p 2.3 GeV production was shifted by about 4 Mev comparing to that
    before septum accident. Min valified that the dipole NMR give the same
    field before and after the accident. One difference is that the beam position before are shifted down by 3mm. Therefore I made these 2 plots using optics C12 data (3409, 3412, 3414, P0=2.251) with sieve IN. These plos show that there is about 2.x MeV shift in nu for 4mm (MCC unit) vertical beam position change. All holes behavious in the same way.
    The P0 of the production runs was 2.228 and with rasters, which might be the reason for the extra 1.x MeV.
    Anyway, this shift can be corrected once the optics calibration is done for the beam position part.

    FIGURE 1

    FIGURE 2