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    User name ent

    Log entry time 19:24:46 on May12,2002

    Entry number 3306

    keyword=beam angle changed

    MCC can not get the beam centered on both 1H04A and 1H04B, the best they can do is give a horizontal offset of 0.9 mm on 1H04A. This corresponds to a beam angle offset of 0.15 mr. The suspicion is that there is not a good match between the Hall A beam line and the rest of accelerator. Before today, this was remedied by offsetting the beam on 1H01 by 5 mm. However, this BPM is used for FFB and this caused the
    earlier FFB/trip problems. This is not expected to be a fast fix, especially as the
    experts have been in all day to fix orbit problems or are out of town.
    We decide, after talking to the spokesperson, to allow the 0.15 mr beam angle offset,
    and take harp scans to verify the beam angle.