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    User name paschke

    Log entry time 10:25:00 on April 02, 2010

    Entry number 315734

    This entry is a followup to: 315721

    keyword=Detector aligned to thin C elastic peak at end of Owl shift

    This log entry comes late, after a few winks were captured by tired PREX crew.

    At the end of Owl, we aligned the detector to the this C elastic peak. Even at full raster, most of the elastic stripe was covered by the detector. I am not able to make any of the plots we need, but hopefully Dustin (and some other folks, if we can get help) can turn out the appropriate plots soon.

    Qualitiatively: the left arm coverage is excellent, with the biggest surprise being that the transverse (focal plane Y) coordinate range which was covered by the detector appeared to span beyond the known physical size of the detector.... possibly some coordinate definition or resolution issue.

    The right am shows a bizarre shoulder in the transverse distribution which is not understood. The detector edge is not sharp in this shoulder (which again suggests that the plot we are making is not a pure transverse coordinate at the detector) but clearly the shoulder is at least partly real. In addition, we observed the distribution to change shape at the end of our studies, which was not understood.

    One significant problem unearthed in last night's study: The At-Hole events appear on the opposite side of the transverse distribution than we thought... so we need to go move hardware to capture that peak.



    A copy of this log entry has been emailed to: souder@physics.syr.edu, rom@jlab, kkumar@physics.umass.edu, nilanga@jlab.org, dalton@jlab.org, mcnulty@jlab.org, lerose@jlab.org