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    User name D. Lhuillier

    Log entry time 00:29:53 on October14,2005

    Entry number 156764

    Followups:

    keyword=Beam tune

    Spent several hours trying to minimize the Compton background. Beam spot size measurements in the hall A line were compatible with Jay Benesch simulation but both electron and photon background rates were a factor ~100 too high.
    Tune of the prebuncher helped reducing the electron rate to acceptable level (50Hz/uA) but didn't improve the photon rate.
    Last night both rates were very low when we were using the hall B laser so we switched back to this laser for a while, with no significant change.
    Other tricks useful in the past (dogleg setting, scan of the quad upstream the compton chicane, scan of beam position) didn't helped either.
    We are running out of ideas for tonight and decide to continue our test plan:

    * Check phase advance
    * Put LH2 target in at low current (5uA) and measure septum and target heating.
    * Increase beam current to 20uA. Check response of the detectors and monitors. Perform raster scan and scanner scan.