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    User name T.Chang

    Log entry time 08:15:29 on December 8,2000

    Entry number 53122

    keyword=T. Chang

    0:05 Move L-arm colimators from "open" to "sieve"
    0:09 started run 1709. 10cm dummy target, 5 uA beam, no raster. we took 17k events.
    0:15 The spectrometer is now moved to 23.767 degree, Q^2=4.8
    0:20 L-arm colimator move from "sieve" to "open"
    0:30 Changed the Q1, Q2, Q3 polarity to positive, waiting for the tech to change the dipole polarity.
    1:15 The technician comes. Hall-A is in control access.
    2:00 Dipole polarity changed. Switch on the quadrapoles. Back to beam permit.
    We found that the Dipole momentum reading is lower than the desired momentum when the current reaches the setting. Try recycling Q2 and Q3, but this doesn't help. 2:20 try page John LeRose
    2:30 OK, decide to pin down the beam position and profile first while waiting. take some data on carbon target using 5uA beam.
    2:35 Put in 3x3 raster. Raster size 3x4 observed.
    2:40 Switch to 15 cm H2 target. checking beam optics. request for 50 uA.
    2:50 Found Fpp trips off. probably long time ago
    3:10 Found VDC HV trips. We reset the HV crate and it comes back on.
    3:20 Dipole problem persists. Cycling quads again doesn't solve the problem.
    4:00 Try to set the dipole current manually to 1200 A. M3/M4 OverTemp becomes fault. Call technician.
    4:45 Gary Dezern came in and reset the magnet power supply for us. The dipole momentum problem persists.
    5:30 page Javier Gomez...

    Start a test run just to see how bad the things are:
    1714...........05:27/6:06........................junk, just to try the tdc calibration program.

    5:50 call Javier. He told us to turn on the dipole regulator. This fixes the problem. Wait till the magnetic field stables. Starts good run finally.

    Run............start/stop..............events.............comments
    1715.........06:07/06:59.............0.7M..............1st good run at Q^2=4.8 GeV
    1716.........07:03/07:50.............0.7M...............good run
    1717.........07:51/ continue to next shift.

    Summary:

    * L-arm moved to 23.77 degree; Q^2=4.8 GeV
    * Polarity changed to positive.