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    User name K. Grimm

    Log entry time 16:00:18 on October24,2009

    Entry number 296457

    keyword=Day Shift Summary

    SL: Klaus Grimm
    TO: Chun-Min Jen
    3rd: Salvatore Frullani


    Summary

    Production runs: NONE

    Compton runs:
    08:36 Compton run 20655
    - during the run the beam was tuned to nominal BMPA and BPMB positions
    increasing the Compton background rates
    - One or two GSP PMT HV trips


    Details

    08:00 Status shift change
    - Both spectrometer magnets are down starting yesterday evening
    - lH2 target loop1 is filled and ready to go since yesterday evening
    - target position: empty target
    - beam current: 70uA for Compton tuning
    - raster: OFF (doesn't matter for compton tuning, raster is after compton)

    08:20 Requesting 100uA for "production compton runs"

    08:21 Noticed that beam position is not at nominal position
    08:26 Apparently there are problems delivering 100uA
    08:35 MCC opened up the collimator slits (so its not done by cranking up thye laser powerby )for delivering nominal 100uA.
    The best that MCC can give us is ~93uA.
    08:51 Compton GSO HV tripped. Turned it on again (-1800V)
    08:53 Called MCC for to tuning the beam to nominal beam position. MCC noticed that the orbit lock was off.
    09:00 Seems like that the request for nominal beam position affects the quality of the Compton tuning because the Compton
    background rate got worse. Asked Diancheng and Megan Friend about the impact of beam position tuning affecting Compton
    but we could not clarify it. Megan asked MCC for tuning the Compton with nominal BPMA and BPMB beam positions.

    09:27 MCC wants to go back to the old beam position settings for tuning the Compton and check if Compton improves compared
    to now with nominal beam position.

    09:36 MCC talking to Megan for improving Compton tuning.
    09:51 Wouter is entering the couting house.Ed Folts is onsite now.
    10:22 Beam current 10uA per Megan's request for Compton runs
    11:04 Hall A is in controlled access. Ed and Heidi are trying to solve the various magnet problems.
    13:15 Ed Folts status: http://www.jlab.org/~adaq/halog/html/0910_archive/091024131529.html
    14:55 Apparently the A/C is not working in the Counting House. While we are sweating a bit I'm more concerned about
    the electronics in the middle room. I contacted the Gate House and they will get hold of the Service Plant for us.
    15:30 Right Q2 tripped/quenched again. Short controled access with Wouter and Klaus for resetting Q2R PS located at the electronics racks platform.
    15:40 Power plant technician arrived and is working on the AC unit in front of the counting house.