• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name brads

    Log entry time 15:43:48 on February 14, 2007

    Entry number 193173

    keyword=Runplan for Wednesday SWING

    Page the RC when it looks like we'll get beam soon. If beam arrives before
    I do then
    - confirm that the target is in the EMPTY position
    - 5 uA with a 5x2 raster from MCC
    - - wait while MCC works out the inevitable bugs after the down
    - request 0.2 uA

    Once stable beam returns we will take a Calorimeter run at 0.2 and 0.5 uA.
    - request 30x8 from MCC to get ~7x7 on Slug

    Then we will take data with the Left arm at 12.5deg (Kin 'W'). The rates will
    be quite high in the LHRS, so keep a close eye on the VDC currents in
    particular.
    - start with 0.2 uA and check the scaler rates before running on each new target
    - Take 2 runs with 10^6 events each for Ta, C, B, Li (total of 2 million events per target)
    We'll use pretty low beam currents here (and for the 14 degree run). See the
    comments below regarding limiting the beam current and setting prescales.

    Page RC 1/2 hour before the above runs finish. When done we will take
    a controlled access and move the spectrometer to 14deg (escorted access is
    needed to replace a protective floor pin).

    The next step is to repeat Kinematic 'X' (14 deg).

    Then we move to Kinematic 'F' (46 deg), and complete
    - 1 run on Ta
    - 1 run on Carbon
    - 2 runs on Boron
    - 2 runs on Li

    The next shift will continue with Kin G, H, I, ...

    ---------------------------
    General instructions follow:
    ---------------------------
    The list of kinematics is on the bulletin board to the left of the
    whiteboard.
    - The LHRS is the one that changes angle. The RHRS stays put.
    - Please do _not_ adjust/tweak/correct/update the momentum settings for
    either arm. The readbacks are correct even though they show up red. See
    the screen snapshot taped above the "Hall A Tools" monitor for reference.

    Take 2 runs per target with either
    10^6 events per run,
    - OR -
    one hour per run,
    whichever comes first.

    Do an online replay for both arms for every run. Note that the green
    'reference' histos will not match unless you know how to modify the
    detectorL.cfg, detectorR.cfg 'golden' file entries and pick an earlier run
    with the same target and kinematics. Use your best judgment and/or manually
    bring up another online GUI for a similar earlier run if you think something
    is really wrong with an online histogram.

    Start a full replay for only ONE of the two Carbon runs, and ONE of the
    two Li runs you at each kinematic point.

    Beam currents are limited to:
    - Target MAX Current Raster
    - Ta 20 uA 1.5x1.5 (MCC: 5x2)
    - Boron 20 uA 2x2 (MCC: 8x3)
    - Carbon 20 uA 2x2 (MCC: 8x3)
    - Li 5 uA 2x2 (MCC: 8x3)
    NOTE: do not exceed 5 (five) uA on the Lithium -- the target could melt!
    The smaller raster for the Ta target should get rid of the 'superfluous' Al
    peak in the dp spectrum.

    Double check the beam spot on target using raster++.

    The current you want to run on the other targets should be 'self-limited' in
    order left arm prescale in the single digits, or to keep the right arm VDC
    currents below 15 uA (see below), but don't exceed the listed maximums in any
    circumstance. Please make sure the raster is on at all times for the Li
    target.

    We want the prescaled rates on T1 and T3 are roughly 1 kHz for all
    kinematics/targets.
    - T2, T4 can be around 10-50 Hz
    Adjust the beam current to keep the prescale on the left arm in the single
    digits where possible (ps=1 is good), but you shouldn't need to go below
    1 uA.

    Keep an eye on the VDC currents (Hall A Tools GUI) and make sure they stay
    below 15 uA. The right arm will be the limiting factor since you may want to
    increase the beam current to keep the left arm rates reasonable as the LHRS
    moves to larger angles.
    - VDC currents are displayed on Hall A Tools GUI

    Don't hesitate to page the RC if you have any questions/concerns or you fear
    the magic smoke is going to escape.


    A copy of this log entry has been emailed to: berman@jlab.org