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    User name Pitt

    Log entry time 21:36:33 on November 6,2002

    Entry number 51089

    keyword=Proposed run plan for owl shift

    Proposed run plan for owl shift tonight
    ________________________________________
    NOTE: There is also a request to the analysis shift near the end of
    this message.

    This plan should be done at the same current as last night; in fact the
    conditions should be as close as possible to what they were last night.

    Basically do the same program as last night with the following exceptions:

    For tonight, we will have the feedback program do the charge feedback
    automatically, but the position feedback should be done manually.

    1. When you start up the feedback, you should select BCM=2 (so it
    uses BCM2 for the charge feedback) and BPM=2 (so it uses BPM G0B; the
    last stripline).

    2. For the runtype on the DAQ, you can put it into ts_scaler mode. We
    don't need all the other information.

    3. When you start up the feedback, disable position feedback and only
    enable charge feedback. Probably 10 minutes is a reasonable update
    time for the charge feedback, but adjust it as you think appropriate
    given the size of the errors.

    4. For the position differences, you will keep track of them using the
    G0 realtime monitor. Instructions for this should be somewhere in the
    manuals, or you can ask the previous shift crew how to run it. You
    will want to look at the X and Y position difference histograms for
    G0B (I'm not sure what they are called in realtime).

    5. Start up the realtime and take data for about 30 minutes; compute
    the postion differences in x and y (and their errors) and note them
    in a log file.

    6. I have written a code that will compute the desired change in Vx and
    Vy. It also takes account of the fact that there is a significant
    coupling between the position differences and the IA voltage. Everything
    is found in /home/gzero/users/pitt/feedback. Before you use it the
    first time you must set the correct calibration constants in
    cal_matrix.dat. Help on this is in the README file.

    Then just type pos_change, and it will ask you for the measured
    x and y position differences. It will return the needed CHANGES
    to V_X, V_Y, and IA voltages. The returned values should be ADDED
    to the current values.

    7. After the changes are made you can kill realtime and restart it
    (or there is also a clear button but Wolfgang told me he hadn't tried it
    before). Then wait another 30 minutes and make another change. Leave
    the main DAQ run going the whole time.


    To the analysis crew:
    The following two types of plots would be useful:

    1. Postion differences (X and Y) and charge asymmetry versus time within
    a run. Each value should be binned in intervals of about 5 minutes (2250
    quartets. I think Jason basically already has such a script written.


    2. Integrated values of the above quantities versus time. This is different
    from step 1. The plots should still have a point plotted every 5 minutes
    or so, but each point will be the average of that quantity back to
    t=0. So for charge asymmetry you would have:

    t value

    5 min charge asymmetry average from t=0 to 5 mins
    10 min charge asymmetry averaged from t=0 to 10 mins
    15 min charge asymmetry average from t=0 to 15 mins

    If the feedback is working this should clearly illustrate that it is homing
    in more precisely on zero as time progresses.