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    User name jpchen

    Entry time Wed Jul 28 10:12:17 EDT 1999

    Entry number 66

    keyword=Minutes of 7/14 analysis meeting

    Minutes of 7/14 analysis meeting:

    Present: lexandre Deur, Pibero Djawotho, Ioannis Kominis, Steffen Jensen, Feng Xiong,
    Xiaodong Jiang, Seonho Choi, Sebastien Incerti, Mark Jones, Gordon Cates, Krishna Kumar,
    Mike Finn, Paul Souder, Haiyan Gao and Jian-ping Chen.

    1) Xiaodong: While working the cross section, found that charge with BCM down3 and down10 has
    a difference up to about 3% at 3 uA. Calibration were done only at 5 uA, 10 uA and higher. So there
    is a large difference at low beam current. J. P. suggested to not use step calibration constant,
    but interpolate between calibrated beam current.

    2) Alexandre: Showed beam position analysis: using raster current with offset from average of BPM.
    It is much faster than using BPM corrected with raster phase event by event.

    3) Ioannis: Showed Cherenkov and shower pion rejection and electron efficiency.
    For one run with large pion background, in e arm, pion rejection from Cherenkov is 63,
    combined with shower (one-d) cut, the rejection is about 3000 with electron efficiency of 99%.
    For hadron arm, combined Cherenkov and shower efficiency is 3000 with electron efficiency of 96%.
    Also showed the cell density measurement summary. The 3 methods (optical and mechanical) are in
    good agreement.

    4) Steffen: Worked with Sebastien on water calibration analysis. Modeled the thermal polarization
    with Bloc equation. Extracted T1 from the ratio of the up and down sweep NMR amplitude. , which
    agrees well with the world T1 data. Studied cell position dependence, Q curve corrections, T2 effect
    and other systemetic effects. Plan to do Q curve study at the target lab (He3 vs water and
    temperature dependence).

    5) Seonho: Comparison of the reconstructed and focal plane quantities of e arm vs h arm.
    Also showed the trigger inefficiency study. Doing production runs. Discussed the problem
    for production: computing power.