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    User name aregjan

    Log entry time 19:55:52 on January22,2002

    Entry number 80402


    keyword=HRS momentum resolution analyzis

    A quick analyzis of the HRS momentum resolution was performed.
    We looked on p-p_c, where p is the measured momentum, and p_c
    the one calculated from proton angle, assuming elastic electron scattering
    on the protons.

    The difference should be centered on zero, and its
    st. deviation includes in itself the momentum and angular
    resolutions of HRS. For the whole acceptance it was
    found to be 4.23MeV.

    After this we divided the calorimeter plane into 4x4 sectors,
    and for each sector redid the analyzis. It was noticed that
    the central peak of (p-p_c) shifted by as much as 3MeV.
    Bellow you can see the values of for each
    sector. The chart is arranged in calorimeter's coordinate

    0.71 1.1 -0.26 -0.34

    1.35 1.34 -0.65 -0.5

    1.45 1.22 -0.75 -1.57

    1.8 0.54 -1.36 -1.42

    Bellow you can see two pictures of p-p_c.

    On the first one there are two plots. The black one includes cuts
    on y_tg (HRS coordinates), on calorimeter energy (>1.2GeV),
    on coincidences and coinc. time. The red one as well includes
    a cut on the correlation of the HRS and calorimeter angles -- in
    order to chose the elastic electron events.

    The second plot is just a "zoom" on the red plot, with a fit.

    FIGURE 1