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    User name I.Rachek

    Log entry time 09:15:45 on January24,2002

    Entry number 80553

    keyword=Calorimeter threshold calibration

    In Runs 1499 - 1512 we have scaned the calorimeter threshold by setting
    DAC which supplies voltage, controlling the threshold of 56 "Sum-32"
    discriminators in the calorimeter trigger. Below are the results.
    Note that the resulting energy threshold does not have a sharp shape,
    therefore shown are central values and a "widths" - a range where
    registration efficiency rises from 0 to 1.


    DAC [mV] : -40 -55 -70 -85 -100 -115 -130 -145 -160 -175
    Thres.[MeV]: 371 472 571 703 816 921 1065 1160 1274 1377
    Width [MeV]: 130 136 178 228 249 241 336 292 312 334

    Central values are fitted by a liner function :
    Thres [MeV] = 60.0 + 7.55 * DAC[mV]

    This is inserted into a set_calo_thr script, so the threshold now can be set
    in a-onl@adaql2 :
    set_calo_thr THRESHOLD[MeV]
    and read back by
    get_calo_thr




    FIGURE 1