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    User name Miyoshi

    Log entry time 19:11:51 on February21,2000

    Entry number 21486

    keyword=SSD threshold calibration

    SSD external threshold calibration was done.

    We use 12 bit CAMAC DAC to change threshold.

    When the parameter for DAC is 3079, external threshold is below:

    plane 1(FEB #100) : 317.4mV
    plane 2(FEB #101) : 317.8mV
    plane 3(FEB #103) : 317.6mV
    plane 4(FEB #104) : 317.7mV
    plane 5(FEB #107) : 317.0mV
    plane 6(FEB #108) : 316.0mV
    plane 7(FEB #109) : 317.0mV
    plane 8(FEB #110) : 317.4mV
    plane 9(FEB #114) : 317.2mV
    plane 10(FEB #118) : 319.3mV

    These values are the same as internal threshold.
    We will start taking SSD data at this threshold settings.

    When the parameter for DAC is 3899, external threshold is below:

    plane 1(FEB #100) : 818mV
    plane 2(FEB #101) : 818mV
    plane 3(FEB #103) : 818mV
    plane 4(FEB #104) : 818mV
    plane 5(FEB #107) : 818mV
    plane 6(FEB #108) : 816mV
    plane 7(FEB #109) : 818mV
    plane 8(FEB #110) : 817mV
    plane 9(FEB #114) : 816mV
    plane 10(FEB #118) : 819mV

    By using these values, we decide DAC parameter setting.

    For example, we want to go up threshold by 20mV,
    we should change DAC parameter 3079 to 3102(3079+33), and so on.

    DAC parameter set used when taking data will be included in CRL file(*.crl or *.c).