• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name R. Michaels

    Log entry time 11:38:22 on January 14, 2008

    Entry number 225397

    This entry is a followup to: 225391

    keyword=re: TDC location

    Having the L-arm TDCs at around channel 3500 is dangerous.
    Conservatively, one wants to avoid the first 50 nsec and
    the last 50 nsec of a TDC range; this means putting the
    signal between between channel 1000 and 3000. But I guess
    we ran the whole experiment this way (?). The TDC is nonlinear
    at the start and end of it's range. What's more, the trailing
    edge of a pulse causes an "overflow" (data=4095) if it overlaps
    "too much" with the end of the range. Offline you may try to
    see if you lost hits (effectively an inefficiency) using
    the PMT pulse heights (ADC) and other info. In the future
    we should aim for 1000 < TDC < 3000.

    -Bob

    A copy of this log entry has been emailed to: camsonne@jlab.org,jpchen@jlab.org,vasulk@jlab.org