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    User name R. Michaels

    Log entry time 00:37:47 on January 7,2003

    Entry number 90653

    This entry is a followup to: 90646

    keyword=ESPACE helicity and DAQ

    I'm not in a position to check the ESPACE algorithm myself, but I have
    written the C++ equivalent of this for the new analyzer and used that just
    now to investigate this problem. Note, it is known that the ESPACE algorithm
    is superior (I haven't worked as hard as Xiadong) but the overlap is >= 98 %
    so it's a rough check.

    The problem with the Right arm data is the nature of the deadtime -- apparently
    the DAQ "dies" for anomolously long periods of time, or order 1 second. The
    probability of this is sufficiently high that my C++ code throws out most data.

    In the meantime, I analyzed the scaler data (which has zero deadtime) and see
    that the G0 helicity structure is PERFECT for both Left and Right spectrometers.
    So, there is hope that when we cure the Right arm DAQ disease, ESPACE will
    work fine. Meanwhile it should be checked on Left arm (someone, please ?).

    Note, there should be no problem with helicity due to deadtime -- in principle --
    because whether the deadtime is high or low, you should see all transitions since
    the probabilty to be dead for all of 30 milliseconds (one helicity pulse) is
    negligible *IF* the deadtime is normal. Typical DAQ deadtime is 200 microseconds
    and exists <= 35% of the time. But if the DAQ skips several whopping seconds,
    you may have trouble reconstructing the helicity reliably. One help is that you can
    corroborate the 100 kHz timestamp using the 2nd timestamp (1024 Hz) available
    in scalers.