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    User name R. Michaels

    Log entry time 14:49:40 on September27,2004

    Entry number 132221

    Followups:

    keyword=helicity in Fastbus ADC (always was)

    As I've noted elsewhere, the helicity info is recorded by a VME
    I/O register in roc 11. The issue I looked into just now is
    whether the data are also going into a Fastbus ADC (for desired
    redundancy). I found the data in L-arm roc3, slot 25, channels
    14 & 15, and in R-arm roc1, slot 25, chan 14 & 15. Chan 14, 15
    are the helicity and its complement (actually [14,15] correspond
    to [15,14] between L & R arm). From a quick check, they agree well
    with the VME I/O, but it needs further check (in particular
    I'm not sure what happens when gate==0, i.e. Pockel Cell
    is blanked). I'll analyze it some more later.

    And whatever I said before, forget about it. These data have existed
    in Fastbus since the start of DVCS.