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    User name R. Michaels

    Log entry time 13:56:36 on October 6,2002

    Entry number 87468

    This entry is a followup to: 87402


    keyword=helicity errors reported, run 1173

    During ESPACE replay of run 1173, there were 7 helicity "disasters" in 50k
    events, but the scaler software says there are no helicity problems. This
    implies there are either problems with the event data or the algorithm.
    Looking through the end-run summaries from scalers, I see that since run 1133,
    only 1 run, 1152, reporting errors (for 3.2 seconds which is the time it takes to
    recover from a bad helicity sequence). Making a double-check of the ESPACE algorithm
    is a high priority for me this week (as I said, it could be the data).

    How many bad events in run 1173 ? Since recovery takes 3.2 seconds and there
    were 7 "disasters", this represents 8300 events or 17% of the 50k analyzed. This
    is consistent with the histogram "HELXJ2" from ESPACE which reports the
    helicity flag. It's a lot.