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    User name R. Michaels

    Log entry time 22:59:27 on July27,2006

    Entry number 175603

    keyword=trigger work, after pulsing, etc

    Mike Paolone and I plugged in T1 on L-arm so it doesn't reflect
    back. This fixed the R-arm "apparent deadtime" problem.

    We looked on the scope on L-arm at the double pulsing. No solid
    measurements of these rates, but it seems: PMTs have a high (50+ %)
    probability to afterpulse, and trigger T3 has a ~1 % after pulse.
    So this would explain a livetime of order 101% for cosmics and
    probably for beam too if the prescale factors are high. We noticed
    that S0 has no after pulsing. So we decided to do the simplest
    thing: create a new trigger T6 which is S0.and.S1.and.S2 using the
    MLU which already has these signals with proper timing (note S0
    here means the AND of the 2 PMTs on S0). We're setting that up
    now. The experiment should still take a fair amount of T3 to
    verify/cross-check, plus the fact that sometimes S0 is removed.