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    User name R. Michaels

    Log entry time 15:48:35 on November26,2000

    Entry number 52527


    keyword=trigger modifications

    Over the Thanksgiving break, the following changes were made to
    the R-arm trigger. Note, the L-arm was left untouched.

    1. Some timing adjustments to make PMT signals line up.

    2. Discriminator inputs re-arranged so that S1 goes into channels
    1-6 and S2 into 9-14. (Previously it had been 1-12 but now we
    skip 7,8). This facilitates the new definition of T1. Note, this implies
    a change to detmap.config for R-arm scintillators.

    3. New definition of T1 trigger: The L+R results of paddles
    1-6 on S1 are first OR'd. These emerge from a rear NIM output
    of the 4516 unit used to make L+R. Similarly for S2. Then we
    form (S1-OR).AND.(S2-OR). Timing adjusted to be the same
    as the former S-Ray. It was 65 nsec faster than former S-Ray.

    4. The T2 definition: Ignore S-ray. If new T1 is present, make no T2,
    but if T1 is absent, form T2 from 2/3 of S1,S2, and Cerenkov. This is
    similar to before, where T2 is exclusive of T1, but the new definition of
    T1 takes the place of S-ray. The S-ray (result of 1st MLU) still exists and
    is cabled up, but it is ignored, except in one respect: It goes to the scaler
    channel 17 (starting from 0) in the normalization scaler. It should not be
    much different from T1 rate. In principle we could also keep a prescaled
    sample of T1 and S-ray to compare.

    That's it for now. I should be finished with trigger tests by Tuesday night.
    Meanwhile, the L-arm trigger and DAQ should be usually available.