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    User name R. Michaels

    Log entry time 17:04:57 on March28,2007

    Entry number 197590

    Followups:

    keyword=trigger adjustments part I

    The e04018 experiment requires a minimum beta of 0.21.
    This implies a time difference between spectrometers of 320 nsec.
    This was accomplished, but just barely. Here's what I did today:

    1. Add 64 nsec to Rdelay1 to delay T1 further, providing the
    necessary range.

    2. Delay T3 by 56 nsec to compensate (necessary to form coinc.)

    3. Reduce Rdelay2 after Trig. Super. by the corresponding amount.

    4. Adjust database delay for TCR (coinc. time measurement on R-arm).
    To get 50 nsec more headroom I took 48 nsec out of database and
    added it with physical cable. (Didn't check TCL yet.)

    5. Adjusted RT delays. We were very tight on L-arm, as expected.
    I therefore added 16 nsec to the RT which will move T0 later.
    This will be ok for VDCs and ADCs but we should check scintillator
    TDCs that they're still in range.

    Problems (minor):
    ==================

    1. The EDTM pulser boxes have a limited delay range, so for momentum
    below 950 MeV (helium-4) the coinc. time picture (overlap of
    T1 and T3) will move because the boxes can't "keep up". Of course
    it won't move for physics.
    Going to beta=0.21 (800 MeV) it moves 63 nsec.
    But the pulser still makes coinc.
    Note, fixing this requires minor surgery on EDTM boxes, scheduled
    for summer shutdown.

    2. Ideally the CODA event type for T3 (called g.evtype=3) should
    be pure T3 while type 5 should be T5. However, T3 arrives early
    at the trigger supervisor. It was probably like that last Fall.
    This is no problem if you use D.evtypebits to sort out the trigger
    type. Can't make T3 later because of limited headroom on RT.
    Can't make T5 earlier, it's as fast as possible.

    Things to do:
    ==============

    1. Check T6. Is plugged in and looked ok at a glance but need to
    check for headroom. Alex ?

    2. Makis wants a new T7 defined as T1.and.T4. Not sure if we have
    enough channels of digital delay. I'll think about it tomorrow.

    3. Check TCL (coinc. time on L-arm).

    4. Check scint TDCs -- are they in range ?