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    User name R. Michaels

    Log entry time 15:50:51 on June 6,2007

    Entry number 204466

    Followups:

    keyword=Need no trigger timing mods for e03101

    The experiment e03101 cares about T1,T2,T3,T4,T5.
    They do not care about T6,T7.

    This halog documents what has to be done to accomodate
    the kinematic range of e03101. According to my notes, the
    experiment sometimes runs with the L-arm slower by 38 nsec.
    The trigger GUI has already been modified to allow this,
    and to allow protons on both HRS. The GUI is also
    compatible with continued running of helium-3 & 4.

    The "bottom line" is that *NO* CHANGES are needed to
    the trigger hardware or database !!

    Here are the details for Alex and whoever cares to digest.

    When we adjust momentum (equivalently delay time difference
    between HRS), we adjust 5 things relevant to T1-T5:

    1. T1 delay by delay module "Rdelay1" in 1st 4 channels.
    When L-arm is slower, we must add delay. We have 160 nsec
    of headroom to add on this module --> ok.

    2. L1A delay by Rdelay2, 6th thru 9th chan. Slow L-arm must
    reduce this delay, have 96 nsec headroom --> ok. (Note,
    the minimum delay is 8, so a "0" is actually an 8.)

    3. T2 delayed in Rdelay1, 7th - 9th. Slow L-arm must add delay,
    have 32 nsec headroom (a shortfall of 6 nsec, which is quite ok).

    4. Coinc. time TCR, 10th-16th in Rdelay2, Slow L-arm must subtract
    some delay. We have tons of headroom here (504 nsec !).

    5. Coinc. time TCL, 4th-9th in Ldelay2, Slow L-arm must add delay,
    have 160 nsec headroom --> ok.

    Therefore, all requirements of e03101 will be met transparently
    by the trigger as it exists. Not surprising, since 38 nsec is
    not very much.