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    User name Templon

    Log entry time 23:26:22 on October 6,2000

    Entry number 49579

    keyword=trigger downloading and more notes on coinc time

    some notes (important for change to py-1e this morning). we are flying blind
    since we cannot see the coinc time peak at these kinematics, since the
    corrected time optimization is not working. however, bob and i independently
    checked how the gate was set. bob's notes are in the paper logbook.
    here are mine. i went thru and looked at the coinc time peak (tc spectrum,
    not tc_cor). for the other kinematics. i also checked with bob's program
    to calculate the TOF in the hadron arm vs. hadron momentum. since
    TOF changes there with momentum, different hadron settings require
    different coinc triggers and hence the trigger downloading.
    here is what i found:

    
setting	mom(p)	peak pos	TOF
    
PY-1B	 869.9	160.2	40.00
    
PY-1C	1014.8	169.9	30.75
    
PY-1D	1193.5	178.0	23.11
    
PY-1E	1430.5	[184.5]	16.64
    
PY-1F	1657.1	[188.5]	12.67

    one can see that there is a linear correlation with slope (minus) unity for
    PY-1[B,C,D] between our peak posn and TOF. The last two peak pos
    are predicted ones based on the supposition that Bob's TOF calc continues
    to be correct as p goes up ;-) Right now, our coinc window is from
    150 to 210. So right now, we are a little bit to the right of center.
    When we switch to PY-1E it only gets better. Hence there is no need
    to download a new trigger for the new setting.