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    User name R. Michaels

    Log entry time 03:17:05 on July 8,2010

    Entry number 330748

    This entry is a followup to: 330740

    keyword=re: strange timing

    I investigated a little more the strange timing peaks.
    Here's an example.

    L.s2.lt[2] and others have two peaks for the event types 4 and 1.
    For event type 1 they look like self-timing peaks.

    These correspond to two VDC time spectra shifted by 200 units =
    100 nsec. A very obnoxious correction. It's as if there were
    after-pulsing on the S2 phototubes but I think it's not that simple.

    Meanwhile for R-HRS there doesn't seem to be the same double
    peaking for the same run (fig 2). T4 is coinc and T3 shows a
    self-timing peak. The lack of a jump for R-HRS T4 suggests
    there is no after-pulsing in the L1A (gates).

    Right now I think there is a flakey module on L-HRS downstream of
    the trigger supervisor, involved in the gates.
    It would help a lot if we could observe this with cosmics or a pulser
    because then it could be isolated during an access.


    FIGURE 1

    FIGURE 2