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    User name V. Sulkosky

    Log entry time 15:43:24 on May 10, 2011

    Entry number 358826

    This entry is a followup to: 358785


    keyword=re: R-HRS timing issue

    I rechecked the timing on the right RHS.  All the cabling appears to be 
    correct.  I also checked the source of the stops and gates for the TDCs 
    and ADCs, respectively.  The TDCs stops have traditionally come from the
    back plane of the fastbus crates via thick twin-ax cables.  This is still
    true.  The ADCs receive their gates from the front panel inputs.  The 
    path for the gates still follow the same cabling used from APEX last 
    I took a series of runs with different configurations.
    Run 3397 is from April SRC running on 4He.
    Run 4315 is the first carbon run we took on Sunday evening.
    Run 4334 is from cosmics taking during Tuesday owl shift
    Run 4342 is with the strobe signal unplugged from the retiming module
    This causes about a 112 ns shift in timing.
    Run 4343 is with the strobe ECL cable inverted before going into the 
    retiming module
    With the strobe ECL cable flip, the timing peak in S1 for run 3397 from
    April and the cosmic run 4343 taken today fall on top of each other.
    This seems to indicate that the polarity of the strobe signal was flipped
    during SRC and must have gotten flipped back right before or 
    during x>2.
    For now, I left the strobe ECL polarity flipped.  We will check the 
    right arm timing once beam comes back.

    A copy of this log entry has been emailed to: fomin,doug,rom,camsonne,yez,eip@tauphy.tau.ac.il , sgilad@mit.edu,igor.korover@gmail.com,nmuangma

    RHRS Timing Comparison