[Halld-pid] Time-of-Flight Meeting Mintues, October 21, 2014

[Mark M. Ito]

Folks,

Please find the minutes below and at

https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_21,_2014#Minutes 
.

   -- Mark

_______________________________


  GlueX TOF Meeting, October 21, 2014 Minutes

Present:

  * *FSU*: Hussein Al Ghoul, Sasha Ostrovidov
  * *JLab*: Mark Ito, Aristeidis Tsaris, Beni Zihlmann


    Work in the Hall

Aristeidis brought us up-to-date with recent TOF work.

  * He conducted a cross-training session on October 13 for would-be TOF
    experts along with the start counter training conducted by Eric Pooser.
  * There were two inefficient modules in the monitoring histograms last
    week. See the vertical band on page one of his plots
    <http://hadron.physics.fsu.edu/%7Earisteidis/fix.pdf>. He traced
    this to a double swap, both the high voltage and the signal cables
    from neighboring PMTs had been exchanged.
  * Two channels showed a negative overshoot in the ADCs. See page two
    for the waveform. This was fixed by swapping out the cables from the
    splitter to the ADCs for new ones for both channels.
  * He has checked in the initial set of online monitoring histograms
    for the TOF.
  * He is working with Simon Taylor to incorporate a TOF display into
    hdview2. This version is like the "simple viewer" developed at FSU.


    The Mode 7 Blues

  * Data taken over the weekend (24 million events) in mode 7 has
    problems with the ADCs
      o Mode 7 does not have waveform data, instead it reports pedestal,
        pulse integral, and leading-edge time.
  * The read-out threshold was set at 10 counts, when the pedestal value
    was 200. Only pulse integral data was non-zero as expected for this
    (mis-)configuration.
  * Aristeidis tried a value of 200 counts for the threshold and some of
    the channels were fixed.
  * He will try 210 and see if they all come around.
  * Beni suggests a 5 sigma threshold. Sasha reports that the pedestal
    width is about 1 to 2 counts.
  * We discussed an appropriate value of the number of samples before
    threshold crossing (NSB) and the number after threshold crossing
    (NSA) that are kept in the pulse integral. We decided that NSB = 10
    and NSA = 45 were good values. There is another pair of NSB/NSA
    parameters for the trigger. We were not sure how they are used.
  * Aristeidis noted that the stand-alone TOF trigger could not be run
    from Sergey Furletov's general DAQ GUI, only by using the system
    that Sascha Somov set-up for us. We thought it would be nice if we
    could run both ways.
  * The standalone trigger was broken recently. Sascha S. fixed it; we
    don't know how.


-- 
Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295

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