[Halld-pid] Time-of-Flight Meeting Minutes, September 23, 2020

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_September_23,_2020#Minutes> 
and below.

   -- Mark

____________________________________


    GlueX TOF Meeting, September 23, 2020, Minutes

Present: Eugene Chudakov, Mark Ito (chair), Sasha Ostrovidov, Simon 
Taylor, Beni Zihlmann

There is a recording of this meeting 
<https://bluejeans.com/s/xuLlTUxjlLK/> on the BlueJeans site. Use your 
JLab credentials to gain access.


      Review of minutes from the last meeting

We went over the minutes from September 9th 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_September_9,_2020#Minutes>, 
hot off the presses. We mainly discussed repairs to the TOF during the SAD.

  * Sasha mentioned that he thought if there is broken light guide on at
    the top of the array, it might be able to be repaired without
    dismounting the entire array.
  * Beni told us is the next step is for him to do a comprehensive
    review of counter performance and identify candidates for PMT
    replacement or light guide repair.
  * We agreed we should contact Paul Eugenio and discuss the idea of
    getting him up hear to effect/supervise repairs. Such a plan is
    hugely complicated during a pandemic, clearly.


      Calibration

  * Beni reported that there are still a few runs from the end of the
    run period that need calibration.
  * He also has done a re-calibration of the bulk of the runs after
    fixing a problem with peak finding in the distributions of the L-R
    time differences. He did not have to re-do the walk corrections,
    thus avoiding the problematic ADC reported previously.
  * There was an email discussion about the size of the TOF calibration
    skim. Beni needs to got through 70 files per run, which is a large
    fraction of the total raw data, mainly to get enough exposure for
    the outer counters. There was even a thought about a special trigger
    to help out with this requirement. Mark will forward the messages to
    Beni.


      TOF end-of-run report

  * Beni turned off all of the detector voltages after the run had ended.
  * The electronics in the Hall are still mostly on. The decision on
    when to turn them off has not been made.


      Upcoming Run

Beni noted that SRC and PrimEx do not have any special requirements for 
the TOF, but they should be aware that tracking is needed to verify the 
calibration. Eugene reminded us that SRC uses a normal GlueX set-up, 
just with a different target and that PrimEx will run without the 
solenoid field and will not use the tracking chambers. He also mentioned 
that there was some straight track running in the summer run just past.


      Action Item Recap

 1. Decide on when to ship PMTs to JLab from FSU (Mark, Paul Eugenio)
 2. Prepare a complete draft of the TOF NIM paper. (all)
 3. Make a plan for TOF repair during the SAD, including Paul in the
    discussion. (all)
 4. Send TOF calibration skim email discussion to Beni. (Mark)


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