[Halld-pid] Time-of-Flight Meeting Minutes, October 24, 2018

[Mark Ito]

People,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_24,_2018#Minutes> 
and below.

        -- Mark

__________________________________________


    GlueX TOF Meeting, October 24, 2018, Minutes

Present:

  * *JLab: * Thomas Britton, Ashley Ernst, Mark Ito (chair), Sasha
    Ostrovidov, Simon Taylor, Beni Zihlmann

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


      Announcement

The JAG Tailgate Party is today from 3 pm to 6 pm on the field behind 
the Residence Facility.


      Review of minutes from the October 10 meeting

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_10,_2018#Minutes>. 



        Lucite Shield Simulation

Thomas has transferred his knowledge on the HDDS geometry of the Lucite 
shield to Ashley. The main missing piece is the material definition. She 
has been busy with the calibration but will start on this soon.


        Particle ID Working Group

Thomas has agreed to convene a meeting of the new Particle 
Identification Working group. He will make an announcement next week.


      Two current issues with TOF

Beni and Sasha reported on a couple of areas of concern.

  * TOF ADC config file <https://logbooks.jlab.org/entry/3613851>. Beni
    reported several channels with FADC configuration/performance
    issues. See the log entry for details.
  * Additional info <http://128.186.19.133/%7Eostrov/tof/20181024/>.
    Sasha reports two problems: (1) intermittent drop out of FADC scaler
    channels and (2) strange baseline noise, intermittently on one of
    the channels Beni flagged in his log message. See his addendum to
    the Beni's log entry for details. Beni and Ashley will look at the
    channel on a scope tomorrow during the down time.


      Calibration Status

Ashley showed slides of mean-times[?] measured from a recent run. She 
noted that there are a significant number of channels where the fit does 
not converge. She analyzed a run with four TOF skim files; Beni remarked 
that she needs more events; he recommends using a run with between 80 
and 100 files.


      Upgrade Plan: Option #3

Sasha reported that Paul has been thinking about another option for 
re-configuring the inner region of the TOF. This involves having per 
plane 4 half-length counters (those that do not span the beam hole) of 
3/4 width (4.5 cm wide) and 6 half-width counters (3.0 cm wide). Outside 
of those. See figure below. This is option #3. It has 4 more PMTs per 
plane than the current array. Recall that option #2 has the same number 
of PMTs as the current array. This option does have a problem with 
accommodating the light guides for the three consecutive half-width 
counters; Paul is working on this. Sasha is planning to estimate rates 
for this configuration as well.

Option #3 <https://halldweb.jlab.org/wiki/index.php/File:Option3.jpg>
Retrieved from 
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  * This page was last modified on 24 October 2018, at 16:27.

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

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