[Halld-pid] Time-of-Flight Meeting Minutes, July 1, 2020

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_July_1,_2020#Minutes> 
and below.

   -- Mark


    GlueX TOF Meeting, July 1, 2020, Minutes

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

There is a recording of this meeting <https://bluejeans.com/s/5hlOh/> on 
the BlueJeans site. Use your JLab credentials to gain access.


      Announcements

Next week the turn on of the GlueX detector will start in earnest.


      Review of minutes from the last meeting

We went over the minutes from June 17 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_June_17,_2020#Minutes>. 
Sasha reports that the paperwork from Hamamatsu shows that indeed 23 is 
the correct number of PMTs ordered.


      New PMTs testing

Sasha presented results from testing the new PMTs 
<http://hadron.physics.fsu.edu/~ostrov/tof/20200701/>. He described the 
preliminary tests, and the gain measurements using the single 
photoelectron peak. Please see his webpage, linked above, for the plots 
and a nice description and discussion of his results.


      TOF NIM paper

Sasha has complete three sections for the paper.

 1. Testing done during the design phase. This has been entered into
    Overleaf.
 2. Tests done on components before construction.
 3. Tests performed on the completed modules.

He notes that there is some overlap with parts already written by Paul 
and Beni and asked for advice on how to proceed. We encouraged him to 
talk to the authors of the sections in question and/or put the sections 
into the complete paper to facilitate broader discussion of how to 
resolve any conflicts.


      Attenuation lengths in Monte Carlo

Beni brought our attention to two related GitHub issues, one on the 
halld_sim site <https://github.com/JeffersonLab/halld_sim/issues/128>, 
the other on the hdgeant4 site 
<https://github.com/JeffersonLab/HDGeant4/issues/159>. It appears that 
the wrong light attenuation scheme is being used in hdgeant4 giving poor 
agreement between data and simulation for energy deposition, with the 
simulation giving a value a factor of two too low. hdgeant(3) may also 
have pathologies. Beni is actively working on straightening out the 
situation.


      Action Item Recap

 1. Decide on when to ship PMTs to JLab from FSU (Mark, Paul Eugenio)
 2. Start looking at the NIM paper as a whole. (all)
 3. Continue work on the attenuation problem in Monte Carlo (Beni)

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  * This page was last modified on 1 July 2020, at 12:37.

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