[Halld-pid] Time-of-Flight Meeting Minutes, November 18, 2020

[Mark Ito]

Folks,

Please find the minutes from our last meeting here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_November_18,_2020#Minutes> 
and below.

   -- Mark

_________________________________________


    GlueX TOF Meeting, November 18, 2020, Minutes

Present: Mark Ito (chair), Sasha Ostrovidov, Susan Schadmand, Simon 
Taylor, Beni Zihlmann

There is a recording of this meeting 
<https://bluejeans.com/s/Ql4TetXuMdl>. Log into the BlueJeans site 
<https://jlab.bluejeans.com> first to gain access (use your JLab 
credentials).


      Review of minutes from the last meeting

We went over the minutes from November 4 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_November_4,_2020#Minutes> 
without significant comment.


      Gain Study

Beni described the study he did to look at PMT gains 
<https://logbooks.jlab.org/entry/3857729> at different beam current 
conditions during the CPP test period in the run just past.

The apparent gains seem to rise significantly, 10-15%, at low beam 
current, which is not what one would naively expect. He think that the 
effect is due to low-level background in the Hall dominating the 
pulse-height spectrum when the beam is on. The spectra are averaged on a 
channel-by-channel basis and there is no coincidence requirement on each 
PMT. Beni plans to look at individual amplitude distributions to confirm 
this picture.

He does see that the response from PMT 69 looks suspicious in this study 
as well as in previous studies.


      TOF NIM paper

Sasha reported that Paul Eugenio has been working on the paper.


      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)


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