GlueX TOF Meeting, November 18, 2020

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GlueX Time-of-Flight Meeting
Wednesday, November 18, 2020
10:00 am EST
BlueJeans: 350 531 998


  1. Announcements
  2. Review of minutes from the last meeting
  3. Gain Study (Beni)
  4. TOF NIM paper
  5. Action Item Recap


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2020 on the JLab CUE. This directory is accessible from the web at .


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

There is a recording of this meeting. Log into the BlueJeans site first to gain access (use your JLab credentials).

Review of minutes from the last meeting

We went over the minutes from November 4 without significant comment.

Gain Study

Beni described the study he did to look at PMT gains 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)