GlueX TOF Meeting, June 27, 2017

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GlueX Time-of-Flight Meeting
Tuesday, June 27, 2017
11:00 am EDT
JLab: CEBAF Center, Room F326/327


  1. Announcements
  2. Review of minutes from the previous meeting
  3. Calibration Status
  4. Active Dividers
  5. Counter reconfiguration
  6. NIM Paper (Paul)
  7. Action Item Recap



Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2017 on the JLab CUE. This directory is accessible from the web at .



  • FSU: Sasha Ostrovidov
  • JLab: Thomas Britton, Brad Cannon, Mark Ito (chair), Simon Taylor, Beni Zihlmann

There is a recording of this meeting on the BlueJeans site.

Event Viewer

Thomas announced that the 3-D event viewer project is moving ahead and encouraged us to think about how we would like to have the TOF represented visually.

New Timewalk Correction

  • Beni checked one run with the new correction. There was a problem with the reference paddle, but other than that the correction does as well as the previous scheme.
  • If further checks look good, he will do a full re-calibration of the Spring 2017 data.
  • The new scheme requires new tables to be loaded in the CCDB.

Energy Calibration

  • Brad has succeed in fitting peaks starting from Beni's ROOT file.
  • He has also started the Monte Carlo needed to interpret the energy in the peaks.
  • He is running into a ROOT, issue: the code crashes. He is tracking it down.
  • There is one paddle with a MIP at 9000 counts in the integral. Nominal is half that. Some of the outer counters did have higher gain. He is studying whether we need to lower the HV on this counter.

TOF Efficiency Studies

  • Beni has started looking at TOF efficiency as a function of x-y over the face of the TOF.
  • For charged track that point to the TOF, he checks for a corresponding TOF point.
  • He only starts to see efficiency problems for tracks with momentum less than 1 GeV/c.

PMT Testing

Sasha reports that they have recruited students to do the testing at FSU. They are currently struggling with a non-cooperative Lecroy HV mainframe.

NIM Paper

Beni relayed Elton Smith's suggestion that we put the NIM paper into the GlueX Document Git repository at .