GlueX TOF Meeting, December 5, 2018

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GlueX Time-of-Flight Meeting
Wednesday, December 5, 2018
10:00 am EST
JLab: CEBAF Center, Room F226
BlueJeans Meeting number is 350 531 998


  1. Announcements
  2. Review of minutes from the November 7 meeting
  3. Calibration Status
  4. Lucite Shield Geometry File:Tof shielding.pdf
  5. Upgrade Plan
  6. NIM Paper (Paul)
  7. Action Item Recap


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2018 on the JLab CUE. This directory is accessible from the web at .



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

There is a recording of this meeting on the BlueJeans site. Use your JLab credentials to access it.

Review of minutes from the November 7 meeting

We went over the minutes. Ashley and Mark fixed her HDGeant4 problem that afternoon.

Calibration Status

Ashley reported that she had calibrated 216 run from Fall 2018, everything up to run 51734. The constants have been entered into CCDB. There are only a small number of runs left to do.

She had a question about the proper Zihlmann-authored script to use for CCDB entry. She will consult with Beni about the details offline.

Lucite Shield Geometry

Ashley reported that she has a complete geometry for the shield ready to go. For details, see her slides.

  • She met with Paul Eugenio to confirm the number (one) and size (large) of the Lucite sheets that were installed. This was confirmed with measurements she and Beni performed in the Hall. The dimensions have been rendered in the TOF HDDS XML file.
  • She found materials, already in HDDS, suitable for modeling the shield.
  • She succeeded in visualizing the new geometry in HDGeant4.
  • She will consult with Thomas on doing rate studies using MCwrapper. The main goal is to reproduce the rate reduction observed in the Hall.
  • After the meeting she and Mark put the new geometry on a branch of hdds, namely "tof_shield_ace" and pushed it to GitHub. They also built it successfully on ifarm.

Upgrade Plan

Paul was unable to attend but after the meeting sent slides detailing his latest thinking about the TOF upgrade, including two options for geometry changes and corresponding cost estimates. Sasha reported that rate studies are underway and he sees a reduction of a factor of two in the rate in the highest rate counters.