GlueX TOF Meeting, August 14, 2019

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GlueX Time-of-Flight Meeting
Wednesday, August 14, 2019
10:00 am
JLab: CEBAF Center, Room F226
BlueJeans: 350 531 998


  1. Announcements
  2. Review of minutes from the last meeting
  3. Upgrade Status
  4. Software Issues
    • Structure of TOF II software
  5. Action Item Recap


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2019 on the JLab CUE. This directory is accessible from the web at .



  • FSU: Ashley Ernst, Paul Eugenio, Sasha Ostrovidov
  • JLab: 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 last meeting

We went over the minutes from the meeting on July 31.

Mark called attention to the item describing the nylon bolts that will be used as physical stops to prevent the vertically-oriented paddles from slipping. Paul wondered if the Lucite shield could be made with an outline to produce a marker (via the boundary between high and low rate regions) of the physical position of the counters so that slippage could be monitored in data. We discussed the idea only briefly.

Construction Status

Paul gave us an update.

  • Jason Barlow and Edmundo Barriga were at the lab last week. They tested all of the modules that will go back into TOF array. A few had some pin-hole-sized light leaks which were taped over. All modules are in working order.
  • Fabrication is finishing up. Three are in need of repair due to the ends of light guides that inadvertently got buffed yielding weak glue joints. The gluing stand does not accommodate modules with PMTs attached; it is getting modified to do so.
  • The wooden boxes are being moved to the area where they will receive the finished modules. Styrofoam is getting cut. The details of the packing procedure are being worked out.
  • The collars are complete and are ready to be packed.
  • The estimate now is to initiate transport of the modules in two weeks time.

Structure of TOF II software

We briefly discussed the plan to keep our software backward compatible with the TOF I geometry while implementing changes needed for TOF II.

  • Ashley described progress so far. She modified the geometry in HDDS. The version of the TOF geometry used will be controlled by the CCDB. Sean Dobbs has modified halld_recon to key off of the number of paddles in the TOF geometry to decide whether to reconstruct the data as TOF I or TOF II.
  • Beni had a discussion with Mark on how to proceed with the calibration software. They proposed that the TOF II calibration be a independent set of code from that developed for TOF II. That avoids a myriad of if-then-else structures in the code.
  • These philosophies are not obviously in harmony. It is not clear that they need to be, but discussion should be had as soon as Sean returns from travel.