GlueX TOF Meeting, March 15, 2012

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Thursday, March 15, 2012
10:00 am EST
JLab: ARC, Room 428


  1. Announcements
  2. Minutes from the last meeting
  3. Mechanical design: Tim, Chuck
  4. Prototype status: Paul, Sasha
  5. TDC choice: all
  6. Contract Status: Mark, Paul
  7. Calibration and Alignment discussion.



  1. ESNet: 8542553
  2. EVO: EVO site


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2012-1Q on the JLab CUE. This directory is accessible from the web at .

Chairman's Cell Phone




  • FSU: Sasha Ostrovidov
  • JLab: Chuck Hutton, Mark Ito (chair), Tim Whitlatch

Prototype Status

Sasha working on attaching the light guides to the prototype in a removable manner.

Mechanical Design

Tim and Chuck have been working on changes from discussions at the last meeting. He remarked that good recommendations were offered by the FSU team.

  • The main support structure has been changed from a bent 1/2-inch plate to machined U-channel, where the basic stock is a standard item. This simplifies the manufacturing considerably, reducing it to machining one edge and possible straightening.
  • Mark reported Elton's concern about avoiding putting pressure on the scintillator to prevent crazing. This would mean support by the light guide only.
    • Tim pointed out that there might be significant stresses on the scintillator even then and wondered if that was a worry. Mark agreed to look into this.
    • Chuck was concerned that the flat section of the light guide next to the scintillator was a bit narrow to be used to support the entire module, given other tolerances that might move the support area. The flat section is only about 1 cm wide.
  • Tim brought re-raised the idea of scale models
    • a full-scale model of a corner of the array as Paul suggested last time
    • a 1/4-scale of the entire assembly, to look for assembly/installation problems
    • If the FSU Physics machine shop is available for this kind of work, then there are huge cost savings.
  • We will aim for another design meeting on Tuesday, March 20. Mark will try to set it up.

Action Items

  • Look into issue of avoiding pressure on the scintillator. -> Mark
  • Set up next design meeting. -> Mark