GlueX TOF Meeting, July 18, 2013

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GlueX Time-of-Flight Meeting
Thursday, July 18, 2013
10:00 am EDT
JLab: CEBAF Center, F326/327


  1. Announcements
  2. Review of last TOF bi-weekly meeting
  3. Construction news
  4. Installation plan and document
  5. Drop Seevogh connection for TOF meetings?



  1. ESNet: 8542553
  2. SeeVogh:

Desktop Sharing

  1. Go to
  2. In the "join a meeting" box enter the code: 1833622
  3. Fill in the participant registration form.


To connect by telephone:

  1. dial:
  2. enter access code followed by the # sign: 1833622#


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2013-3Q on the JLab CUE. This directory is accessible from the web at .



  • FSU: Paul Eugenio, Sasha Ostrovidov
  • JLab: Chuck Hutton, Mark Ito (chair)

Review of last TOF meeting

We reviewed the minutes of the June 20th meeting.

  • There has not been any progress adding the frame-part machining at FSU to the construction contract. Mark with check with Kathleen Jones on where this stands.
  • We have been having some confusion at JLab on ordering the iron shields. These issues will be resolved soon.
  • Chuck will circulate an updated rendering of the rail support system for the TOF.
  • Paul sent Chuck the set of links to the assembly procedures being followed at FSU. These look like they will suffice for generating documentation do be archived at JLab.
  • We will schedule an installation in the next week or so.

Construction news

Module production

Module production is going forward at the rate of about 8 per week for wrapped modules with light guides and PMTs attached. Paul hopes to finish by the end of August or early September.

The finished modules are tested for light leaks before wrapping with protective felt.

The full cosmic testing procedure is still being developed, but when that is in place six modules a day can be tested.

Re-polishing light guides

It was thought that light guide polishing was finished, but about 40 of them were found with sub-standard surface quality. These were from early in production. They will be re-done.

New shelving

FSU is building new shelving in several of the work areas to store modules: the high bay, testing lab, and wrapping lab. That way if a room is not ready to accept modules from a previous step, those modules can be stored in the room where the previous step was performed, rather than moving them to the final storage room in the basement.


  • Engineering student has taken job in Atlanta and will be moving.
  • A new student started today, one or two more will be hired.
  • Two students that are continuing in their jobs have to move from the university for three weeks due to the end of the summer term.

PMT clippers

Ian Winger has designed and built a tool for easily and cleanly breaking the epoxy joint between the light guide and the PMT in case this needs to be done in the Hall in the future. It has been tested with old PMTs and works well. It is not very long, but in any case Chuck will check the drawings and see if there is sufficient space around the PMTs to apply the tool should it become necessary.

FSU will develop a documented procedure for replacing a PMT. They will use the mini-TOF to test the process.

FADC spectrum

Sasha showed a spectrum of integrated pulses from the FADC-250. Data was obtained from a 5-counter set-up and the trigger was a 10-fold coincidence (5 counters, 2 ends each). Since Fernando replaced the fuses, the one Flash that Sasha has been using has been on for about two weeks now. Clipped pulses are visible and there is mysterious bump at low pulse-height. Sasha is trying to decide where to set the HV for the tests.

Mark reported that he and Beni had been looking at reflections from the 50/50 splitters. Reflections are seen, but are not large.


We decided to discontinue use of SeeVogh for the TOF meetings now that we are using ReadyTalk for desktop sharing.

New Action Items

  1. Check with Procurement on contract modification.
  2. Get the steel shield raw material ordered and shipped.
  3. Circulate updated rail support design.
  4. Find a time for an installation meeting.
  5. Finish study of reflections from the splitter.