GlueX TOF Meeting, July 3, 2019

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GlueX Time-of-Flight Meeting
Wednesday, July 3, 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 Slides
  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: Paul Eugenio, Sasha Ostrovidov
  • JLab: Fernando Barbosa, Eugene Chudakov, 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 June 19.

  • We re-agreed that we should use the scheme that Fernando is proposing where the cables and labels undergo minimum disruption in the Hall. The number will have to be adjusted via the translations table for the software to work.
  • Paul has asked Nick Sandoval and Chris Stanislav to transfer channel labeling, currently present only on the shields to corresponding positions on the frame. The shields will be removed during the upgrade and thus the label positions will be lost.
  • Fernando told us we are good on splitters in response to Mark's question.
  • Fernando told us we have a spare TDC in response to Beni's question.

Late PMT delivery schedule

Mark reported that the PO for the additional 17 new PMTs for the upgrade as issued has a delivery date of October 25, too late for incorporation into new modules. He spoke with Ardavan Ghassemi of Hamamatsu. Ardavan will contact the factory and see if delivery can be advanced, but it is very unlikely that the PMTs will come early enough. From the discussion:

  • We have 25 new tubes in hand, all at FSU, plus some spares. The new tubes were ordered to bring the FSU supply to 48, the number of additional tubes needed for the upgrade. So we are 23 tubes short.
  • The new plan is to use tubes from the current array for the new modules. There are 40 tubes in the current array that will come down when modules are replaced. Paul will be traveling to JLab this month and will remove them from their modules as installed in the Hall. A manlift will be required. Radcon will have to be contacted to survey the tubes before removal from the Hall.

Delivery of completed modules to JLab is still on track for the end of July.

Construction Update

Paul gave us an update.

  • Light guide material ordered from one of the two vendors we used showed reduced transmission in the UV, despite assurances that the modules came from the same manufacturer used by the other vendor. Paul showed plots of transmission data that demonstrate the effect. See the figures below. Additional material has been ordered and the sub-standard light guides are being remade.


  • The stock of ESR on-hand at FSU turned out to be less than expected. Paul contacted 3M. They do not sell ESR in the size we need (they sell small sheets, not rolls) but Paul was able to find an engineer who, after being told of the scientific value of our project, donated a roll for our modules.
  • All of the scintillator is now wrapped with ESR.
  • The light guides are mostly made, polished, and wrapped.
  • The gluing of light guides onto scintillator has started.
  • PMTs have been attached on some modules.
  • A test of a complete module will be done next week.
  • There is a wiki page at FSU (password required) with information on the upgrade. Here, for example, is a diagram of where the various light-guides go.


  • The shipping box has been designed and list of materials drawn up. Paul will send the information to Mark to get it ordered.
  • The new iron shields (8 of them) are in-house now and will get primed and painted.
  • We need to follow up with Tim Whitlatch on the status of the support brackets.

TOF Upgrade Geometry

Ashley had complete the new HDDS files for the upgraded TOF. She has checked it in on the branch "tof_upgrade" on the HDDS GitHub repository. She showed slides with diagrams containing all of the information needed for the new geometry, all shown in contrast to the analogous components of the old geometry.