GlueX TOF Meeting, July 31, 2019

From GlueXWiki
Jump to: navigation, search

GlueX Time-of-Flight Meeting
Wednesday, July 31, 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
  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: Edmundo Barriga, Ashley Ernst, Paul Eugenio, Sasha Ostrovidov
  • JLab: Mark Ito (chair), Tim Whitlatch

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 17. Mark got the shipping authorization and the modified loan agreement in place so that Paul could take the PMTs down to FSU.

Upgrade Status

Paul was at JLab last week and worked with engineering and technical staff in the Hall. The week's activities went well:

IMG 20190729 115119.jpg

  • The TOF was un-mounted and dis-assembled. See the photo above.
  • Modules were inspected for damage. All light guides and phototubes were intact. There were only minor tears in the Tedlar wrapping in a few locations.
  • Nearly all the vertically-oriented modules showed a significant shift (up to an inch) in the downward direction relative to the iron shields and thus relative to the frame. The bottom tubes were sticking out, the top tubes were recessed in their shields.
    • Nylon bolts will be threaded through new tapped holes in the bottom row of shields to provide a physical stop against motion of the tubes in their shields.
  • The rubber strips that are compressed the between the steel frame and the scintillator needs to be replaced.
  • Also, the soft foam padding that supports the light guides in their channel will be replaced. Paul will send Tim his records of the material we used last time.
  • All modules will need to be tested. Edmundo and Jason Barlow (students from FSU) will arrive next week to perform the tests. JLab folks need to help get them set up with a scope and HV supply as well as room to work in the Hall.
  • There are some new holes that need to be drilled in the frame for the new positions of the inner modules. The frame will be completely disassembled to drill those holes. Records of relative orientation and location of any shimming will be made first.
  • The new modules will be shipped directly to the Hall, not staged in ESB as they were last time.
  • Paul will check progress of the machine shop on the remaining collars.
  • All of the short modules have been tested at FSU.
  • There were a few modules where the light guide ends were buffed after polishing, potential compromising the strength of the glue joint. Paul has been mechanically stressing the joints to make sure no weak ones make it through.
  • Tim had asked Stephanie Worthington to produce drawings of the acrylic beam hole support box from the 3-D model and send them to Paul.
  • Mark asked Paul to send him the serial numbers of the tubes that were mounted on scintillators Y-22, Y-23, Y-24, and Y-25 (short modules, oriented horizontally) to confirm their location in the (legacy) channel map he is putting together.

Software Issues

Ashley reported that the reconstruction software has been changed by Sean to reflect the upgrade based on the geometry prepared by Ashley. They are in the process of testing and hope to produce monitoring histograms from simulated bggen data.