GlueX TOF Meeting, May 23, 2013

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GlueX TOF Meeting
Thursday, May 23, 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



  1. ESNet: 8542553
  2. SeeVogh:

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To connect by telephone:

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Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2013-2Q on the JLab CUE. This directory is accessible from the web at .



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


  • Twelve splitters have been sent from JLab to FSU as per Paul's request. They have not been received yet.
  • FSU has requested two LeCroy 1450 series HV cards to instrument their set-up. Sergey Boyarinov of Hall B agreed to lend them to us. We are waiting for Sergey Pozdnyakov to return from vacation; he will pull the modules for us.

Review of last TOF bi-weekly meeting

We went over the minutes of the May 9th meeting. Points raised during discussion included:

  • Testing of all scintillators is done. The attenuation lengths vary from 240 to 410 cm. (See discussion below).
  • Sasha has started work on the driver software for the FADC-250.
  • Mark has still not seen the detailed invoice information. Paul was shown the proposed breakdown earlier in the week. It was may have already been sent to JLab Procurement.
  • The cost of scintillator has not appeared in the invoices, but was only paid by FSU recently. That cost should appear in the next invoice.
  • At the assembly and installation meeting two Fridays ago, Chuck presented assembly plans, and received comments. He is working on the final drawings for the support structure. The next meeting will be mid-June. The FSU technical staff will attend that meeting to discuss having FSU machine some of the parts for the structure. Paul asked whether we need a contract for that work, and we did not think that that was necessary, but Mark will raise the issue with Tim Whitlatch. Chuck is focusing attention on drawings for pieces that can be fabricated at FSU.
  • David Lawrence has continued to work on translation tables and he will produce a document summarizing the scheme for us to review.
  • Beni re-iterated his commitment to changing the geometry in the simulation to reflect the half-width counters.

Construction News

Counter and PMT Matching

Paul asked us to recall that they have been holding off gluing new modules until all of the scintillators have been tested and had their attenuation length measured so that that can be considered in module placement and matching with PMTs. Sasha showed plots of the results of the measurements and a few figures showing how modules and PMTs have been matched up. Sasha described the criteria used for the various module types. Generally speaking, the criteria considered were:

  1. pair noisy PMTs with quiet ones
  2. match PMTs of similar gain
  3. put scintillators with long attenuation length in the center
  4. put high gain PMTs in the center

FSU raised the question of whether the noisy tubes should all be on one side, or should they be randomized or alternated. Paul thought the same side would make it easier to spot systematics, Mark thought alternating would help in cases of neighboring counters hit by the same particle near the ends. We decided to continue the discussion offline.

Construction Updates

  • There are now five complete modules in the test lab.
  • Nine more modules have light guides glued on and are ready for wrapping.
  • Many of the procedures are being streamlined, mainly to do assembly steps in batch where possible rather than module at a time. For example
    • gluing several modules before wrapping.
    • testing light guides in the light box
    • sanding to prepare the light guide surface for gluing
    • preparing the ESR for wrapping
  • There is now a new template for cutting the ESR pieces used the wrap the curved light guide portion of the modules.
  • A new procedure has been instituted where the protective wrap around the scintillator is tagged and bagged when it is removed just before wrapping, leaving physical evidence that it was in fact removed. Paul noted that Maurizio is keeping careful track of who is doing what as the work by the students progresses.
  • Maurizio finished the five PMT-to-light-guide gluing fixtures.
  • Maurizio has been working on stiffening the shelving that will store the complete modules.
  • FSU is working to build a shipping box prototype, to validate the design.

Testing a Complete Module

Mark encouraged FSU to go ahead and test one of the completed modules, at least crudely, to validate the full design and complete construction method, and not to wait for the flash ADC driver development or the final configuration of the module test stand. FSU agreed to do some tests right away using the previously used set-up with short trigger counters. Mark thought that those results would be interesting, even without time-walk corrections, for proof-of-principle. Sasha noted that that kind of test would not take long to do.

Collaboration-wide Meetings

Paul mentioned that now that the semester is over he will be able to present progress at the bi-weekly collaboration meetings and at the bi-weekly installation meetings.

Procedures for JLab

Mark mentioned that we need to have copies of all of the procedures followed during construction for archival purposes and for reference in the drawings. Since Chuck is finalizing some of the drawings now, we need to get started transmitting the information. We agreed to discuss details of format and organization for these documents offline.

Related to the drawings, Chuck asked for specifications for thickness and manufacturer for the ESR wrapping material. Paul will send him a copy of the PO.