[Halld-pid] Time-of-Flight Meeting Minutes, May 23, 2013

[Mark M. Ito]

Find the minutes at 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_May_23,_2013#Minutes 
and below.
______________________________________________

GlueX TOF Meeting, May 23, 2013
Minutes

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

Announcements

      * 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 [26]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 [27]plots of the results
    of the measurements and a few [28]figures showing how modules and PMTs
    have been matched up. Sasha described the [29]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.

    Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_May_23,_2013"

References

   26. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_May_9,_2013#Minutes
   27. http://hadron.physics.fsu.edu/TOF/database/SCIN_led.html
   28. http://hadron.physics.fsu.edu/TOF/database/scin_pmt_match.html
   29. 
http://hadron.physics.fsu.edu/wiki/index.php/Matching_PMTs_to_scintillators

-- 
Mark M. Ito, Jefferson Lab, marki at jlab.org, (757)269-5295