[Halld-pid] Time-of-Flight Meeting Minutes, October 25, 2012

[Mark M. Ito]

Find the minutes below and at

 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_25,_2012#Minutes
_____

GlueX TOF Meeting, October 25, 2012
Minutes

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

Announcement

      * The second shipment of 30 PMTs has been sent from Hamamatsu. they
        have not yet arrived at FSU. The [27]nominal shipment schedule is
        posted on this wiki.

Mechanical Design

Mini-TOF Construction

    Paul reviewed [28]his wiki page (standard GlueX username and password)
    showing progress and status. Photos of some of the machined parts are
    also shown.

TOF Gluing Fixture

    Machine shop work for the [29]gluing structure is underway. Parts for a
    nine-bar fixture are being made though only a five-bar version will be
    constructed initially. Ian Winger will start assembly next week.

TOF Module Wrapper

    Paul will put together a wiki page on this item, a long rectangular
    channel to help wrap the scintillator. An example was shown as part of
    his talk at the last collaboration meeting.

Contract Status

Assessment of PMT batch 1

    Sasha has been looking at the 38 PMTs received from Hamamatsu on
    October 5. A MySQL database has been set up to store parameters and
    test results for each tube. See [30]his wiki page for details.

    H showed results from gain measurements done on each tube done by
    measuring the position of the single-photo-electron peak. The results
    track the data sheet from Hamamatsu to about 5% for a given tube.

    The results for quantum efficiency show the first two tubes with vastly
    different values (a factor of four difference). The measurement is done
    with a Americium source and after correction for gain, give a relative
    value for the cathode sensitivity between the two tubes. Sasha is
    checking his set-up.

    FSU will send four tubes, including the two already tested, to JLab and
    the quantum efficiency measurement will be repeated.

Procurements

    The two long-lead-time items are the scintillator and the light guide
    material.
     1. scintillator The PO went out on October 3rd. since then Paul called
        Eljen and he expects the first-article counters to arrive on
        November 21.
     2. light-guide material The order got stuck in FSU Purchasing, but was
        finally issued earlier this week. Ninety-two feet of acrylic bar
        (in four-foot sections) is expected to arrive November 5. The
        machine shop is set up to machine the long light-guides for the
        half-width counters. The first patch of acrylic will feed that
        process. Then they will set up for the standard light-guides.

    Paul is still pursuing getting ESR material in rolls rather than in
    small sheets. He is putting together a specification document to
    explain the intended use and importance of the larger sheets.

Change request

    Mark posted, on the DocDB, [31]documents related to the TOF change
    request we submitted at the end of September. The schedule changes were
    made to facilitate tracking under the Project's earned-value management
    system (EVMS).

    Retrieved from 
"https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_25,_2012"

References

   27. https://halldweb1.jlab.org/wiki/index.php/TOF_PMT_Shipping_schedule
   28. http://hadron.physics.fsu.edu/wiki/index.php/MiniTOF
   29. http://hadron.physics.fsu.edu/wiki/index.php/GluingStructure
   30. http://hadron.physics.fsu.edu/wiki/index.php/GlueX_Time-of-Flight
   31. 
http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2109


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