[Halld-pid] Start Counter Meeting Minutes, June 26, 2014

[Mark Ito]

Colleagues,

Please find the minutes below and at 
https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_June_26,_2014#Minutes 
.

   -- Mark
___________________________________________________

GlueX Start Counter Meeting, June 26, 2014
Minutes

    Present:
      * FIU: Werner Boeglin, Eric Pooser
      * JLab: Chuck Hutton, Mark Ito (chair), Beni Zihlmann

Readiness Review

    Eric reported that he has a rough draft of all procedures for
    construction, with the exception of the polishing procedures (which
    have not been finalized, see below). He plans to compile all of them
    into one document in advance of the review.

    At the last meeting we decided on July 8 for the review. We thought
    that that was still a good date, even considering recent events (see
    below).

Construction News

    Eric gave us an update.
      * The support structure arrived safe and sound at FIU. It has been
        mounted on the assembly jig; no problems with the fit.
      * They are starting to play around with the assembly jig now that the
        support structure is in place. They are practicing with old
        scintillator test pieces.
      * Werner has sent an email to Robert McNeal detailing the problems we
        have encountered with their work and asking for some form of
        compensation. McNeal has responded via voice-mail; they are looking
        into it.

Scintillator Rehabilitation

    Eric gave a presentation on steps being taken to improve surface
    quality of the scintillators and on timing test results. See [18]his
    slides for complete details. Some take-aways:
      * Polishing improves surface quality, both visually and in the timing
        tests.
      * The haze reported previously is not visible after polishing.
      * Time resolution from unpolished scintillator is not much different
        from "good" prototype counters.

    These are encouraging results.

    There is the remaining question about long-term damage due to use of an
    inappropriate cleaning solution. It is too early to judge now; if
    effects appear, they may not occur for another few weeks.

Other Items

      * Werner proposed looking at the paddles under a microscope as had
        been done in the past.
      * The light tightening discussion has been deferred due to recent
        events.
      * FIU asked about dates for Nick Sandoval's trip to Miami.
      * It turned out that there was no problem with the SiPM in the test
        set-up at FIU. Nick looked at it and returned it to FIU. The
        trigger circuit for the test set-up was the culprit.

References

   18. https://halldweb1.jlab.org/talks/2014-2Q/Polishing_Tests.pdf

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