[Halld-pid] Start Counter Meeting Minutes, March 20, 2014

[Mark Ito]

Folks,

Please find the minutes below and at

https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_March_20,_2014#Minutes 
.

   -- Mark
____________________________________________________________________________________

GlueX Start Counter Meeting, March 20, 2014
Minutes

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

    Find a recording this meeting [23]here.

Announcements

    Werner initiated a no-cost extension to the contract. It would have
    expired at the end of the month. The extension has been fully executed
    (both parties have signed).

Review Minutes from Previous Meeting

    We looked over [24]items from the March 6th meeting.
      * "y"-scan with the Test Stand: the time resolution was measured for
        different positions of the SiPMs with respect to the scintillator
        along the "radial" direction. The qualitatively, the results show
        less dependence on position than we might have feared; an offset of
        up to 0.5 mm is not serious. The measurements do need to be
        repeated; the translation stage was damaged and that has been
        holding things up.
      * Eric has been working on the calibration procedure. He has a
        prototype set of classes for doing the calibration. He is drafting
        a proposal for the set of calibration constants we will need. The
        parametrization for the time-walk correction is still being
        studied. He will give a talk on his work at the Calibration Meeting
        next week.

Review of Bruce's Q/A Visit to Eljen

    We discussed Bruce Lenzer's visit and the [25]notes from Mark on the
    conference call we had with folks at Eljen. Things look a lot better
    now. We thought that it really helped that Bruce was able to go out
    there. Thirty good scintillators have already been produced, twenty
    more (to complete the order) should be done in two weeks.

    Eric will follow up with McNeal on taking shipment of these first
    thirty ASAP. Even if they prefer to have all fifty on hand before
    starting production, we would like to know if they like what they see
    with this batch.

Support Structure Construction Status

    Eric gave us a [26]very detailed report on measurements of the
    dimensions of one of the paddles, complete with pictures. The counter
    was wrapped in aluminum foil as we plan to do. This counter with
    wrapping turns out to be the same thickness as the nominal scintillator
    itself, without wrapping, thus this paddle is under spec.

    Eric will go ahead and measure a few more of the paddles on hand at
    FIU.

    We decided if these additional measurements indicate that the width
    being under spec is typical, we will fix on a gap between the
    scintillators of 100 microns when sizing dimensions of the the support
    structure.

    Werner floated the idea of making two aluminum support rings and only
    drilling holes in one, keeping the other in stock in case there are
    surprises.

    Eric suggested we try to get measurements from McNeal as well. We
    agreed that this should be pursued.

    Retrieved from
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_March_20,_2014"

References

   23. 
https://halldweb1.jlab.org/talks/2014-1Q/start_counter_2014-03-20/index.htm
   24. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_March_6,_2014#Minutes
   25. 
https://halldweb1.jlab.org/wiki/index.php/Private:Quality_Assurance_Meeting_with_Eljen,_March_17,_2014
   26. https://halldweb1.jlab.org/talks/2014-1Q/Paddle_Measurements.pdf

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