[Halld-pid] Minutes, Time-of-Flight Meeting, February 2, 2012

[Mark M. Ito]

Colleagues,

Find the minutes at 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_February_2,_2012#Minutes 
and below as text.

   -- Mark
   _____

GlueX TOF Meeting, February 2, 2012

Minutes

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

Minutes from the last meeting

    We reviewed the [22]minutes from the January 19th meeting. Some items
    received continuing discussion in this meeting. See below.

Contract

    Procurement at JLab and the Office of Sponsored Research at FSU are in
    touch and are exchanging information about the construction contract.

Mechanical Design

    There have been a couple of conference calls with the design teams on
    the design of the light guides for the half-width (or split) paddles.
    We have agreement on a final design in hand.

    Chuck showed the [23]latest drawings, demonstrating the assembly steps
    we might follow on the floor of the Hall.

    We talked a little about how the thickness of the scintillator wrapping
    material affects the design. Paul agreed to send us numbers on the
    thickness.

    Paul showed a jig, produced by his machine shop, for gluing PMT's to
    the light guides. The light guide is housed in an aluminum frame and
    there is a clamp for holding the PMT while the glue dries.

Prototype Status

    Sasha showed [24]results from on-going tests of the eight-stage
    phototubes from Hamamatsu. The gains are a several times lower than for
    the ten-stage, as expected, but still show good separation from
    pedestal. Efficiency was reduced to about 80% when using a 30 mV
    discriminator threshold, for triggers in the middle of the counter (no
    amplification). Time resolution measurements are in the works.

TDC Choice

    Paul was wondering if there is any data-acquisition-based reason for
    not using the CAEN VX1290 TDC's. They see better performance with this
    unit than with the F1 TDC at FSU, both with a pulser and with detector
    pulses. They are purchasing the unit they have; up until now it has
    been on loan from CAEN. Paul is willing to loan it out if that helps
    answer any questions.

    Mark promised to ask the DAQ folks if there is any fundamental reason
    we cannot use it.

Action Items

     1. Paul agreed to send us numbers on the thickness of the scintillator
        wrapping.
     2. Mark will ask about compatibility of the CAEN VX1290 TDC with the
        GlueX DAQ.

    Retrieved from
    
"https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_February_2,_2012"

References

   22. 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_January_19,_2012#Minutes
   23. https://halldweb1.jlab.org/talks/2012-1Q/tof%20assy.pptx
   24. 
https://halldweb1.jlab.org/talks/2012-1Q/First%20results%20from%208-stage%20PMTs.html

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