[Halld-pid] Time-of-Flight Meeting Minutes, December 20, 2012

[Mark M. Ito]

Find the minutes at

 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_December_20,_2012#Minutes

and below.
___

GlueX TOF Meeting, December 20, 2012
Minutes

Present:
    FSU: Sasha Ostrovidov
    JLab: Chuck Hutton, Mark Ito (chair)

PMT Testing

      * There are four undergraduates working on testing PMTs now.
      * 130 PMTs have been received ([22]batches 1, 2, and 3).
           + All of them have been tested with an LED, with gain measured
             via a visible single-photoelectron peak. All tubes passed.
           + 70% of them have been tested with an americium source to look
             at photocathode efficiency
           + 10% of them have been tested with a cesium source on a sodium
             iodide crystal.

Wrapping Material

    Paul Eugenio has succeeded in negotiating purchase of rolls of ESR
    material from 3M, rather than in the 2×3 foot sheets that were
    originally offered. The rolls are 8 inches wide and about 1000 feet
    long. Also, there will be no adhesive layer attached to the material;
    the total thickness will be 1 mil. The purchase order has already been
    sent to 3M. Shipment is expected sometime in January.

Scintillator Bars

    The six scintillator bars for the mini-TOF have been received at FSU: 2
    regular, 2 half-width, and 2 half-length bars. Eljen's [23]measurements
    of the dimensions show that some are out of tolerance by one or two
    mils less than the 5 mil limit. Eljen also shipped [24]performance data
    on the scintillator. (The interpretation of the "light output" spectrum
    a mystery currently.)

    Although they have not been shipped yet, Eljen reports that in the next
    batch of 76 regular bars, 12 of them are 1/8 inch short. A decision on
    whether to accept these has not been made. Chuck will look at the
    mechanical implications.

    Sasha is setting up for measurements on the scintillator received. They
    will be put into the dark box, with a spring loaded mechanism to hold
    the PMTs, and tested with a strontium source at various locations along
    the bar. Both ADC and TDC data will be taken to get attenuation length
    and speed of light.

Mini-TOF Assembly

    All parts have been made for the support structure. Sasha plans to
    finish testing the scintillator this week so that gluing of the light
    guides can start in January. The schedule for starting assembly of the
    complete schedule will also depend on when the ESR material arrives.

Design Work

    Chuck is putting the mini-TOF ideas as they currently stand into the
    design of the complete TOF.

Retrieved from 
https://halldweb1.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_December_20,_2012

References

   22. https://halldweb1.jlab.org/wiki/index.php/TOF_PMT_Shipping_schedule
   23. 
http://hadron.physics.fsu.edu/TOF/doc/Eljen_Dimension_Report-1stArticle.pdf
   24. 
http://hadron.physics.fsu.edu/TOF/doc/Eljen_Scint_Test_Report-1stArticle.pdf

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