[Halld-pid] Minutes, GlueX Target Meeting, Dec. 21 '10

[Mark M. Ito]

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Target_Meeting%2C_December_21%2C_2010#Minutes 
and as text below.

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GlueX Target Meeting, December 21, 2010
Minutes

    Present:
      * JLab: Hovanes Egiyan, Mark Ito (chair), Chris Keith, Yi Qiang, Tim
        Whitlatch, Elliott Wolin
      * UMass: Rory Miskimen


Refrigerator Capacity

    Chris talked to the manufacturer of the pulse tube refrigerator we are
    considering and was told that the most common use of the unit was for
    helium liquefaction, so operation of a ^4He target would not be a
    problem. It should provide 1.5 W at 4 K. At liquid hydrogen
    temperatures is should be able to provide 20 to 30 W.

    Hovanes mentioned that for photon running in Hall B with hydrogen the
    target uses about 5 W. A heater is used to regulate the temperature
    (and thus prevent the hydrogen from freezing). A few Watts needs to be
    provided typically.

    Chris also noted that in Halls A and C they typically run hydrogen at
    19 K, at about 3 psi over atmospheric pressure, supercooled to avoid
    bubbles.

    Helium-3 requires more power and is not in the plan at present.

Work Plan

    Chris plans to start work on our target system this Spring. He and Tim
    have identified some of the major work areas:
      * gas system
      * refrigerator system
      * heat transfer system

    Right now he is swamped with polarized target work for Hall A.

    Chris: contact physicist to be able to operate target without adult
    supervision

Controls

    Hovanes brought up the issue of controls.
      * Chris has starting looking at the flow diagrams for the Saclay
        target system in Hall B. He thinks things can probably can be
        simpler.
      * In Halls A and C the dependence of externally controlled valves has
        been minimized; mechanical controls are used whenever possible. We
        should probably do the same for Hall D.


Schedule

    Mark flashed the [25]target costs and schedule that is in the current
    baseline. As part of the ETC change request Tim is updating this
    section (WBS 1.5.5.2) adding some new items and updating cost estimates
    and starting dates. For example, the purchase of a refrigerator is not
    in the current baseline. Right now both he and Chris do feel we are in
    any sort of schedule trouble.

Next Meeting

    We decided to meet again in 4 weeks. Mark will schedule a meeting.

    Retrieved from
    "http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Target_Meeting%2C_December_21%2C_2010"

References

   25. https://halldweb1.jlab.org/talks/2010-12/12%20Gev%201552%2020Dec2010%20PMC.pdf

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