[Halld-target] GlueX Target Meeting Minutes, May 17

[Mark M. Ito]

Find the minutes at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Target_Meeting%2C_May_17%2C_2011#Minutes 
and below as text.

   ==

GlueX Target Meeting, May 17, 2011
Minutes

    Present: Hovanes Egiyan, Jim Fochtman, Mark Ito, Chris Keith, Tim
    Whitlatch

Requirements

    We went over the [26]target requirements list that Tim prepared. The
    following items came up in discussion:
      * Five hundred Gauss on the cold head is maximum according to the
        manufacturer. Is this OK?
      * We want to be able to cool the target in one shift.
      * The average diameter of the target is spec'ed at 2 cm. Is that OK?
      * Length of target is 40 cm: can this be finalized?
      * The maximum OD of the scattering chamber driven by start counter
        and that is driven in turn by the CDC.
      * What is the alignment requirement for target?
      * How well do we have to know the density of the liquid?

    Additional requirements were raised in the discussion:
      * specification of quality of scattering chamber vacuum (prevent
        freezing material on target)
      * flammable gas compatibility of system
      * interlock of nearby electrical systems and/or ignition sources if
        target cell ruptures
           + hydrogen gas sensors will be needed
           + pressure switch on vacuum chamber
      * specify stainless steel tubing
      * specify welding whenever possible


Drawings

    Tim showed the current [28]drawing of the target, scattering chamber,
    and start counter area from Slava.

P&ID

    We looked over the two versions of a [30]piping and instrumentation
    diagram for the target that Chris prepared
      * Hydrogen and deuterium tanks outside connect to a single line going
        to the Hall.
      * A vent line goes outside hall; a manual valve is provided.
      * The vacuum pump needs an explosion-proof motor.
      * In the second version, the gas panel is mounted outside hall so
        changing gas could be done without access to the Hall. It would
        still be manual operation.

    Other considerations:
      * We could put gas panel and control electronics in the "target"
        rack.
      * Electronics needed:
           + temperature controller
           + local visual read-back for pressure transducers would be nice
             to have
           + turbo controller for scattering chamber
           + vacuum gauge controller
      * These designs allow automatic transition to cold gas in the target
        cell, but not to vacuum.


Next Area of Work

      * The next step is to work on the mechanical design for target
        condenser, cell, scattering chamber.
      * We may not want to have the cold head provide any mechanical
        support; copper braid could provide flexible thermal coupling.
      * Jim will contact Chris to work out issues before the next meeting

    Retrieved from
    
"[32]http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_Target_Meeting%2C_May_17%2C_2011"

References

   26. 
https://halldweb1.jlab.org/talks/2011-2Q/Hall%20D%20Target%20Requirements.docx
   28. 
https://halldweb1.jlab.org/talks/2011-2Q/GlueX%20Target%20General%20Layout-Sketch-1.pdf
   30. https://halldweb1.jlab.org/talks/2011-2Q/p_and_i_target.pdf