GlueX Target Meeting, April 12, 2011

From GlueXWiki
Jump to: navigation, search

Location, Time

Tuesday, April 12, 2011
1:00 pm EST
JLab: CEBAF Center, Room F326/327


  1. Review minutes from previous meeting: all
  2. Target Mechanical Design: Tim, Chris
  3. MOU status: Mark


Video Conferencing


To connect by telephone:

  1. dial:
  2. enter access code followed by the # sign: 3421244#


Talks can be deposited in the directory /group/halld/www/halldweb/html/talks/2011-2Q on the JLab CUE. This directory is accessible from the web at .


Present: Hovanes Egiyan, Mark Ito, Chris Keith, Rory Miskimen, Tim Whitlatch (chair), Elliott Wolin

  • Tim brought along drawings and notes made two years ago, modeled on the Hall B cryotarget.
    • We may need to pick Steve Christo's brain, especially about lessons learned in Hall B.
    • The Hall B targets are Kapton, with DP190 epoxy joining the seams. The scattering chambers are made of Rohacell.
    • We will have to perform pressure tests on the cells. Current code may be more stringent than standards at the time the Hall B targets were commissioned.
  • The refrigerator will be bought in October or November.
    • The model being considered can liquify hydrogen starting from room temperature, at about a liter per hour, corresponding to 15 watts at 20 K. Liquid hydrogen volume looks to be of order a liter. Helium-4 will take longer to liquify.
    • The requirement that we want to be able to empty/fill the target on the time-scale of a few hours (preferably less) was restated.
    • The refrigerator have no cold moving parts.
  • We will have to design and build the heat exchanger and heating element. The refrigerator will stay on continuously and temperature of the hydrogen controlled with a heater in the cold head.
  • The gas panel can probably copied from that used by Q-Weak.
  • Mechanical considerations
    • The target, its plumbing, and the refrigerator (including cold head) will all be a "rigid body". Adjustment of the position of the target on the beam line will be accomplished by positioning the entire structure.

Items for the Next Meeting

  • Chris will create a P&I diagram for the gas/refrigerator system
  • Chris will distribute the manual for the refrigerator so others can get started thinking about the relevant controls and monitoring.
  • We will invite Steve to the next meeting.
  • Next meeting in about a month.