GlueX Target Meeting, April 12, 2011
Tuesday, April 12, 2011
1:00 pm EST
JLab: CEBAF Center, Room F326/327
- Review minutes from previous meeting: all
- Target Mechanical Design: Tim, Chris
- MOU status: Mark
- ESNet: 8542553
- Meeting URL: http://evo.caltech.edu/evoNext/koala.jnlp?meeting=vsvivIe8eIItIvasatItas
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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 https://halldweb.jlab.org/talks/2011-2Q/ .
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.