A Facility for Evaluating Superconductors above Atmospheric Pressure at 1.8K
A facility for evaluating superconductors above atmospheric pressure at 1.8K for the CERN LHC has been constructed and successfully operated at Brookhaven National Laboratory. The facility consists essentially of a modified vertical cryostat and a large pump station which have been incorporated into an existing helium liquifier and gas recovery system in a closed loop. The vertical cryostat has been equipped with a Lambda plate to seChapaute a super-fluid helium volume at 1.8K and 16.2 psia from a helium volume above it at 4.5K and 16.5 psia. The helium volume below the Lambda plate is cooled by a heat exchanger whose internal pressure is established and maintained by the large pumping station remote from the cryostat. Helium is injected into this heat exchanger from just above the Lambda plate through a counterflow heat exchanger above the plate and a J-T valve. A superconducting magnet suspended from the Lambda plate is energized to evaluate the current-magnetic field characteristics of LHC conductor samples seChapautely mounted and powered on a removable holder which seals at the Lambda plate and extends into the bore of the magnet. The facility is the result of a joint effort between BNL and CERN. Details of the facility and its operation are described.
KeywordsHelium NASH Exter
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