A Gaseous-Helium Cooling System for a High-Tc Superconducting Coil
A gaseous-helium cooling system for a high-Tc coil operating at 20K is described. The system uses a two-stage Gifford-McMahon (GM) coldhead and counterflow heat exchangers to cool a pressurized flow of helium gas from room temperature down to approximately 19K. The cold helium gas circulates through a vacuum-insulated transfer line to a single-pass heat exchanger in contact with an epoxy-impregnated high-Tc coil The coil was wound using 2000 meters of Bi-2223 tape produced by Intermagnetics General Corporation (IGC). A water-cooled rotary compressor supplies pressurized helium gas to both the GM coldhead and the helium gas cooling circuit, in parallel. Descriptions of the coldbox configuration, the flow control and temperature monitoring systems, the high-Tc coil, and the test dewar are given. Test results, including the cooldown and energization of the Bi-2223 coil, are included.
KeywordsHeat Exchanger Coil Heating Heat Leak Coil Heat Exchanger Coil Assembly
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