20 kA HTS Current Leads for the INFN Magnet Test Facility

The Italian National Institute for Nuclear Physics, within a larger cooperation with other partners, is setting up a new facility at University of Salerno for testing superconducting magnets for accelerators. The setup includes, further to the supercritical He 200 W@4.5 K refrigerator, and the 20 kA power converter, a suitable pair of HTS 20 kA current leads. To keep an optimized system flexibility, the current leads are designed with HTS technology, which allows for reduction of both the conduction heat leak on its cold end, and the Joule heating. In addition to match the cryogenic plant features, the current leads, at current level below 10 kA, are designed to operate with cold He flow provided by the refrigeration plant, thus avoiding LN2 flow. When running the current leads at full current we shall use an additional LN2 bath and evaporation stream to boost the He refrigeration power needed in the copper section of the current leads. This cooling scheme requires a dedicated design of the heat exchangers. In this work we report the numerical analyses of the current leads, concerning only the normal conducting section, to support this refrigeration scheme which have to match two different heat loads.