Development of 40 tesla class hybrid magnet system

The construction of a 40-T class hybrid magnet system is in progress at the National Research Institute for Metals, Japan. The present design concept for this system includes a 15-T superconducting magnet with a room-temperature clear bore of 400 mm and a 20-T polyhelix-type water-cooled resistive magnet with a clear bore of 50 mm, and a 25-T resistive magnet with a clear bore of 30 mm. The total maximum field to be reached is 40 T for the clear bore of 30 mm, and 35 T for the clear bore of 50 mm. Analytical results on the mechanical stress induced in the magnet system are presented. A new design of a Cu-housing conductor with vacancy is proposed for reducing the transverse compressive stress of the Nb/sub 3/Sn monolith. Cu-Al/sub 2/O/sub 3/ and Cu-Cr alloys are used as the conductor materials for the 25-T and 20-T water-cooled magnets, respectively. The final designs of the water-cooled magnets are also presented.<
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