Conductively cooled Nb/sub 3/Sn magnet system for a magnetic refrigerator

A Nb/sub 3/Sn magnet system for use in a magnetic refrigerator has been developed and tested. The system incorporates four asymmetric windings arranged as two Helmholtz pairs to produce two profiled field regions, required for a Carnot cycle. System components are cooled by conductive heat transfer to enable eventual operation in vacuum without liquid helium. Design features include low-resistance joints and superconducting interconnecting buses for low-ohmic losses in the persistent mode. The magnets are produced by the wind-and-react method on iron forms, followed by epoxy impregnation. The system requirements and design are described in further detail, and test results are presented.