High-Speed Spin Testing of Bi-2212 Superconducting Wires for High-Field NMR Magnet Qualification: Final Progress Report

Abstract

Abstract This paper summarizes an NIH-funded research project designed to study the strength of high temperature superconductors under high circumferential hoop stress, in order to qualify these materials for high-field (> 1 GHz-class) NMR magnets. The unique approach presented here is to spin test coils at high rotational speeds, approaching 50,000 rpm, in order to induce mechanical hoop stresses which are equivalent to the magnetic Lorentz stresses experienced by a high-field solenoid insert coil. Bi-2212 wires and coils were tested in sub-cooled nitrogen to determine if any mechanical damage was imparted by each spin test. These preliminary experimental results demonstrate that, with further development, this test could prove to be a simple method for qualifying superconducting wires for high-field insert magnets.