Evaluation of Nb3Sn superconductors for use in a 23.5 T NMR magnet

In order to evaluate the feasibility of using Nb₃Sn superconductors to generate fields as high as 23.5 T in NMR magnets, the Battelle Pacific Northwest Laboratories has initiated a conductor development and evaluation program. We report the results of one part of that program involving the Wang NMR/LBL team. Based on a preliminary magnet design, and after extensive discussion with various conductor manufacturers, conductors which had been optimized for use at fields above 20 T were purchased. These conductors have been evaluated with respect to mechanical and electrical properties. In particular, the strain dependence of the critical current density has been measured at 1.8 K and 23.5 T. These results, together with coil tests, are reported in this paper