Round Subelement, Ta-Nb Barrier, Tube Type Nb3Sn - 51a

The DOE is seeking superconductor technologies in support of magnets for use in high energy physics (HEP) accelerators. The specific need is for strands that can operate in the 12-15 T or higher regime, have deff values of 30 µm or less, have non-Cu Jc values of 3000 A/mm2 or more, and have stable operation throughout their operational fields. In addition, these strands need to be readily available at a reasonable cost. This project will develop technology to improve the Jc of Tube-Type conductors from their presently demonstrated values of 2200 A/mm2 at 12 T and 4 K to values near 3000 A/mm2, while improving strand deformation tolerance. The approach involves the development of a round subelement geometry to maximize the use of conductor real-estate. The use of barriers around individual subelements also will be explored, in order to slow Sn diffusion outside of the barrier and flatten the Sn concentration profile in the subelement. Commercial Applications and other Benefits as described by the awardee: In addition to HEP applications, these conductors should enable low-cost high-field magnets in the 8 to 20 T range to be commercially feasible. This range includes particle accelerators and fusion magnets, MRI, NMR, research magnets, and high-gradient high-field separator magnets. Also, 11 T magnets potentially could find use in accelerators for proton radiation for cancer therapy