Design of internal-tin Nb3Sn current switch strand andstrand for accelerator magnets

摘要

Different areas of internal-tin Nb3Sn strands application have been analyzed. It was shown that internal-tin strands could be most promising for use in persistent current switches and for high field, enhanced current magnet systems. Appropriate Nb3Sn internal-tin strands have been designed, fabricated and tested. The design of Nb3Sn strand for current switch consists of high resistance Cu-Sn-Ni matrix and Nb3Sn filaments. It was shown that Nb3Sn switch strand 0.9 mm in dia has a current capacity of 1 kA at 4.2 K, 1 T and resistance above 8 μΩ*cm at 20 K. For the magnets of next generation accelerators Nb3Sn internal-tin strand with enhanced current capacity has been designed. Critical current density of that strand was above 2000 A/mm2 at 4.2 K, 12 T, 0.1 μV/cm