Precursor for a Nb3Sn superconductor wire, method for manufacturing the same, Nb3Sn superconductor wire, and superconducting magnet system

摘要

A precursor for a Nb3Sn superconductor wire to be manufactured by the internal diffusion method. The precursor includes Nb-based single core wires (2a), Sn-based single core wires (2b), and a cylindrical diffusion barrier (27) made of Ta or Nb. Each Nb-based single core wire (2a) includes a Nb-basedcore (23) coated with a Cu-based coating (24) made of a Cu-based matrix. Each Sn-based single core wire (2b) includes a Sn-based core (25) coated with a Cu-based coating (26) made of a Cu-based matrix. The Nb-based single core wires (2a) and the Sn-based single core wires (2b) are regularly disposed in the diffusion barrier. The Nb-based single core wires (2a) include at least two kinds of Nb-based single core wires (2a) having different Cu/Nb ratios and the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating (24) to the Nb-based core (23).