Abstract: A precursor for a Nb3Sn superconductor wire to be manufactured by the internal diffusion method, includes a plurality of Nb-based single core wires, each of which includes a Nb-based core coated with a Cu-based coating including a Cu-based matrix, a plurality of Sn-based single core wires, each of which includes a Sn-based core coated with a Cu-based coating including a Cu-based matrix; and a cylindrical diffusion barrier including Ta or Nb, in which the plurality of Nb-based single core wires and the plurality of Sn-based single core wires are regularly disposed, wherein the plurality of Nb-based single core wires include Nb-based single core wires having a Cu/Nb ratio of 0.4 or more, wherein the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating to the Nb-based core.

Abstract: A precursor for a Nb3Sn superconductor wire to be manufactured by the internal diffusion method, includes a plurality of Nb-based single core wires, each of which includes a Nb-based core coated with a Cu-based coating including a Cu-based matrix, a plurality of Sn-based single core wires, each of which includes a Sn-based core coated with a Cu-based coating including a Cu-based matrix; and a cylindrical diffusion barrier including Ta or Nb, in which the plurality of Nb-based single core wires and the plurality of Sn-based single core wires are regularly disposed, wherein the plurality of Nb-based single core wires include Nb-based single core wires having a Cu/Nb ratio of 0.4 or more, wherein the Cu/Nb ratio is a cross sectional area ratio of the Cu-based coating to the Nb-based core.

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