Superconducting circuit, production method of superconducting joints, superconducting magnet, and production method of superconducting magnet

摘要

A superconducting circuit comprising a superconducting joint (13) that joints a niobium titanium superconducting wire (12) has a structure where a filament (18) made of niobium titanium alloy is arranged in a matrix (19) made of copper or copper alloy and other superconducting wire (12). In operation, a magnetic field intensity where the superconducting joint (13) is placed is smaller than the magnetic field intensity where a main coil (1a, 1b) of the niobium titanium superconducting wire (12) in a portion other than the superconducting joint (13) is placed. When the niobium titanium superconducting wire (12) in the superconducting joint (13) and the niobium titanium superconducting wire (12) in the portion other than the superconducting joint (13) are placed in the same magnetic field intensity, a critical current density of the filament (18) in the superconducting joint (13) is lower than the critical current density of the filament (18) in the niobium titanium superconducting wire (12) in the portion other than the superconducting joint (13).