Superconducting Joint Technology for a Low-temperature Superconducting Wire

Abstract

Synopsis: The superconducting joint is utilized for superconducting magnets operated using persistent current mode. MRI, NMR, and MCZ, which are commercial products in the superconducting market, are also operated using persistent current mode, and are constructed with low-temperature superconducting wires. Since these magnets need a constant and stable magnet field for long period of time, the superconducting joints must have extremely low resistivity, lower than 10-11 Ω to avoid rapid degradation of the magnetic field. Commercial low-temperature superconducting wires have NbTi or Nb3Sn filaments embedded in stabilizing materials such as copper or aluminum matrixes. To realize a low-resistance joint, the stabilizing materials are removed and the mutual filaments are directly jointed. This manuscript introduces superconducting joint methods for low-temperature superconducting wires, which has been developed by the superconducting magnet manufactures and related R&D institutions.