Fabrication and Current-Carrying Characterization
of a Small-Diameter MgB2 Superconducting Coil Using Ultra-Fine Wires
中山 武, 牧田 健一, 大坪 正人 (日本超電導応用開発), 菊地 孝一 (SOLIZE PARTNERS)
Abstract:To investigate the feasibility of small-diameter superconducting coils using React and Wind MgB2 ultra-fine wires, a cryogenic test system and prototype coils were fabricated. The coils were wound with 936 turns wire with a diameter of 75 μm reacted at NIMS and wound on 20 mm bobbin. Energization tests were conducted at 2 A against a critical current of about 7 A. Magnetic field measurements using an external sensor agreed with theoretical values in all 15 tests, confirming superconducting current flow throughout the coil. Stable operation was also observed during one-hour energization and after re-cooling following cryocooler shutdown.