Development of a large high-current-density Nb3Sn superconductor made by solid-liquid diffusion method

A 3KA class multifilamentary Nb3Sn superconductor has been developed by using solid-liquid diffusion method. The conductor has a very high critical current density of 1.0 × 10⁵A/cm²at 10 T excluding Cu. The conductor was fabricated in a large quantity and wound into a 40 cm bore Nb3Sn magnet to prove its availability for a large high field magnet. The magnet attained to its designed operation point of 10 T with 2KA without quenching, when the currnet density in the magnet exceeded 74 A/mm².