Characteristics of cryocooled racetrack magnet fabricated using REBCO coated conductor

We successfully fabricated a racetrack magnet comprising a stack of 4 single pancake coils with REBCO coated conductor fabricated by the IBAD/PLD method. We measured the critical current (Ic) of the racetrack magnet and the central magnetic field at 77, 50, 40, 30 and 20 K under conduction-cooled conditions, the magnet Ic was measured as 450 A at 20 K using a criterion of 1E-6V / cm. We investigated the stability of the racetrack magnet at 20 K, the magnet was in a steady state at I /Ic ratios of 0.80 (360 A) and 0.85 (382.5 A) at 20 K for 60 min. In the last few years, REBCO coated conductors having a performance greater than a few hundred amperes per cm at 77 K have been developed for superconducting applications. Coils that use REBCO coated conductors are expected to have the high operating current (Iop) against the critical current (Ic) of the coil. In this paper we report the experimental results of a small cryocooled racetrack magnet (70 x 150 mm in inner diameter, 100 x 180 mm in outer diameter, 27 mm in height, 50 m (12.5 m x 4 coils) in total length) fabricated using a REBCO coated conductor, formed by IBAD/PLD method. We measured the critical current of the magnet from 50 K to 20 K under cryocooled conditions. The critical current was found to be 450 A at 20 K. The magnetic field of 0.54 T was generated at the center of the magnet. We also investigated the stability of the racetrack magnet, at the current of 382.5 A, and Iop/Ic ratio of approximately 85%, for 1 h at 20 K.