Abstract
REBa2Cu3Ox (REBCO, RE = rare-earth) coated conductors are expected to show high performance in superconducting applications because of their high mechanical strength and high current density in magnetic fields. More characteristics data of REBCO coils with larger diameters are required for use of these conductors in practical superconducting applications. We fabricated a cryo-cooled high-temperature superconducting (HTS) magnet, which was composed of 24 pancake coils with an inner diameter of 260 mm, using REBCO coated conductors. The stored energy of the magnet was 426 kJ. The total length of the REBCO coated conductors was approximately 7.2 km. These conductors were laminated with a copper stabilizer and were fabricated by Fujikura Ltd. using ion-beam-assisted-deposition (IBAD) and pulsed-laser-deposition (PLD) methods. Before fabricating the magnet, all pancake coils were evaluated in terms of their V-I characteristics in liquid nitrogen in order to confirm the characteristics without degradation. After the fabrication, the magnet was cooled down to 24 K using a GiffordMcMahon (GM) cryocooler. We were successful in excitation of the magnet up to 5 T. Furthermore, we confirmed that a 1% current reversal of the coil current could stabilize the axial central magnetic field drift of the magnet.
