Cryogen-Free 23 T Superconducting Magnet with a 7.5 T YBa₂Cu₃O₇Insert Coil

In order to develop a cryogen-free high-field superconducting magnet generating over 20 T, a YBa2Cu3O7 (Y123)-coated conductor insert coil is used to enhance a cryogen-free 18 T superconducting magnet. The Y123 tape does not require stainless steel reinforcement. The Y123 insert coil, which is almost the same size as the current Bi2Sr2Ca2Cu3O10 (Bi2223) insert coil, is designed to generate 7.5 T at 187 A. It is able to achieve this since without stainless steel reinforcement the number of turns can be greatly increased. A cryogen-free superconducting magnet can achieve a static magnetic field of 23 T, which is higher than that generated by practical superconducting magnets using liquid helium. (C) 2009 The Japan Society of Applied Physics