15T CRYOCOOLED NB3SN SUPERCONDUCTING MAGNET WITH A 52 MM ROOM-TEMPERATURE BORE

We succeeded in demonstrating a 15.1T cryocooled Nb3Sn superconducting magnet with a 52 mm room temperature bore. Two operating currents of 157 A and 90 A for the divided section coils were utilized for the fir st time in a cryocooled superconducting magnet system. It is found tha t the current leads are no longer the dominant heat loads because of t he use of high-temperature superconductors. In order to realize a high -field cryocooled superconducting magnet comparable to the usual super conducting magnet immersed in liquid helium at 4.2 K, we maintained th e coil temperature at a value below 5.0 K during the field sweep in a high magnetic field region.