Development of 9.5 T NbTi cryogen-free magnet

A 9.5 T cryogen-free superconducting NbTi magnet system has been designed, constructed and tested at Cryomagnetics, Inc. The system has a horizontal /spl Phi/32 mm clear room temperature bore through the high field region. The cryostat has a compact 432 mm outside diameter by 305 mm length. The magnet system, featured high-Tc BSCCO current leads and NbTi superconducting persistent switch, and was cooled directly by a new generation pulse tube refrigerator. Tests show that the magnet generates a magnetic field up to 9.5 T with 0.1% homogeneity over a 10 mm diameter volume. The cool-down time from room temperature to operating temperature is approximately 14 hours. The magnet was charged from zero to 9.5 T In less than 10 minutes. After intentional quench at 9.2 T. the system recovered in temperature in less than 3 hours. In this paper, the design, analysis and the system test results are reported.