Design and Test of Conduction-Cooled High Homogenous Magnetic Field Superconducting Magnet for Gyrotron

A conduction-cooled superconducting magnet with the warm room of Phi 80 mm and the center field of 0~4 T was designed, fabricated and tested. The magnet can be operated for two different sets of coils which have different homogenous regions with lengths of 150 mm and 250 mm. The homogeneity of magnetic field is about plusmn0.25%. All the homogeneous regions are with the same starting point. The center field is decayed to 1/6-1/7 from the original point to 195 mm. The operating temperature of the magnet is defined at the 5.5 K for the conduction-cooled magnet to take into account the temperature rise during charging current. The thermal equilibrium of the superconducting magnet and cryogenic system is analysed to define ramping rate, operating current and margin of superconducting magnet. The detailed design and fabrication of the superconducting magnet for gyrotron are discussed. The test results show that the superconducting magnet can generate the requirement of magnetic field distribution.