A fast-ramp superconducting magnet for HGMS

A superconducting High Gradient Magnetic Separation (HGMS) sample test facility has been constructed at the IEE CAS. In order to shorten the magnet charging time, it is necessary not only to reduce the magnet inductance, but also to increase the cryogenic stability. Based on our experience, narrow LHe channel cooling inside the high current density magnet is a good solution. In this paper, design, construction and test results are described. The solenoid is wound with 1.46 mm/spl times/2.4 mm and 1.26 mm/spl times/2.4 mm rectangular NbTi-Cu composite, the filament diameter is about 25 /spl mu/m, and the length, the inner and outer diameter are 420 mm, 176 mm and 232 mm, respectively. The channel between two layers is formed by 0.5 mm/spl times/4 mm epoxy fibreglass strip along the axis. The central field of 5.45 T has been reached and the charging speed of 9 T/min has been achieved.