A superconducting Magnet with Center Field of 10 T and 100 mm Warm Bore

Q. Wang1, L. Yan1, B. Zhao1, S. Song1, Y. Dai1, Y. Lei1, H. Wang1, H. –C. Huang2
(1. Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100080, China;
2. Diamond Light Source, Ltd., Diamond House Chilton Didcot OXON OX11 0DE, UK)
Abstract: A conduction-cooled superconducting magnet with central field of 10T and warm bore of 100 mm was designed based on a Nb3Sn and two NbTi superconducting coils. At the first stage, the NbTi coils have been fabricated and tested. A two-stage 4 K Gifford-McMahon (GM) cryocooler with the second-stage power in 1W, 4.2K is used to cool the magnet from room temperature to 4 K. The superconducting magnet with the same power supply has the operating current of 116A. The magnet can be rotated with a support frame to be operated with either horizontal or vertical position. A pair of Bi-2223 high temperature superconducting current leads was employed to reduce heat leakage into 4.2K level. The NbTi coils reach to the operating current of 120A without training effect to be observed during charging of the magnet during 40 minutes charging time and generate the center field of 6.5T. The training effect in the NbTi magnet directly cool-down by cryocooler and inter-winding support structure in magnet can be remarkably improved. The superconducting magnet has been stably operated for more than 275 hours with 6.5T. In this paper, the detailed design, fabrication, stress analysis and quench protection characteristics are presented.
Key words: conduction-cooled superconducting magnet; FEA detailed model; training effect