G-M制冷机作为冷凝泵在传导冷却超导磁体系统中的应用

USING G-M REFRIGERATOR AS CRYOPUMP IN CONDUCTION COOLED SUPERCONDUCTING MAGNET SYSTEM

成功研制了 6TNbTi传导冷却超导磁体系统 ,制冷机为二级G M制冷机。磁体冷却到4K需用 74h左右 ,目前磁体系统已分别完成了 115A(6T) ,4 5h和 95A ,2 6 4h的无间断运行实验。制冷机可在长达 15d(35 9h)的时间里 ,对系统抽真空 ,然后维持系统真空在 1 5× 10 - 2 Pa左右 ,其间不再使用扩散泵对超导磁体系统抽真空。

A 6 T NbTi superconducting magnet cooled by a two-stage 4 K G-M refrigerator w as developed successfully.The magnet was cooled to 4 K in 74 h. The magnet syste m has been tested for 115 A(6 T),45 h and 95 A,264 h continuously till now.The s ystem vacuum was rarefied and the vacuum 1.5×10 -2Pa was maintained by G -M refrigerator for a long time of 15 days (359 h) and the diffusion pump was no longer used in the period.