We are developing a cryocooler cooled 6T superconducting magnet without liquid helium and/or liquid nitrogen. This magnet, which is directly cooled by two 4K Gifford-McMahon(GM) cryocoolers in vacuum, consists of an graded NbTi coil, Bi-based oxide superconducting current leads and a persistent current switch. The coil is made using two types of NbTi wires and a copper bobbin. The coil with an inner diameter of 260mm, an outer diameter of 329mm, and a height of 334mm, is impregnated with grease to ensure a good heat conduction. The operating current for a central field of 6T in the 220mm room temperature bore is 152A. A mechanical persistent current switch is used to limit the load from the switch into the 4K GM cryocooler. Designed temperature of the magnet is 4. 9 K at the operating current of 152 A.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering