The Design and Winding Method of a Conduction-Cooled 1.5 T Bi-2223 High Temperature Superconducting Magnet

A conduction-cooled 1.5 T high temperature superconducting (HTS) magnet was designed. The magnet will be used to provide a steady and confining magnetic field, which requires the uniformity within ±5% of the central field, over a ¿ 25 mm × 120 mm cylindrical region. Totally 0.8 km Bi-2223 HTS tapes will be used to wind 22 double-pancakes. The inner and outer diameters are 60 mm and 88 mm respectively; the notched shape was employed to improve the field uniformity. An improved method other than the traditional was employed to determine the size of the magnet. The magnet is expected to be cooled down to 30 K by a GM cryocooler through the conduction cooling method. The operating current is 100 A, with which the magnet generates 1.5 T at the center of the bore. In order to facilitate the winding process and enhance the heat conduction, a new method was specially developed to wind the double-pancake, which was named as the "cassette-pancake".