Design and Fabrication of a Conduction-Cooled Superconducting Magnet for Hall Sensor Calibration

There are some requirements for the superconducting magnet used as the standard source of magnetic field to calibrate some magnetic probes such as Hall sensors and NMR probes. A conduction-cooled superconducting magnet for Hall sensor calibration has been designed with the center field of 7 T and the warm bore with the diameter of 50 mm. The superconducting magnet consists of six NbTi superconducting coils. The homogeneity of magnetic field is designed with 80 ppm (parts per million) in diameter of spherical volume (DSV) of 25 mm. A GM cryocooler with 1.5 W @4.2 K is employed to cool down the system. The design, fabrication, and testing of the superconducting magnet are reported in this paper.