Development of a Superconducting Magnet System for Microwave Application

A superconducting magnet with an available warm bore of 100 mm and a central field of 5 T has been designed, manufactured and tested for the research of microwave application. The magnet is composed of three coaxial coils based on magnetic field homogeneity considerations, namely one main coil and two compensation coils. All coils are connected in series and can be charged with a single power supply. The magnetic field homogeneity is less than ±2.5% in a 20 mm diameter and 250 mm length of a cylindrical volume. In addition, a two-stage GM cryocooler with a capacity of 1 W at 4 K was used to cool the superconducting magnet. The cryocooler used can prevent the liquid helium from boil-off and lead to a zero loss during static operation. In this paper, the magnet design, manufacture, mechanical behavior analysis, and the performance test results of the magnet are presented.