Electromagnetic design of actively shielded MRI magnet for dedicated mice imaging

A 3.0 T MRI magnet using MgB2 superconductors with conduction cooling for dedicated mice imaging was designed. The magnet configuration is determined by the central magnetic field strength, maximum magnetic field, magnetic field uniformity, uniformity volume, stray field, and coil costs. Linear programming was used to optimize the superconducting magnet of the MRI system. The optimized superconducting magnet can generate a central field of 3.0 T with field homogeneity better than 10 ppm in a 50 mm diameter of spherical volume (DSV). Actively shielded coils with opposite current densities were adopted to reduce the stray field. Finite element methods were used to analyze the mechanical stress and strain in the MgB2 coils during winding, cool-down from room temperature and electromagnetic excitation. The analysis results showed that the strain on the coils is within the design criteria. In this paper, the coil optimization design, electromagnetic and stress analysis were given.