Electromagnetic Design of a 0.5 T REBCO MRI Magnet for Brain MRI Imaging

A 0.5 T REBCO MRI coil with a warm bore of 560 mm was designed for head imaging using linear programming (LP) and nonlinear programming (NLP). The LP method was used to determine the initial distribution of the coil cluster, followed by the NLP method, which optimized the radii and heights of the coil blocks using this initial layout as a reference. Both layer-winding and double-pancake (DP) winding coils were explored for developing MRI magnets. The layer-winding coil enabled the MRI magnet to achieve a uniformity of 10 parts per million (ppm) over a 200-mm diameter spherical volume. In contrast, the DP winding coils attained a field uniformity of 17.6 ppm without employing either iron or superconducting shim coils. The stray magnetic field of the MRI magnet was designed to be within 0.5 mT at radial and axial positions of 3.2 and 4.2 m, respectively. Because the REBCO magnet has a substantial temperature margin, it can be effectively cooled using solid nitrogen at 35 K or through conduction cooling. This article presents the electromagnetic design and mechanical analysis results of the coils.