Design Optimization Method of Permanent Magnet for Open MRI Using Dot Sensitivity Analysis

Permanent magnets (PMs) are widely utilized in various industries thanks to their significant potential. In open Magnetic Resonance Imaging (MRI) systems, research is actively being conducted to reduce weight and cost through the efficient use of magnets. However, existing numerical optimization techniques often require high computational costs due to their reliance on iterative Finite Element Analyses (FEA). This paper proposes a permanent magnet optimization method utilizing magnet dot sensitivity to overcome this limitation. The dot sensitivity provides information on how the magnet topology should be formed for system optimization. By integrating this sensitivity information with a genetic algorithm (GA), we established an optimization method with a low computational cost. The proposed method was validated by designing an H-shaped magnet for an open MRI system.