A low-field portable Halbach magnet for mouse detection

Magnetic resonance imaging (MRI) in mice is important for facilitating the establishment of medical models. In order to develop a low-cost magnetic resonance sensor for mouse detection, a multilayer stacked Halbach magnet is proposed in this paper. Firstly, the Halbach with 6-layer magnetic ring is used as the basic structure, and the field homogeneity in the region of interest (ROI) is optimized by adjusting the parameters of each layer height and layer gap. On this basis, a genetic algorithm (GA) is used to further optimize the above parameters. The final magnet structure has a cylindrical target area with a diameter of 50 mm and a height of 50 mm, which can accommodate a whole mouse for detection. The field strength of the target area is 265.565 mT and the inhomogeneity is 38.9 ppm. Based on its performance, this magnet has the potential to be the primary magnet for portable magnetic resonance operating at low fields in the future.