Optimization of a High Screening Performance and Low Noise Magnetically Shielded Cylinder for SERF Atomic Magnetometer

To resolve the contradiction between the shielding performance and the magnetic noise in the design of magnetically shielded cylinder (MSC), an MSC optimization design method based on particle swarm optimization with multistage inertia weights algorithm (MW-PSO) is proposed. Using the segmented magnetic noise and material volume as constraints and taking the axial shielding factor as the target, the structure of a four-layer MSC is optimized to achieve the expected results. According to the previous optimization results, the relationship curve between the change rate of the axial shielding factor and that of the magnetic noise is obtained, and the structure parameters of the optimal four-layer MSC are determined by the extreme points of the curve. The simulation analyses are conducted to verify the effectiveness of the method. The results show that compared with the initial MSC designed by the conventional method, the axial and radial shielding factors of the optimized MSC are increased by 17.95 times and 15.3 times, respectively; meanwhile, the magnetic noise is decreased by 15%.