Analysis and Reconstruction of Magnetic Noise Model for Single-Ended Open Magnetic Shielding Cylinder

Accurately estimating and suppressing magnetic noise within magnetocardiography (MCG) devices is of great significance for improving the accuracy of MCG measurements. However, the calculation of magnetic noise inside a single-ended open magnetic shielding cylinder (MSC) lacks an accurate magnetic noise model. This paper analyzes and reconstructs the magnetic noise model (R-MN model) based on the variable-parameter magnetic loss separation model to address this issue. By incorporating appropriate penalty terms into the objective function, the variable-parameter magnetic loss separation model achieves high-precision loss separation utilizing the Artificial Hummingbird Algorithm. Compared with the conventional magnetic noise calculation method, the proposed R-MN model can reduce the root mean square error of noise prediction by 96.8%. The permalloy-nanocrystalline MSC composite structure designed based on the R-MN-model reduces the intrinsic average magnetic noise of the conventional MSC within the frequency range of 1-40 Hz from 11.77 fT/Hz¹ᐟ² to 4.41 fT/Hz¹ᐟ². This study provides theoretical foundations and technical support for designing low-noise, large-scale, and asymmetrically structured magnetic shielding devices.