Design of an optimized biomagnetic measurement surface by a spherical-multipole approach

The spherical-multipole technique is applied to find the best distribution of the magnetometers in an array for biomagnetic measurements, e.g., for Magnetoencephalography (MEG) and Magnetocardiography (MCG). By investigating the condition number of a matrix depending only on the measurement points and not on the source points, we find that the optimum choice consists of equally located magnetometers distributed on a connected double-layer surface. The results are of interest particularly in the context of new passive and uncooled magneto-electric (ME) sensors which might be able to replace conventional SQUID magnetometers in the future.