Superconducting and high-permeability shields modeled for biomagnetism and nondestructive testing

Numerical modeling studies have been carried out for the design of superconducting and high-permeability shields for SQUID-based nondestructive evaluation and biomagnetic measurements. We used finite-element-method software to model magnetic shields with both axial and planar symmetry in axial and transverse uniform noise fields. Improvements in signal-to-noise ratio at the location of the SQUID were calculated for different shield geometries with line current and magnetic dipole sources at various locations near the shield.