Superconducting magnetic shielding for SQUID-based systems operating in low fields

A SQUID-based assembly has been designed, built and tested to evaluate the effectiveness of SQUID superconducting magnetic shielding for systems operating in external fields less than 10 gauss. This system is designed to measure changes in magnetic induction interior to test shields due to changes in external field and temperature. Preliminary experimental results are presented in order to study the shielding performance of commercially available superconducting materials and to identify significant parameters for shielding effectiveness. In addition, empirical results are compared with a derived expression describing thermally induced field changes in terms of variations in penetration depth.