SQUID and SQUID system developments for biomagnetic applications.
This report describes developments carried out at the author's institution concerning SQUIDs and SQUID systems, based on both conventional niobium technology and high-Tc superconductors. The developments are aimed at increasing the acceptance of SQUID systems by the user from the technical point of view. Reliability and ease of operation are improved by simpler electronics, faster response and reduced number of leads in multichannel systems, and higher operating temperature. The developments include a DC SQUID with FM read-out, resulting in the most compact SQUID electronics so far, a planar microwave biased RF SQUID with very high slew rate, and efforts to create reliable SQUIDs with sufficient sensitivity for biomagnetic applications that are cooled by liquid nitrogen.