Recent developments in squid applications

Out of the many possible SQUID applications a few illustrative examples will be presented: non destructive evaluation of wafer doping profiles; geophysical radio magnetic sounding; detection of binding specific immune reactions with magnetic markers; tracking of a gastrointestinal transit; determination of the blockage of a nerve signal propagation in the lumbar spine; biomagnetic vector magnetometer for magnetic heart signal investigations. All applications mentioned above have been performed till now only with liquid helium cooled SQUIDs. The applicability of high-Tc SQUIDs depends first of all on its reliable performance in environmental ac and de magnetic fields. A recently developed single layer MTS-SQUID will be described with a field noise at 1 Hz of 65 fT/root Hz when cooled in a magnetic field of 64 mu T Such a SQUID is a good candidate for most of those applications.