77 Kelvin SQUID magnetometers as detectors of metallic objects

1Superconducting Quantum Interference Devices (SQUIDs) are the most sensitive detectors of magnetic fields. Their remarkable sensitivity has created interest in their use as detectors of mines and submarines, but their value to date has been limited by the need to cool them with liquid helium. This situation has now changed, as SQUIDs now operate at 77K in liquid nitrogen. We propose a design study to evaluate the performance of such high temperature SQUIDs, to identify Navy applications that are made possible because of the reduced cost, weight and size of systems utilizing such SQUIDs, and to design a prototype system for Navy use.