Superconducting instrument systems

Abstract
Some recently developed superconducting instrument systems which are based upon the use of a highly reliable thin-film superconducting quantum interference device (SQUID) are discussed in detail. These SQUID's, which are shown to have a noise temperature of less than 2 × 10-4K, are capable of measuring: 1) magnetic flux with a sensitivity of 10-11Gċcm2rms/√Hz; 2) magnetic field with a sensitivity of 10-11G rms/√Hz; 3) magnetic field gradient with a sensitivity of 10-11(G/cm) rms/√Hz. We present construction details and performance data on systems capable of making the above measurements.