Patent attributes
More sensitive (especially due to reduced interference of flux noise) than a conventional SQUID, an inventive SQUID's major component is a hollow cylindric structure comprising one or more annular Josephson junctions. Each annular Josephson junction is defined by two superconductive annuli and an interposed non-superconductive annulus. Inventive practice is variable, e.g., in terms of number and/or spacing of Josephson junctions, and/or as having one or more shunts connecting two or more Josephson junctions, and/or as having one or more vortices each threaded through a Josephson junction. The inventive cylindric structure is positioned proximate a magnetic field of interest so that the latter is aligned with the longitudinal axis of the former. Electrical current is transmitted through the inventive cylindric structure in the longitudinal-axial direction so that, based on the quantum interference associated with the one or more annular Josephson junctions, the measured output voltage is indicative of the magnetic field.