Industrial experience with an array Josephson junction

An Array Josephson Junctin (AJJ) has been in operation at Lockheed Missiles & Space Co. (LMSC) since September 1986. The AJJ was fabricated at the U.S. National Bureau of Standards (NBS) in Boulder, Co. It has been used on a routine basis for calibration of primary solid state reference standards near 1.0 volts since January 1987. Uncertainties at this voltage level are presently estimated at less than 0.3 ppm.