Industrial experience with an array Josephson junction

An array Josephson junction (AJJ) has been in operation at Lockheed Missiles and Space Co. (LMSC) since September 1986. The AJJ was fabricated at the US 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 V since January 1987. The uncertainty of the measurement system has been estimated to be less than 0.1 p.p.m.<>