Compact 2 V Cryocooled Programmable Josephson Voltage Standard for Direct On-Site Quantum Voltage Comparisons

This paper evaluates the performance of a new type of 2 V traveling cryocooled Programmable Josephson Voltage Standard for performing on-site verification of quantum voltage standards. Direct comparison with a 10 V system showed agreement of 8 parts in 10^11 at 2 V. This result shows that, despite the lower voltage, the direct Josephson-to-Josephson system comparison method provides a two orders-of-magnitude improvement over traveling Zener standards for verifying Josephson voltage standards.