Comparison of a Multichip 10-V Programmable Josephson Voltage Standard System With a Superconductor–Insulator–Superconductor-Based Conventional System

We developed a 10-V dc programmable Josephson voltage standard (PJVS) using a multichip technique. The PJVS was based on NbN/TiNx/NbN junctions and operated using a 10-K compact cryocooler. We carried out an indirect comparison with a superconductor-insulator-superconductor-based conventional Josephson voltage standard (JVS) by measuring the voltage of a 10-V zener diode reference standard. The combined standard uncertainty of the comparison wasuc= 0.03 muV(k= 1), and the relative combined standard uncertainty was 3 times10-9.