The development of differential programmable josephson voltage standard toward quantum voltmeter with microvolt range

This paper presents a differential programmable Josephson voltage standard developed at NIM. By the means of a Josephson voltage compensated by the other, the differential programmable Josephson voltage standard can be used as a high-precision ultra low-voltage standard to calibrate the microvolt ranges of nanovoltmeters. And based on it, we will develop the quantum voltmeter which is able to cover DC voltage from 0 V to 10 V, to complete DVM calibration in all the ranges. The measurement results show the difference between the measurement and the nominal value of 1 microvolt is -0.17 nV, with the relative standard deviation of 1.4 × 10
^-3
. The measurement and uncertainty analysis has certified the standard shows satisfactory reliability and stability. In addition, the double channel array also has been developed to simplify the differential system.