Calibrating Ultrastable Low-Noise Current Amplifiers of the Second Generation With a Cryogenic Current Comparator

Input and output stages of the second generation of ultrastable low-noise current amplifiers can be conveniently calibrated by means of a cryogenic current comparator. The uncertainty achievable for measurement durations of less than 2 h makes our calibration setup a helpful tool for the selection of hardware in the development of instrumentation tailored to meet the requirements of special applications.