Quantum voltage standard laboratory
QN2 laboratorio campione tensione Volt

The laboratory realizes the SI voltage unit, the volt (V), by means of the Josephson effect.

Superconducting devices (arrays of Josephson junctions) are radiated by a microwave signal, whose frequency is traceable to the atomic standard, and develop quantized voltages proportional to the microwave frequency. Quantized voltage levels up to +/- 10 V enable the calibration of solid-state secondary standards (Zener) for the dissemination of the voltage unit.

The laboratory equipment allows the generation of dc quantum voltages as well as ac and arbitrary voltage waveforms with Josephson devices cooled down to 4 K in a closed-cycle refrigeration system.