A portable temperature controlled DC Voltage and DC Resistance Reference with Switching Unit (RSU) has been developed at National Institute of Metrological Research (INRIM) to calibrate multifunction electrical instruments involving 10 V, a 1 Ω and a 10 kΩ Standards. The resistors are made with two resistors nets while the 10 V is a low noise-drift INRIM-projected circuit. Preliminary measurement over one-month period shows standards uncertainties span from 3.0×10 -7 to 6.4×10 -7 , suitable for artifact calibration. With a real clock calendar, the RSU can show both the RSU Standards calibration values and updated ones between two calibrations according to an internal algorithm.

A new radiometric measuring system to be used in the terahertz region, equipped with a pyroelectric detector and a standard synchronous sampling system is being developed at INRIM. A black-body cylindrical cavity, suitable for operating from -50°C to 80°C with known thermodynamic temperature and calculable radiant flux, is employed as a polychromatic terahertz source for the calibration of the radiometer. Preliminary tests were performed in order to determine the responsivity and stability of the radiometer in function of the incident power density, at a specific spectral band. A relative uncertainty lower than 0.2% is obtained with radiation peak intensity from 15.76 THz to 18.7 THz.

A system for the precise measurement of electrical quantities by means of the rms value of ac voltages or currents is described. The system is implemented by a multijunction thermal converter and low cost electronic circuits. As a first application the system can both carry out ac voltage comparisons and ac and dc voltage measurements.

Overdamped Nb/Al-AlOx/Nb Josephson junctions are an intermediate state between the SIS and SNS Josephson junctions. With a proper choice of the fabrication parameters, stable and reproducible nonhysteretic current-voltage characteristics have been obtained Featuring critical current densities up to 70 kA/cm2 and characteristic voltages up to 450 muV at 4.2 K, overdamped junctions are suitable for many applications ranging from RSFQ electronic circuits to programmable and ac voltage standards. Tests on single junctions and arrays of series-connected junctions have shown a suitable behaviour when driven by a microwave with frequencies around 75 GHz. The quantized steps have proven to be stable and flat at nV level. These junctions have also shown an improved temperature dependence, which can be interesting in view of the development instrumentation with an integrated quantum voltage reference operated in a closed cycle refrigerator.

A 100 mH standard inductor has been developed for the EUROMET Project n. 607 "Intercomparison of a 100 mH inductance standard". The standard is thermostated. to 0.01/spl deg/C, and configured as a four-terminal pair standard. First characterization results are shown.