New calibration method for coaxial microcalorimeters

The most critical point in the realization of an electrical power standard based on a microcalorimeter is the accurate determination of the microcalorimeter losses and their effect on the measurand, i.e. the effective efficiency of the sensor under calibration. At IEN Galileo Ferraris, a procedure has been introduced that makes the microcalorimeter constant determination more accurate and reliable. Experiments with the 7-mm coaxial microcalorimeter in 50 MHz – 18 GHz range have shown a significant improvement in the uncertainty for the Italian national power standard at the 0.2% level