International comparisons of high-frequency electrical capacity standards

Abstract

In 2007‐2008, we performed comparisons between the Russian Federation and the Czech Republic in the region of measurements on electrical capacity at high frequency. The purpose of the comparisons was to provide mutual relationship of results in the calibration of means of capacitance measurement in both countries by confirming the estimates of uncertainties arising in the comparisons. Comparison participants: Siberian State Research Institute of Metrology ( SNIIM) in Russia (pilot institute); and Czech Metrological Institute (CMI) in the Czech Republic. For the comparison, we used a set of transported standards developed in SNIIM of capacity 10, 100, and 1000 pF, working frequencies 1, 10, 20, and 30 MHz. In the region of measurement, the unit of electrical capacity in Russia was the special central standard GET 107-77 [1, 2] on the basis of the units of length and time. The transfer of the dimension of the unit by the secondary and the working standards was provided by the method of comparison and reglamentation of the intergovernal standard [3] and confirmed in the SNIIM by calibration methods. The standard measurement apparatus and the SNIIM standards, including the transported standards, had unified two-conduction connecting devices: unipolar coaxial-cylindrical joiners with the following characteristics: internal diameter of an outside electrode of coaxial 20 mm, an outside diameter of an internal electrode of 13.18 mm, and a wave resistor of a coaxial system of 25 Ω. The standard capacities of 10, 100, and 1000 pF of 16380A [4] in the Czech Republic were calibrated in the BIPM at a frequency of 1 kHz. At the working frequencies, the standards were calibrated from the frequency dependence of the capacitance (frequency course) at the INRIM Metrological Institute of Italy [5, 6]. The calibration in frequency course was performed at frequencies up to 15 MHz and used without loss of accuracy up to a frequency of 20 MHz (for a capacitance of 1000 pF) for 30 MHz (for capacitances of 10 and 100 pF). From the calibrated standards, the dimensions of unity were transmitted by means of standard measuring apparatus, in particular broad-band autobalance meters of impedance. The stan