Determination of the von Klitzing constantR_Kin terms of the BNM calculable capacitor—fifteen years of investigations

Abstract

The von Klitzing constant R K has been previously determined at the Bureau National de Métrologie (BNM) in 1986 and 1993. Considering the recommendation of the Comité Consultatif d'Electricité working group on the quantum Hall effect in 1988, as well as the differences between the values of the fine structure constant obtained from different methods, it appears to be particularly important that we continue to develop and improve the direct determinations of R K .

Improvement of the Measurement Chain Linking the Farad to the OHM at LNE

“…Details of the implementation of these bridges are given in the reference [2]. Figure 2 hereafter shows the principle of a coaxial AC bridge for impedance comparison.…”

“…Direct measurement of RK is obtained by linking the ohm produced from the quantum Hall effect to the farad achieved from a Thompson-Lampard calculable capacitor [2,3], using a dedicated high precision measurement chain. At LNE, the last determination of RK was conducted in 2000 with an uncertainty of 5 parts in 10 8 [2].…”

“…At LNE, the last determination of RK was conducted in 2000 with an uncertainty of 5 parts in 10 8 [2]. In order to reach the target uncertainty of one part in 10 8 , the LNE needs to build a new calculable capacitor and to improve the associated measuring chain.…”

Thermal characterization of a coaxial calculable resistor

“…The coaxial resistor made at Inmetro follows the 4-connector, 2-plane design described in Refs. [7], [8]. The resistor element consists of a isaohm wire of 0.014 mm cross section approximately 11 cm long.…”

Wide frequency range quadrature bridge comparator Pont

“…To provide these investigations, transformer quadrature bridges are usually used. The main world-renowned laboratories (BIPM, NIST, NML, NPL, PTB, VNIIM, etc) in developed countries have their own primary standards, based on the Calculable Capacitor and Quantum Hall Resistance [2][3][4][5][6][7][8][9] and very accurate quadrature bridges with original constructions [10][11][12][13][14][15][16] for their comparison.…”