A resistance bridge based on a cryogenic current comparator achieving sub-$10^{-9}$ measurement uncertainties

Abstract

A new resistance bridge has been built at the Laboratoire national de métrologie et d'essais (LNE) to improve the ohm realization in the $Syst\grave{e}meInternational$ (SI) of units from the quantum Hall effect. We describe the instrument, the performance of which relies on two synchronized and noise-filtered current sources, an accurate and stable current divider and a cryogenic current comparator (CCC) having a low noise of $80pA.t/H{\mathrm{z}}^{1/2}$. The uncertainty budget for the measurement of the 100 $\Omega /(R_{\mathrm{K}}/2)$ ratio, where $R_{\mathrm{K}}$ is the von Klitzing constant, amounts to a few parts in $10^{10}$ only.

14 pages, 16 figures, Accepted in IEEE. Trans. Instrum. Meas