The realization of the quantum Hall standard of resistance at the BIPM

The first measurements of the quantum Hall resistance at the Bureau International des Poids et Mesures (BIPM) have been carried out using a silicon MOSFET sample at magnetic flux densities up to 13.2 T and at temperatures near 0.5 K. New measurement equipment has been constructed and used to establish an accurate link to the present resistance standard with a relative uncertainty, given as a one-standard-deviation estimate, of 7.6 × 10⁻⁸. The results are 4RH (4) = (25 812.8511 ± 0.0020) Ω69-BI for June 1, 1986. Using the very recently revised value for the relation between Ω69-BI and the Commonwealth Scientific and Industrial Research Organization (CSIRO) determinations of the ohm gives 4RH (4) = (25 812.8087 ± 0.0027) Ω.