Optimizing acoustic measurements of the Boltzmann constant

We review the progress in acoustic metrology of gases that has occurred since the 1988 measurement of the universal gas constant R using a spherical acoustic resonator. The advances in understanding resonators and in calculating the thermophysical properties of helium ab initio suggest that today one could determine Boltzmannʹs constant k B from acoustic measurements using either helium or argon with a relative uncertainty less than 10−6. To cite this article: M.R. Moldover, C. R. Physique 10 (2009).