Polarizability of Helium and Gas Metrology

Top Cited Papers
Publisher Website
Google Scholar
Abstract
Using a quasispherical, microwave cavity resonator, we measured the refractive index of helium to deduce its molar polarizability in the limit of zero density. We obtained , where the standard uncertainty (9.1 ppm) is a factor of 3.3 smaller than that of the best previous measurement. If the theoretical value of is accepted, these data determine a value for the Boltzmann constant that is only larger than the accepted value. Our techniques will enable a helium-based pressure standard and measurements of thermodynamic temperatures.