Precision acoustic gas analyzer for binary mixtures

Abstract

We describe a cylindrical acoustic resonator which has been used for the determination of the molar concentration of a binary mixture of gases. We achieved an absolute accuracy better than 0.001 independent of the concentration or the type of gas. The practical factors limiting the accuracy are discussed in detail and their effect on the performance has been evaluated using gas samples prepared by precisely measured partial pressures. The device is routinely used to measure the concentration of 3He–4He mixtures.