An Automated Apparatus for Measuring Sound Speeds in Hazardous Gases

Published

June 1, 1998

Author(s)

John J. Hurly

Abstract

Our laboratory has developed an automated apparatus for measuring the sound speed in hazardous gases such as those used in processing semiconductors. The sound speed (P,T) is deduced from measurements of the acoustic resonance frequencies of a gas-filled, cylindrical cavity. After the cavity is calibrated with argon, the uncertainty in the sound speed is less than +0.01%. The (P,T) data span the temperature and pressure ranges 200 K - 475 K and 50 kPa - 1500 kPa. From measured sound speeds we derive the ideal gas heat capacities with a typical uncertainty of only 0.1%. The equation of state is also deduced from (P,T). The densities deduced from acoustic data agree within +0.1% with densities determined by a non-acoustic technique. Recent measurements in SF₆, CF₄, and C₂F₆ will be used to illustrate the system's capabilities. Work in progress on BCl₃ will also be discussed.

Proceedings Title

Proceedings of the Joint Meeting of the 16th International Congress on Acoustics and the 137th meeting of the Acoustical Society of America

Conference Dates

June 16-20, 1998

Conference Title

International Congress on Acoustics

Pub Type

Conferences

Keywords

equation of state, heat capacity, sound speed, thermodynamic properties, virial coefficients

Citation

Hurly, J. (1998), An Automated Apparatus for Measuring Sound Speeds in Hazardous Gases, Proceedings of the Joint Meeting of the 16th International Congress on Acoustics and the 137th meeting of the Acoustical Society of America (Accessed April 29, 2024)