ACOUSTIC GAS THERMOMETRY

Published

January 16, 2014

Author(s)

Michael R. Moldover, Roberto M. Gavioso, James B. Mehl, Laurent Pitre, Michael de Podesta, Jintao Zhang

Abstract

We review the principles, techniques and results from primary acoustic gas thermometry (AGT). Since the establishment of ITS-90, the International Temperature Scale of 1990, spherical and quasi-spherical cavity resonators have been used to realize primary AGT in the temperature range 7 K to 552 K. Throughout the sub-range 90 K 90). (Here T is the thermodynamic temperature and T90 is the temperature on ITS-90.) With a minor exception, the resulting values of (T - T₉₀) are mutually consistent within 3 ×10^-1 T . These consistent measurements were obtained using helium and argon as thermometric gases inside cavities that had radii ranging from 40mm to 90 mm and that had walls made of copper or aluminium or stainless steel. The AGT values of (T - T₉₀) fall on a smooth curve that is outside {+or-}u(T90), the estimated uncertainty of T₉₀. Thus, the AGT results imply that ITS-90 has errors that could be reduced in a future temperature scale. Recently developed techniques imply that low-uncertainty AGT can be realized at temperatures up to 1350 K or higher and also at temperatures in the liquid-helium range.

Citation

Metrologia

Volume

51

Issue

02/01/2014

Pub Type

Journals

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Keywords

acoustic resonators, acoustic thermometry, gas thermometry, primary thermometry, microwave resonators

Citation

Moldover, M. , Gavioso, R. , Mehl, J. , Pitre, L. , de, M. and Zhang, J. (2014), ACOUSTIC GAS THERMOMETRY, Metrologia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914033 (Accessed October 31, 2024)