Title :
Improved apparatus to determine the Boltzmann constant using a large quasi-spherical acoustic resonator
Author :
Pitre, L. ; Sparasci, F. ; Risegari, L. ; Guianvarc´h, C. ; Plimmer, M.D. ; Himbert, M.E.
Author_Institution :
Lab. Commun de Metrol., LNE-CNAM, La Plaine St. Denis, France
Abstract :
There is currently great interest in a new definition of the SI unit of temperature based on a fixed value of the Boltzmann constant k. This paper describes work towards an improved determination of k from the measurement of the speed of sound in argon in a quasi-spherical resonator at constant temperature near 273.16 K. The speed is extracted from acoustic resonance frequencies extrapolated to ideal gas behavior while the dimensions of the resonator are determined from microwave resonance frequencies. We outline key aspects of the experiment namely thermometry and pressure measurement, acoustic and microwave resonances and gas handling.
Keywords :
acoustic resonators; acoustic variables measurement; argon; constants; microwave resonators; pressure measurement; temperature measurement; Ar; Boltzmann constant; argon; gas handling; ideal gas behavior; microwave resonance frequencies; pressure measurement; quasispherical acoustic resonator; speed of sound; thermometry; Acoustic measurements; Acoustics; Argon; Frequency measurement; Microwave measurement; Resonant frequency; Temperature measurement; Acoustic resonance; Boltzmann constant; Microwave resonance; Thermometry;
Conference_Titel :
Precision Electromagnetic Measurements (CPEM 2014), 2014 Conference on
Conference_Location :
Rio de Janeiro
Print_ISBN :
978-1-4799-5205-2
DOI :
10.1109/CPEM.2014.6898331
