# New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas

@article{Pitre2017NewMO, title={New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas}, author={Laurent Pitre and Fernando Sparasci and Lara Risegari and C{\'e}cile Guianvarc'h and C Martin and Marc Himbert and Mark Plimmer and Adrien Allard and Benoit Marty and P Alberto Giuliano Albo and Bo Gao and Michael R Moldover and James B. Mehl}, journal={Metrologia}, year={2017}, volume={54}, pages={856 - 873} }

The SI unit of temperature will soon be redefined in terms of a fixed value of the Boltzmann constant k derived from an ensemble of measurements worldwide. We report on a new determination of k using acoustic thermometry of helium-4 gas in a 3 l volume quasi-spherical resonator. The method is based on the accurate determination of acoustic and microwave resonances to measure the speed of sound at different pressures. We find for the universal gas constant R = 8.314 4614(50) J·mol−1·K−1. Using…

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