New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas
| Autor: | James B. Mehl, P. A. Giuliano Albo, Marc Himbert, B. Marty, A. Allard, Bo Gao, Cécile Guianvarc'H, F. Sparasci, Laurent Pitre, M.D. Plimmer, C Martin, Lara Risegari, Michael R. Moldover |
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| Přispěvatelé: | Laboratoire commun de métrologie LNE-CNAM (LCM), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE )-Conservatoire National des Arts et Métiers [CNAM] (CNAM), Laboratoire National de Métrologie et d'Essais [Trappes] (LNE ), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Ricerca Metrologica (INRiM), Chinese Academy of Sciences [Beijing] (CAS), National Institute of Standards and Technology [Gaithersburg] (NIST) |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Scale of temperature
Thermodynamics 01 natural sciences Measure (mathematics) quasi-sphere 010309 optics symbols.namesake Helium-4 triaxial ellipsoid Speed of sound 0103 physical sciences Avogadro constant Gas constant [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det] 010306 general physics ComputingMilieux_MISCELLANEOUS speed of sound definition of the kelvin Physics acoustic resonance General Engineering Volume (thermodynamics) Boltzmann constant microwave resonance symbols |
| Zdroj: | Metrologia Metrologia, IOP Publishing, 2017, 54 (6), pp.856-873. ⟨10.1088/1681-7575/aa7bf5⟩ Metrologia (0026-1394) (Iop Publishing Ltd), 2017-12, Vol. 54, N. 6, P. 856-873 |
| ISSN: | 0026-1394 1681-7575 |
| DOI: | 10.1088/1681-7575/aa7bf5⟩ |
| Popis: | 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-litre volume quasi-spherical resonator. The method is based on the accurate determine of acoustic and microwave resonances to measure the speed of sound at different pressures. We find for the universal gas constant R = 8.31 44614 (50) Jmol-1K-1. Using the current best available value of the Avogadro constant, we obtain k = 1.38 064 878(83) ×10^(23) JK-1 with u(k) / k = 0.60 x 10^(-6), where the uncertainty u is one standard uncertainty corresponding to a 68 % confidence level. This value is consistent with previous determinations and with that of the 2014 CODATA adjustment of the fundamental constants (Mohr et al., Rev. Mod. Phys. 88, 035009 (2016)), within the standard uncertainties. We combined the present values of k and u(k) with earlier values that were measured at LNE. Assuming the maximum possible correlations between the measurements, (klsubgpresentl/subg/〈k〉-1) = 0.071×10lsupg-6l/supg and the combined ur(k) is reduced to 0.56×10lsupg-6l/supg. Assuming minimum correlations, (klsubgpresentl/subg/〈k〉-1) = 0.10×10lsupg-6l/supg and the combined ur(k) is reduced to 0.49×10lsupg-6l/supg. |
| Databáze: | OpenAIRE |
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