Measurement of the Boltzmann constant by the Doppler broadening technique at a 3,8x10-5 accuracy levelReportar como inadecuado




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1 LPL - Laboratoire de Physique des Lasers 2 LNE- INM - Laboratoire National de Métrologie et d-Essais - Institut National de Métrologie

Abstract : In this paper, we describe an experiment performed at the Laboratoire de Physique des Lasers and dedicated to an optical measurement of the Boltzmann constant . With the proposed innovative technique, determining comes down to an ordinary frequency measurement. The method consists in measuring as accurately as possible the Doppler absorption profile of a rovibrational line of ammonia in thermal equilibrium. This profile is related to the Maxwell-Boltzmann molecular velocity distribution along the laser beam. A fit of the absorption line shape leads to a determination of the Doppler width proportional to sqrtkT and thus to a determination of the Boltzmann constant. The laser source is an ultra-stable CO2 laser with a wavelength . The absorption cell is placed in a thermostat keeping the temperature at 273.15 K within 1.4 mK. We were able to measure with a relative uncertainty as small as 3.8x10-5, which represents an improvement of an order of magnitude for an integration time comparable to our previous measurement published in 2007 1





Autor: Khelifa Djerroud - Cyril Lemarchand - Alexandre Gauguet - Christophe Daussy - Stephan Briaudeau - Benoît Darquié - Olivier Lope

Fuente: https://hal.archives-ouvertes.fr/



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