We report on a new optical implementation of primary gas thermometry based on laser-absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) (0,0,0)->(1,2,1) transition in a CO2 gas at thermodynamic equilibrium. Doppler width measurements as a function of the gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of about 1.6 over 10000.
Primary gas thermometry by means of laser-absorption spectroscopy: Determination of the boltzmann constant
CASA, Giovanni;CASTRILLO, Antonio;DI SERAFINO, Daniela;GIANFRANI, Livio
2008
Abstract
We report on a new optical implementation of primary gas thermometry based on laser-absorption spectrometry in the near infrared. The method consists in retrieving the Doppler broadening from highly accurate observations of the line shape of the R(12) (0,0,0)->(1,2,1) transition in a CO2 gas at thermodynamic equilibrium. Doppler width measurements as a function of the gas temperature, ranging between the triple point of water and the gallium melting point, allowed for a spectroscopic determination of the Boltzmann constant with a relative accuracy of about 1.6 over 10000.File in questo prodotto:
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