Primary gas thermometry by means of laser-absorption spectroscopy: determination of the Boltzmann constant.
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) nu1+2nu2(0)+nu3 transition in CO2 gas at thermodynamic equilibrium. Doppler width measurements as a function of 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 approximately 1.6 x 10(-4).
Dipartimento di Scienze Ambientali, Seconda Università di Napoli, Via Vivaldi 43, I-81100 Caserta, Italy.
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G
Casa
A
A
Castrillo
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G
Galzerano
R
R
Wehr
A
A
Merlone
D
D
Di Serafino
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P
Laporta
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L
Gianfrani