The synthetic double wavelength technique: a simple robust method for thermodynamic temperature determination

Stéphan Briaudeau (1) , Frédéric Bourson (1) , Olga Kozlova (1) , Mohamed Sadli (1) , Annick Razet (1)

1 LCM - Laboratoire commun de métrologie LNE-CNAM

This paper describes a new relative technique developed at LNE-Cnam, for the determination of the thermodynamic temperature of blackbodies without recourse to a radiometric reference. This technique is referred to as the 'synthetic double wavelength technique' (SDWT) as it is considered to be a particular case of the 'double wavelength technique' (DWT). It offers a new experimental technique for the determination of the thermodynamic temperature at high temperature and as such a new means for the mise-en-pratique of the new definition of the kelvin achievable by any national metrology institute provided a multi-wavelength radiation thermometer combining large and narrow bandwidths is available. In this work, a first experimental implementation of this technique based on a wavelength-tuneable spectroradiometer providing both narrowband and broadband signals with the particularity of the broadband signal being virtually synthesised from the spectral distribution of the narrowband signals sampled over a wide spectral range. SDWT determination of the thermodynamic temperature of a blackbody at 2760 K was performed with a level of uncertainty that confirms the promising capabilities of this technique.

Mots clés: temperature unit; kelvin; SI; mise en pratique; dissemination; thermodynamic temperature; double wavelength technique

Domaines: Physique [physics]

Stéphan Briaudeau, Frédéric Bourson, Olga Kozlova, Mohamed Sadli, Annick Razet. The synthetic double wavelength technique: a simple robust method for thermodynamic temperature determination. Metrologia, 2020, 57 (2), pp.025014. ⟨10.1088/1681-7575/ab7173⟩. ⟨hal-03602591⟩