Application of the thermal wave resonator to the measurement of the thermal diffusivity of gas mixtures

A gas analyzer device based on thermal wave interference in a cavity is pre sented. The thermal diffusivity of CO2:air mixtures as a function of the re lative concentration is measured. It is demonstrated that different concent rations of CO2 in air can be detected with accuracy using the described exp erimental device. The results presented here open the possibility to perfor m routine measurements of thermal diffusivity of binary gas mixtures and us ing this parameter to monitor the relative gas concentration. (C) 2001 Amer ican Institute of Physics.