The photothermal radiometry (PTR) signal is analyzed in order to simultaneously obtain the thermal diffusivity and effusivity of solid materials. Analytical procedures that allow the determination of the thermal parameters via a frequency scan of the amplitude or the phase of the PTR signal are presented. The measurement procedures do not involve a multiparameter-fit optimization algorithm. The methods have been used for the measurement of thermophysical properties of vitreous carbon and lead-itanate-zirconate ceramic samples.

Articles you may be interested inHigh accuracy, self-calibrating photopyroelectric device for the absolute determination of thermal conductivity and thermal effusivity of liquids Rev. Sci. Instrum. 80, 054904 (2009); 10.1063/1.3131625 On the accurate determination of thermal diffusivity of liquids by using the photopyroelectric thickness scanning method Rev. Sci. Instrum. 78, 024902 (2007);We present a systematic theoretical and experimental investigation on the accuracy of thermal diffusivity ␣ and thermal effusivity e of liquids measured by the photopyroelectric ͑PPE͒ method in back-detection configuration ͑BPPE͒. Special cases corresponding to different cell structures are analyzed in terms of error determination of ␣ and e for water and ethylene glycol. We propose a new normalization procedure allowing for estimation of these parameters with accuracy of 2% on ␣ and 5% on e over extended frequency range. The normalization eliminates the frequency-dependent influence of the transducer impedance and associated electronics, reduces the errors due to coupling fluid between cell components, and reduces the number of temperature-dependent parameters that must be known in order to characterize the sample. Technical solutions for improving the performances are suggested. Another goal of the study was to demonstrate the possibility of the BPPE method to yield small variations of thermal parameters as a function of temperature. We found good agreement with the literature data for the temperature coefficients (⌬␣/␣)/⌬T ϭ0.267Ϯ0.015%/K for water and (⌬e/e)/⌬Tϭ0.10Ϯ0.05%/K for ethylene glycol, between 20 and 60°C. The special case implying the normalization to a reference material and with a glass substrate for the pyroelectric sensor is shown to be the best adapted to the determination of both thermal parameters and of their temperature dependence.

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