Photoacoustic signal with two heating sources: theoretical predictions and experimental results for the open photoacoustic cell technique
Aloisi Somer, Anderson Gonçalves, Thiago V. Moreno, Gerson Kniphoff da Cruz, Mauro Luciano Baesso, Nelson G. C. Astrath, Andressa Novatski
Abstract
Abstract A theoretical model for the photoacoustic signal with an analytical solution for the open photoacoustic cell technique is performed. The thermal diffusion (TD) and thermoelastic bending (TE) contributions from the sample and window of the open-cell are considered in the model. The analytical solution was submitted to simulations varying the thermal diffusivity, optical absorption coefficient, thickness and the amplitudes of the TD and TE contributions. The proposed theoretical model was applied to experimental data from different glasses, and quantitative analysis was achieved by calibrating the PA signal based on the TD and TE in an aluminum foil. The results demonstrate the reliability of the analytical solution for determining the thermal diffusivity of the samples.