Photoacoustic signal with two heating sources: theoretical predictions and experimental results for the open photoacoustic cell technique

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.

Формирование Фотоакустического Отклика В Двуслойной Структуре Полимер/Гель

“…Механизм формирования ФА-сигнала от образцов гидрогелей в экспериментах, выполненных в настоящей работе, сходен с тем, который имеет место в классическом варианте газомикрофонного ФА-метода " открытого окна", (open window (OW)) [19][20][21].…”

Thermal Fractional Diffusion: Experimental Evidence from the Discrepancies in the Amplitude and Phase in Photothermal Technique

“…The Photoacoustic signal (PA) has been extensively studied to obtain the thermal properties of solid materials [1,2,3,4,5,6,7,8,9,10,11,12,13,14].…”

“…However, the acquired final result δP measured , or electrical signal, is influenced by the measurement system using a transfer function H(f ) and noise N (f ) [22,23,24,25,26,9,1].…”