Photoacoustic Measurements of Thermal Diffusivity. Description of the "Drum Effect"

Abstract

For a thermally thick sample (thickness ℓs, thermal conductivity ks, specific heat Cs) the R-G theory /1/ gives pressure variations δp1 detected on the front surface of a sample (fig 1a)depending on the modulation frequency f as fig 2 shows for the modulus |δP1|.