Designing aspects of photoacoustic cell for crystalline solids

Today, non-destructive analysis techniques for solids are playing an important role in industrial applications and scientific as well as technological research. Photoacoustic method is one of such non-destructive methods, in which generation of acoustic waves takes place due to the absorption of the modulated incident radiation. Photoacoustic cell is a base for photoacoustic research. Hence design and performance optimization play an important role in determining the efficiency of that cell. The design of the photoacoustic cell depends on various aspects like mode of operation, thermal diffusion, nature of the radiation source, and type of the detector. In this paper, designing aspects of a new photoacoustic cell for crystalline solids are presented. A mathematical expression for population density of absorbing molecules in the excited state of a crystalline solid during photoacoustic interaction in terms of the radiative and collisional time constants is also determined.