Performance of the photoacoustic Helmholtz cavity resonator cell excited by photoacoustic and electromechanical method

This paper presents method and performance of the double Helmholtz photoacoustic resonator that can be used to improve excitation of acoustical response of the photoacoustic cell by photoacoustic effect and by electromechanical means. The presented method can be used to evaluate energy efficiency of the cell and the associated electronic circuit, to determine overall sensitivity of the set-up, its signal to noise ratio, etc. Electromechanical means of exciting acoustic field inside double Helmholtz photoacoustic cell is easy to perform and allows to simulate photoacoustic signal response in various experimental set-ups. This method uses acoustical pressure produced by a piezoelectric disc mounted in the cell and driven from an external oscillator circuit. The practical experiments show good adherence of the photoacoustic cell frequency dependent acoustical characteristics, obtained by electromechanical method and by photoacoustic method. Equivalents of acoustical response of the photoacoustic cell by both methods has been shown.