Influence of Radius of Photoacoustic Cell and Background Gas Type on Photoacoustic Spectroscopy Gas Measurement System

The gas detection performance of photoacoustic spectroscopy devices can be effectively improved by optimizing the photoacoustic cell (PAC) structure. In this paper, the frequency response of PACs with multiple radius and background gases were simulated. The results show that the sound pressure decreases as the modulation frequency increases. The smaller the radius, the greater the sound pressure value. The sound pressure intensity inside the photoacoustic cell increases as the gas heat capacity ratio increases, especially for a PAC with a radius of 3 mm. Three different background gases (He, N2 and SF6) are filled in the PAC. The results show that the background gas has an effect on the sound pressure signal. The sound pressure signal will also increase as the heat capacity ratio of the background gas increases, the sequence of the PA signals’ intensity is He>N2>SF6. The research results provide reference method and idea for the optimal design of photoacoustic cells.