光声光谱技术作为一种先进的光学检测技术, 已成功应用于各种痕量气体检测场合。实现多气体的光声光谱检测, 同时保证高的检测灵敏度是检测器设计的核心目标。针对测量需求设计, 优化了一种基于亥姆霍兹共振的光声光谱多气体检测器, 使用有限元分析方法对检测器进行了设计和仿真分析, 对光声池的结构参数以及温度和压力特性进行了优化和分析。仿真结果表明: 对光声池结构参数进行优化和对温度压力进行控制可以提高检测器检测灵敏度; 采用光源IR-19时, 激发腔Φ38 mm×9 mm, 连接管Φ5.9 mm×10.2 mm和探测腔Φ30 mm×5.8 mm为光声光谱检测器的最优化参数。经实验验证, 检测器对CO气体的检测精度达到5.08 ppm(1 ppm=10-6)。研究结果为痕量多气体的光声光谱检测提供了设计参考。

As one of the most advanced optical detection techniques, photoacoustic spectroscopy has been successfully used in the area of trace gas detection. Realizing a multi-gas photoacoustic spectroscopy sensor while keeping a high detection sensitivity was the design purpose. For the detection application, a multi-gas photoacoustic spectroscopy sensor based on the Helmholtz resonance was designed and optimized. The sensor was modeled by using the finite element method and optimized for its parameters, including the dimensions of excitation cavity, connecting tube and detection cavity. Also the temperature and pressure properties of the sensor were investigated. As a result, the detection sensitivity could be improved by optimizing the parameters and controlling the temperature and pressure. The optimizing result shows that the gas sensor has a best performance with the infrared light source IR-19, and parameters with excitation cavity of Φ38 mm×9 mm, connecting tube of Φ5.9 mm×10.2 mm and detection cavity of Φ30 mm×5.8 mm. Tested by the experiment, the detection limit of 5.08 ppm is achieved for the CO gas detection. The study results also provide the reference for design of photoacoustic sensor in multi-gas detection.