基于差分模式激发光声光谱法的气体检测系统研究

本文介绍了一种新型光声光谱检测方法—差分模式激发光声光谱法,该方法通过计算同一光声池内两种不同声共振模式下光声信号强度的比值,间接测得被测气体浓度值。结合适当的滤光片,可实现对不同气体的测量。本文以高效数据处理芯片DSP作为核心处理单元,简化了系统结构,提高了响应速度,便于修改程序,改进检测算法。实验结果表明,在压力为98000Pa温度为295K的条件下,对丙酮蒸气的检测极限度可达23ppm.m-1。

Gas Detector Based on Differential Mode Excitation Photoacoustic Spectroscopy

A new gas detector based on a novel photoacoustic scheme named Differential Mode Excitation Photoacoustic Spectroscopy (DME-PAS) is presented. This method takes advantage of the selective excitation of two different modes in a resonant photoacoustic cell and the gas concentration is derived from the amplitude ratio of these acoustic modes indirectly. The method can detect different gas with optical filter. Efficient data processing cell DSP was chosen as central cell, reducing the system components and making faster a reaction. Meanwhile, it’s convenient to change detecting algorithm according to modifying program. Experiments show that the obtained limit of detection is 23 ppm·m-1 at 98 000Pa and 295 K.