根据污染气体的光谱吸收特性与荧光特性, 设计了一套时分复用检测系统, 既可以使用光谱吸收法检测甲烷和二氧化硫又可以使用荧光法检测二氧化硫。 系统采用组合可切换光源、 共用光路、 气室及信号处理部分, 首先进行光谱吸收和荧光的特性测量, 然后进行光谱吸收法检测甲烷与二氧化硫浓度实验, 以及紫外荧光法检测二氧化硫浓度实验。 经过光谱吸收和荧光的特性测量得出吸收法测二氧化硫和甲烷的吸收峰处的激发波长分别为280 nm和1.64 μm, 荧光法测二氧化硫最佳激发波长为220 nm。 经光谱吸收法实验可得甲烷浓度与相对强度的线性关系和二氧化硫浓度与输出电压的线性关系, 线性度分别为98.7%, 99.2%; 经荧光法实验可得二氧化硫浓度与电压成线性关系, 线性度达到了99.5%。 研究表明, 该系统能使用于污染气体的光谱吸收检测和紫外荧光检测。 将两种测量方式组合在一起, 降低了成本与体积, 同时此系统也可用于其他气体的检测, 有一定的应用价值。

According to the spectral absorption characteristics of polluting gases and fluorescence characteristics, a time-division multiplexing detection system is designed. Through this system we can detect Methane (CH4) and sulfur dioxide (SO2) by using spectral absorption method and the SO2 can be detected by using UV fluorescence method. The system consists of four parts: a combination of a light source which could be switched, the common optical path, the air chamber and the signal processing section. The spectral absorption characteristics and fluorescence characteristics are measured first. Then the experiment of detecting CH4 and SO2 through spectral absorption method and the experiment of detecting SO2 through UV fluorescence method are conducted, respectively. Through measuring characteristics of spectral absorption and fluorescence, we get excitation wavelengths of SO2 and CH4 measured by spectral absorption method at the absorption peak are 280 nm and 1.64 μm, respectively, and the optimal excitation wavelength of SO2 measured by UV fluorescence method is 220 nm. we acquire the linear relation between the concentration of CH4 and relative intensity and the linear relation between the concentration of SO2 and output voltage after conducting the experiment of spectral absorption method, and the linearity are 98.7%, 99.2% respectively. Through the experiment of UV fluorescence method we acquire that the relation between the concentration of SO2 and the voltage is linear, and the linearity is 99.5%. Research shows that the system is able to be applied to detect the polluted gas by absorption spectrum method and UV fluorescence method. Combing these two measurement methods decreases the costing and the volume, and this system can also be used to measure the other gases. Such system has a certain value of application.