消光棱镜气室气体检测特性分析

Analysis of Gas Measurement Characteristics of Prism Gas Cell by Light Extinction Method

在消光法气体浓度检测中,使用了两个相同的直角棱镜增大透射光束在气体中的光程,利用其对光束的全反射特性提高了气室的检测灵敏度;使用凸透镜对旁轴光束聚焦,解决了二次测量中输出光束平移问题;给出了旁轴光束条件下光束的传输特性方程及灵敏度的定性表达,并对灵敏度进行了仿真分析;使用单波长测量法对气体浓度进行了计算,并分析了系统误差。

In the measurement of gas concentration by means of the light extinction,two identical rectangu lar prisms are used to increase the optical path of transmitted light in the gas and the detection sensitivity of the gas cell is improved by making use of total internal reflection of prisms.Focusing of the paraxial light beam by means of convex lens solves the problem that output beam moves in the second measurement.Transmission equa tion of probing light beam and the sensitivity of the system are proposed in the condition of the paraxial light beam,and simulation analysis is made for the sensitivity.Based on the measurement method of single wave length,the gas concentration and system error are calculated and analyzed respectively.