基于中红外腔衰荡光谱的CO_(2)检测系统研制

Development of Carbon Dioxide Detection Device Based on Mid-Infrared Cavity Decay Spectroscopy Technology

^(14)C是核反应放射性流出物中最受关注的放射性核素之一,核设施产生的^(14)C主要与CO_(2)标记,因此对^(14)CO_(2)气体进行在线检测具有重要意义。本研究采用腔衰荡光谱技术(CRDS),以CO_(2)为研究对象,选取^(14)CO_(2)吸收谱线的中心波长2 209.11 cm^(-1)附近检测^(14)CO_(2)的吸收光谱。采用中红外波段量子级联激光器、光学谐振腔、合理的光路设计和气体管路设计,研制基于中红外腔衰荡光谱的CO_(2)检测系统。并采用研制的系统检测不同浓度的CO_(2)(0.5%~1.3%)进行验证。结果表明,待测气体浓度与衰荡时间的倒数之间呈线性相关,证实研制的中红外腔衰荡光谱系统可行。该系统成功实现了对不同浓度CO_(2)气体在中红外波段下的精准测量,使用中红外腔衰荡技术测量得到^(14)CO_(2)的吸收光谱。为未来激光光谱快速原位检测14CO_(2)研究提供了重要的技术支持。

With the rapid development of the nuclear industry,the amount of waste to be treated and monitored increases,and the potential emissions will also increase,and C-14 needs to be monitored.C-14 produced by nuclear facilities is mainly combined with CO_2,so sensitive monitoring of ~(14)CO_(2gas) is of great significance.In this paper,cavity ring-down spectroscopy(CRDS) is used to detect the CO_(2) absorption spectrum by selecting the center wave number of ~(14)CO_(2) absorption line around2 209.11 cm~(-1).A CO_(2) detection system based on mid-infrared cavity ring-down spectroscopy is developed by using a quantum cascade laser in mid-infrared band,an optical resonator,and a reasonable optical path design and gas pipeline design.Based on the developed system,different concentrations of CO_2(0.5%-1.3%) were detected,and the experimental data were fitted and analyzed,and the results were found to be consistent with the theoretical formula,which confirmed the feasibility of the developed mid-infrared cavity ring-down spectrum system.The system has successfully realized the accurate measurement of different concentrations of CO_(2) gas in the midinfrared band,the absorption spectrum of ~(14)CO_(2) was measured by mid-infrared cavity ring-down technique,which provides an important technical support and foundation for the future study of laser spectral detection of ~(14)CO_2.