Ppb级探测灵敏度的CO_(2)腔衰荡光谱仪  

Cavity ring-down spectrometer of CO2 with ppb detection sensitivity

作　　者：刘英 胡迈[3] 王兴平 许振宇 何亚柏 阚瑞峰 LIU Ying;HU Mai;WANG Xingping;XU Zhenyu;HE Yabai;KAN Ruifeng(Anhui Institute of Optics and Fine Mechanics,Hefei Institute of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China;Department of Mechanical and Automation Engineering,The Chinese University of Hong Kong,Hong Kong 999077,China)

机构地区：[1]中国科学院合肥物质科学研究院安徽光学精密机械研究所,安徽合肥230031 [2]中国科学技术大学,安徽合肥230026 [3]香港中文大学机械和自动化工程系,中国香港999077

出　　处：《光学精密工程》2023年第20期2921-2929,共9页Optics and Precision Engineering

基　　金：粤港关键领域重点突破项目资助(No.2004A10403021);广东省攻关项目资助(No.2006A10401006)。

摘　　要：二氧化碳(Carbon dioxide,CO_(2))是大气中最主要的温室气体,具有大气本底浓度高而年变化量小的特点。因此,对其浓度进行高精度的监测是实现“双碳”目标的重要环节。本文基于连续波光腔衰荡光谱技术,搭建了一套探测灵敏度低至ppb的CO_(2)气体传感装置。系统中选取了中心波长为6251.760 cm-1的CO_(2)吸收线、设计了超高精细度(>300000)的石英玻璃型法布里-珀罗谐振腔和高性能的温度、压力控制模块。腔内气体的温度和压力在24 h的变化量分别小于0.07℃和15 Pa。Allan方差的结果显示,系统在303 s的最佳积分时间下,可获得0.7×10-12 cm-1的检测限,对应的CO_(2)最低可检测浓度为1.6 ppb。在较大的CO_(2)浓度范围内,系统响应的线性相关系数为0.99994。最后,系统以10 s的响应时间,对大气中的CO_(2)浓度进行了2天的连续观测,其结果与商用仪器(Picarro,G2401)的监测数据高度一致,排除人体呼气干扰后的相对偏差优于6‰。该系统具有结构简单、成本低、灵敏度极高的特点,在痕量气体监测领域将具有广阔的应用前景。Carbon dioxide(CO_(2))is the most important greenhouse gas in the atmosphere,characterized by high concentrations with minimal annual fluctuations.Therefore,high-precision monitoring of its con-centration is an important link to realize the objective of the"double carbon."In this study,a CO_(2) gas sens-ing device,with detection sensitivity in the ppb level,was constructed based on continuous-wave cavity ring-down spectroscopy.The CO_(2) absorption line with a central wavelength of 6251.760 cm-1 was select-ed.Moreover,a quartz glass Fabry-Perot resonant cavity with ultra-high fineness(>300000)and tem-perature and pressure control modules with good performance were designed in the system.The changes in gas temperature and pressure in the cavity during 24 h are less than 0.07℃and 15 Pa,respectively.The Allan variance result shows that the system can obtain a detection limit of 0.7×10-12 cm-1 at an opti-mal integration time of 303 s.For carbon dioxide,the detection limit corresponds to a minimum detectable concentration of 1.6×10-9.The linear correlation coefficient of the system's response is 0.99994 over a wide range of CO_(2) concentrations.Finally,an observation of the atmospheric CO_(2) was conducted for 2 days with a system response time of 10 s.The results are in good agreement with the monitoring data from the commercial instrument(Picarro,G2401),and the deviation between the two devices is less than 6‰after excluding the interference from human exhalation.With its simple structure,low cost,and extremely high sensitivity,the system exhibits a broad application in the field of trace gas monitoring.

关 键 词：CO_(2)探测 光学传感 光腔衰荡光谱 极高灵敏度 

分 类 号：TP394.1[自动化与计算机技术—计算机应用技术] TH691.9[自动化与计算机技术—计算机科学与技术]