基于QEPAS技术的乙炔微量气体高灵敏度检测研究  

Study on High Sensitive Detection of Acetylene Trace Gas Based on QEPAS

作　　者：马欲飞 佟瑶 张立功 何应[1] 张静波[1] 王龙[1] 龙金虎 于欣[1] 孙锐[2] MA Yu-fei TONG Yao ZHANG Li-gong HE Ying ZHANG Jing-bo WANG Long LONG Jin-hu YU Xin SUN Rui(State Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001, China Post-doctoral Mobile Station of Power Engineering and Engineering Thermophysics, Harbin Institute of Technology, Harbin 150001, China)

机构地区：[1]哈尔滨工业大学可调谐(气体)激光技术重点实验室,黑龙江哈尔滨150001 [2]哈尔滨工业大学动力工程及工程热物理博士后流动站,黑龙江哈尔滨150001

出　　处：《光谱学与光谱分析》2017年第9期2869-2872,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(61505041);黑龙江省自然科学基金项目(F2015011);中国博士后科学基金特别资助项目(2015T80350);中国博士后科学基金面上项目(2014M560262);黑龙江省博士后科学基金项目(LBH-Z14074);黑龙江省博士后科学基金特别资助项目(LBH-TZ0602);哈尔滨市科技创新人才专项资金项目(2016RAQXJ140);中央高校基本科研业务费专项资金项目(HIT.NSRIF.2015044)资助

摘　　要：石英增强光声光谱(QEPAS)是近年来发展起来的一种痕量气体探测技术,具有系统体积小、价格低廉、探测灵敏度高等优点。乙炔(C_2H_2)是一种化学性质活泼的有毒气体,对它进行高灵敏度检测在变压器故障诊断、环境监测等领域有着重要的意义,基于此,采用QEPAS技术对C_2H_2微量气体展开高灵敏度检测研究。采用输出波长为1.53μm的连续波分布反馈半导体激光器作为激发光源。为了提高信噪比和简化数据处理过程,QEPAS传感器系统采用波长调制和2次谐波探测技术。为了提高QEPAS系统信号幅值,相比于常见的共振频率为32.768kHz的石英音叉,采用了共振频率较低的30.72kHz石英音叉作为声波传导器,同时还优化了石英音叉与激光束的空间位置、激光波长调制深度,并添加了声波微共振腔,选择的微共振腔长度为4mm、内径为0.5mm,最终获得了2.7ppm的优异检测极限,归一化噪声等效吸收系数为1.3×10^(-8) cm^(-1)·W·Hz^(-1/2)。Quartz-enhanced photoacoustic spectroscopy（QEPAS）technology invented lately uses a commercially available mm sized piezoelectric quartz tuning fork（QTF）as an acoustic wave transducer.A high Q-factor and a^30kHz resonance frequency of the QTF improve QEPAS selectivity and immunity to environmental acoustic noise.QEPAS sensor has the advantages of high sensitivity,selectivity and compactness.Acetylene（C_2H_2）,a toxic and harmful gas,has great significance in high sensitive detection in many fields such as the detection of fault gases in transformers and environmental monitoring.In this paper,QEPAS technology was employed to detect C_2H_2.A continuous-wave distributed feedback（DFB）single mode diode laser emitting at1.53μm was used as the exciting source.In order to reduce the sensor background noise and simplify the data process,a wavelength modulation spectroscopy and a 2nd harmonic detection technique were employed.To increase the QEPAS signal amplitude,unlikely the usually used quartz tuning fork（QTF）with resonance frequency of 32.768 kHz,a novel QTF with 30.72 kHz was adopted as the acoustic wave tr and ucer.The position between laser beam and QTF and the laser wavelength modulation depth were optimized.In the meanwhile,micro-resonator was added into the QEPAS sensor system, and the length and inner diameter of the mR tubes were selected to be 4mm and 0.5mm,respectively.Finally,a 2.7ppm minimum detection limit was obtained, and the corresponding normalized noise equivalent absorption（NNEA）coefficient was 1.3×10^-8 cm^-1·W·Hz^-1/2.

关 键 词：QEPAS C_2H_2气体 共振频率 微共振腔 

分 类 号：TN249[电子电信—物理电子学]