基于石英增强光声光谱的HCl痕量气体高灵敏度探测研究

发布时间：2018-04-06 23:00

本文选题：QEPAS　切入点：HCl气体　出处：《光谱学与光谱分析》2017年04期

【摘要】：HCl是一种有毒有害气体,对其高灵敏度探测具有非常重要的意义,然而到目前为止,采用激光光谱的手段对其探测的研究报道很少。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。以5 000ppm HCl∶N_2混合气作为待测目标,采用输出波长为1 742.38nm的分布反馈连续波单纵模半导体激光器,开展对基于QEPAS技术的HCl高灵敏度探测研究。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。研究中,首先对声波探测系统中微共振腔强声波增强特性进行了讨论,选择了"共轴"形式的声波微共振腔,并对其尺寸进行了优化,选择的微共振管长度为4mm、内径为0.5mm。实验中研究了激光波长调制深度对QEPAS系统产生的信号幅度的影响,当QEPAS系统积分时间为1s、激光波长调制深度为0.23cm~(-1)时,获得了815ppb的优异检测极限,归一化噪声等效吸收系数为7.41×10~(-9)cm~(-1)·W·Hz~(-1/2)。在后续的实验中,可在待测HCl气体中加入水汽分子,提高HCl分子的热弛豫速率,进一步提高HCl-QEPAS传感器系统的信号强度。
[Abstract]:HCl is a kind of toxic and harmful gas, which has very important significance for its high sensitivity detection. However, so far, there are few reports on the detection of HCl by means of laser spectroscopy.Quartz enhanced photoacoustic spectroscopy (QEPAS) is a kind of trace gas detection technology developed in recent years, which has the advantages of small volume, low price and high detection sensitivity.Taking 5 000ppm HCl:N_2 mixture as the target to be tested, a distributed feedback CW single longitudinal mode semiconductor laser with output wavelength of 1 742.38nm is used to study the high sensitivity detection of HCl based on QEPAS technology.In order to improve the signal-to-noise ratio (SNR) and simplify the data processing process, the QEPAS sensor system adopts wavelength modulation and second harmonic detection techniques.In the study, the enhancement characteristics of the strong acoustic wave in the microresonator are discussed. The "coaxial" acoustic microresonator is selected and its size is optimized. The length of the microresonator is 4mm and the inner diameter is 0.5mm.In subsequent experiments, water vapor molecules can be added to the HCl gas to increase the thermal relaxation rate of HCl molecules, and the signal intensity of the HCl-QEPAS sensor system can be further improved.
【作者单位】：哈尔滨工业大学可调谐(气体)激光技术重点实验室;哈尔滨工业大学动力工程及工程热物理博士后流动站;
【基金】：国家自然科学基金项目(61505041,91441130) 黑龙江省自然科学基金项目(F2015011) 中国博士后科学基金项目(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,LBH-TZ0602) 中央高校基本科研业务费专项资金项目(HIT.NSRIF.2015044)资助
【分类号】：O657.3

【相似文献】