机场危险品检测的光声光谱遥测原理研究

A fundamental research of a novel method of remote detection of explosive and chemical hazardous materials at airport based on photoacoustic spectroscopy is proposed, in order to meet the need of national interest of improving the airport safety. The micro quartz tuning fork made of MEMS technology provides high quality factor Q. The acoustic signals can be detected through the resonance of the fork to identify the presence of the hazardous elements. The vibration amplitude of the micro tuning fork is inspected by the reflection laser method. The reflected light from the testing object is focused on the tiny tuning fork, which increases the light power density. Using above methods, the measuring sensitivity can be improved by 3-5 orders of magnitude than that of existing methods. These methods also improve anti-noise performance against environmental disturbance. The measurement range is around 2-5 meters in an opening environment. In this project we will evaluate the possible influencing factors and the design criterion of this new remote detection principle based on photoacoustic spectroscopy. A principle prototype will be built in order to lay a solid foundation for further practical application. This project has no need of sample pre-concentration, and has many advantages such as remote sensing, extreme high sensitivity, operational safety, non-invasive testing, low cost and high speed measurement. This project presents a brand new testing principle for fast detection of the explosives and chemical hazardous materials at airport. It is important for the improvement of the civil aviation safety. This project meets the requirements of “new theory and method in safety check” listed on the “Civil aviation joint research funds” guide manual.

针对加强机场安全检测的国家需求，研究一种用于机场爆炸物等危险品“远距离遥测”的光声光谱新原理。采用微电子机械系统(MEMS)技术加工微石英音叉,利用其品质因子Q很高的特性，通过微音叉共振来探测光声信号；利用激光来检测微音叉振幅，以及利用被测物的反射光聚焦于微音叉上来增加光功率密度等方法, 使测量灵敏度比传统光声光谱技术提高3－5个数量级，并具有很强的抗环境干扰能力，可以实现远距离(2-5米)、开放环境下的光声光谱测量。项目将探明这种光声光谱遥测新原理的影响因素、设计准则等，研制原理样机，为实际应用打下坚实基础。本项目方案检测时不需要样品制备、预浓缩等步骤，具有远距离遥测、灵敏度高、安全、非侵入、成本低、检测时间短等优点，为机场微量爆炸物和液体化学危险品检测提供一种全新的检测原理，对进一步提高民航安全具有重要的意义。项目符合“民航联合研究基金”指南的中“安全检查新理论与方法”的要求。

针对目前恐怖活动日渐猖獗，航空部门急需加强机场安全检测的现实需求。本项目尝试探索研究一种用于机场爆炸物等危险品“远距离遥测”的光声光谱新原理。项目采用微电子机械系统(MEMS)技术加工的微石英音叉以及商用微音叉，来作为光声光谱的探测元件，利用其共振特性来检测被测物的反射光，利用其品质因子 Q 很高的特性，从而实现高信噪比探测。项目建立了基于石英音叉的完整的光声光谱遥测原型系统，开发了光声光谱遥测系统所需的激光调制仪，研究出了音叉微小振幅的两种探测方法：光学方法和压电信号检测法。开发了光学测量音叉振幅的探测电路，以及压电法音叉振幅的探测电路，并开发了相应的测量软件。项目利用所开发的系统进行了大量光声光谱实际测量实验研究，并理论和实验研究了激光器功率、激光照射在音叉上的位置、反光膜结构尺寸和位置等多种因素对光声光谱测量的影响规律。实验研究了真空封装对音叉共振特性的影响规律。项目提出采用天文望远镜的方案，极大地提高了系统的探测距离。本项目研究的通过微音叉共振来探测光声信号；利用激光来检测微音叉振幅，以及利用天文望远镜将被测物的反射光聚焦于微音叉上来增加光功率密度等方法, 使测量灵敏度有质的提高，并具有很强的抗环境干扰能力，成功实现了距离6米的、开放环境下的光声光谱测量。项目所研究的技术，以及建立的原型系统和实验研究结果、经验，为将来的实际应用研究打下了良好基础。本项目的研究为机场安全检测提供了一种新思路，具有远距离遥测、灵敏度高、安全、非侵入、成本低、检测时间短等优点，为将来进一步的实用化和工程化研究提供了理论及实践的经验和依据，具有较重要的理论和实际意义。项目研究过程中发表了12篇学术论文，申请了3项发明专利，获得了完全的知识产权，并培养了多名研究生。