Aspects of the Application of Cavity Enhanced Spectroscopy to Nitrogen Oxides Detection

Sensors

Jacek Wojtas¹  Janusz Mikolajczyk² 

[1] Institute of Optoelectronics, Military University of Technology, 2 Gen. S. Kaliskiego St., Warsaw 00-908, Poland;

关键词: CEAS;    CRDS;    absorption spectroscopy;    laser spectroscopy;    nitrogen oxides detection;    NO_x detection;    explosives detection;   

DOI  :  10.3390/s130607570

来源: mdpi

【 摘 要 】

This article presents design issues of high-sensitive laser absorption spectroscopy systems for nitrogen oxides (NO_x) detection. Examples of our systems and their investigation results are also described. The constructed systems use one of the most sensitive methods, cavity enhanced absorption spectroscopy (CEAS). They operate at different wavelength ranges using a blue—violet laser diode (410 nm) as well as quantum cascade lasers (5.27 μm and 4.53 μm). Each of them is configured as a one or two channel measurement device using, e.g., time division multiplexing and averaging. During the testing procedure, the main performance features such as detection limits and measurements uncertainties have been determined. The obtained results are 1 ppb NO₂, 75 ppb NO and 45 ppb N₂O. For all systems, the uncertainty of concentration measurements does not exceed a value of 13%. Some experiments with explosives are also discussed. A setup equipped with a concentrator of explosives vapours was used. The detection method is based either on the reaction of the sensors to the nitrogen oxides directly emitted by the explosives or on the reaction to the nitrogen oxides produced during thermal decomposition of explosive vapours. For TNT, PETN, RDX and HMX a detection limit better than 1 ng has been achieved.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.