A compact portable and standalone point sensor has been developed for the detection and identification of precursors of improvised\nexplosive devices (IEDs) and to be part of a network of sensors for the discovery of hidden bomb factories in homeland security\napplications. The sensor is based on quartz enhanced photoacoustic spectroscopy (QEPAS), and it implements a broadly tunable\nexternal cavity quantum cascade laser source (EC-QCL). It makes use of an optical cell purposely designed with a miniaturized\ninternal volume, to achieve fast response and high sensitivity, and that can also be heated to improve sensitivity towards less volatile\ncompounds. The sensor has been assembled and successfully tested in the lab with several compounds, including IED�s precursors\nsuch as acetone, nitromethane, nitric acid, and hydrogen peroxide. The identification capability and limits of detection near the\nppm level have been estimated for all these compounds.
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