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Viola R.,Centro Ricerche Elettro Ottiche | Liberatore N.,Centro Ricerche Elettro Ottiche | Luciani D.,Centro Ricerche Elettro Ottiche | Mengali S.,Centro Ricerche Elettro Ottiche | Pierno L.,Selex Sistemi Integrati SpA
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The Nerve gases are persistent gases that appear as very challenging menace in homeland security scenarios, due to the low pressure vapor at ambient temperature, and the very low lethal concentrations. A novel approach to the detection and identification of these very hazardous volatile compounds in large areas such as airports, underground stations, big events arenas, aimed to a high selectivity (Low false alarm probability), has been explored under the SENSEFIB Corporate Project of Finmeccanica S.p.A. The technical demonstrator under development within the Project is presented. It is based on distributed line sensors performing infrared absorption measurements to reveal even trace amounts of target compounds from the retrieval of their spectral fingerprint. The line sensor is essentially constituted by a widely tunable external cavity quantum cascade laser (EC-QCL), coupled to IR thermoelectrically cooled MCT fast detectors by means of a infrared hollow core fibers (HCF). The air is sampled through several micro-holes along the HCF, by means of a micropump, while the infrared radiation travels inside the fiber from the source to the detector, that are optically coupled with the opposite apertures of the HCF. The architecture of the sensor and its principle of operation, in order to cover large areas with a few line sensors instead of with a grid of many point sensors, are illustrated. The sensor is designed to use the HCF as an absorption cell, exploiting long path length and very small volume, (e.g fast response), at the same time. Furthermore the distributed sensor allows to cover large areas and/or not easily accessible locations, like air ducts, with a single line sensor by extending the HCF for several tens of meters. The main components implemented in the sensor are described, in particular: the EC-QCL source to span the spectral range of wavelength between 9.15um and 9.85um; and the hollow core fiber, exhibiting a suitably low optical loss in this spectral range (<1dB/m). Also, the characteristics of detectors and associated electronics for signal processing and data acquisition are discussed. Main results from preliminary measurements carried out are also presented. © 2010 SPIE.

Corsi C.,Centro Ricerche Elettro Ottiche
Advances in Optical Technologies | Year: 2012

Infrared science and technology has been, since the first applications, mainly dedicated to security and surveillance especially in military field, besides specialized techniques in thermal imaging for medical diagnostic and building structures and recently in energy savings and aerospace context. Till recently the security applications were mainly based on thermal imaging as surveillance and warning military systems. In all these applications the advent of room temperature, more reliable due to the coolers avoidance, low cost, and, overall, completely integrable with Silicon technology FPAs, especially designed and tailored for specific applications, smart sensors, has really been impacted with revolutionary and new ideas and system concepts in all the infrared fields, especially for security applications. Lastly, the advent of reliable Infrared Solid State Laser Sources, operating up to the Long Infrared Wavelength Band and the new emerging techniques in Far Infrared Submillimeter Terahertz Bands, has opened wide and new areas for developing new, advanced security systems. A review of all the items with evidence of the weak and the strong points of each item, especially considering possible future developments, will be reported and discussed. © 2012 Carlo Corsi.

Mengali S.,Centro Ricerche Elettro Ottiche | Liberatore N.,Centro Ricerche Elettro Ottiche | Luciani D.,Centro Ricerche Elettro Ottiche | Viola R.,Centro Ricerche Elettro Ottiche | And 11 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Analytical instruments based on InfraRed Absorption Spectroscopy (IRAS) and Gas Chromatography (GC) are today available only as bench-top instrumentation for forensic labs and bulk analysis. Within the 'DIRAC' project funded by the European Commission, we are developing an advanced portable sensor, that combines miniaturized GC as its key chemical separation tool, and IRAS in a Hollow Fiber (HF) as its key analytical tool, to detect and recognize illicit drugs and key precursors, as bulk and as traces. The HF-IRAS module essentially consists of a broadly tunable External Cavity (EC) Quantum Cascade Laser (QCL), thermo-electrically cooled MCT detectors, and an infrared hollow fiber at controlled temperature. The hollow fiber works as a miniaturized gas cell, that can be connected to the output of the GC column with minimal dead volumes. Indeed, the module has been coupled to GC columns of different internal diameter and stationary phase, and with a Vapour Phase Pre-concentrator (VPC) that selectively traps target chemicals from the air. The presentation will report the results of tests made with amphetamines and precursors, as pure substances, mixtures, and solutions. It will show that the sensor is capable of analyzing all the chemicals of interest, with limits of detection ranging from a few nanograms to about 100-200 ng. Furthermore, it is suitable to deal with vapours directly trapped from the headspace of a vessel, and with salts treated in a basic solution. When coupled to FAST GC columns, the module can analyze multi-components mixes in less than 5 minutes. © 2013 SPIE.

Corsi C.,Centro Ricerche Elettro Ottiche | Dundee A.,Centro Ricerche Elettro Ottiche | Laurenzi P.,Centro Ricerche Elettro Ottiche | Liberatore N.,Centro Ricerche Elettro Ottiche | And 8 more authors.
Advances in Optical Technologies | Year: 2012

Advanced IR emitters and sensors are under development for high detection probability, low false alarm rate, and identification capability of toxic gases. One of the most reliable techniques to identify the gas species is absorption spectroscopy, especially in the medium infrared spectral range, where most of existing toxic compounds exhibit their strongest rotovibrational absorption bands. Following the results obtained from simulations and analysis of expected absorption spectra, a compact nondispersive infrared multispectral system has been designed and developed for security applications. It utilizes a few square millimeters thermal source, a novel design multipass cell, and a smart architecture microbolometric sensor array coupled to a linear variable spectral filter to perform toxic gases detection and identification. This is done by means of differential absorption spectroscopic measurements in the spectral range of the midinfrared. Experimental tests for sensitivity and selectivity have been done with various chemical agents (CAs) gases and a multiplicity of vapour organic compounds (VOCs). Detection capability down to ppm has been demonstrated. © 2012 Carlo Corsi et al.

Liberatore N.,Centro Ricerche Elettro Ottiche | Luciani D.,Centro Ricerche Elettro Ottiche | Mengali S.,Centro Ricerche Elettro Ottiche | Viola R.,Centro Ricerche Elettro Ottiche | And 7 more authors.
Lecture Notes in Electrical Engineering | Year: 2014

A new detection system for ATS and their precursors has been designed and a bench-top demonstrator has been realized. A test campaign has been performed in order to assess the overall system behavior, and the results confirmed the feasibility of this type of device. © 2014 Springer Science+Business Media.

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