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J. Hernandez, B. Lendl et al.:
"Optical Technologies For The Identification Of Explosives";
Bericht für European Commission; 2013.

Terrorism is a real and growing threat in the world, and more than 60% of the terrorist attacks are carried out by the use of Improvised Explosive Devices (IED). The need of new security tools is a fact; OPTIX project provides a new tool for IED detection form a safe distance. OPTIX system is a transportable system that consists of laser based technologies, LIBS and Raman spectroscopies. Furthermore, research on IR spectroscopy has been done in the project framework. OPTIX is capable to detect traces and bulk amounts of explosives, in solid and liquids in certain conditions.
The use of Raman and LIBS techniques can be alternative or simultaneous. The OPTIX prototype is focussed for the detection of explosives on visible surfaces or when the IED is hidden in a transparent object. Furthermore, during the execution of the project, it has been tested that Raman technology is capable of detecting explosives inside opaque containers.
OPTIX system can perform at a standoff distance of 20 meter.
The working principles of are the following:
LIBS, atomic emission spectroscopy. High energy laser is focused on the sample´s surface, creating plasma. Emissions when the plasma cools down are captured and analysed.
Raman technology is molecular spectroscopy. Laser radiation on the surface of a sample produces an energy transfer affecting the vibrational states of the molecules. Light is scattered with different wavelengths depending on the molecular structure of the material.
IR technique is molecular spectroscopy. After fragmentation of the molecules with a high energy laser pulse, absorption in the IR region of the released NO and NO2 groups are measured, the ratio determining the explosive nature of the sample.
The three techniques share common equipment, optics and laser , which helps the integration in a single platform:
 Laser: A compact high energy laser providing 532 nm, 1064 nm and tunable IR outputs in the range from 5,2 to 6,3 μm.
 Optics: The laser has to be focused on the sample with the necessary energy density for each technology. Emissions from the distant sample in the spectral range from 350 to 950 nm and 5,2 to 6,3 μm are collected. The three technologies will share most of the optical elements.
 Spectrometry: A new ultra sensitive spectrometer has been developed for Raman and increased timing precision has been implemented on a CCD based spectrometer for LIBS.
 All the spectra generated by each technique are analysed by chemometrics module. New algorithms for spectral information extraction for the spectroscopies has been developed to increase reliability of the system.
OPTIX (Optical Technologies for the Identification of explosives) is a project funded by the European Commission under the Seventh Framework Programme (FP7). OPTIX consrtium is composed of a balanced set of technological and industrial partners, from big industry to SMEs, from universities to research organisation, and topped with a best-in-class end user. The geographical distribution of OPTIX covers 6 EU Members States.

standoff detection, LIBS, RAMAN, IR, explosives