Detection of Explosives
Researcher: Prof. Ilana Bar
Department: Physics
Faculty: Natural Sciences
Email: ibar@bgu.ac.il
Prof. Ilana Bar focuses on developing laser-based spectroscopic methods for detection and identification of explosives and related compounds. Over the years, Bar has dealt with finding new concepts for detection and revealing the characteristic signatures of analytes, using different methods. In recent years, she and her team have focused on vibartional spectroscopies, based on linear and nonlinear Raman processes for detection of solid particles and for finding the best conditions for obtaining high sensitivities.
They have recently developed a modular, compact Raman spectrometer, based on a green laser pointer, which was applied to detection of harmful compounds, including liquids in glass vials, particles of solids and even individual particles of around 20 –40 mm diameter obtained from residues of latent human fingerprints.
Based on our preliminary results, they found that this system shows high performance and real time detection capabilities for harmful compounds, and by taking advantage of the portability it offers, it could be considered as a potential candidate for field applications.
Explosives - detection, sampling and characterization
Researcher: Prof. Yehuda Zeiri
Department: Biomedical Engineering
Email: yehuda@bgu.ac.il
During the last decade extensive research related to detection and characterization of explosive traces has been carried out in Prof. Zeiri's laboratories. During this period expertise was developed in a number of subjects including:
1. The use of a wide variety of analytical chemistry methods to detect small amounts of explosives. The methods used include chromatography (both gas and liquid) using various detectors (FID, ECD and MS), detection based on ion mobility measurements (DMS and IMS) as well as spectroscopic measurements mainly Raman spectroscopy. These wide range of methods allow us to detect very small trace amounts of explosives.
2. The study of adhesion forces between explosive particles and various substrates. The substrates include hard materials such as metals, plastics, glass etc. as well as soft and biological substrates such as cloth, hair and rubber. The measurements are carried out using two different approaches. In the first Atomic Force Microscope is used to measure directly the adhesion force between a particle and the substrate. The other method is based on aerodynamic measurements in which an inert gas jet is used to remove particles from the substrate. In both cases theoretical modeling is used to obtain a better understanding of the data obtained in the measurements are.
3. Swab experiments using a simple system developed in the laboratory that allows control of the force acting during the swab process. This system allows the comparison of the efficiency of different clothes to collect trace amounts of explosive from various substrates.
4. Extensive effort is devoted to theoretical investigation of the characteristics of various explosives. Two theoretical tools are being used, the first is molecular dynamics based on atomic and molecular level simulations to describe the dynamics associated with the detonation process in explosives. The other type of studies is based on quantum mechanical electronic structure calculations. Here, the properties of the explosives and the thermal decomposition mechanism are studied. These two approaches enable the investigation of the chemical reactions that occur during detonation, to evaluate explosive sensitivity, influence of defect on the detonation properties etc.
