Standoff detection of bacterial spores by field deployable coherent Raman spectroscopy

: Vibrational spectroscopies offer great potential for standoff detection of chemical and biological warfare agents, avoiding contamination to the operator and equipment. Among them, particularly promising is Coherent anti-Stokes Raman scattering (CARS) spectroscopy, using synchronized pump/Stokes laser pulses to set up a vibrational coherence of target molecules at a laser focus, which is read by further interaction with a probe pulse, resulting in the emission of a coherent beam detectable at a distance. CARS has previously demonstrated the capability to detect bacterial spores based on the Raman spectrum of the characteristic molecule calcium dipicolinate (CaDPA); however, a complex and bulky laser technology, which is only suitable for a laboratory environment, was employed. Here we develop a broadband CARS setup based on a compact, industrial grade ytterbium laser system. We demonstrate high signal-to-noise ratio detection of Bacillus atrophaeus spores at a concentration of 105 cfu/mm2, at a standoff distance of 1 m, and an acquisition time of 1 s. Our system, which combines chemical specificity and sensitivity along with improved ruggedness and portability, paves the way to a new generation of instruments for real-world standoff detection of chemical and biological threats

Chemical classification of explosives

This work comprehensively reviews some fundamental concepts about explosives and their two commonly used classifications based on either their velocity of detonation or their application. These classifications are highly useful in the military/legal field, but completely useless for the chemical determination of explosives. Because of this reason, a classification of explosives based on their chemical composition is comprehensively revised, discussed and updated. This classification seeks to merge those dispersed chemical classifications of explosives found in literature into a unique general classification, which might be useful for every researcher dealing with the analytical chemical identification of explosives. In the knowledge of the chemical composition of explosives, the most adequate analytical techniques to determine them are finally discussed

Standoff Sensing Technology Based on Laser-Induced Breakdown Spectroscopy: Advanced Targeting, Surveillance and Reconnaissance in Security and Architectural Heritage Applications

Due to the ability to perform simultaneous, multi-element and real-time analysis without pretreatment and doing from a distance, laser induced breakdown spectroscopy (LIBS) in standoff mode is now considered a cutting-edge analytical technology. All these features have allowed its application in various fields such as security, environment, cultural heritage protection and space exploration, among the more outstanding. Nonetheless, the fact of working to long distances involves greater difficulties than in a lab-scale. Thus, in a first part of this memory, the behavior of the analytical signal has been assessed. On the other hand, a second part demonstrates the applicability of the technique in standoff mode for solving real-life problems. • Fundamental studies 1. Main causes affecting the uncertainty of the analytical signal in standoff LIBS. One of the most sensitive issues in standoff LIBS is maybe the large variability observed in the analytical response of distant targets. Therefore, in this work, a standoff LIBS sensor has been used to assessment of the laser beam delivering up to a distant target as well as the properties of the light emitted from the plasma induced gathered by the sensor. • Applications standoff LIBS 1. Evaluation of the Cultural Heritage: Malaga Cathedral. Cultural heritage is a valuable source of history and a unique and irreplaceable legacy of our past. While sometimes an artwork can be transported to the laboratory for its analysis, in other cases this option is not feasible. The ease compaction in mobile platforms of LIBS instrumentation for in situ analysis, allows for moving the system sensor to the location of the sample. For first time a standoff LIBS system has been used to characterize and analyze the composition of building materials as well as potential sources of contamination in a historic building on difficult to access areas, since this technology only requires a clear line of sight to the target. I. Location and identification of explosive-contaminated fingerprint. Nowadays, it is clear that the detection of explosives due to numerous terrorist attacks requires a special attention. LIBS is an attractive technology to anticipating this type of threats. In the present work, the ability of a mobile LIBS sensor to locate and identify fingerprints of explosives residues (DNT, TNT, RDX, PETN and chloratite ) on different surfaces (aluminum and glass) from a minimum distance of 30m has been demonstrated. Chemical distribution maps of the different residues with 100% effectiveness were developed. However, despite the effectiveness of the technique in the localization and detection of explosives residues, one of the main problems is the identification of products that share a similar elemental composition, and thus a similarity in the analytical response. In this memory have been developed and implemented chemometric algorithms, which are capable of adapting to different working ranges, to distinguish residues of organic explosives of traces of dairy products, such as olive oil, motor oil, hand cream, gasoline, fuel oil, etc. on a metal surface (aluminum). This strategy allows categorize the residues assessed with a 100% accuracy and error rates below 5 %. II. Forensic studies for the determination of radiological material. Although radioactivity has numerous applications in everyday life, the danger of a radiological dispersal event, either by natural causes or malicious (dirty bombs) is more than evident. Therefore, the detection and identification of explosives as well as their monitoring and quantification from a safe location is demanded. The potential of standoff LIBS to scan, analyze and quickly characterize the radiological contamination in various objects of street furniture has been here evaluated. The results have demonstrated the selectivity and sensitivity of the technology to detect radioactive surrogates such as Co, Ba, Sr, Cs, Ir and U on substrates of aluminum, clay, concrete and glass. It have been also demonstrated the capabilities of the technique for simultaneous and in situ analysis of explosive and radiological evidence in a post-detonation scenario

Explosive Detection Equipment and Technology for Border Security

This report contains a brief survey of Explosives Detection Technology,as it is applied for inspection of goods and passengers at borders, and explains the role of European legislation and the European Commission¿s research programs in this field. It describes the techniques of trace and bulk explosives detection that are in use, the latest techniques that are in development and the characteristics of explosives that are, or might be, used to provide a signature for exploitation in detection technology. References to academic reviews are included for those wishing to study the subject in greater depth. Some additional details are given concerning plastic and liquid explosives, which are a threat of particular current importance. The report also contains a brief account of relevant European trade, safety and security legislation, a description of recent policy initiatives and tables of related European Commission funded research projects. Contact details of commercial companies selling explosive detection products are also provided.JRC.G.6-Sensors, radar technologies and cybersecurit

Long-Wave Infrared Supercontinuum Source and Sensor for Standoff Sensing and Trace Particle Identification

This dissertation is based on the development of a long-wave infrared supercontinuum source, and the utilization of this source in a Fourier transform based standoff optical sensor. The spectra from trace particles deposited on smooth surfaces are measured with the sensor and simulated using a Bobbert-Vlieger model. We create an ultra-broadband, all-fiber supercontinuum source that emits infrared energy from 1.6 - 11μm. We utilize a master oscillator parametric amplifier with Erbium/Ytterbium and Thulium amplifiers to pump a cascade of ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN), arsenic sulfide, and arsenic selenide fibers. This source is power scalable and can emit up to 417 mW at 800 kHz pulse repetition frequency, with 69 mW beyond 7.5μm. The output from the long-wave infrared supercontinuum source is near-diffraction limited single mode output that can be collimated to a one inch spot.The output of the source is then tested for feasability of use in commercial FTIR based systems. Although not optimized for 1.5 ns pulsed sources, we are able to measure transmission spectra of polystyrene samples, thin films on wafers and 50μL of acetone that has been evaporated in a 10 cm length gas cell and compare to those illuminated with the systems internal globar. We find that even though the input optics are not optimized, the incident energy on the samples is an order of magnitude higher than that of the globar source. We develop a long-wave infrared standoff sensor by coupling the output of the source to a refraction based FTIR interferometer. The modulated energy is then guided to hit targets that are 3.6 m away from the sensor. The system estimates the energy of each pulse and creates an interferogram that is Fourier transformed into resultant spectra. The linearity of the sensor is verified via the measurement of thin films of SiO2 and polyimide on silicon wafers. This sensor is then used for standoff volatile gas and bulk sample scattering measurements. We then focus on the measurement and modeling of trace chemicals that have deposited on smooth substrates. We measure concentrations as low as 6.5 μg/cm2 on glass substrates. Furthermore, we measure the diffuse reflectance of RDX, acetaminophen, and caffeine on glass, aluminum, and silicon substrates. Each of these chemicals exhibit spectral features between 950 and 1800 cm−1 and substrate based dependencies in reflectance spectra. We simulate these effects with a Bobbert-Vlieger model that takes particle size distribution into account. We find that a range of particle sizes smoothens and broadens reflectance features and changes in target orientation and differences in particle shape can strongly impact the spectra between 1800 and 4000 wavenumbers. We use our Bobbert-Vlieger model to create a library of exemplary spectra based on systematically changing the parameters of the particle size distribution. This library is employed to identify unknown powders based on the root mean square error between the second derivative of measured spectra and those in the library.PHDApplied PhysicsUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/163040/1/ramartma_1.pd

Terahertz data processing for standoff detection of improvised explosive devices

Improvised Explosive Devices (IEDs) are homemade, non-conventional explosive devices, which are used to destruct and incapacitate individuals and property. IEDs are becoming a popular weapon of attack among terrorists and insurgents due to their easy of making and capability to cause major damage. Hence, is has become necessary to develop efficient systems for detecting and disarming these devices. The Terahertz technology which uses electromagnetic radiations between 0.3 THz to 10 THz for imaging is one of the most recently developed detection techniques and is ideally suitable for detection of IEDs and similar devices. Although a lot of work has been done for developing a standoff detection system for detecting IEDs using Terahertz imaging, it is still needed to develop advanced techniques for processing of the THz data. In this thesis, efficient signal processing techniques are developed for standoff, real time and wide area detection of IEDs. The signal processing algorithm is a two stage algorithm where the first stage is a preprocessing stage. In this stage, THz data from a large field is given to the correlation filters which detect hotspots in the field where an IED could be present. This stage avoids the computational burden of processing data from the entire field in the second stage. In the second stage, THz data from the hotspots of stage one are unmixed to find the individual explosive materials in each data point/pixel. The unmixing is done using a variant of the Independent Component Analysis algorithm which separates only the required component. Once the components are separated, they are analyzed to see if any of them matches an explosive. Thus, the presence of an IED or explosive can be accurately determined within the field --Abstract, page iii

Remote laser spectroscopy at standoff distances for heritage applications

In this project, remote standoff laser spectroscopy systems working at 3–15 m have been developed for cultural heritage research, employing Raman spectroscopy, laser induced breakdown spectroscopy (LIBS), and laser induced fluorescence spectroscopy (LIF). To address the problems encountered during in situ analysis due to environmental restrictions, the adoption of remote techniques offers advantages such as convenient deployment on the ground, allowing sensitive measurements over long integration time and there is no need to redeploy for different areas of interest. The research focuses on the design and development of remote standoff laser spectroscopy systems with special needs in heritage research considered, as well as their application for in situ analysis. A remote standoff Raman system was developed and optimised. It is the first of its kind that is dedicated to cultural heritage research. It can identify most of common historic artist pigments. A daylight subtraction procedure enables the remote standoff Raman system to operate in the presence of indoor ambient light. Laser induced degradation effect was studied using various laser configurations on a range of common pigments. The remote standoff Raman system is proved to be safe for the analysis of most pigments tested when using typical integration time required for Raman measurements. In situ remote macro-Raman mapping is achieved in two field campaigns, revealing the pigments distribution on wall paintings and salt distribution in historical buildings in costal environments. A remote standoff LIBS system was developed. Assisted with Raman and reflectance spectroscopy, a multimodal approach allowing in situ standoff depth-resolved material identification of wall paintings was demonstrated for the first time. The combined elemental, molecular and reflectance information contributes to a more complete data interpretation. Consequently, the stratigraphy of whitewashed wall paintings was successfully uncovered in a unique field campaign

Multivariate Analysis in Management, Engineering and the Sciences

Recently statistical knowledge has become an important requirement and occupies a prominent position in the exercise of various professions. In the real world, the processes have a large volume of data and are naturally multivariate and as such, require a proper treatment. For these conditions it is difficult or practically impossible to use methods of univariate statistics. The wide application of multivariate techniques and the need to spread them more fully in the academic and the business justify the creation of this book. The objective is to demonstrate interdisciplinary applications to identify patterns, trends, association sand dependencies, in the areas of Management, Engineering and Sciences. The book is addressed to both practicing professionals and researchers in the field