This PDF file contains the front matter associated with SPIE Proceedings Volume 6954, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

The challenge of sampling explosive materials for various high threat military and civilian operational scenarios requires the community to identify and exploit other chemical compounds within the mixtures that may be available to support stand-off detection techniques. While limited surface and vapor phase characterization of IEDs exist, they are insufficient to guide the future development and evaluation of field deployable explosives detection (proximity and standoff) capabilities. ECBC has conducted a limited investigation of three artillery ammunition types to determine what chemical vapors, if any, are available for sensing; the relative composition of the vapors which includes the more volatile compounds in munitions, i.e., plastersizers and binders; and the sensitivity needed detect these vapors at stand-off. Also in partnership with MIT-Lincoln Laboratory, we performed a background measurement campaign at the National Training Center to determine the baseline ambient amounts and variability of nitrates and nitro-ester compounds as vapors, particulates, and on surfaces; as well as other chemical compounds related to non-energetic explosive additives. Environmental persistence studies in contexts relevant to counter-IED sensing operations, such as surface residues, are still necessary.

We have used a simultaneous 10.6 micron CO₂ laser pulse to enhance the Laser Induced Breakdown Spectroscopy (LIBS) emission from a 1.064 micron Nd:YAG laser induced plasma on a hard target. The enhancement factor was found to be one or two orders of magnitude, depending upon the emission lines observed and the target composition. The output energy of the 5 ns Nd:YAG laser pulse was about 50 mJ and was focused to a 1 mm diameter spot to produce breakdown. The CO₂ laser pulse (100 ns spike, 5 microsec tail) had a similar energy density on target (0.06 J/mm²). Timing overlap of the two laser pulses within 1 microsecond was important for enhancement to be observed. Enhancement of neutral atomic emission was usually on the order of 5-20X, while enhancement of ionized species tended to be higher, 10-200X. We attribute the increase in both the atmospheric components and the +1 and +2 ionic emission to heating of the Nd:YAG plasma by the coincident CO₂ laser. Such inverse bremsstrahlung absorption of CO₂ laser radiation by the free electrons of plasma is well known. We are conducting additional studies to better quantify the effects of laser beam mode, pulse-to-pulse jitter, temporal pulse shaping, and optimization of these parameters for different LIBS target compositions.

We describe a gamma-ray imaging camera (GIC) for active interrogation of explosives being developed by NASA/GSFC and NSWC/Carderock. The GIC is based on the Three-dimensional Track Imager (3-DTI) technology developed at GSFC for gamma-ray astrophysics. The 3-DTI, a large volume time-projection chamber, provides accurate, ~0.4 mm resolution, 3-D tracking of charged particles. The incident direction of gamma rays, E > 6 MeV, are reconstructed from the momenta and energies of the electron-positron pair resulting from interactions in the 3-DTI volume. The optimization of the 3-DTI technology for this specific application and the performance of the GIC from laboratory tests is presented.

The Photonics Research Center at the United States Military Academy is conducting research to demonstrate the feasibility of combining hyperspectral imaging and Raman spectroscopy for remote chemical detection over a broad area of interest. One limitation of future trace detection systems is their ability to analyze large areas of view. Hyperspectral imaging provides a balance between fast spectral analysis and scanning area. Integration of a hyperspectral system capable of remote chemical detection will greatly enhance our soldiers' ability to see the battlefield to make threat related decisions. It can also queue the trace detection systems onto the correct interrogation area saving time and reconnaissance/surveillance resources. This research develops both the sensor design and the detection/discrimination algorithms. The one meter remote detection without background radiation is a simple proof of concept.

MIT Lincoln Laboratory has developed a concept that could enable remote (10s of meters) detection of trace explosives' residues via a field-portable laser system. The technique relies upon laser-induced photodissociation of nitro-bearing explosives into vibrationally excited nitric oxide (NO) fragments. Subsequent optical probing of the first vibrationally excited state at 236 nm yields narrowband fluorescence at the shorter wavelength of 226 nm. With proper optical filtering, these photons provide a highly sensitive explosives signature that is not susceptible to interference from traditional optical clutter sources (e.g., red-shifted fluorescence). Quantitative measurements of trace residues of TNT have been performed demonstrating this technique using a breadboard system, which relies upon a pulsed optical parametric oscillator (OPO) based laser. Based on these results, performance projections for a fieldable system are made.

We report on the delivery of low energy ultra-short (<1 ps) laser pulses for laser induced breakdown spectroscopy (LIBS). Ultra-short pulses have the advantage of high peak irradiance even at very low pulse energies. This opens the possibility to use compact, rare-earth doped fiber lasers in a portable platform for point detection applications using LIBS for elemental analysis. The use of low energy ultra-short pulses minimizes the generation of a broad continuum background in the emission spectrum, which permits the use of non-gated detection schemes using very simple and compact spectrometers rather than large and delicate intensified charge-coupled devices (ICCDs). The pulse energies used to produce high-quality LIBS spectra in this investigation are some of the lowest reported and we investigate the threshold pulse requirements for a number of near IR pulse wavelengths (785-1500 nm) and observe that the pulse wavelength has no effects on the threshold for observation of plasma emission or the quality of the emission spectra obtained.

A Deep-UV LIBS system has been constructed for the standoff detection of Explosives, and potentially Chemical, Biological, Radiological, and Nuclear (CBRN) substances. A Q-Switched Nd:YAG Laser operating in at 266nm was used for excitation of the LIBS plasma and future Raman excitation. This plasma was enhanced by the means of a nearly simultaneous CO₂ laser which results in a method referred to as Townsend Effect Plasma Spectroscopy (TEPS). Spectra covering the range of 240-800nm at standoff distances are presented. The classical emission lines (i.e. C, N, O, H, etc) of the energetic samples were observed and a peak ratio technique was used to differentiate between benign and energetic samples of interest.

High resolution chemical imaging of surfaces can be achieved using Tip Enhanced Raman Spectroscopy(TERS), an emerging technique that combines scanning probe microscopy with optical spectroscopy and takes advantage of apertureless near-field optics to obtain lateral resolution dramatically better than that provided by conventional optics. So far a 20 nm lateral resolution in chemical imaging of a surface has been achieved. The plasmonic structures on the tip used for imaging could also be used for novel, high sensitivity, local chemical and biological sensing. However, the silver plasmonic structures suffer from limited lifetimes due to morphological changes resulting from heating, wear during imaging, and tarnishing. The lifetimes of silver plasmonic structures on flat surfaces (as model systems) and on silicon nitride TERS tips have been extended by depositing over the silver an ultrathin (3nm) silicon oxide (SiO_x) coating. With this thickness protective coating, the contrast factor for the tip, which is the key parameter controlling one's ability to image with the tip, is decreased slightly (~10%) initially, but the rate at which the signal enhancement degrades is sharply reduced. The silver layer on an unprotected tip was mechanically damaged after only three images of a polymer surface, while a silver layer protected by SiO_x remained intact after scanning three images.

Controlled molecular photofragmentation and ionization achieved with shaped femtosecond laser pulses is coupled with mass spectrometry to achieve a powerful multidimensional tool for fast, accurate, reproducible and quantitative molecular identification. Specific pulse shaping functions are introduced to enhance structure-dependent differences in fragmentation fingerprints. Identification of geometric and structural isomer mixtures is demonstrated. Receiver operational (ROC) curves from our experimental data demonstrate the enhanced reliability that can be achieved by femtosecond laser control mass spectrometry. The potential use of this method for identification of chemicals and explosives with no false alarms is discussed.

Cold plasma applicators have been used in the Medical community for several years for uses ranging from hemostasis ("stop bleeding") to tumor removal. An added benefit of this technology is enhanced wound healing by the destruction of infectious microbial agents without damaging healthy tissue. The beam is typically one millimeter to less than a centimeter in diameter. This technology has been adapted and expanded to large area applicators of potentially a square meter or more. Decontamination applications include both biological and chemical agents, and assisting in the removal of radiological agents, with minimal or no damage to the contaminated substrate material. Linear and planar multiemitter array plasma applicator design and operation is discussed.

We report advances made on the development of a fiber optic nerve agent sensor having its entire length as the sensing element. Upon exposure to sarin gas or its simulant, diisopropyl fluorophosphate, the cladding changes color resulting in an alteration of the light intensity throughput. The optical fiber is multimode and consists of a fused-silica core and a nerve agent sensitive cladding. The absorption characteristics of the cladding affect the fiber's spectral attenuation and limit the length of light guiding fiber that can be deployed continuously. The absorption of the cladding is also dependent on the sensor formulation, which in turn influences the sensitivity of the fiber. In this paper, data related to the trade-off of sensitivity, spectral attenuation, and length of fiber challenged will be reported. The fiber is mass produced using a conventional fiber optic draw tower. This technology could be used to protect human resources and buildings from dangerous chemical attacks, particularly when large areas or perimeters must be covered. It may also be used passively to determine how well such areas have been decontaminated.

Imaging Fourier transform spectrometry (FTS) was applied to remotely identify liquids on various surfaces. The spectra are dependent on the liquid film (composition and dimensions), the background surface and the illumination (artificial source or radiation from the sky). A radiative transfer model was applied to calculate spectra of the liquid films. By classifying the background materials by their optical properties, a reduced set of spectra was created as reference signatures for automatic identification. Based on the radiative transfer model, an automatic identification algorithm was implemented. Measurements were performed with an imaging Fourier transform spectrometer developed at TUHH. The results of the analysis are displayed by a video image overlaid with an image of the identified liquid. Various liquids on diverse surfaces were identified automatically. In addition to active measurements, passive measurements without an artificial source of radiation were performed. The results presented show that by means of the radiative transfer model, automatic remote identification of liquid contamination is possible.

Sionex Differential Mobility Spectrometer (DMS) sensors can be used as standalone detectors in many applications because of their outstanding sensitivity and selectivity. However, in applications like field screening for toxic chemicals and explosives, the number of possible interferents may be so high that additional separation becomes useful for identification and for quantitative measurement. For these cases, we have developed several different hybrid technologies. (1) DMS-IMS² integrates bipolar differential mobility ion filtration with IMS drift time measurement in IMS drift tubes, one tube for each ion polarity. (2)The Sionex GC-DMS (microAnalyzer) combines a pre-concentrator, a rapid and selective GC column that operates at high temperature in an air recirculation loop, and DMS ion filtration and detection. (3) Sionex DMS-MS interfaces have been developed for several types of mass spectrometers, and dramatically improve mass spec performance by filtering out unwanted species to reduce chemical noise and improve measurement accuracy. The Sionex DMS-IMS² first uses DMS to select positive and negative ions based on ion mobility variation with field (the α(E) function), then uses paired IMS sections to measure the low field mobility (K(0)). DMS separation depends on many properties including the distribution of internal charges, rigidity, and clustering. The IMS drift times depend on molecular size and conformation at low fields. A number of applications of this technology will be described, including CWA's, TIC/TIM, and explosives. The Sionex microAnalyzer GC-DMS system combines sophisticated preconcentration, thermal desorption, GC temperature ramping, and DMS separation and detection in a compact, portable and field-deployable package. The list of applications for this technology is growing rapidly, currently including CWAs, BTEX, H₂S and mercaptans, and others. Sionex DMS-MS interfaces are being used to make quantitative measurements of biomarkers, including breath markers, biofluid markers, and cancer-linked agents. DMS-MS improves the performance / cost tradeoff for the mass spectrometer, greatly speeds analysis compared to LC-MS, and maintains measurement accuracy.

Improvised explosive devices (IEDs), vehicle-borne improvised explosive devices (VBIEDs), and suicide bombers are a major threat to many countries and their citizenry. The ability to detect trace levels of these threats with a miniature, hand-held, reagentless, standoff sensor represents a major improvement in the state of the art of CBE surface sensors. Photon Systems, Inc., in collaboration with Jet Propulsion Laboratory, recently demonstrated a new technology hand-held sensor for reagentless, close-range, standoff detection and identification of trace levels CBE materials on surfaces. This targeted ultraviolet CBE (TUCBE) sensor is the result of an Army Phase I STTR program. The resulting 5lb, 5W, flashlight-sized sensor can discriminate CBE from background materials using a combination of deep UV excited resonance Raman (RR) and laser induced native fluorescence (LINF) emissions resulting from excitation by a new technology deep UV laser. Detection and identification is accomplished in less than 1ms. Standoff excitation of suspicious packages, vehicles, persons, and other objects that may contain hazardous materials is accomplished using wavelengths below 250nm where Raman and native fluorescence emissions occupy distinctly different wavelength regions. This enables simultaneous detection of RR and LINF emissions with no interferences. The sensor employs fused RR/LINF chemometric methods to extract the identity of targeted materials from background clutter. Photon Systems has demonstrated detection and identification of 100ng/cm2 of explosives materials at a distance of 1 meter using a sensor with 3.8 cm optical aperture. Expansion of the optical aperture to 38 cm in a lantern-sized sensor will enable similar detection and identification of CBE materials at standoff distances of 10 meters. As a result of excitation and detection in the deep UV and the use of a gated detection system, the sensor is solar blind and can operate in full daylight conditions.

One approach to CBRNE detection is analytical monitoring with portable spectroscopy systems. Such a technique needs to work in adverse environments, be amenable to use by field operators, and, given the sensitive nature of the target materials, should have an extremely rapid response time with no false negatives. This research demonstrates that surface-enhanced Raman scattering (SERS) is capable of detecting ppb levels of CBRNE materials with high sensitivity and no false positives. We present reproducible and selective detection using novel SERS structures that exhibit an inherently uniform surface morphology, leading to rapid, reproducible manufacturing. Our work includes receiver-operator characteristic (ROC) curves for the detection of both conventional and improvised nitro explosives at low signal-to-noise ratios. We also present the detection of added CBRNE materials including chemical and biological agents as well as nuclear enriching materials. Our expertise extends to instrumentation of portable, robust Raman spectrographs that can be packaged with our sensors for a versatile security tool with applications extending from points of entry to points of production, from people to objects and freight.

The in situ location and identification of discrete liquid droplets on surfaces is a technically challenging problem. Successful solutions often combine real time imaging and optical spectroscopic techniques. To this end, we present results of initial experiments using a dual-band mid- and shortwave IR (1.3 - 4.5 μm) imaging device to differentiate between a selection of mineral and synthetic oils. The illumination source is an optical parametric oscillator comprising a periodically-poled LiNbO₃ crystal internally pumped by a Nd:YVO₄ laser, which is pumped by a 3 W diode laser. The source can produce output powers of ca. 0.3 and 0.1 W in the signal and idler fields, respectively. System size and complexity are minimised by use of an MCT single element detector and images are acquired by raster scanning of the target. The reflection, absorption and/or scatter of the incident radiation by the liquids and their surroundings provide a method for spatial location, whereas the characteristic spectra obtained from each sample can be used to uniquely identify the deposited substance. Both static and video images can be obtained at a range of < 10 metres by this apparatus.

Emerging applications in Defense and Security require sensors with state-of-the-art sensitivity and capabilities. Among these sensors, the imaging spectrometer is an instrument yielding a large amount of rich information about the measured scene. Standoff detection, identification and quantification of chemicals in the gaseous state is one important application. Analysis of the surface emissivity as a means to classify ground properties and usage is another one. Imaging spectrometers have unmatched capabilities to meet the requirements of these applications. Telops has developed the FIRST, a LWIR hyperspectral imager. The FIRST is based on the Fourier Transform technology yielding high spectral resolution and enabling high accuracy radiometric calibration. The FIRST, a man portable sensor, provides datacubes of up to 320×256 pixels at 0.35mrad spatial resolution over the 8-12 μm spectral range at spectral resolutions of up to 0.25cm^-1. The FIRST has been used in several field campaigns, including the demonstration of standoff chemical agent detection. More recently, an airborne system integrating the FIRST has been developed to provide airborne hyperspectral measurement capabilities. The airborne system and its capabilities are presented in this paper. The FIRST sensor modularity enables operation in various configurations such as tripod-mounted and airborne. In the airborne configuration, the FIRST can be operated in push-broom mode, or in staring mode with image motion compensation. This paper focuses on the airborne operation of the FIRST sensor.

OPTRA and University of North Carolina are developing an imaging open-path Fourier transform infrared (I-OP-FTIR) spectrometer for 3D profiling of chemical and biological agent simulant plumes released into test ranges and chambers. An array of I-OP-FTIR instruments positioned around the perimeter of the test site, in concert with advanced spectroscopic algorithms, enables real time tomographic reconstruction of the plume. The approach will be considered as a candidate referee measurement for test ranges and chambers. This Small Business Technology Transfer (STTR) effort combines the instrumentation and spectroscopic capabilities of OPTRA, Inc. with the computed tomographic expertise of the University of North Carolina, Chapel Hill. In this paper, we summarize progress to date and overall system performance projections based on the instrument, spectroscopy, and tomographic reconstruction accuracy. We then present a preliminary optical design of the I-OP-FTIR.

Integrating a sensor suite with ability to discriminate potential Chemical/Biological (CB) events from high-explosive (HE) events employing an acoustic sensor array with a Time Difference of Arrival (TDOA) algorithm. Developing a cueing mechanism for more power intensive and range limited sensing CB techniques. Enabling the event detection algorithm to locate to a blast event using TDOA further information is provided of the event as either Launch/Impact and further as either CB/HE. The point of interest information is gathered to give a viewing window to a range limited chemical sensing system that exploits spectroscopy to determine the contents of the chemical event. The sensor suite is the system that will provide this information on the move while the chemical sensor will have adequate time to determine the contents of the event from a safe stand-off distance. The system exploits acoustic sensors to provide early detection and identification of CB attacks at ranges exceeding 2500m. The integration of these algorithms with the TDOA algorithm provides a complex suite of algorithms that can give early warning detection and highly reliable look direction from a great stand-off distance for a moving vehicle to determine if a candidate blast event is of potential CB type.

The fundamental difficulty of achieving a coherently enhanced sensing method at standoff distances greater than 10 meters has been solved by single-beam coherent anti-Stokes Raman scattering and by actively measuring and eliminating chromatic dispersion experienced by the broad-bandwidth (100 nm) laser pulses. Characteristic Raman spectra for several chemicals in gas, liquid, and solid states, are successfully obtained from a 12 meter standoff distance. The results obtained indicate this is a promising approach to standoff detection of chemicals, hazardous contaminations, and explosives.

Defence Research and Development Canada (DRDC) - Valcartier is currently developing a ruggedized passive standoff sensor for the detection of chemical warfare agents (CWAs) based on differential Fourier-transform infrared (FTIR) radiometry. This system is referred to as the Compact ATmospheric Sounding Interferometer (CATSI) Engineering Development Model (EDM). The CATSI EDM sensor is based on the use of a double-beam FTIR spectrometer that is optimized for optical subtraction. A description of the customized sensor is given along with a discussion on the detection and identification approaches that have been developed. Preliminary results of validation from a number of laboratory measurements and open-air trials are analyzed to establish the capability of detection and identification of various toxic and non-toxic chemical vapor plumes. These results clearly demonstrate the capability of the passive differential radiometric approach for the standoff detection and identification of chemical vapors at distances up to a few kilometers from the sensor.

Long-wave infrared hyperspectral sensors provide the ability to detect gas plumes at stand-off distances. A number of detection algorithms have been developed for such applications, but in situations where the gas is released in a complex background and is at air temperature, these detectors can generate a considerable amount of false alarms. To make matters more difficult, the gas tends to have non-uniform concentrations throughout the plume making it spatially similar to the false alarms. Simple post-processing using median filters can remove a number of the false alarms, but at the cost of removing a significant amount of the gas plume as well. We approach the problem using an adaptive subpixel detector and morphological processing techniques. The adaptive subpixel detection algorithm is able to detect the gas plume against the complex background. We then use morphological processing techniques to isolate the gas plume while simultaneously rejecting nearly all false alarms. Results will be demonstrated on a set of ground-based long-wave infrared hyperspectral image sequences.

Chart Venture Partners' (CVP) approach to investing in Chemical, Biological, Radiological, Nuclear, and Explosives (CBRNE) detection technologies can be best understood in the context of the unique partnership between the firm's two founding institutions. CVP was founded as a partnership between the Chart Group, a New York-based merchant banking and venture capital boutique, and InSitech Incorporated, a 501(c)(3) non-profit commercial partnership intermediary for the U.S. Army's Armament Research Development and Engineering Center (ARDEC) at Picatinny Arsenal in New Jersey. The partnership between Chart Group and Insitech has yielded a new investment model. Unlike most venture funds, CVP operates with a singular focus on early-stage defense and security technologies, with the important caveat that everything we invest in must also have dual-use application in large-scale commercial markets. CVP believes that early-stage CBRNE companies require five qualities to be viable investment candidates and successful start-up companies: Great Science, Strong IP Positions, Recognized Scientific Champions, Identified Dual-Use Market Pull, and "Real World" Technical Performance Data. When earlystage CBRNE companies decide to seek venture capital and pursue higher growth dual-use business models, we often find that certain issues arise that are not always fully contemplated at the outset, and that can create gaps between what the start-up companies are offering to investors and what those investors are seeking from their potential portfolio companies. These same issues can have significant positive or negative impact on shareholder value over time, depending on how they are managed. Specifically, startups should consider carefully their strategies related to business development, market positioning, government funding, and investment syndicate formation.

In-Q-Tel is a strategic investment firm that works to identify, adapt, and deliver innovative technology solutions to support the missions of the Central Intelligence Agency and the broader U.S. Intelligence Community (IC). Launched by the CIA in 1999 as a private, independent, not-for-profit organization, IQT's mission is to identify and partner with companies developing cutting-edge technologies that serve the national security interests of the United States. Working from an evolving strategic blueprint defining the Intelligence Community's critical technology needs, IQT engages with entrepreneurs, growth companies, researchers, and venture capitalists to deliver technologies that provide superior capabilities for the CIA and the broader IC. To date, IQT has reviewed more than 6,300 business proposals, invested in more than 100 companies, and delivered more than 140 technology solutions to the U.S. Intelligence Community.

ARCH is interested in building leading, highly-valued companies from leading research. Toward that end we value innovations created by the leading researchers in the world, many of which are funded to solve critical scientific challenges including those in the instrumentation and CBRNE area. The most important CBRNE innovations we have seen at ARCH are breakthroughs involving significant unaddressed technology risk and have the potential for broad proprietary intellectual property as a result. The model ARCH has evolved in instrumentation is to look for a breakthrough innovation, with strong intellectual property and continue to strengthen the patent estate through the life of the company. ARCH looks to build companies around leading interdisciplinary scientific and engineering teams, and we favor platform technology that can be applied to multiple market applications both commercial and government. As part of a strategy to build a great company, addressing important CBRNE challenges can help a company strengthen its technical team and its IP estate. This supports a focus on early low volume markets on the way toward addressing a fuller portfolio of applications. Experienced Venture Capitalists can help this process by identifying important executive talent, partners and applications, offering financial syndication strength, and helping shape the company's strategy to maximize the ultimate value realized.

This research examines standardizing a method for the rapid/semi-automated identification of microbial contaminates. It introduces a method suited to test for food/water contamination, serology, urinalysis and saliva testing for any >1 micron sized molecule that can be effectively bound to an identifying marker with exclusivity. This optical biosensor method seeks to integrate the semi-manual distribution of a collected sample onto a "transparent" substrate array of binding sites that will then be applied to a standard optical data disk and run for analysis. The detection of most microbe species is possible in this platform because the relative scale is greater than the resolution of the standard-scale digital information on a standard CD or DVD. This paper explains the critical first stage in the advance of this detection concept. This work has concentrated on developing the necessary software component needed to perform highly sensitive small-scale recognition using the standard optical disk as a detection platform. Physical testing has made significant progress in demonstrating the ability to utilize a standard optical drive for the purposes of micro-scale detection through the exploitation of CIRC error correction. Testing has also shown a definable trend in the optimum scale and geometry of micro-arrayed attachment sites for the technology's concept to reach achievement.

Calculation of scattering properties of biological materials has classically been addressed using numerical calculations based on T-matrix theory. These calculations use bulk optical properties, particle size distribution, and a limited selection of shape descriptors to calculate the resulting aerosol properties. However, the most applicable shape available in T-matrix codes, the spheroid, is not the best descriptor of most biological materials. Based on imagery of the spores of Bacillus atrophaeus and Bacillus anthracis, capsule and egg shapes are mathematically described and programmed into the Amsterdam Discrete Dipole Approximation (ADDA). Spectrally dependent cross sections and depolarization ratios are calculated and a comparison made to spheroidal shapes of equivalent sizes.

Optical cross-sections of biological warfare simulants, killed agents, and live agents are needed to assess the standoff detection performance of active lidar and passive FTIR systems. To aid in this investigation, Johns Hopkins University Applied Physics Laboratory (JHU/APL) has developed a technique to determine the index of refraction of biological materials in the visible region using a combination of transmission measurements and anomalous diffraction theory (ADT). The spectral measurements using a dual beam grating spectrometer provide a basis for calculating the optical cross section of suspended particles. ADT is then used to convert the cross section result into index of refraction. A summary of this procedure is described along with the results for silica microspheres and Bacillus globijii (BG). A comparison of these results to published data is also presented.

Aerosol backscatter and extinction cross-sections are required to model and evaluate the performance of both active and passive detection systems. A method has been developed that begins with laboratory measurements of thin films and suspensions of biological material to obtain the complex index refraction of the biological material from the UV to the LWIR. Using that result with particle size distribution and shape information as inputs to T-matrix or discrete dipole approximation (DDA) calculations yields the extinction cross-section and backscatter cross section as a function of wavelength. These are important inputs to the lidar equation. In a continuing effort to provide validated optical cross-sections, measurements have been made on a number of high purity biological species in the laboratory as well as measurements of material released at recent field tests. The resulting observed differences between laboratory and field measurements aid in distinguishing between intrinsic and extrinsic effects, which can affect the characteristic signatures of important biological aerosols. A variety of biological and test aerosols are examined, including Bacillus atrophaeus (BG), and Erwina, ovalbumin, silica and polystyrene.

The three-dimensional shapes of microscopic objects are becoming increasingly important for battlespace CBRNE sensing. Potential applications of microscopic 3D shape observations include characterization of biological weapon particles and manufacturing of micromechanical components. Aerosol signatures of stand-off lidar systems, using elastic backscatter or polarization, are dictated by the aerosol particle shapes and sizes that must be well characterized in the lab. A low-cost, fast instrument for 3D surface shape microscopy will be a valuable point sensor for biological particle sensing applications. Both the cost and imaging durations of traditional techniques such as confocal microscopes, atomic force microscopes, and electron scanning microscopes are too high. We investigated the feasibility of a low-cost, fast interferometric technique for imaging the 3D surface shape of microscopic objects at frame rates limited only by the camera in the system. The system operates at two laser wavelengths producing two fringe images collected simultaneously by a digital camera, and a specialized algorithm we developed reconstructs the surface map of the microscopic object. The current implementation assembled to test the concept and develop the new 3D reconstruction algorithm has 0.25 micron resolution in the x and y directions, and about 0.1 micron accuracy in the z direction, as tested on a microscopic glass test object manufactured with etching techniques. We describe the interferometric instrument, present the reconstruction algorithm, and discuss further development.

Small non-coding RNA sequences have recently been discovered as unique identifiers of certain bacterial species, raising the possibility that they can be used as highly specific Biowarfare Agent detection markers in automated field deployable integrated detection systems. Because they are present in high abundance they could allow genomic based bacterial species identification without the need for pre-assay amplification. Further, a direct detection method would obviate the need for chemical labeling, enabling a rapid, efficient, high sensitivity mechanism for bacterial detection. Surface Plasmon Resonance enhanced Common Path Interferometry (SPR-CPI) is a potentially market disruptive, high sensitivity dual technology that allows real-time direct multiplex measurement of biomolecule interactions, including small molecules, nucleic acids, proteins, and microbes. SPR-CPI measures differences in phase shift of reflected S and P polarized light under Total Internal Reflection (TIR) conditions at a surface, caused by changes in refractive index induced by biomolecular interactions within the evanescent field at the TIR interface. The measurement is performed on a microarray of discrete 2-dimensional areas functionalized with biomolecule capture reagents, allowing simultaneous measurement of up to 100 separate analytes. The optical beam encompasses the entire microarray, allowing a solid state detector system with no scanning requirement. Output consists of simultaneous voltage measurements proportional to the phase differences resulting from the refractive index changes from each microarray feature, and is automatically processed and displayed graphically or delivered to a decision making algorithm, enabling a fully automatic detection system capable of rapid detection and quantification of small nucleic acids at extremely sensitive levels. Proof-of-concept experiments on model systems and cell culture samples have demonstrated utility of the system, and efforts are in progress for full development and deployment of the device. The technology has broad applicability as a universal detection platform for BWA detection, medical diagnostics, and drug discovery research, and represents a new class of instrumentation as a rapid, high sensitivity, label-free methodology.

Technologies based on Differential Mobility Spectrometry (DMS) are ideally matched to rapid, sensitive, and selective detection of chemicals like biomarkers. Biomarkers linked to exposure to radiation, exposure to CWA's, exposure to toxic materials (TICs and TIMs) and to specific diseases are being examined in a number of laboratories. Screening for these types of exposure can be improved in accuracy and greatly speeded up by using DMS-MS instead of slower techniques like LC-MS and GC-MS. We have performed an extensive series of tests with nanospray-DMS-mass spectroscopy and standalone nanospray-DMS obtaining extensive information on chemistry and detectivity. DMS-MS systems implemented with low-resolution, low-cost, portable mass-spectrometry systems are very promising. Lowresolution mass spectrometry alone would be inadequate for the task, but with DMS pre-filtration to suppress interferences, can be quite effective, even for quantitative measurement. Bio-fluids and digests are well suited to ionization by electrospray and detection by mass-spectrometry, but signals from critical markers are overwhelmed by chemical noise from unrelated species, making essential quantitative analysis impossible. Sionex and collaborators have presented data using DMS to suppress chemical noise, allowing detection of cancer biomarkers in 10,000-fold excess of normal products^1,2. In addition, a linear dynamic range of approximately 2,000 has been demonstrated with accurate quantitation³. We will review the range of possible applications and present new data on DMS-MS biomarker detection.

Fourier Transform Infrared (FTIR) spectroscopy provides a highly selective and reproducible means for the chemically-based discrimination of intact microbial cells which make the method valuable for large-scale screening of foods. The goals of the present study were to assess the effect of chemical interferents, such as food matrices, different sanitizing compounds and growth media, on the ability of the method to accurately identify and classify L. innocua, L. welshimeri, E. coli, S. cholerasuis, S. subterranea, E. sakazakii, and E. aerogenes. Moreover, the potential of FTIR spectroscopy for discrimination of L. innocua and L. welshimeri of different genotypes and the effect of growth phase on identification accuracy of L. innocua and L. welshimeri were tested. FTIR spectra were collected using two different sample presentation techniques - transmission and attenuated total reflection (ATR), and then analyzed using multivariate discriminant analysis based on the first derivative of the FTIR spectra with the unknown spectra assigned to the species group with the shortest Mahalanobis distance. The results of the study demonstrated 100% correct identification and differentiation of all bacterial strains used in this study in the presence of chemical interferents or food matrices, better than 99% identification rate in presence of media matrices, and 100% correct detection for specific bacteria in mixed flora species. Additionally, FTIR spectroscopy proved to be 100% accurate when differentiating between genotypes of L. innocua and L. welshimeri, with the classification accuracy unaffected by the growth stage. These results suggest that FTIR spectroscopy can be used as a valuable tool for identifying pathogenic bacteria in food and environmental samples.

Relatively few reports have investigated the determination and classification of pathogens such as the National Institute of Allergy and Infectious Diseases (NIAID) Category A Bacillus anthracis spores and cells (BA), Yersinia species, Francisella tularensis (FT), and Category B Brucella species from FTIR spectra. We investigated the classification ability of the Fourier transform infrared (FTIR) spectra of viable pathogenic and non-pathogenic NIAID Category A and B bacteria. The impact of different growth media, growth time and temperature, rolling circle filter of the data, and wavelength range were investigated for their microorganism differentiation. Various 2-D PC plots provided differential degrees of separation with respect to the four viable, bacterial genera including the BA sub-categories of pathogenic spores, vegetative cells, and nonpathogenic vegetative cells. FT spectra were separated from that of the three other genera. The BA pathogenic spore strains 1029, LA1, and Ames were clearly differentiated from the rest of the dataset. Yersinia species were distinctly separated from the remaining dataset and could also be classified by growth media. This work provided evidence that FTIR spectroscopy can separate the four major pathogenic bacterial genera of NIAID Category A and B biological threat agents.

The Neutron Imaging Camera (NIC) is based on the Three-dimensional Track Imager (3_DTI) technology developed at GSFC for gamma-ray astrophysics applications. The 3-DTI, a large volume time-projection chamber, provides accurate, ~0.4 mm resolution, 3-D tracking of charged particles. The incident direction of fast neutrons, En > 0.5 MeV, are reconstructed from the momenta and energies of the proton and triton fragments resulting from 3He(n,p)3H interactions in the 3-DTI volume. The performance of the NIC from laboratory is presented.

We have developed a ground-breaking algorithm, ASEDRA, to post-process scintillator detector spectra to render photopeaks with high accuracy. The post-processed spectrum is comparable with resolved full energy peaks rendered by high resolution HPGe semiconductor detectors. ASEDRA, or "Advanced Synthetically Enhanced Detector Resolution Algorithm," is currently applied to NaI(Tl) detectors, which are robust, but suffer from poor energy resolution. ASEDRA rapidly post-processes a NaI(Tl) detector spectrum over a few seconds on a standard laptop without prior knowledge of sources or spectrum features. ASEDRA incorporates a novel denoising algorithm based on an adaptive Chi-square methodology called ACHIP, or "Adaptive Chi-quare Processed denoising." Application of ACHIP is necessary to remove stochastic noise, yet preserve fine detail, and can be used as an independent tool for general noise reduction. Following noise removal, ASEDRA sequentially employs an adaptive detector response algorithm to remove the spectrum attributed to specific gammas. Tests conducted using a 2"×2" NaI(Tl) detector, along with a HPGe detector demonstrate the accuracy of ASEDRA; in this paper, we present results using a 152Eu source. Analysis of ASEDRA results show correct identification of at least 15 photopeaks from ¹⁵²Eu, with relative yield ratios of major lines to better than a factor of two for most cases (referencing the ¹⁵²Eu 344 keV photopeak), enabling better than a factor of four improvement in resolving peaks compared with unprocessed NaI(Tl). Moreover, denoising and synthetic resolution enhancement algorithms can be adapted to any detector. ACHIP and ASEDRA are covered under a Provisional Patent, Registration Number #60/971,770, 9/12/2007, USPTO.

Container inspection system is characterized as greatly changing dynamic range, geometric distortion, counting fluctuation and interference data, etc. This paper introduces an approach to generate two-view images for comparison by means of image data acquisition, a method to reconstruct 3D reviewing, and processing technology with a special image correction algorithm, that is to correct image data acquired first and then adjust image gray datum line and contrast combining with other image processing methods, which greatly improves image quality of Cobalt-60 based inspection system compared with ordinary image processing methods.

Tests of existing electronic neutron dosimeters by military and civilian groups have revealed significant performance limitations. To meet the operational requirements of emergency response personnel to a radiological/nuclear incident as well as those in the nuclear industry, a new END has been developed. It is patterned after a unique commercial neutron spectral dosemeter known as the N-probe. It uses a pair of small special scintillators on tiny photomultiplier tubes. Special electronics were designed to minimize power consumption to allow for weeks of operation on a single charge. The size, performance, and data analysis for the END have been designed to meet/exceed international standards for electronic neutron dosimeters. Results obtained with the END prototype are presented.

This paper discusses the ongoing development of a compact, unattended low-power radiation detection system designed for autonomous operation in regions with limited or no supporting infrastructure. This application motivates our focus on two of the more challenging system development problems: (1) the development of compact, low-power electronics for gamma-ray spectrometers and neutron detectors, and (2) analysis algorithms capable of distinguishing special nuclear material from benign sources in the opaque signatures of mid-resolution spectrometers. We discuss our development efforts on these fronts and present results based on implementation in a proof-of-principle system composed of two 5-cm × 10-cm × 41-cm NaI(Tl) crystals and eight 40-cm ³He tubes.