Iodine-based compound semiconductors may allow one to build a portable gamma-ray spectrometer with improved efficiency and energy resolution compared to many other portable spectrometer devices. Iodine-based semiconductors have a wide band gap that allows these detectors to operate without any cooling mechanism. Bismuth iodide (BiI₃), lead iodide (PbI₂) and mercuric iodide (HgI₂) have theoretical gamma-ray detection efficiencies approximately 2-3 times higher than CdZnTe, the current compound semiconductor material proposed for use in several homeland/national security applications, over the range of 200-3000 keV. At 662 keV, BiI₃, HgI₂ and PbI₂ have theoretical intrinsic photopeak efficiencies of 16.8%, 19.3% and 19.9%, respectively, while CdZnTe has a photopeak efficiency of 9.03%. In addition, gamma-ray spectrometers made from iodine-based compound semiconductor materials have demonstrated energy resolutions (FWHM) less than 2% at 662 keV. A 2% FWHM represents a significant improvement over many of today's scintillator-based radiation detectors used for homeland/national security purposes. We present some fundamental challenges in working with iodine-based semiconductors, including crystal growth issues and properties of the materials limiting radiation detector size, and the need for advanced electrode designs. Finally, we present elementary measurements illustrating the detection capabilities of iodine-based compound semiconductor materials.

We have designed, built, and laboratory-tested a unique shield design that transforms the complex neutron spectrum from PuBe source neutrons, generated at high energies, to nearly exactly the neutron signature leaking from a significant spherical mass of weapons grade plutonium (WGPu). This equivalent "X-material shield assembly" (Patent Pending) enables the harder PuBe source spectrum (average energy of 4.61 MeV) from a small encapsulated standard 1-Ci PuBe source to be transformed, through interactions in the shield, so that leakage neutrons are shifted in energy and yield to become a close reproduction of the neutron spectrum leaking from a large subcritical mass of WGPu metal (mean energy 2.11 MeV). The utility of this shielded PuBe surrogate for WGPu is clear, since it directly enables detector field testing without the expense and risk of handling large amounts of Special Nuclear Materials (SNM) as WGPu. Also, conventional sources using Cf-252, which is difficult to produce, and decays with a 2.7 year half life, could be replaced by this shielded PuBe technology in order to simplify operational use, since a sealed PuBe source relies on Pu-239 (T½=24,110 y), and remains viable for more than hundreds of years.

Hand-Held RadioIsotope Identification Devices (HHRIID) are defined as a new class of portable neutron/gamma radiation detectors with specifications presented in the ANSI Standards N42.33 and N42.34. We have proposed a novel HHRIID design concept which uses a single photosensor to detect light emitted by two optically separated scintillator materials, one optimized for gamma detection and the other optimized for neutron detection. This work describes the performance of a modified charge integration discrimination method developed to test the viability of the new design. The scintillators chosen for the experiment were LYSO and ZnS:Ag/LiF.

The ASEDRA algorithm (Advanced Synthetically Enhanced Detector Resolution Algorithm) is a tool developed at the University of Florida to synthetically enhance the resolved photopeaks derived from a characteristically poor resolution spectra collected at room temperature from scintillator crystal-photomultiplier detector, such as a NaI(Tl) system. This work reports on analysis of a side-by-side test comparing the identification capabilities of ASEDRA applied to a NaI(Tl) detector with HPGe results for a Plutonium Beryllium (PuBe) source containing approximately 47 year old weapons-grade plutonium (WGPu), a test case of real-world interest with a complex spectra including plutonium isotopes and 241Am decay products. The analysis included a comparison of photopeaks identified and photopeak energies between the ASEDRA and HPGe detector systems, and the known energies of the plutonium isotopes. ASEDRA's performance in peak area accuracy, also important in isotope identification as well as plutonium quality and age determination, was evaluated for key energy lines by comparing the observed relative ratios of peak areas, adjusted for efficiency and attenuation due to source shielding, to the predicted ratios from known energy line branching and source isotopics. The results show that ASEDRA has identified over 20 lines also found by the HPGe and directly correlated to WGPu energies.

We report on the design of a neutron detector using industry standard ³He tubes to count delayed neutrons during the interrogation of cargo containers for the presence of Special Nuclear Material (SNM). Simulations of the detector design were run for delayed neutron spectra for a variety of cargos containing SNM using the Monte Carlo computer code COG. The simulations identified parameters crucial to optimize the detector design. These choices include moderating material type and thickness, tube spacing, tube pressure and number of tubes. An experimental prototype was also constructed based on the simulated design specifications. This paper discusses the parameters that lead up to the optimized detector design. It also compares the performance of the Monte Carlo simulated design and the experimental detector when exposed to a ²³⁹Pu-Be source.

FNIT (the Fast Neutron Imaging Telescope), a detector with both imaging and energy measurement capabilities, sensitive to neutrons in the range 0.8-20 MeV, was initially conceived to study solar neutrons as a candidate design for the Inner Heliosphere Sentinel (IHS) spacecraft of NASA's Solar Sentinels program and successively reconfigured to locate fission neutron sources. By accurately identifying the position of the source with imaging techniques and reconstructing the Watt spectrum of fission neutrons, FNIT can detect samples of special nuclear material (SNM), including heavily shielded and masked ones. The detection principle is based on multiple elastic neutron-proton scatterings in organic scintillators. By reconstructing n-p event locations and sequence and measuring the recoil proton energies, the direction and energy spectrum of the primary neutron flux can be determined and neutron sources identified. We describe the design of the FNIT prototype and present its energy reconstruction and imaging performance, assessed by exposing FNIT to a neutron beam and to a Pu fission neutron source.

Oral samples, including saliva, offer an attractive alternative to serum or urine for diagnostic testing. This is particularly true for point-of-use detection systems. The various types of oral samples that have been reported in the literature are presented here along with the wide variety of analytes that have been measured in saliva and other oral samples. The paper focuses on utilizing point-detection of infectious disease agents, and presents work from our group on a rapid test for multiple bacterial and viral pathogens by monitoring a series of targets. It is thus possible in a single oral sample to identify multiple pathogens based on specific antigens, nucleic acids, and host antibodies to those pathogens. The value of such a technology for detecting agents of bioterrorism at remote sites is discussed.

Rapid, point of care (POC) testing has been increasingly deployed as an aid in the diagnosis of infectious disease, due to its ability to deliver rapid, actionable results. In the case of HIV, a number of rapid test devices have been FDA approved and CLIA-waived in order to enable diagnosis of HIV infection outside of traditional laboratory settings. These settings include STD clinics, community outreach centers and mobile testing units, as well as identifying HIV infection among pregnant women and managing occupational exposure to infection. The OraQuick^® rapid test platform has been widely used to identify HIV in POC settings, due to its simplicity, ease of use and the ability to utilize oral fluid as an alternative specimen to blood. More recently, a rapid test for antibodies to hepatitis C virus (HCV) has been developed on the same test platform which uses serum, plasma, finger-stick blood, venous blood and oral fluid. Clinical testing using this POC test device has shown that performance is equivalent to state of the art, laboratory based tests. These devices may be suitable for rapid field testing of blood and other body fluids for the presence of infectious agents.

Governmental agencies charged with protecting the health of the population and agriculture have several main strategic objectives including the detection of harmful agents, the identification of vulnerable biological targets, the prediction of health outcomes and the development of countermeasures. New technologies are urgently needed in several critical areas of bio-chemical defense: economical and minimally invasive biosensors for field use in humans and other species important for agriculture and infrastructure, universal analytical platforms for broad-based, early warnings of threats and technologies guiding the development of countermeasures. A new technology called Stress Response Profiling (SRP) was recently developed by the Gaia Medical Institute. SRP provides a universal analytical platform for monitoring health status based on measurements of physiological stress. The platform is implemented through handheld devices that can be used for noninvasive detection of early-stage health problems. This paper summarizes SRP features, advantages and potential benefits for critical areas of homeland defense.

Emergency Diagnostics, Homeland Security, Epidemiological Preparedness and the high cost of the Health Care Systems have increased demand for affordable and mobile point of care (POC) devices with highest sensitivity, specificity and rapid time to result. We have developed pocket sized systems for point of care and field based tests based on fluorescence read-out. The core consists of battery operated, 90 gram electro-optical units with optional wireless data transfer, which have been optimized to achieve highest accuracy and sensitivity paired with simplicity of use. The robust systems have been applied to molecular diagnostics such as DNA based testing, immunodiagnostics as well as environmental monitoring and agricultural testing. We will show examples of DNA testing, testing of drugs and toxins, cell based assays and water monitoring. We will discuss drivers and rationale for mobile testing platforms and address critical points such as sample preparation and sampling problems e.g. target delivery in small volumes. ESE's battery-operated handheld and mobile testing platforms have been shown to provide sensitive, accurate, and specific results, as well as rapid turnaround. The stand-alone devices demonstrate operational and physical robustness, and they can be manufactured to be affordable. Some underlying assays work directly from clinical samples such as urine or blood.

Current understanding of how to restore a wide area that has been contaminated following a large biological attack is limited. The Department of Homeland Security and Department of Defense are executing a four-year collaborative program named the Interagency Biological Restoration Demonstration (IBRD) program. This program is aimed at developing technologies, methods, plans and policies necessary to restore a wide area, including military installations and critical infrastructures, in the event of a large outdoor aerosol release of anthrax. The IBRD program partner pilot city is the Seattle Urban Area to include Fort Lewis, WA and McChord Air Force Base. A front-end systems analysis was conducted as part of IBRD, to: 1) assess existing technologies and processes for wide area restoration; from this, 2) develop an "as-is" decision framework for wide area restoration; and 3) identify and prioritize capability gaps. Qualitative assessments and quantitative analyses, including sensitivity, timeline and case study analyses, were conducted to evaluate existing processes and rank capability gaps. This paper describes the approach and results from this front-end systems analysis.

Bioluminescent bioreporters carrying the bacterial lux gene cassette have been well established for the sensing and monitoring of select chemical agents. Their ability to generate target specific visible light signals with no requirement for extraneous additions of substrate or other hands-on manipulations affords a real-time, repetitive assaying technique that is remarkable in its simplicity and accuracy. Although the predominant application of lux-based bioluminescent bioreporters has been towards chemical compound detection, novel genetic engineering schemes are yielding a variety of new bioreporter systems that extend the lux sensing mechanism beyond mere analyte discrimination. For example, the unique specificity of bacteriophage (bacterial viruses) has been exploited in lux bioluminescent assays for specific identification of foodborne bacterial pathogens such as Escherichia coli O157:H7. With the concurrent ability to interface bioluminescent bioreporter assays onto integrated circuit microluminometers (BBICs; bioluminescent bioreporter integrated circuits), the potential exists for the development of sentinel microchips that can function as environmental monitors for multiplexed recognition of chemical and biological agents in air, food, and water. The size and portability of BBIC biosensors may ultimately provide a deployable, interactive network sensing technology adaptable towards chem/bio defense.

Surface Plasmon Resonance (SPR) has become a widely accepted technique for real-time detection of interactions between receptor molecules and ligands. Antibody may serve as receptor and can be attached to the gold surface of the SPR device, while candidate analyte fluids contact the detecting antibody. Minute, but detectable, changes in refractive indices (RI) indicate that analyte has bound to the antibody. A decade ago, an inexpensive, robust, miniature and fully integrated SPR chip, called SPREETA, was developed. University of Washington (UW) researchers subsequently developed a portable, temperature-regulated instrument, called SPIRIT, to simultaneously use eight of these three-channel SPREETA chips. A SPIRIT prototype instrument was tested in the field, coupled to a remote reporting system on a surrogate unmanned aerial vehicle (UAV). Two target protein analytes were released sequentially as aerosols with low analyte concentration during each of three flights and were successfully detected and verified. Laboratory experimentation with a more advanced SPIRIT instrument demonstrated detection of very low levels of several select biological agents that might be employed by bioterrorists. Agent detection under field-like conditions is more challenging, especially as analyte concentrations are reduced and complex matricies are introduced. Two different sample preconditioning protocols have been developed for select agents in complex matrices. Use of these preconditioning techniques has allowed laboratory detection in spiked heavy mud of Francisella tularensis at 10³ CFU/ml, Bacillus anthracis spores at 10³ CFU/ml, Staphylococcal enterotoxin B (SEB) at 1 ng/ml, and Vaccinia virus (a smallpox simulant) at 10⁵ PFU/ml. Ongoing experiments are aimed at simultaneous detection of multiple agents in spiked heavy mud, using a multiplex preconditioning protocol.

We present a characterization of the metal-affinity driven self-assembly between luminescent CdSe-ZnS core-shell semiconductor quantum dots (QDs) and either peptides or proteins appended with various length terminal polyhistidine tags. We first monitor the kinetics of self-assembly between surface-immobilized QDs and proteins/peptides under flow conditions (immobilized). To accomplish this, the QDs were immobilized onto functionalized substrates and then exposed to dye-labeled peptides/proteins. By using evanescent wave excitation of the substrate, self-assembly was assessed by monitoring the time-dependent changes in the dye fluorescence. This configuration was complemented with experiments using freely diffusing QDs and proteins/peptides (solution-phase) via energy transfer between QDs and dye-labeled proteins/peptides. Cumulatively, these measurements allowed determination of kinetic parameters, including association and dissociation rates (k_on and k_off) and the binding constant (K_d). We find that self-assembly is rapid with an equilibrium constant K_d^-1 in the low nM. We next demonstrate the importance of understanding this self-assembly by creating QD-peptide bioconjugates which we employ as substrates to monitor the cleavage activity of proteolytic enzymes. This confirms that metal-affinity interactions can provide QD-bioconjugates that are functional and stable.

As part of the U.S. Department of Homeland Security Detect-to-Protect program, a multilab [Sandia National Laboratories (SNL), Lawrence Livermore National Laboratories (LLNL), Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), and Los Alamos National Laboratory (LANL)] effort is addressing the need for useable detect-to-warn bioaerosol sensors for public facility protection. Towards this end, the SNL team is employing rapid fluorogenic staining to infer the protein content of bioaerosols. This is being implemented in a flow cytometry platform wherein each particle detected generates coincident signals of forward scatter, side scatter, and fluorescence. Several thousand such coincident signal sets are typically collected to generate a probability distribution over the scattering and fluorescence values. A linear unmixing analysis is performed to differentiate components in the mixture. After forming a library of pure component distributions from measured pure material samples, the distribution of an unknown mixture of particles is treated as a linear combination of the pure component distributions. The scattering/fluorescence probability distribution data vector a is considered the product of two vectors, the fractional profile f and the scattering/fluorescence distributions from pure components P. A least squares procedure minimizes the magnitude of the residual vector e in the expression a = fP^T + e. The profile f designates a weighting fraction for each particle type included in the set of pure components, providing the composition of the unknown mixture. We discuss testing of this analysis approach and steps we have taken to evaluate the effect of interferents, both known and unknown.

As part of the U.S. Department of Homeland Security Detect-to-Protect (DTP) program, a multilab [Sandia National Laboratories (SNL), Lawrence Livermore National Laboratories (LLNL), Pacific Northwest National Laboratory (PNNL), Oak Ridge National Laboratory (ORNL), and Los Alamos National Laboratory (LANL)] effort is addressing the need for useable detect-to-warn bioaerosol sensors for public facility protection. Towards this end, the SNL team is investigating the use of rapid fluorogenic staining to infer the protein content of bioaerosols. This is being implemented in a flow cytometer wherein each particle detected generates coincident signals of correlated forward scatter, side scatter, and fluorescence. Several thousand such coincident signal sets are typically collected to generate a distribution describing the probability of observing a particle with certain scattering and fluorescence values. These data are collected for sample particles in both a stained and unstained state. A linear unmixing analysis is performed to differentiate components in the mixture. In this paper, we discuss the implementation of the staining process and the cytometric measurement, the results of their application to the analysis of known and blind samples, and a potential instrumental implementations that would use staining.

In the authors' previous work, a sequence of image-processing algorithms was developed that was suitable for detecting and classifying ships from panchromatic Quickbird electro-optical satellite imagery. Presented in this paper are several new algorithms, which improve the performance and enhance the capabilities of the ship detection software, as well as an overview on how land masking is performed. Specifically, this paper describes the new algorithms for enhanced detection including for the reduction of false detects such as glint and clouds. Improved cloud detection and filtering algorithms are described as well as several texture classification algorithms are used to characterize the background statistics of the ocean texture. These detection algorithms employ both cloud and glint removal techniques, which we describe. Results comparing ship detection with and without these false detect reduction algorithms are provided. These are components of a larger effort to develop a low-cost solution for detecting the presence of ships from readily-available overhead commercial imagery and comparing this information against various open-source ship-registry databases to categorize contacts for follow-on analysis.

We present an algorithm that produces a fused false color representation of a combined multiband IR and visual imaging system for maritime applications. Multispectral IR imaging techniques are increasingly deployed in maritime operations, to detect floating mines or to find small dinghies and swimmers during search and rescue operations. However, maritime backgrounds usually contain a large amount of clutter that severely hampers the detection of small targets. Our new algorithm deploys the correlation between the target signatures in two different IR frequency bands (3-5 and 8-12 μm) to construct a fused IR image with a reduced amount of clutter. The fused IR image is then combined with a visual image in a false color RGB representation for display to a human operator. The algorithm works as follows. First, both individual IR bands are filtered with a morphological opening top-hat transform to extract small details. Second, a common image is extracted from the two filtered IR bands, and assigned to the red channel of an RGB image. Regions of interest that appear in both IR bands remain in this common image, while most uncorrelated noise details are filtered out. Third, the visual band is assigned to the green channel and, after multiplication with a constant (typically 1.6) also to the blue channel. Fourth, the brightness and colors of this intermediate false color image are renormalized by adjusting its first order statistics to those of a representative reference scene. The result of these four steps is a fused color image, with naturalistic colors (bluish sky and grayish water), in which small targets are clearly visible.

Defence R&D Canada is developing a Collaborative Knowledge Exploitation Framework (CKEF) to support the analysts in efficiently managing and exploiting relevant knowledge assets to achieve maritime domain awareness in joint operations centres of the Canadian Forces. While developing the CKEF, anomaly detection has been clearly recognized as an important aspect requiring R&D. An activity has thus been undertaken to implement, within the CKEF, a proof-of-concept prototype of a rule-based expert system to support the analysts regarding this aspect. This expert system has to perform automated reasoning and output recommendations (or alerts) about maritime anomalies, thereby supporting the identification of vessels of interest and threat analysis. The system must contribute to a lower false alarm rate and a better probability of detection in drawing operator's attention to vessels worthy of their attention. It must provide explanations as to why the vessels may be of interest, with links to resources that help the operators dig deeper. Mechanisms are necessary for the analysts to fine tune the system, and for the knowledge engineer to maintain the knowledge base as the expertise of the operators evolves. This paper portrays the anomaly detection prototype, and describes the knowledge acquisition and elicitation session conducted to capture the know-how of the experts, the formal knowledge representation enablers and the ontology required for aspects of the maritime domain that are relevant to anomaly detection, vessels of interest, and threat analysis, the prototype high-level design and implementation on the service-oriented architecture of the CKEF, and other findings and results of this ongoing activity.

Previously, we have investigated the use of Long-Wave Infra-Red (LWIR) polarimetric imaging for the detection of surface swimmers in a maritime environment. While better contrast and longer range are expected with Mid-Wave Infra-Red (MWIR) polarimetric imaging, the cost of such a system is higher than a polarimetric imager operating in the LWIR due to the advent of higher-performance micro-bolometer imaging arrays. The actual performance of a MWIR polarimetric imager to detect a person in the water is presented. A comparative analysis of system cost between MWIR and LWIR systems is also discussed.

Recent flight tests of the Airborne Reconfigurable Imaging System (ARIS) developed by BAE Systems have demonstrated several key capabilities for day-night multiple target detection and tracking of maritime surface vessels. The flight test system includes the integration of BAE Systems-developed real-time image processing algorithms with multispectral band electro-optical (EO) (RGB)/mid-wave infrared (MWIR) sensors and a COTS turreted system. Presented here are significant flight test results that demonstrate real-time multispectral sensor image co-registration, geo-registration, fusion, target detection and tracking. High performance geo-pointing and line-of-sight stabilization capabilities enable the airborne system to provide maritime domain awareness objectives for search and rescue, persistent surveillance of moving and stationary targets, contraband traffic control through detection and tracking of concealed vessels, and autonomous tracking of both moving and stationary vessels. Solar glint and cloud coverage false alarms are minimized while multiple target detections and tracks are maintained. The fundamental real-time processing methodologies used for ARIS are applied to a COTS multiple field of view system with high-resolution RGB and mid-wave infrared (MWIR) video rate imaging. The techniques discussed for this four spectral band system can be applied to both extended multispectral systems (greater than four spectral bands) and hyperspectral systems to further enhance system capabilities for analogous terrestrial applications.

This paper presents a MISR Visualization Experimental Environment which provides support to the development, evaluation, experimentation, and transitioning of information visualization approaches to emulate the essential elements of a future RMP. The environment provides a means of integrating and sharing the output of visualization tools; storing, accessing and managing showcase examples of visual representations via an underlying visualization reference model; and providing access to underlying data sources supplied through simulation, representative data, and operational data. Visualization design and experimentation activities are also briefly introduced. The MISR experimental environment may be used to characterize the various techniques evaluated and the results of experiments will be introduced as inputs of the environment knowledge base. It is expected that the experimentation undertaken, supported by a MISR experimental environment, will identify novel visualization approaches to be integrated in the future RMP and have the potential to enhance maritime domain awareness.

Due to technical advances and the changing political environment sensor management has become increasingly knowledge intensive. Aboard navy ships however, we see a decrease of available knowledge, both quantitative and qualitative. This growing discrepancy drives the need for automation of sensor management. Since the goal of sensor deployment is to have a complete and accurate operational picture relative to the mission we propose a three-stage sensor manager, where sensor task requests are generated based on the uncertainty in the (expected) objects' attributes. These tasks are assigned to available and suited sensors, which in turn are fine-tuned for the task at hand. When trying to reduce the uncertainty in the classification solution one must first define how the classification process actually works. We discuss why the classification process needs to be automated as well and show how such classification algorithms will most likely work in the future.

SeaSpider is an R&D tool to investigate the development of a software agent that would aid an operator in gathering information about marine vessels from public sources on the Internet. This information would supplement sensor information used for Intelligence, Surveillance, and Reconnaissance (ISR) to enhance Maritime Domain Awareness (MDA) and to complete the Recognized Maritime Picture (RMP). Specifically, SeaSpider is fine-tuned to search for, extract, integrate, and display information about locations (ports), dates and times, and activities (arrival, in berth, departure). One module manages World Wide Web (WWW) searches and retrieves the web pages; another module extracts relevant ship activities, integrates them and populates a database; a third module retrieves information from the database in response to user-generated queries. In this paper, the SeaSpider concept is introduced, the design details of the prototype are presented, and performance is analyzed, with a view towards future research.

The Maritime Security Laboratory (MSL) at Stevens Institute of Technology supports research in a range of areas relevant to harbor security, including passive acoustic detection of underwater threats. The difficulties in using passive detection in an urban estuarine environment include intensive and highly irregular ambient noise and the complexity of sound propagation in shallow water. MSL conducted a set of tests in the Hudson River near Manhattan in order to measure the main parameters defining the detection distance of a threat: source level of a scuba diver, transmission loss of acoustic signals, and ambient noise. The source level of the diver was measured by comparing the diver's sound with a reference signal from a calibrated emitter placed on his path. Transmission loss was measured by comparing noise levels of passing ships at various points along their routes, where their distance from the hydrophone was calculated with the help of cameras and custom software. The ambient noise in the Hudson River was recorded under varying environmental conditions and amounts of water traffic. The passive sonar equation was then applied to estimate the range of detection. Estimations were done for a subset of the recorded noise levels, and we demonstrated how variations in the noise level, attenuation, and the diver's source level influence the effective range of detection. Finally, we provided analytic estimates of how an array improves upon the detection distance calculated by a single hydrophone.

Stevens Institute of Technology has established a research laboratory environment in support of the U.S. Navy in the area of Anti-Terrorism and Force Protection. Called the Maritime Security Laboratory, or MSL, it provides the capabilities of experimental research to enable development of novel methods of threat detection in the realistic environment of the Hudson River Estuary. In MSL, this is done through a multi-modal interdisciplinary approach. In this paper, underwater acoustic measurements and video surveillance are combined. Stevens' researchers have developed a specialized prototype video system to identify, video-capture, and map surface ships in a sector of the estuary. The combination of acoustic noise with video data for different kinds of ships in Hudson River enabled estimation of sound attenuation in a wide frequency band. Also, it enabled the collection of a noise library of various ships that can be used for ship classification by passive acoustic methods. Acoustics and video can be used to determine a ship's position. This knowledge can be used for ship noise suppression in hydrophone arrays in underwater threat detection. Preliminary experimental results of position determination are presented in the paper.

Knowledge of the variability of the acoustic emission characteristics from SCUBA divers is critically important for designing and operating a passive acoustic SCUBA characterization system. Using modeling and experimental measurements in a controlled environment, we identified key source factors influencing the variability of the acoustic emission parameters including Source Band Level (SBL), Spectral Power Density (SPD), and breathing periodicity or emission modulation frequency. The key factors are: equipment, specifically, the design of the first stage (high pressure) regulator and its service life; diver's experience and training; and, finally, operating conditions of the equipment and diver, i.e. tank air pressure and the diver's motion activity. We found, for example, that the SBL could vary as much as 16 dB depending on the equipment used and up to 15 dB depending on the diver's intensity of motion.

In contrast to transmission X-ray imaging systems where inspected objects must pass between source and detector, Compton backscatter imaging allows both the illuminating source as well as the X-ray detector to be on the same side of the target object, enabling the inspection to occur rapidly and in a wide variety of space-constrained situations. A Compton backscatter image is similar to a photograph of the contents of a closed container, taken through the container walls, and highlights low atomic number materials such as explosives, drugs, and alcohol, which appear as especially bright objects by virtue of their scattering characteristics. Techniques for producing X-ray images based on Compton scattering will be discussed, along with examples of how these systems are used for both novel security applications and for the detection of contraband materials at ports and borders. Differences between transmission and backscatter images will also be highlighted. In addition, tradeoffs between Compton backscatter image quality and scan speed, effective penetration, and X-ray source specifications will be discussed.

We present experimental results showing transmission and reflection imaging of approximately 100 μg quantities of particulate explosives residue using a commercial uncooled microbolometer infrared camera and CO₂ laser differential wavelength illumination. Fine particulates may be generated during bomb-making activities and these particulates can tenaciously adhere to packing material, as well as to the clothing or skin of the bomb maker and could be detectable during transportation. A rapid screening method that detects this residue can serve as a first-line screening method in conjunction with more sensitive, but invasive, approaches. Explosives exhibit absorption features in the mid-infrared molecular fingerprint region that spans 3 to 15 μm, which can be probed with many high-brightness sources such as fixed wavelength and tunable quantum cascade lasers, CO₂, CO, and OPO lasers. Commercial uncooled microbolometer cameras typically have detection sensitivity from 7.5 to 13 μm, spanning an absorption region for explosives detection with adequate signal-to-noise ratio. By illuminating a target on and off its absorption wavelengths, ratio images of suspected residue can be obtained without any sample preparation or cooperation and contact with the target. Our proof-of-principle experiment employed tunable CO₂ lasers, with a tuning range from 9.2 to 10.6 μm, overlapping minor absorption features of RDX and Tetryl.

We present a new neutron detection technology capable of high efficiency detection of thermal and cold neutrons with high spatial resolution. It is based on neutron-sensitive microchannel plates (MCPs) converting incident neutrons to electrons, which are then amplified and detected by a variety of different position sensitive readouts. The detection efficiency of those detectors can exceed 50% for thermal neutrons, while the spatial resolution can be better than 20 μm FWHM. Another attractive feature is the capability to time-stamp each incoming neutron with ~microsecond resolution, allowing energy/material resolved studies with pulsed neutron sources. The MCP-based neutron detectors can also be combined with novel MCP-based neuron optics, allowing high resolution angular selective neutron imaging.

Vapor phase sensing and detection of TNT-based explosives is extremely challenging due in part to the low vapor pressure of TNT. We believe one effective strategy for optically based sensing of TNT-based explosives involves focusing not on the spectral signature for pure TNT, but rather on a more volatile series of compounds that are present in TNT as impurities. To date we have catalogued and reported a number of rotationally resolved infrared transition frequencies for nitrobenzene, toluene, o-nitrotoluene, and m-nitrotoluene in the 14 micron region. Here we describe the use of an in-house spectral calibration program that while designed for calibration of Pb-salt diode laser spectra, is quite general and could be utilized for many spectroscopic detection and/or analysis applications. Finally, a sensing measurement for a volatile organic impurity related to RDX-based explosives such as C4 is presented and discussed.

The objective of this project funded by the German BMBF was to show that security relevant substances can be detected in complex matrices at low concentrations using single photon ionization ion trap mass spectrometry (SPI-ITMS). The advantage of such a soft ionization technique is a reduction of unwanted fragment ions in mass spectra allowing identification of signals from complex matrices and enabling MS/MS capability. The MS/MS studies permit low false-positive and false-negative rates. Additionally, the accumulation of the ions in the ion trap decreases the detection limit. To obtain low detection limits the ionization potentials (IPs) of the relevant substances have to be below the IPs of the bulk matrix components. That enables the utilization of a photon energy unaffecting the matrix components resulting in increased sensitivity due to essentially non-existent background signals. As literature values for many ionization potentials are unavailable, IPs of several security relevant substances were determined using monochromatized synchrotron radiation from BESSY, Germany. All analyzed substances exhibited IPs significantly below the IPs of common matrix molecules such as water, nitrogen and oxygen. First measurements with a pre-demonstrator show that it is possible to shield matrix substances using a well chosen photon energy for soft ionization.

Most of the biodetection technologies available on the market have the potential to test water samples for pathogens. Yet municipal water laboratories have been challenging markets for biodetection systems. This manuscript will provide an overview of biodetection technologies that might be useful to municipal water facilities, the types of pathogens and indicators that water laboratories are generally interested in detecting and hardware requirements for biological detection systems that may potentially be used in a municipal water laboratory.

Over the past several years many advances have been made to monitor potable water systems for toxic threats. However, the need for real-time, on-line systems to detect the malicious introduction of deadly pathogens still exists. Municipal water distribution systems, government facilities and buildings, and high profile public events remain vulnerable to terrorist-related biological contamination. After years of research and development, an instrument using multi-angle light scattering (MALS) technology has been introduced to achieve on-line, real-time detection and classification of a waterborne pathogen event. The MALS system utilizes a continuous slip stream of water passing through a flow cell in the instrument. A laser beam, focused perpendicular to the water flow, strikes particles as they pass through the beam generating unique light scattering patterns that are captured by photodetectors. Microorganisms produce patterns termed 'bio-optical signatures' which are comparable to fingerprints. By comparing these bio-optical signatures to an on-board database of microorganism patterns, detection and classification occurs within minutes. If a pattern is not recognized, it is classified as an 'unknown' and the unidentified contaminant is registered as a potential threat. In either case, if the contaminant exceeds a customer's threshold, the system will immediately alert personnel to the contamination event while extracting a sample for confirmation. The system, BioSentry^TM, developed by JMAR Technologies is now field-tested and commercially available. BioSentry is cost effective, uses no reagents, operates remotely, and can be used for continuous microbial surveillance in many water treatment environments. Examples of HLS installations will be presented along with data from the US EPA NHSRC Testing and Evaluation Facility.

The use of digital cameras and camcorders in prohibited areas presents a growing problem. Piracy in the movie theaters results in huge revenue loss to the motion picture industry every year, but still image and video capture may present even a bigger threat if performed in high-security locations. While several attempts are being made to address this issue, an effective solution is yet to be found. We propose to approach this problem using a very commonly observed optical phenomenon. Cameras and camcorders use CCD and CMOS sensors, which include a number of photosensitive elements/pixels arranged in a certain fashion. Those are photosites in CCD sensors and semiconductor elements in CMOS sensors. They are known to reflect a small fraction of incident light, but could also act as a diffraction grating, resulting in the optical response that could be utilized to identify the presence of such a sensor. A laser-based detection system is proposed that accounts for the elements in the optical train of the camera, as well as the eye-safety of the people who could be exposed to optical beam radiation. This paper presents preliminary experimental data, as well as the proof-of-concept simulation results.

Facial recognitions of people can be used for the identification of individuals, or can serve as verification e.g. for access controls. The process requires, that the facial data is captured and then compared with stored reference data. In this context, far better recognition performances can be expected from 3-dimensional facial recognition systems than can be from the 2-dimensional systems which are currently used. The accuracy with which the facial profile can be captured, depends on the speed off the measuring data acquisition i.e. the scanning speed and on the measuring accuracy of the measuring device i.e. the 3D scanner.

We developed an UV image intensifier tube with a GaN photocathode in semi-transparent mode. In UV spectroscopy and low-light-level UV-imaging applications, there are strong demands for improved detectors which have higher quantum efficiency, low dark current, sharper wavelength cut-off response, and stable and robust characteristics. III-Nitrides semiconductor is one of the promising candidate materials to meet these demands. We developed a GaN photocathode which is epitaxially grown by MOCVD method. It has flat and high quantum efficiency from 200 nm to 360 nm. The cathode is incorporated into an image intensifier tube, which shows good gating performance and fine imaging resolution. With these improved performances, the UV image intensifier tube with GaN photocathode will expand its application fields to include UV spectroscopy and UV-imaging in low light.

Explosives detection for national and aviation security has been an area of concern for many years. In order to improve the security in risk areas, much effort has been focused on direct detection of explosive materials in vapor and bulk form. New techniques and highly sensitive detectors have been extensively investigated and developed to detect and identify residual traces that may indicate an individual's recent contact with explosive materials. This paper reports on the use and results of Surface Enhanced Raman Scattering (SERS) technique, to analyze residual traces of explosives in highly diluted solutions by using low-resolution Raman spectroscopy (LRRS). An evaluation of the detection sensitivity of this technique has been accomplished using samples of explosives such as Trinitrotoluene(TNT), Cyclotrimethylenetrinitramine (RDX) and HMX evaluated at different concentrations. Additionally, different SERS substrates have been studied in order to achieve the best enhancement of the Raman spectrum for residual amounts of materials. New substrates produced by gold-coated polystyrene nanospheres have been investigated. Two different sizes of polystyrene nanospheres, 625nm and 992nm, have been used to produce nanopatterns and nanocavities on the surface of a glass slide which has been coated with sputtered gold. Results from homemade substrates have been compared to a commercial gold-coated substrate consisting of an array of resonant cavities that gives the SERS effect. Sample concentration, starting from 1000ppm was gradually diluted to the smallest detectable amount. Raman spectrum was obtained using a portable spectrometer operating at a wavelength of 780nm.

Optical fiber mesh can be applied on some fences to secure some protective facilities. It is necessary to give the fiber macro bending signal in order to detect an intruder at the initial intrusion stage with the off signal from fiber cutting. Therefore, in this work, we made two step signal processing algorithm of the optical fiber mesh for detecting the intruder effectively. First step is composed of the discrimination processing whether the fiber has some macro bending or not. If the signal tells the macro bending, then it means that some intruder tries to invade. Second step is the signal destruction by cutting the optical fiber. This step means that the intruder invaded by cutting the optical fiber mesh.

Illicit nuclear materials represent a threat for the safety of the American citizens, and the detection and interdiction of a nuclear weapon is a national problem that has not been yet solved. Alleviating this threat represents an enormous challenge to current detection methods that have to be substantially improved to identify and discriminate threatening from benign incidents. Rugged, low-power and less-expensive radiation detectors and imagers are needed for large-scale wireless deployment. Detecting the gamma rays emitted by nuclear and fissionable materials, particularly special nuclear materials (SNM), is the most convenient way to identify and locate them. While there are detectors that have the necessary sensitivity, none are suitable to meet the present need, primarily because of the high occurrence of false alarms. The exploitation of neutron signatures represents a promising solution to detecting illicit nuclear materials. This work presents the development of several detector configurations such as a mobile active interrogation system based on a compact RF-Plasma neutron generator developed at LBNL and a fast neutron telescope that uses plastic scintillating-fibers developed at the University of New Hampshire. A human-portable improved Solid-State Neutron Detector (SSND) intended to replace pressurized ³He-tubes will be also presented. The SSND uses an ultra-compact CMOS-SSPM (Solid-State Photomultiplier) detector, developed at Radiation Monitoring devices Inc., coupled to a neutron sensitive scintillator. The detector is very fast and can provide time and spectroscopy information over a wide energy range including fast neutrons.

Vapor collection systems, including solid phase microextraction (SPME), require the ability to selectively collect and concentrate a sample from a large volume of air. In the case of SPME, polymers are needed to adhere to the fiber for greater reproducibility and longer lasting fibers. The polymerization of carbosilanes was investigated and produced polymers with molecular weights over 500,000. This polymer class was then functionalized with hexafluoro-2-propanol (HFIP) end groups that will selectively sorb hydrogen bond basic vapors. The results of vapor testing with these polymers utilizing a variety of platforms such as preconcentrators, Surface Acoustic Wave (SAW) sensors, and microcantilevers will be discussed.

Explosive compounds such as RDX, and HMX present significant challenges to optically based sensors. This difficulty is due in part to the low vapor pressures these compounds possess. One approach for sensing explosives that circumvents the low explosive vapor pressure problem, involves focusing on the trace amounts of relatively high vapor pressure impurities that will be present in the vapor signature. In order to effectively detect these volatile impurities, the spectral signature databases must be readily available. One of our goals therefore, is the generation of a database of high resolution spectral signatures for these volatile organic impurities. Some rather formidable spectroscopic measurement challenges have been encountered while working to extend the spectral signature effort to the 3 micron region. Here we will outline progress to date, with a focus on the volatile organic compounds formaldehyde, acetaldehyde, nitromethane, acetone, isobutene, and cyclohexanone.

Terrorists were targeting commercial airliners long before the 9/11 attacks on the World Trade Center and the Pentagon. Despite heightened security measures, commercial airliners remain an attractive target for terrorists, as evidenced by the August 2006 terrorist plot to destroy as many as ten aircraft in mid-flight from the United Kingdom to the United States. As a response to the security threat air carriers are now required to screen 100-percent of all checked baggage for explosives. The scale of this task is enormous and the Transportation Security Administration has deployed thousands of detection systems. Although this has resulted in improved security, the performance of the installed systems is not ideal. Further improvements are needed and can only be made with new technologies that ensure a flexible Concept of Operations and provide superior detection along with low false alarm rates and excellent dependability. To address security needs Applied Signal Technology, Inc. is developing an innovative and practical solution to meet the performance demands of aviation security. The neu-VISION^TM system is expected to provide explosives detection performance for checked baggage that both complements and surpasses currently deployed performance. The neu-VISION^TM system leverages a 5 year R&D program developing the Associated Particle Imaging (API) technique; a neutron based non-intrusive material identification and imaging technique. The superior performance afforded by this neutron interrogation technique delivers false alarm rates much lower than deployed technologies and "sees through" dense, heavy materials. Small quantities of explosive material are identified even in the cluttered environments.