Automated mapping of explosives particles in composition C-4 fingerprints.

PubMed

Verkouteren, Jennifer R; Coleman, Jessica L; Cho, Inho

2010-03-01

A method is described to perform automated mapping of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) particles in C-4 fingerprints. The method employs polarized light microscopy and image analysis to map the entire fingerprint and the distribution of RDX particles. This method can be used to evaluate a large number of fingerprints to aid in the development of threat libraries that can be used to determine performance requirements of explosive trace detectors. A series of 50 C-4 fingerprints were characterized, and results show that the number of particles varies significantly from print to print, and within a print. The particle size distributions can be used to estimate the mass of RDX in the fingerprint. These estimates were found to be within +/-26% relative of the results obtained from dissolution gas chromatography/micro-electron capture detection for four of six prints, which is quite encouraging for a particle counting approach. By evaluating the average mass and frequency of particles with respect to size for this series of fingerprints, we conclude that particles 10-20 microm in diameter could be targeted to improve detection of traces of C-4 explosives.

Active sampling technique to enhance chemical signature of buried explosives

NASA Astrophysics Data System (ADS)

Lovell, John S.; French, Patrick D.

2004-09-01

Deminers and dismounted countermine engineers commonly use metal detectors, ground penetrating radar and probes to locate mines. Many modern landmines have a very low metal content, which severely limits the effectiveness of metal detectors. Canines have also been used for landmine detection for decades. Experiments have shown that canines smell the explosives which are known to leak from most types of landmines. The fact that dogs can detect landmines indicates that vapor sensing is a viable approach to landmine detection. Several groups are currently developing systems to detect landmines by "sniffing" for the ultra-trace explosive vapors above the soil. The amount of material that is available to passive vapor sensing systems is limited to no more than the vapor in equilibrium with the explosive related chemicals (ERCs) distributed in the surface soils over and near the landmine. The low equilibrium vapor pressure of TNT in the soil/atmosphere boundary layer and the limited volume of the boundary layer air imply that passive chemical vapor sensing systems require sensitivities in the picogram range, or lower. ADA is working to overcome many of the limitations of passive sampling methods, by the use of an active sampling method that employs a high-powered (1,200+ joules) strobe lamp to create a highly amplified plume of vapor and/or ERC-bearing fine particulates. Initial investigations have demonstrated that this approach can amplify the detectability of TNT by two or three orders of magnitude. This new active sampling technique could be used with any suitable explosive sensor.

Aerodynamic sampling for landmine trace detection

NASA Astrophysics Data System (ADS)

Settles, Gary S.; Kester, Douglas A.

2001-10-01

Electronic noses and similar sensors show promise for detecting buried landmines through the explosive trace signals they emit. A key step in this detection is the sampler or sniffer, which acquires the airborne trace signal and presents it to the detector. Practicality demands no physical contact with the ground. Further, both airborne particulates and molecular traces must be sampled. Given a complicated minefield terrain and microclimate, this becomes a daunting chore. Our prior research on canine olfactory aerodynamics revealed several ways that evolution has dealt with such problems: 1) proximity of the sniffer to the scent source is important, 2) avoid exhaling back into the scent source, 3) use an aerodynamic collar on the sniffer inlet, 4) use auxiliary airjets to stir up surface particles, and 5) manage the 'impedance mismatch' between sniffer and sensor airflows carefully. Unfortunately, even basic data on aerodynamic sniffer performance as a function of inlet-tube and scent-source diameters, standoff distance, etc., have not been previously obtained. A laboratory-prototype sniffer was thus developed to provide guidance for landmine trace detectors. Initial experiments with this device are the subject of this paper. For example, a spike in the trace signal is observed upon starting the sniffer airflow, apparently due to rapid depletion of the available signal-laden air. Further, shielding the sniffer from disruptive ambient airflows arises as a key issue in sampling efficiency.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hannum, David W.; Shannon, Gary W.

This report describes the collaboration between the South Texas Specialized Crimes and Narcotics Task Force (STSCNTF) and Sandia National Laboratories (SNL) in a field test that provided prototype hand-held trace detection technology for use in counter-drug operations. The National Institute of Justice (NIJ)/National Law Enforcement and Corrections Technology Center (NLECTC)/Border Research and Technology Center (BRTC) was contacted by STSCNTF for assistance in obtaining cutting-edge technology. The BRTC created a pilot project for Sandia National Laboratories (SNL) and the STSCNTF for the use of SNL’s Hound, a hand-held sample collection and preconcentration system that, when combined with a commercial chemical detector,more » can be used for the trace detection of illicit drugs and explosives. The STSCNTF operates in an area of high narcotics trafficking where methods of concealment make the detection of narcotics challenging. Sandia National Laboratories’ (SNL) Contraband Detection Department personnel provided the Hound system hardware and operational training. The Hound system combines the GE VaporTracer2, a hand-held commercial chemical detector, with an SNL-developed sample collection and preconcentration system. The South Texas Task force reported a variety of successes, including identification of a major shipment of methamphetamines, the discovery of hidden compartments in vehicles that contained illegal drugs and currency used in drug deals, and the identification of a suspect in a nightclub shooting. The main advantage of the hand-held trace detection unit is its ability to quickly identify the type of chemical (drugs or explosives) without a long lag time for laboratory analysis, which is the most common analysis method for current law enforcement procedures.« less

Standoff detection of explosive substances at distances of up to 150 m.

PubMed

Mukherjee, Anadi; Von der Porten, Steven; Patel, C Kumar N

2010-04-10

We report detection and identification of trace quantities of explosives at standoff distances up to 150 m with high sensitivity (signal-to-noise ratio of approximately 70) and high selectivity. The technique involves illuminating the target object with laser radiation at a wavelength that is strongly absorbed by the target. The resulting temperature rise is observed by remotely monitoring the increased blackbody radiation from the sample. An unambiguous determination of the target, TNT, in soil samples collected from an explosives test site in China Lake Naval Air Weapons Station is achieved through the use of a tunable CO(2) laser that scans over the absorption fingerprint of the target explosives. The theoretical analysis supports the observation and indicates that, with optimized detectors and data processing algorithms, the measurement capability can be improved significantly, permitting rapid standoff detection of explosives at distances approaching 1 km. The detection sensitivity varies as R(-2) and, thus, with the availability of high power, room-temperature, tunable mid-wave infrared and long-wave infrared quantum cascade lasers, this technology may play an important role in screening personnel and their belongings at short distances, such as in airports, for detecting and identifying explosives material residue on persons.

Calibration methods for explosives detectors

NASA Astrophysics Data System (ADS)

MacDonald, Stephen J.; Rounbehler, David P.

1992-05-01

Airport security has become an important concern to cultures in every corner of the world. Presently, efforts to improve airport security have brought additional technological solutions, in the form of advanced instrumentation for the detection of explosives, into use at airport terminals in many countries. This new generation of explosives detectors is often used to augment existing security measures and provide a more encompassing screening capability for airline passengers. This paper describes two calibration procedures used for the Thermedics' EGIS explosives detectors. The systems were designed to screen people, electronic components, luggage, automobiles, and other objects for the presence of concealed explosives. The detectors have the ability to detect a wide range of explosives in both the vapor state or as surface adsorbed solids, therefore, calibrations were designed to challenge the system with explosives in each form.

Semi-automated detection of trace explosives in fingerprints on strongly interfering surfaces with Raman chemical imaging.

PubMed

Tripathi, Ashish; Emmons, Erik D; Wilcox, Phillip G; Guicheteau, Jason A; Emge, Darren K; Christesen, Steven D; Fountain, Augustus W

2011-06-01

We have previously demonstrated the use of wide-field Raman chemical imaging (RCI) to detect and identify the presence of trace explosives in contaminated fingerprints. In this current work we demonstrate the detection of trace explosives in contaminated fingerprints on strongly Raman scattering surfaces such as plastics and painted metals using an automated background subtraction routine. We demonstrate the use of partial least squares subtraction to minimize the interfering surface spectral signatures, allowing the detection and identification of explosive materials in the corrected Raman images. The resulting analyses are then visually superimposed on the corresponding bright field images to physically locate traces of explosives. Additionally, we attempt to address the question of whether a complete RCI of a fingerprint is required for trace explosive detection or whether a simple non-imaging Raman spectrum is sufficient. This investigation further demonstrates the ability to nondestructively identify explosives on fingerprints present on commonly found surfaces such that the fingerprint remains intact for further biometric analysis.

Gas chromatography/ion mobility spectrometry as a hyphenated technique for improved explosives detection and analysis

NASA Technical Reports Server (NTRS)

Mercado, AL; Marsden, Paul

1995-01-01

Ion Mobility Spectrometry (IMS) is currently being successfully applied to the problem of on-line trace detection of plastic and other explosives in airports and other facilities. The methods of sample retrieval primarily consist of batch sampling for particulate residue on a filter card for introduction into the IMS. The sample is desorbed into the IMS using air as the carrier and negative ions of the explosives are detected, some as an adduct with a reagent ion such as Cl(-). Based on studies and tests conducted by different airport authorities, this method seems to work well for low vapor pressure explosives such as RDX and PETN, as well as TNT that are highly adsorptive and can be found in nanogram quantities on contaminated surfaces. Recently, the changing terrorist threat and the adoption of new marking agents for plastic explosives has meant that the sample introduction and analysis capabilities of the IMS must be enhanced in order to keep up with other detector developments. The IMS has sufficient analytical resolution for a few threat compounds but the IMS Plasmogram becomes increasingly more difficult to interpret when the sample mixture gets more complex.

Mid-infrared gas absorption sensor based on a broadband external cavity quantum cascade laser

NASA Astrophysics Data System (ADS)

Sun, Juan; Deng, Hao; Liu, Ningwu; Wang, Hongliang; Yu, Benli; Li, Jingsong

2016-12-01

We developed a laser absorption sensor based on a pulsed, broadband tunable external cavity quantum cascade laser (ECQCL) centered at 1285 cm-1. Unlike traditional infrared spectroscopy system, a quartz crystal tuning fork (QCTF) as a light detector was used for laser signal detection. Fast Fourier transform was applied to extract vibration intensity information of QCTF. The sensor system is successfully tested on nitrous oxide (N2O) spectroscopy measurements and compared with a standard infrared detector. The wide wavelength tunability of ECQCL will allow us to access the fundamental vibrational bands of many chemical agents, which are well-suited for trace explosive, chemical warfare agent, and toxic industrial chemical detection and spectroscopic analysis.

Mid-infrared gas absorption sensor based on a broadband external cavity quantum cascade laser.

PubMed

Sun, Juan; Deng, Hao; Liu, Ningwu; Wang, Hongliang; Yu, Benli; Li, Jingsong

2016-12-01

We developed a laser absorption sensor based on a pulsed, broadband tunable external cavity quantum cascade laser (ECQCL) centered at 1285 cm -1 . Unlike traditional infrared spectroscopy system, a quartz crystal tuning fork (QCTF) as a light detector was used for laser signal detection. Fast Fourier transform was applied to extract vibration intensity information of QCTF. The sensor system is successfully tested on nitrous oxide (N 2 O) spectroscopy measurements and compared with a standard infrared detector. The wide wavelength tunability of ECQCL will allow us to access the fundamental vibrational bands of many chemical agents, which are well-suited for trace explosive, chemical warfare agent, and toxic industrial chemical detection and spectroscopic analysis.

The limit of detection for explosives in spectroscopic differential reflectometry

NASA Astrophysics Data System (ADS)

Dubroca, Thierry; Vishwanathan, Karthik; Hummel, Rolf E.

2011-05-01

In the wake of recent terrorist attacks, such as the 2008 Mumbai hotel explosion or the December 25th 2009 "underwear bomber", our group has developed a technique (US patent #7368292) to apply differential reflection spectroscopy to detect traces of explosives. Briefly, light (200-500 nm) is shone on a surface such as a piece of luggage at an airport. Upon reflection, the light is collected with a spectrometer combined with a CCD camera. A computer processes the data and produces in turn a differential reflection spectrum involving two adjacent areas of the surface. This differential technique is highly sensitive and provides spectroscopic data of explosives. As an example, 2,4,6, trinitrotoluene (TNT) displays strong and distinct features in differential reflectograms near 420 nm. Similar, but distinctly different features are observed for other explosives. One of the most important criteria for explosive detection techniques is the limit of detection. This limit is defined as the amount of explosive material necessary to produce a signal to noise ratio of three. We present here, a method to evaluate the limit of detection of our technique. Finally, we present our sample preparation method and experimental set-up specifically developed to measure the limit of detection for our technology. This results in a limit ranging from 100 nano-grams to 50 micro-grams depending on the method and the set-up parameters used, such as the detector-sample distance.

Trace explosives sensor testbed (TESTbed)

NASA Astrophysics Data System (ADS)

Collins, Greg E.; Malito, Michael P.; Tamanaha, Cy R.; Hammond, Mark H.; Giordano, Braden C.; Lubrano, Adam L.; Field, Christopher R.; Rogers, Duane A.; Jeffries, Russell A.; Colton, Richard J.; Rose-Pehrsson, Susan L.

2017-03-01

A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation.

Reducing cross-sensitivity of TiO2-(B) nanowires to humidity using ultraviolet illumination for trace explosive detection.

PubMed

Wang, Danling; Chen, Antao; Jen, Alex K-Y

2013-04-14

Environmental humidity is an important factor that can influence the sensing performance of a metal oxide. TiO2-(B) in the form of nanowires has been demonstrated to be a promising material for the detection of explosive gases such as 2,4,6-trinitrotoluene (TNT). However, the elimination of cross-sensitivity of the explosive detectors based on TiO2-(B) toward environmental humidity is still a major challenge. It was found that the cross-sensitivity could be effectively modulated when the thin film of TiO2-(B) nanowires was exposed to ultraviolet (UV) light during the detection of explosives under operating conditions. Such a modulation of sensing responses of TiO2-(B) nanowires to explosives by UV light was attributed to a photocatalytic effect, with which the water adsorbed on the TiO2-(B) nanowire surface was split and therefore the sensor response performance was less affected. It was revealed that the cross-sensitivity could be suppressed up to 51% when exposed to UV light of 365 nm wavelength with an intensity of 40 mW cm(-2). This finding proves that the reduction of cross-sensitivity to humidity through UV irradiation is an effective approach that can improve the performance of a sensor based on TiO2-(B) nanowires for the detection of explosive gas.

A review on several key problems of standoff trace explosives detection by optical-related technology

NASA Astrophysics Data System (ADS)

Chen, Zhibin; Xiao, Cheng; Xiao, Wenjian; Qin, Mengze; Liu, Xianhong

2016-01-01

To prevent tragic disasters caused by terror acts and warfare threats, security check personnel must be capable of discovering, distinguishing and eliminating the explosives at multiple circumstances. Standoff technology for the remote detection of explosives and their traces on contaminated surfaces is a research field that has become a heightened priority in recent years for homeland security and counter-terrorism applications. There has been a huge increase in research within this area, the improvement of standoff trace explosives detection by optical-related technology. This paper provides a consolidation of information relating to recent advances in several key problems of, without being limited to one specific research area or explosive type. Working laser wavelength of detection system is discussed. Generation and collection of explosives spectra signal are summarized. Techniques for analysing explosives spectra signal are summed up.

Photothermal trace detection in capillary electrophoresis for biomedical diagnostics and toxic materials (invited)

NASA Astrophysics Data System (ADS)

Faubel, Werner; Heissler, Stefan; Pyell, Ute; Ragozina, Natalia

2003-01-01

Two applications of a near-field thermal lens capillary electrophoresis detector in the deep ultraviolet region (pump beam 257 nm wavelength) will be presented: (1) Capillary electrophoretic determination of the pharmaceuticals Tramadol, Verapamil, and Papaverin. Direct separation techniques were used for the different classes of substances with characteristic absorbance spectra. The combination of capillary electrophoresis and the highly sensitive detection with thermal lens spectroscopy permits the analysis of nanoliter volume samples common in biomedical diagnostics without any preconcentration step. (2) The determination of (nonfluorescent) nitro aromatic explosives in contaminated soil. These compounds are detected with the laboratory built thermal lens detector after their separation by micellar electrokinetic chromatography. Its shown that this type of detection makes it possible to obtain limits of detection 1-2 orders of magnitude lower than those obtained with classical absorption spectrometric detection.

Photoacoustic Spectroscopy for Trace Vapor Detection and Standoff Detection of Explosives

DTIC Science & Technology

2016-08-01

ARL-RP-0577 ● AUG 2016 US Army Research Laboratory Photoacoustic Spectroscopy for Trace Vapor Detection and Standoff Detection...Photoacoustic Spectroscopy for Trace Vapor Detection and Standoff Detection of Explosives by Ellen L Holthoff and Paul M Pellegrino Sensors and Electron...

Hyperspectral image analysis for standoff trace detection using IR laser spectroscopy

NASA Astrophysics Data System (ADS)

Jarvis, J.; Fuchs, F.; Hugger, S.; Ostendorf, R.; Butschek, L.; Yang, Q.; Dreyhaupt, A.; Grahmann, J.; Wagner, J.

2016-05-01

In the recent past infrared laser backscattering spectroscopy using Quantum Cascade Lasers (QCL) emitting in the molecular fingerprint region between 7.5 μm and 10 μm proved a highly promising approach for stand-off detection of dangerous substances. In this work we present an active illumination hyperspectral image sensor, utilizing QCLs as spectral selective illumination sources. A high performance Mercury Cadmium Telluride (MCT) imager is used for collection of the diffusely backscattered light. Well known target detection algorithms like the Adaptive Matched Subspace Detector and the Adaptive Coherent Estimator are used to detect pixel vectors in the recorded hyperspectral image that contain traces of explosive substances like PETN, RDX or TNT. In addition we present an extension of the backscattering spectroscopy technique towards real-time detection using a MOEMS EC-QCL.

Detection of nitro-based and peroxide-based explosives by fast polarity-switchable ion mobility spectrometer with ion focusing in vicinity of Faraday detector.

PubMed

Zhou, Qinghua; Peng, Liying; Jiang, Dandan; Wang, Xin; Wang, Haiyan; Li, Haiyang

2015-05-29

Ion mobility spectrometer (IMS) has been widely deployed for on-site detection of explosives. The common nitro-based explosives are usually detected by negative IMS while the emerging peroxide-based explosives are better detected by positive IMS. In this study, a fast polarity-switchable IMS was constructed to detect these two explosive species in a single measurement. As the large traditional Faraday detector would cause a trailing reactant ion peak (RIP), a Faraday detector with ion focusing in vicinity was developed by reducing the detector radius to 3.3 mm and increasing the voltage difference between aperture grid and its front guard ring to 591 V, which could remove trailing peaks from RIP without loss of signal intensity. This fast polarity-switchable IMS with ion focusing in vicinity of Faraday detector was employed to detect a mixture of 10 ng 2,4,6-trinitrotoluene (TNT) and 50 ng hexamethylene triperoxide diamine (HMTD) by polarity-switching, and the result suggested that [TNT-H](-) and [HMTD+H](+) could be detected in a single measurement. Furthermore, the removal of trailing peaks from RIP by the Faraday detector with ion focusing in vicinity also promised the accurate identification of KClO4, KNO3 and S in common inorganic explosives, whose product ion peaks were fairly adjacent to RIP.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burrows, T.A.; Thoma, P.J.

Two types of ion-mobility detectors were evaluated in both laboratory and field tests. Laboratory test results show that these detectors are highly sensitive to dynamite and pistol powder and have good false-alarm agent rejection. Field tests of these two detectors revealed that they would detect dynamite and Ball-C-Propellent in free air. However, neither of the ion-mobility detectors would detect these explosives if the explosives were concealed.

Microbial bioreporters of trace explosives.

PubMed

Shemer, Benjamin; Koshet, Ori; Yagur-Kroll, Sharon; Belkin, Shimshon

2017-06-01

Since its introduction as an explosive in the late 19th century, 2,4,6-trinitrotoluene (TNT), along with other explosive compounds, has left numerous environmental marks. One of these is widespread soil and water pollution by trace explosives in military proving grounds, manufacturing facilities, or actual battlefields. Another dramatic impact is that exerted by the millions of landmines and other explosive devices buried in large parts of the world, causing extensive loss of life, injuries, and economical damage. In this review we highlight recent advances in the design and construction of microbial bioreporters, molecularly engineered to generate a quantifiable dose-dependent signal in the presence of trace amounts of explosives. Such sensor strains may be employed for monitoring environmental pollution as well as for the remote detection of buried landmines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laser-based standoff detection of explosives: a critical review.

PubMed

Wallin, Sara; Pettersson, Anna; Ostmark, Henric; Hobro, Alison

2009-09-01

A review of standoff detection technologies for explosives has been made. The review is focused on trace detection methods (methods aiming to detect traces from handling explosives or the vapours surrounding an explosive charge due to the vapour pressure of the explosive) rather than bulk detection methods (methods aiming to detect the bulk explosive charge). The requirements for standoff detection technologies are discussed. The technologies discussed are mostly laser-based trace detection technologies, such as laser-induced-breakdown spectroscopy, Raman spectroscopy, laser-induced-fluorescence spectroscopy and IR spectroscopy but the bulk detection technologies millimetre wave imaging and terahertz spectroscopy are also discussed as a complement to the laser-based methods. The review includes novel techniques, not yet tested in realistic environments, more mature technologies which have been tested outdoors in realistic environments as well as the most mature millimetre wave imaging technique.

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

NASA Astrophysics Data System (ADS)

Miller, C. J.; Yoder, T. S.

2010-06-01

Explosive trace detection equipment has been deployed to airports for more than a decade. During this time, the need for standardized procedures and calibrated trace amounts for ensuring that the systems are operating properly and detecting the correct explosive has been apparent but a standard representative of a fingerprint has been elusive. Standards are also necessary to evaluate instrumentation in the laboratories during development and prior to deployment to determine sample throughput, probability of detection, false positive/negative rates, ease of use by operator, mechanical and/or software problems that may be encountered, and other pertinent parameters that would result in the equipment being unusable during field operations. Since many laboratories do not have access to nor are allowed to handle explosives, the equipment is tested using techniques aimed at simulating the actual explosives fingerprint. This laboratory study focused on examining the similarities and differences in three different surface contamination techniques that are used to performance test explosive trace detection equipment in an attempt to determine how effective the techniques are at replicating actual field samples and to offer scenarios where each contamination technique is applicable. The three techniques used were dry transfer deposition of standard solutions using the Transportation Security Laboratory’s (TSL) patented dry transfer techniques (US patent 6470730), direct deposition of explosive standards onto substrates, and fingerprinting of actual explosives onto substrates. RDX was deposited on the surface of one of five substrates using one of the three different deposition techniques. The process was repeated for each substrate type using each contamination technique. The substrate types used were: 50% cotton/50% polyester as found in T-shirts, 100% cotton with a smooth surface such as that found in a cotton dress shirt, 100% cotton on a rough surface such as that found on canvas or denim, suede leather such as might be found on jackets, purses, or shoes, and painted metal obtained from a car hood at a junk yard. The samples were not pre-cleaned prior to testing and contained sizing agents, and in the case of the metal, oil and dirt. The substrates were photographed using a Zeiss Discover V12 stereoscope with Axiocam ICc1 3 megapixel digital camera to determine the difference in the crystalline structure and surface contamination in an attempt to determine differences and similarities associated with current contamination deposition techniques. Some samples were analyzed using scanning electron microscopy (SEM) and some were extracted and analyzed with high performance liquid chromatography (HPLC) or gas chromatography with an electron capture detector (GC-ECD) to quantify the data.

Continuous-wave deep ultraviolet sources for resonance Raman explosive sensing

NASA Astrophysics Data System (ADS)

Yellampalle, Balakishore; Martin, Robert; Sluch, Mikhail; McCormick, William; Ice, Robert; Lemoff, Brian

2015-05-01

A promising approach to stand-off detection of explosive traces is using resonance Raman spectroscopy with Deepultraviolet (DUV) light. The DUV region offers two main advantages: strong explosive signatures due to resonant and λ- 4 enhancement of Raman cross-section, and lack of fluorescence and solar background. For DUV Raman spectroscopy, continuous-wave (CW) or quasi-CW lasers are preferable to high peak powered pulsed lasers because Raman saturation phenomena and sample damage can be avoided. In this work we present a very compact DUV source that produces greater than 1 mw of CW optical power. The source has high optical-to-optical conversion efficiency, greater than 5 %, as it is based on second harmonic generation (SHG) of a blue/green laser source using a nonlinear crystal placed in an external resonant enhancement cavity. The laser system is extremely compact, lightweight, and can be battery powered. Using two such sources, one each at 236.5 nm and 257.5 nm, we are building a second generation explosive detection system called Dual-Excitation-Wavelength Resonance-Raman Detector (DEWRRED-II). The DEWRRED-II system also includes a compact dual-band high throughput DUV spectrometer, and a highly-sensitive detection algorithm. The DEWRRED technique exploits the DUV excitation wavelength dependence of Raman signal strength, arising from complex interplay of resonant enhancement, self-absorption and laser penetration depth. We show sensor measurements from explosives/precursor materials at different standoff distances.

Laboratory evaluation of detectors of explosives' effluents

DOT National Transportation Integrated Search

1972-11-30

This document contains the classification, technical description and laboratory evaluation of five commercial detectors for explosives' effluents. It includes an outline of operating principles, test and evaluation procedures. The evaluation is based...

Visual detection of trace nitroaromatic explosive residue using photoluminescent metallole-containing polymers.

PubMed

Toal, Sarah J; Sanchez, Jason C; Dugan, Regina E; Trogler, William C

2007-01-01

The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4-dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole-containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (lambda(em) approximately 400-510 nm) in the presence of the explosive is seen immediately upon illumination with near-UV light (lambda(ex)=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.

Design optimization of Cassegrain telescope for remote explosive trace detection

NASA Astrophysics Data System (ADS)

Bhavsar, Kaushalkumar; Eseller, K. E.; Prabhu, Radhakrishna

2017-10-01

The past three years have seen a global increase in explosive-based terror attacks. The widespread use of improvised explosives and anti-personnel landmines have caused thousands of civilian casualties across the world. Current scenario of globalized civilization threat from terror drives the need to improve the performance and capabilities of standoff explosive trace detection devices to be able to anticipate the threat from a safe distance to prevent explosions and save human lives. In recent years, laser-induced breakdown spectroscopy (LIBS) is an emerging approach for material or elemental investigations. All the principle elements on the surface are detectable in a single measurement using LIBS and hence, a standoff LIBS based method has been used to remotely detect explosive traces from several to tens of metres distance. The most important component of LIBS based standoff explosive trace detection system is the telescope which enables remote identification of chemical constituents of the explosives. However, in a compact LIBS system where Cassegrain telescope serves the purpose of laser beam delivery and light collection, need a design optimization of the telescope system. This paper reports design optimization of a Cassegrain telescope to detect explosives remotely for LIBS system. A design optimization of Schmidt corrector plate was carried out for Nd:YAG laser. Effect of different design parameters was investigated to eliminate spherical aberration in the system. Effect of different laser wavelengths on the Schmidt corrector design was also investigated for the standoff LIBS system.

Threshold magnitudes for a multichannel correlation detector in background seismicity

DOE PAGES

Carmichael, Joshua D.; Hartse, Hans

2016-04-01

Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannelmore » waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes m b = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.« less

Method and system for detecting explosives

DOEpatents

Reber, Edward L [Idaho Falls, ID; Jewell, James K [Idaho Falls, ID; Rohde, Kenneth W [Idaho Falls, ID; Seabury, Edward H [Idaho Falls, ID; Blackwood, Larry G [Idaho Falls, ID; Edwards, Andrew J [Idaho Falls, ID; Derr, Kurt W [Idaho Falls, ID

2009-03-10

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Explosives detection system and method

DOEpatents

Reber, Edward L.; Jewell, James K.; Rohde, Kenneth W.; Seabury, Edward H.; Blackwood, Larry G.; Edwards, Andrew J.; Derr, Kurt W.

2007-12-11

A method of detecting explosives in a vehicle includes providing a first rack on one side of the vehicle, the rack including a neutron generator and a plurality of gamma ray detectors; providing a second rack on another side of the vehicle, the second rack including a neutron generator and a plurality of gamma ray detectors; providing a control system, remote from the first and second racks, coupled to the neutron generators and gamma ray detectors; using the control system, causing the neutron generators to generate neutrons; and performing gamma ray spectroscopy on spectra read by the gamma ray detectors to look for a signature indicative of presence of an explosive. Various apparatus and other methods are also provided.

Characterization and Performance Evaluation of an HPXe Detector for Nuclear Explosion Monitoring Applications

DTIC Science & Technology

2007-09-01

performance of the detector, and to compare the performance with sodium iodide and germanium detectors. Monte Carlo ( MCNP ) simulation was used to...aluminum ~50% more efficient), and to estimate optimum shield dimensions for an HPXe based nuclear explosion monitor. MCNP modeling was also used to...detector were calculated with MCNP by using input activity levels as measured in routine NEM runs at Pacific Northwest National Laboratory (PNNL

Transport of explosives I: TNT in soil and its equilibrium vapor

NASA Astrophysics Data System (ADS)

Baez, Bibiana; Correa, Sandra N.; Hernandez-Rivera, Samuel P.; de Jesus, Maritza; Castro, Miguel E.; Mina, Nairmen; Briano, Julio G.

2004-09-01

Landmine detection is an important task for military operations and for humanitarian demining. Conventional methods for landmine detection involve measurements of physical properties. Several of these methods fail on the detection of modern mines with plastic enclosures. Methods based on the detection signature explosives chemicals such as TNT and DNT are specific to landmines and explosive devices. However, such methods involve the measurements of the vapor trace, which can be deceiving of the actual mine location because of the complex transport phenomena that occur in the soil neighboring the buried landmine. We report on the results of the study of the explosives subject to similar environmental conditions as the actual mines. Soil samples containing TNT were used to study the effects of aging, temperature and moisture under controlled conditions. The soil used in the investigation was Ottawa sand. A JEOL GCMate II gas chromatograph +/- mass spectrometer coupled to a Tunable Electron Energy Monochromator (TEEM-GC/MS) was used to develop the method of analysis of explosives under enhanced detection conditions. Simultaneously, a GC with micro cell 63Ni, Electron Capture Detector (μECD) was used for analysis of TNT in sand. Both techniques were coupled with Solid-Phase Micro Extraction (SPME) methodology to collect TNT doped sand samples. The experiments were done in both, headspace and immersion modes of SPME for sampling of explosives. In the headspace experiments it was possible to detect appreciable TNT vapors as early as 1 hour after of preparing the samples, even at room temperature (20 °C). In the immersion experiments, I-SPME technique allowed for the detection of concentrations as low as 0.010 mg of explosive per kilogram of soil.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmichael, Joshua D.; Hartse, Hans

Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannelmore » waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes m b = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.« less

Laser Desorption of Explosives Traces with Low Vapors Pressure

NASA Astrophysics Data System (ADS)

Akmalov, A. E.; Chistyakov, A. A.; Kotkovskii, G. E.

In this work comparison of the desorption effectiveness of picosecond and nanosecond laser sources (λ = 266, 532 nm) were carried out to investigate the possibility of creating a non-contact sampling device for detectors of explosives on the principles of ion mobility spectrometry (IMS) and field asymmetric ion mobility spectrometry (FAIMS). The results of mass spectrometric studies of TNT (2,4,6-Trinitrotoluene), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), RDX (1,3,5-Trinitro-1,3,5-triazacyclohexane) laser desorption from a quartz substrate are presented. It is shown that the most effective laser source is a Nd:YAG3+ laser (λ = 266 nm; E = 1 mJ; τ = 5-10 ns; q = 108 W/cm2). The typical desorbed mass is 2 ng for RDX, 4-6 ng for TNT and 0.02 ng HMX per single laser pulse. The results obtained make it possible to create a non-contact portable laser sampling device operating in frequency mode with high efficiency.

Microcantilever technology for law enforcement and anti-terrorism applications: chemical, biological, and explosive material detection

NASA Astrophysics Data System (ADS)

Adams, J. D.; Rogers, B.; Whitten, R.

2005-05-01

The remarkable sensitivity, compactness, low cost, low power-consumption, scalability, and versatility of microcantilever sensors make this technology among the most promising solutions for detection of chemical and biological agents, as well as explosives. The University of Nevada, Reno, and Nevada Nanotech Systems, Inc (NNTS) are currently developing a microcantilever-based detection system that will measure trace concentrations of explosives, toxic chemicals, and biological agents in air. A baseline sensor unit design that includes the sensor array, electronics, power supply and air handling has been created and preliminary demonstrations of the microcantilever platform have been conducted. The envisioned device would measure about two cubic inches, run on a small watch battery and cost a few hundred dollars. The device could be operated by untrained law enforcement personnel. Microcantilever-based devices could be used to "sniff out" illegal and/or hazardous chemical and biological agents in high traffic public areas, or be packaged as a compact, low-power system used to monitor cargo in shipping containers. Among the best detectors for such applications at present is the dog, an animal which is expensive, requires significant training and can only be made to work for limited time periods. The public is already accustomed to explosives and metal detection systems in airports and other public venues, making the integration of the proposed device into such security protocols straightforward.

Why Waveform Correlation Sometimes Fails

NASA Astrophysics Data System (ADS)

Carmichael, J.

2015-12-01

Waveform correlation detectors used in explosion monitoring scan noisy geophysical data to test two competing hypotheses: either (1) an amplitude-scaled version of a template waveform is present, or, (2) no signal is present at all. In reality, geophysical wavefields that are monitored for explosion signatures include waveforms produced by non-target sources that are partially correlated with the waveform template. Such signals can falsely trigger correlation detectors, particularly at low thresholds required to monitor for smaller target explosions. This challenge is particularly formidable when monitoring known test sites for seismic disturbances, since uncatalogued natural seismicity is (generally) more prevalent at lower magnitudes, and could be mistaken for small explosions. To address these challenges, we identify real examples in which correlation detectors targeting explosions falsely trigger on both site-proximal earthquakes (Figure 1, below) and microseismic "noise". Motivated by these examples, we quantify performance loss when applying these detectors, and re-evaluate the correlation-detector's hypothesis test. We thereby derive new detectors from more general hypotheses that admit unknown background seismicity, and apply these to real data. From our treatment, we derive "rules of thumb'' for proper template and threshold selection in heavily cluttered signal environments. Last, we answer the question "what is the probability of falsely detecting an earthquake collocated at a test site?", using correlation detectors that include explosion-triggered templates. Figure Top: An eight-channel data stream (black) recorded from an earthquake near a mine. Red markers indicate a detection. Middle: The correlation statistic computed by scanning the template against the data stream at top. The red line indicates the threshold for event declaration, determined by a false-alarm on noise probability constraint, as computed from the signal-absent distribution using the Neyman Pearson criteria. Bottom: The histogram of the correlation statistic time series (gray) superimposed on the theoretical null distribution (black curve). The line shows the threshold, consistent with a right-tail probability, computed from the black curve.

Development of a Coded Aperture X-Ray Backscatter Imager for Explosive Device Detection

NASA Astrophysics Data System (ADS)

Faust, Anthony A.; Rothschild, Richard E.; Leblanc, Philippe; McFee, John Elton

2009-02-01

Defence R&D Canada has an active research and development program on detection of explosive devices using nuclear methods. One system under development is a coded aperture-based X-ray backscatter imaging detector designed to provide sufficient speed, contrast and spatial resolution to detect antipersonnel landmines and improvised explosive devices. The successful development of a hand-held imaging detector requires, among other things, a light-weight, ruggedized detector with low power requirements, supplying high spatial resolution. The University of California, San Diego-designed HEXIS detector provides a modern, large area, high-temperature CZT imaging surface, robustly packaged in a light-weight housing with sound mechanical properties. Based on the potential for the HEXIS detector to be incorporated as the detection element of a hand-held imaging detector, the authors initiated a collaborative effort to demonstrate the capability of a coded aperture-based X-ray backscatter imaging detector. This paper will discuss the landmine and IED detection problem and review the coded aperture technique. Results from initial proof-of-principle experiments will then be reported.

Quantifying the stability of trace explosives under different environmental conditions using electrospray ionization mass spectrometry.

PubMed

Sisco, Edward; Najarro, Marcela; Samarov, Daniel; Lawrence, Jeffrey

2017-04-01

This work investigates the stability of trace (tens of nanograms) deposits of six explosives: erythritol tetranitrate (ETN), pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), and 2,4,6-trinitrophenylmethylnitramine (tetryl) to determine environmental stabilities and lifetimes of trace level materials. Explosives were inkjet printed directly onto substrates and exposed to one of seven environmental conditions (Laboratory, -4°C, 30°C, 47°C, 90% relative humidity, UV light, and ozone) up to 42 days. Throughout the study, samples were extracted and quantified using electrospray ionization mass spectrometry (ESI-MS) to determine the stability of the explosive as a function of time and environmental exposure. Statistical models were then fit to the data and used for pairwise comparisons of the environments. Stability was found to be exposure and compound dependent with minimal sample losses observed for HMX, RDX, and PETN while substantial and rapid losses were observed in all conditions except -4°C for ETN and TNT and in all conditions for tetryl. The results of this work highlight the potential fate of explosive traces when exposed to various environments. Published by Elsevier B.V.

Quantifying the Stability of Trace Explosives under Different Environmental Conditions using Electrospray Ionization Mass Spectrometry

PubMed Central

Sisco, Edward; Najarro, Marcela; Samarov, Daniel; Lawrence, Jeffrey

2017-01-01

This work investigates the stability of trace (tens of nanograms) deposits of six explosives: erythritol tetranitrate (ETN), pentaerythritol tetranitrate (PETN), cyclotrimethylenetrinitramine (RDX), cyclotetramethylenetetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), and 2,4,6-trinitrophenylmethylnitramine (tetryl) to determine environmental stabilities and lifetimes of trace level materials. Explosives were inkjet printed directly onto substrates and exposed to one of seven environmental conditions (Laboratory, −4 °C, 30 °C, 47 °C, 90 % relative humidity, UV light, and ozone) up to 42 days. Throughout the study, samples were extracted and quantified using electrospray ionization mass spectrometry (ESI-MS) to determine the stability of the explosive as a function of time and environmental exposure. Statistical models were then fit to the data and used for pairwise comparisons of the environments. Stability was found to be exposure and compound dependent with minimal sample losses observed for HMX, RDX, and PETN while substantial and rapid losses were observed in all conditions except −4 °C for ETN and TNT and in all conditions for tetryl. The results of this work highlight the potential fate of explosive traces when exposed to various environments. PMID:28153227

Simulations of Si-PIN photodiode based detectors for underground explosives enhanced by ammonium nitrate

NASA Astrophysics Data System (ADS)

Yücel, Mete; Bayrak, Ahmet; Yücel, Esra Barlas; Ozben, Cenap S.

2018-02-01

Massive Ammonium Nitrate (NH4-NO3) based explosives buried underground are commonly used in terror attacks. These explosives can be detected using neutron scattering method with some limitations. Simulations are very useful tools for designing a possible detection system for these kind of explosives. Geant4 simulations were used for generating neutrons at 14 MeV energy and tracking them through the scattering off the explosive embedded in soil. Si-PIN photodiodes were used as detector elements in the design for their low costs and simplicity for signal readout electronics. Various neutron-charge particle converters were applied on to the surface of the photodiodes to increase the detection efficiency. Si-PIN photodiodes coated with 6LiF provided the best result for a certain energy interval. Energy depositions in silicon detector from all secondary particles generated including photons were taken into account to generate a realistic background. Humidity of soil, one of the most important parameter for limiting the detection, was also studied.

Target detection portal

DOEpatents

Linker, Kevin L.; Brusseau, Charles A.

2002-01-01

A portal apparatus for screening persons or objects for the presence of trace amounts of target substances such as explosives, narcotics, radioactive materials, and certain chemical materials. The portal apparatus can have a one-sided exhaust for an exhaust stream, an interior wall configuration with a concave-shape across a horizontal cross-section for each of two facing sides to result in improved airflow and reduced washout relative to a configuration with substantially flat parallel sides; air curtains to reduce washout; ionizing sprays to collect particles bound by static forces, as well as gas jet nozzles to dislodge particles bound by adhesion to the screened person or object. The portal apparatus can be included in a detection system with a preconcentrator and a detector.

In-injection port thermal desorption for explosives trace evidence analysis.

PubMed

Sigman, M E; Ma, C Y

1999-10-01

A gas chromatographic method utilizing thermal desorption of a dry surface wipe for the analysis of explosives trace chemical evidence has been developed and validated using electron capture and negative ion chemical ionization mass spectrometric detection. Thermal desorption was performed within a split/splitless injection port with minimal instrument modification. Surface-abraded Teflon tubing provided the solid support for sample collection and desorption. Performance was characterized by desorption efficiency, reproducibility, linearity of the calibration, and method detection and quantitation limits. Method validation was performed with a series of dinitrotoluenes, trinitrotoluene, two nitroester explosives, and one nitramine explosive. The method was applied to the sampling of a single piece of debris from an explosion containing trinitrotoluene.

Electrode configuration and signal subtraction technique for single polarity charge carrier sensing in ionization detectors

DOEpatents

Luke, Paul

1996-01-01

An ionization detector electrode and signal subtraction apparatus and method provides at least one first conductive trace formed onto the first surface of an ionization detector. The first surface opposes a second surface of the ionization detector. At least one second conductive trace is also formed on the first surface of the ionization detector in a substantially interlaced and symmetrical pattern with the at least one first conductive trace. Both of the traces are held at a voltage potential of a first polarity type. By forming the traces in a substantially interlaced and symmetric pattern, signals generated by a charge carrier are substantially of equal strength with respect to both of the traces. The only significant difference in measured signal strength occurs when the charge carrier moves to within close proximity of the traces and is received at the collecting trace. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge and to determine the position at which the charge carrier originated within the ionization detector.

Electrode configuration and signal subtraction technique for single polarity charge carrier sensing in ionization detectors

DOEpatents

Luke, P.

1996-06-25

An ionization detector electrode and signal subtraction apparatus and method provide at least one first conductive trace formed onto the first surface of an ionization detector. The first surface opposes a second surface of the ionization detector. At least one second conductive trace is also formed on the first surface of the ionization detector in a substantially interlaced and symmetrical pattern with the at least one first conductive trace. Both of the traces are held at a voltage potential of a first polarity type. By forming the traces in a substantially interlaced and symmetric pattern, signals generated by a charge carrier are substantially of equal strength with respect to both of the traces. The only significant difference in measured signal strength occurs when the charge carrier moves to within close proximity of the traces and is received at the collecting trace. The measured signals are then subtracted and compared to quantitatively measure the magnitude of the charge and to determine the position at which the charge carrier originated within the ionization detector. 9 figs.

Photo-vibrational sensing of trace chemicals and explosives by long-distance differential laser Doppler vibrometer

NASA Astrophysics Data System (ADS)

Fu, Yu; Liu, Huan; Hu, Qi; Xie, Jiecheng

2017-05-01

Photoacoustic/photothermal spectroscopy is an established technique for trace detection of chemicals and explosives. Normally high-sensitive microphone or PZT sensor is used to detect the signal in photoacoustic cell. In recent years, laser Doppler vibrometer (LDV) is proposed to remote-sense photoacoustic signal on various substrates. It is a highsensitivity sensor with a displacement resolution of <10pm. In this research, the photoacoustic effect of various chemicals and explosives is excited by a quantum cascade laser (QCL) at their absorbance peak. A home-developed differential LDV at 1550nm wavelength is applied to detect the vibration signal at 100m. A differential configuration is applied to minimize the environment factors, such as environment noise and vibration, air turbulence, etc. and increase the detection sensitivity. The photo-vibrational signal of chemicals and explosives on different substrates are detected. The results show the potential of the proposed technique on detection of trace chemicals and explosives at long standoff distance.

A Photoluminescence-Based Field Method for Detection of Traces of Explosives

PubMed Central

Menzel, E. Roland; Menzel, Laird W.; Schwierking, Jake R.

2004-01-01

We report a photoluminescence-based field method for detecting traces of explosives. In its standard version, the method utilizes a commercially available color spot test kit for treating explosive traces on filter paper after swabbing. The colored products are fluorescent under illumination with a laser that operates on three C-size flashlight batteries and delivers light at 532 nm. In the fluorescence detection mode, by visual inspection, the typical sensitivity gain is a factor of 100. The method is applicable to a wide variety of explosives. In its time-resolved version, intended for in situ work, explosives are tagged with europium complexes. Instrumentation-wise, the time-resolved detection, again visual, can be accomplished in facile fashion. The europium luminescence excitation utilizes a laser operating at 355 nm. We demonstrate the feasibility of CdSe quantum dot sensitization of europium luminescence for time-resolved purposes. This would allow the use of the above 532 nm laser. PMID:15349512

Novel laser induced photoacoustic spectroscopy for instantaneous trace detection of explosive materials.

PubMed

El-Sharkawy, Yasser H; Elbasuney, Sherif

2017-08-01

Laser photoacoustic spectroscopy (LPAS) is an attractive technology in terms of simplicity, ruggedness, and overall sensitivity; it detects the time dependent heat generated (thermo-elastic effect) in the target via interaction with pulsed optical radiation. This study reports on novel LPAS technique that offers instant and standoff detection capabilities of trace explosives. Over the current study, light is generated using pulsed Q-switched Nd:YAG laser; the generated photoacoustic response in stimulated explosive material offers signature values that depend on the optical, thermal, and acoustical properties. The generated acoustic waves were captured using piezoelectric transducer as well as novel customized optical sensor with remotely laser interferometer probe. A digital signal processing algorithm was employed to identify explosive material signatures via calculation of characteristic optical properties (absorption coefficient), sound velocity, and frequency response of the generated photoacoustic signal. Customized LPAS technique was employed for instantaneous trace detection of three main different high explosive materials including TNT, RDX, and HMX. The main outcome of this study is that the novel customized optical sensor signals were validated with traditional piezoelectric transducer. Furthermore, the customized optical sensor offered standoff detection capabilities (10cm), fast response, high sensitivity, and enhanced signal to noise ratio. This manuscript shaded the light on the instant detection of trace explosive materials from significant standoffs using novel customized LPAS technique. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent advances and remaining challenges for the spectroscopic detection of explosive threats.

PubMed

Fountain, Augustus W; Christesen, Steven D; Moon, Raphael P; Guicheteau, Jason A; Emmons, Erik D

2014-01-01

In 2010, the U.S. Army initiated a program through the Edgewood Chemical Biological Center to identify viable spectroscopic signatures of explosives and initiate environmental persistence, fate, and transport studies for trace residues. These studies were ultimately designed to integrate these signatures into algorithms and experimentally evaluate sensor performance for explosives and precursor materials in existing chemical point and standoff detection systems. Accurate and validated optical cross sections and signatures are critical in benchmarking spectroscopic-based sensors. This program has provided important information for the scientists and engineers currently developing trace-detection solutions to the homemade explosive problem. With this information, the sensitivity of spectroscopic methods for explosives detection can now be quantitatively evaluated before the sensor is deployed and tested.

Screening for trace explosives by AccuTOF™-DART®: an in-depth validation study.

PubMed

Sisco, Edward; Dake, Jeffrey; Bridge, Candice

2013-10-10

Ambient ionization mass spectrometry is finding increasing utility as a rapid analysis technique in a number of fields. In forensic science specifically, analysis of many types of samples, including drugs, explosives, inks, bank dye, and lotions, has been shown to be possible using these techniques [1]. This paper focuses on one type of ambient ionization mass spectrometry, Direct Analysis in Real Time Mass Spectrometry (DART-MS or DART), and its viability as a screening tool for trace explosives analysis. In order to assess viability, a validation study was completed which focused on the analysis of trace amounts of nitro and peroxide based explosives. Topics which were studied, and are discussed, include method optimization, reproducibility, sensitivity, development of a search library, discrimination of mixtures, and blind sampling. Advantages and disadvantages of this technique over other similar screening techniques are also discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Artificial Olfactory System for Trace Identification of Explosive Vapors Realized by Optoelectronic Schottky Sensing.

PubMed

Guo, Linjuan; Yang, Zheng; Dou, Xincun

2017-02-01

A rapid, ultrasensitive artificial olfactory system based on an individual optoelectronic Schottky junction is demonstrated for the discriminative detection of explosive vapors, including military explosives and improvised explosives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Progressing the analysis of Improvised Explosive Devices: Comparative study for trace detection of explosive residues in handprints by Raman spectroscopy and liquid chromatography.

PubMed

Zapata, Félix; de la Ossa, Mª Ángeles Fernández; Gilchrist, Elizabeth; Barron, Leon; García-Ruiz, Carmen

2016-12-01

Concerning the dreadful global threat of terrorist attacks, the detection of explosive residues in biological traces and marks is a current need in both forensics and homeland security. This study examines the potential of Raman microscopy in comparison to liquid chromatography (ion chromatography (IC) and reversed-phase high performance liquid chromatography (RP-HPLC)) to detect, identify and quantify residues in human handmarks of explosives and energetic salts commonly used to manufacture Improvised Explosive Devices (IEDs) including dynamite, ammonium nitrate, single- and double-smokeless gunpowders and black powder. Dynamite, ammonium nitrate and black powder were detected through the identification of the energetic salts by Raman spectroscopy, their respective anions by IC, and organic components by RP-HPLC. Smokeless gunpowders were not detected, either by Raman spectroscopy or the two liquid chromatography techniques. Several aspects of handprint collection, sample treatment and a critical comparison of the identification of compounds by both techniques are discussed. Raman microscopy and liquid chromatography were shown to be complementary to one another offering more comprehensive information for trace explosives analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Explosive detection using high-volume vapor sampling and analysis by trained canines and ultra-trace detection equipment

NASA Astrophysics Data System (ADS)

Fisher, Mark; Sikes, John; Prather, Mark

2004-09-01

The dog's nose is an effective, highly-mobile sampling system, while the canine olfactory organs are an extremely sensitive detector. Having been trained to detect a wide variety of substances with exceptional results, canines are widely regarded as the 'gold standard' in chemical vapor detection. Historically, attempts to mimic the ability of dogs to detect vapors of explosives using electronic 'dogs noses' has proven difficult. However, recent advances in technology have resulted in development of detection (i.e., sampling and sensor) systems with performance that is rapidly approaching that of trained canines. The Nomadics Fido was the first sensor to demonstrate under field conditions the detection of landmines with performance approaching that of canines. More recently, comparative testing of Fido against canines has revealed that electronic vapor detection, when coupled with effective sampling methods, can produce results comparable to that of highly-trained canines. The results of these comparative tests will be presented, as will recent test results in which explosives hidden in cargo were detected using Fido with a high-volume sampling technique. Finally, the use of canines along with electronic sensors will be discussed as a means of improving the performance and expanding the capabilities of both methods.

Printable sensors for explosive detonation

NASA Astrophysics Data System (ADS)

Griffith, Matthew J.; Cooling, Nathan A.; Elkington, Daniel C.; Muller, Elmar; Belcher, Warwick J.; Dastoor, Paul C.

2014-10-01

Here, we report the development of an organic thin film transistor (OTFT) based on printable solution processed polymers and employing a quantum tunnelling composite material as a sensor to convert the pressure wave output from detonation transmission tubing (shock tube) into an inherently amplified electronic signal for explosives initiation. The organic electronic detector allows detection of the signal in a low voltage operating range, an essential feature for sites employing live ordinances that is not provided by conventional electronic devices. We show that a 30-fold change in detector response is possible using the presented detector assembly. Degradation of the OTFT response with both time and repeated voltage scans was characterised, and device lifetime is shown to be consistent with the requirements for on-site printing and usage. The integration of a low cost organic electronic detector with inexpensive shock tube transmission fuse presents attractive avenues for the development of cheap and simple assemblies for precisely timed initiation of explosive chains.

49 CFR 1544.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2013 CFR

2013-10-01

... provided in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, or a physical...) Preventing or deterring the carriage of any explosive or incendiary. Each aircraft operator operating under a...

49 CFR 1544.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2011 CFR

2011-10-01

... provided in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, or a physical...) Preventing or deterring the carriage of any explosive or incendiary. Each aircraft operator operating under a...

49 CFR 1544.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2012 CFR

2012-10-01

... provided in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, or a physical...) Preventing or deterring the carriage of any explosive or incendiary. Each aircraft operator operating under a...

49 CFR 1544.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2014 CFR

2014-10-01

... provided in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, or a physical...) Preventing or deterring the carriage of any explosive or incendiary. Each aircraft operator operating under a...

Controlled fabrication of silver nanoneedles array for SERS and their application in rapid detection of narcotics

NASA Astrophysics Data System (ADS)

Yang, Yong; Li, Zhi-Yuan; Yamaguchi, Kohei; Tanemura, Masaki; Huang, Zhengren; Jiang, Dongliang; Chen, Yuhui; Zhou, Fei; Nogami, Masayuki

2012-03-01

Novel surface-enhanced Raman scattering (SERS) substrates with high SERS-activity are ideal for novel SERS sensors, detectors to detect illicitly sold narcotics and explosives. The key to the wider application of SERS technique is to develop plasmon resonant structure with novel geometries to enhance Raman signals and to control the periodic ordering of these structures over a large area to obtain reproducible Raman enhancement. In this work, a simple Ar+-ion sputtering route has been developed to fabricate silver nanoneedles arrays on silicon substrates for SERS-active substrates to detect trace-level illicitly sold narcotics. These silver nanoneedles possess a very sharp apex with an apex diameter of 15 nm and an apex angle of 20°. The SERS enhancement factor of greater than 1010 was reproducibly achieved by the well-aligned nanoneedles arrays. Furthermore, ketamine hydrochloride molecules, one kind of illicitly sold narcotics, can be detected down to 27 ppb by using our SERS substrate within 3 s, indicating the sensitivity of our SERS substrates for trace amounts of narcotics and that SERS technology can become an important analytical technique in forensic laboratories because it can provide a rapid and nondestructive method for trace detection.

49 CFR 1546.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2014 CFR

2014-10-01

... in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, a physical search... of any explosive or incendiary. Each foreign air carrier operating a program under § 1546.101(a), (b...

49 CFR 1546.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2012 CFR

2012-10-01

... in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, a physical search... of any explosive or incendiary. Each foreign air carrier operating a program under § 1546.101(a), (b...

49 CFR 1546.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2013 CFR

2013-10-01

... in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, a physical search... of any explosive or incendiary. Each foreign air carrier operating a program under § 1546.101(a), (b...

49 CFR 1546.205 - Acceptance and screening of cargo.

Code of Federal Regulations, 2011 CFR

2011-10-01

... in its security program. Such methods may include TSA-approved x-ray systems, explosives detection systems, explosives trace detection, explosives detection canine teams certified by TSA, a physical search... of any explosive or incendiary. Each foreign air carrier operating a program under § 1546.101(a), (b...

Optimizing detector geometry for trace element mapping by X-ray fluorescence.

PubMed

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris; Kirz, Janos; Vogt, Stefan

2015-05-01

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples. Copyright © 2015. Published by Elsevier B.V.

Optimizing detector geometry for trace element mapping by X-ray fluorescence

PubMed Central

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris; Kirz, Janos; Vogt, Stefan

2016-01-01

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples. PMID:25600825

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersivemore » detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Trace Explosives Signatures from World War II Unexploded Undersea Ordnance

NASA Technical Reports Server (NTRS)

Darrach, M. R.; Chutjian, A.; Plett, G. A.

1998-01-01

Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion some 50 years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas chromatograph/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance that appeared to be physically intact gave good explosives signatures at the parts per billion level, whereas ordnance that had been cracked open during the explosion gave no signatures at the 10 parts per trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea unexploded ordnance.

Design of an explosive detection system using Monte Carlo method.

PubMed

Hernández-Adame, Pablo Luis; Medina-Castro, Diego; Rodriguez-Ibarra, Johanna Lizbeth; Salas-Luevano, Miguel Angel; Vega-Carrillo, Hector Rene

2016-11-01

Regardless the motivation terrorism is the most important risk for the national security in many countries. Attacks with explosives are the most common method used by terrorists. Therefore several procedures to detect explosives are utilized; among these methods are the use of neutrons and photons. In this study the Monte Carlo method an explosive detection system using a 241 AmBe neutron source was designed. In the design light water, paraffin, polyethylene, and graphite were used as moderators. In the work the explosive RDX was used and the induced gamma rays due to neutron capture in the explosive was estimated using NaI(Tl) and HPGe detectors. When light water is used as moderator and HPGe as the detector the system has the best performance allowing distinguishing between the explosive and urea. For the final design the Ambient dose equivalent for neutrons and photons were estimated along the radial and axial axis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct Analysis in Real Time Mass Spectrometry of Potential By-Products from Homemade Nitrate Ester Explosive Synthesis

PubMed Central

Sisco, Edward; Forbes, Thomas P.

2016-01-01

This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially nitrated and dimerized by-products of homemade nitrate ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and nitrate were observed in the mass spectral responses of these compounds. A global optimum temperature of 350 °C for the by-products investigated here, enabled single nanogram to sub nanogram trace detection. Matrix effects were examined through a series of mixtures containing one or more compounds (sugar alcohol precursors, by-products, and/or explosives) across a range of mass loadings. The explosives MS responses experienced competitive ionization in the presence of all by-products. The magnitude of this influence corresponded to both the degree of by-product nitration and the relative mass loading of the by-product to the explosive. This work provides a characterization of potential by-products from homemade nitrate ester synthesis, including matrix effects and potential challenges that might arise from the trace detection of homemade explosives (HMEs) containing impurities. Detection and understanding of HME impurities and complex mixtures may provide valuable information for the screening and sourcing of homemade nitrate ester explosives. PMID:26838397

Trace Detection of RDX, HMX and PETN Explosives Using a Fluorescence Spot Sensor

PubMed Central

Wang, Chen; Huang, Helin; Bunes, Benjamin R.; Wu, Na; Xu, Miao; Yang, Xiaomei; Yu, Li; Zang, Ling

2016-01-01

1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and pentaerythritol tetranitrate (PETN), the major components in plastic explosives, pose a significant threat to public safety. A quick, sensitive, and low-cost detection method for these non-volatile explosives is eagerly demanded. Here we present a fluo-spot approach, which can be employed for in situ detection of trace amount of explosives. The sensor molecule is a charge-transfer fluorophore, DCM, which is strongly fluorescent in its pristine state, but non-fluorescent after the quick reaction with NO2· (or NO2+) generated from the UV photolysis of RDX, HMX (or PETN). When fabricated within silica gel TLC plate, the fluo-spot sensor features high sensitivity owing to the large surface area and porous structure of the substrate. The sensor reaction mechanism was verified by various experimental characterizations, including chromatography, UV-Vis absorption and fluorescence spectroscopy, MS and 1H NMR spectrometry. The fluo-spot also demonstrated high selectivity towards RDX, HMX and PETN, as no significant fluorescence quenching was observed for other chemical compounds including common nitro-aromatic explosives and inorganic oxidative compounds. The DCM sensor can also be used as an economical spray kit to directly spot the explosives by naked eyes, implying great potential for quick, low-cost trace explosives detection. PMID:27146290

Trace Detection of RDX, HMX and PETN Explosives Using a Fluorescence Spot Sensor.

PubMed

Wang, Chen; Huang, Helin; Bunes, Benjamin R; Wu, Na; Xu, Miao; Yang, Xiaomei; Yu, Li; Zang, Ling

2016-05-05

1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and pentaerythritol tetranitrate (PETN), the major components in plastic explosives, pose a significant threat to public safety. A quick, sensitive, and low-cost detection method for these non-volatile explosives is eagerly demanded. Here we present a fluo-spot approach, which can be employed for in situ detection of trace amount of explosives. The sensor molecule is a charge-transfer fluorophore, DCM, which is strongly fluorescent in its pristine state, but non-fluorescent after the quick reaction with NO2· (or NO2(+)) generated from the UV photolysis of RDX, HMX (or PETN). When fabricated within silica gel TLC plate, the fluo-spot sensor features high sensitivity owing to the large surface area and porous structure of the substrate. The sensor reaction mechanism was verified by various experimental characterizations, including chromatography, UV-Vis absorption and fluorescence spectroscopy, MS and (1)H NMR spectrometry. The fluo-spot also demonstrated high selectivity towards RDX, HMX and PETN, as no significant fluorescence quenching was observed for other chemical compounds including common nitro-aromatic explosives and inorganic oxidative compounds. The DCM sensor can also be used as an economical spray kit to directly spot the explosives by naked eyes, implying great potential for quick, low-cost trace explosives detection.

Pipeline Processing with an Iterative, Context-based Detection Model

DTIC Science & Technology

2014-04-19

stripping the incoming data stream of repeating and irrelevant signals prior to running primary detectors , adaptive beamforming and matched field processing...framework, pattern detectors , correlation detectors , subspace detectors , matched field detectors , nuclear explosion monitoring 16. SECURITY CLASSIFICATION...10 5. Teleseismic paths from earthquakes in

Broadband infrared imaging spectroscopy for standoff detection of trace explosives

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; McGill, R. Andrew

2016-05-01

This manuscript describes advancements toward a mobile platform for standoff detection of trace explosives on relevant substrates using broadband infrared spectroscopic imaging. In conjunction with this, we are developing a technology for detection based on photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). PT-IRIS leverages one or more IR quantum cascade lasers (QCL), tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. Here we describe methods to increase both sensitivity to trace explosives and selectivity between different analyte types by exploiting a broader spectral range than in previous configurations. Previously we demonstrated PT-IRIS at several meters of standoff distance indoors and in field tests, while operating the lasers below the infrared eye-safe intensity limit (100 mW/cm2). Sensitivity to explosive traces as small as a single 10 μm diameter particle (~1 ng) has been demonstrated.

Device for Detection of Explosives, Nuclear and Other Hazardous Materials in Luggage and Cargo Containers

NASA Astrophysics Data System (ADS)

Kuznetsov, Andrey; Evsenin, Alexey; Gorshkov, Igor; Osetrov, Oleg; Vakhtin, Dmitry

2009-12-01

Device for detection of explosives, radioactive and heavily shielded nuclear materials in luggage and cargo containers based on Nanosecond Neutron Analysis/Associated Particles Technique (NNA/APT) is under construction. Detection module consists of a small neutron generator with built-in position-sensitive detector of associated alpha-particles, and several scintillator-based gamma-ray detectors. Explosives and other hazardous chemicals are detected by analyzing secondary high-energy gamma-rays from reactions of fast neutrons with materials inside a container. The same gamma-ray detectors are used to detect unshielded radioactive and nuclear materials. An array of several neutron detectors is used to detect fast neutrons from induced fission of nuclear materials. Coincidence and timing analysis allows one to discriminate between fission neutrons and scattered probing neutrons. Mathematical modeling by MCNP5 and MCNP-PoliMi codes was used to estimate the sensitivity of the device and its optimal configuration. Comparison of the features of three gamma detector types—based on BGO, NaI and LaBr3 crystals is presented.

A Waveform Detector that Targets Template-Decorrelated Signals and Achieves its Predicted Performance: Demonstration with IMS Data

NASA Astrophysics Data System (ADS)

Carmichael, J.

2016-12-01

Waveform correlation detectors used in seismic monitoring scan multichannel data to test two competing hypotheses: that data contain (1) a noisy, amplitude-scaled version of a template waveform, or, (2) only noise. In reality, seismic wavefields include signals triggered by non-target sources (background seismicity) and target signals that are only partially correlated with the waveform template. We reform the waveform correlation detector hypothesis test to accommodate deterministic uncertainty in template/target waveform similarity and thereby derive a new detector from convex set projections (the "cone detector") for use in explosion monitoring. Our analyses give probability density functions that quantify the detectors' degraded performance with decreasing waveform similarity. We then apply our results to three announced North Korean nuclear tests and use International Monitoring System (IMS) arrays to determine the probability that low magnitude, off-site explosions can be reliably detected with a given waveform template. We demonstrate that cone detectors provide (1) an improved predictive capability over correlation detectors to identify such spatially separated explosive sources, (2) competitive detection rates, and (3) reduced false alarms on background seismicity. Figure Caption: Observed and predicted receiver operating characteristic curves for correlation statistic r(x) (left) and cone statistic s(x) (right) versus semi-empirical explosion magnitude. a: Shaded region shows range of ROC curves for r(x) that give the predicted detection performance in noise conditions recorded over 24 hrs on 8 October 2006. Superimposed stair plot shows the empirical detection performance (recorded detections/total events) averaged over 24 hr of data. Error bars indicate the demeaned range in observed detection probability over the day; means are removed to avoid risk of misinterpreting range to indicate probabilities can exceed one. b: Shaded region shows range of ROC curves for s(x) that give the predicted detection performance for the cone detector. Superimposed stair plot show observed detection performance averaged over 24 hr of data analogous to that shown in a.

Stand-off detection of trace explosives by infrared photothermal imaging

NASA Astrophysics Data System (ADS)

Papantonakis, Michael R.; Kendziora, Chris; Furstenberg, Robert; Stepnowski, Stanley V.; Rake, Matthew; Stepnowski, Jennifer; McGill, R. Andrew

2009-05-01

We have developed a technique for the stand-off detection of trace explosives using infrared photothermal imaging. In this approach, infrared quantum cascade lasers tuned to strong vibrational absorption bands of the explosive particles illuminate a surface of interest, preferentially heating the explosives material. An infrared focal plane array is used to image the surface and detect a small increase in the thermal intensity upon laser illumination. We have demonstrated the technique using TNT and RDX residues at several meters of stand-off distance under laboratory conditions, while operating the lasers below the eye-safe intensity limit. Sensitivity to explosives traces as small as a single grain (~100 ng) of TNT has been demonstrated using an uncooled bolometer array. We show the viability of this approach on a variety of surfaces which transmit, reflect or absorb the infrared laser light and have a range of thermal conductivities. By varying the incident wavelength slightly, we demonstrate selectivity between TNT and RDX. Using a sequence of lasers at different wavelengths, we increase both sensitivity and selectivity while reducing the false alarm rate. At higher energy levels we also show it is possible to generate vapor from solid materials with inherently low vapor pressures.

Fate dynamics of environmentally exposed explosive traces.

PubMed

Kunz, Roderick R; Gregory, Kerin E; Aernecke, Matthew J; Clark, Michelle L; Ostrinskaya, Alla; Fountain, Augustus W

2012-04-12

The chemical and physical fates of trace amounts (<50 μg) of explosives containing 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and pentaerythritol tetranitrate (PETN) were determined for the purpose of informing the capabilities of tactical trace explosive detection systems. From these measurements, it was found that the mass decreases and the chemical composition changes on a time scale of hours, with the loss mechanism due to a combination of sublimation and photodegradation. The rates for these processes were dependent on the explosive composition, as well as on both the ambient temperature and the size distribution of the explosive particulates. From these results, a persistence model was developed and applied to model the time dependence of both the mass and areal coverage of the fingerprints, resulting in a predictive capability for determining fingerprint fate. Chemical analysis confirmed that sublimation rates for TNT were depressed by UV (330-400 nm) exposure due to photochemically driven increases in the molecular weight, whereas the opposite was observed for RDX. No changes were observed for PETN upon exposure to UV radiation, and this was attributed to its low UV absorbance.

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE PAGES

Sun, Yue; Gleber, Sophie -Charlotte; Jacobsen, Chris; ...

2015-01-01

We report that trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral responsemore » of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. In conclusion, we conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Optimizing detector geometry for trace element mapping by X-ray fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie -Charlotte; Jacobsen, Chris

We report that trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral responsemore » of energy dispersive detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. In conclusion, we conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Infrasonic and seismic signals from earthquakes and explosions observed with Plostina seismo-acoustic array

NASA Astrophysics Data System (ADS)

Ghica, D.; Ionescu, C.

2012-04-01

Plostina seismo-acoustic array has been recently deployed by the National Institute for Earth Physics in the central part of Romania, near the Vrancea epicentral area. The array has a 2.5 km aperture and consists of 7 seismic sites (PLOR) and 7 collocated infrasound instruments (IPLOR). The array is being used to assess the importance of collocated seismic and acoustic sensors for the purposes of (1) seismic monitoring of the local and regional events, and (2) acoustic measurement, consisting of detection of the infrasound events (explosions, mine and quarry blasts, earthquakes, aircraft etc.). This paper focuses on characterization of infrasonic and seismic signals from the earthquakes and explosions (accidental and mining type). Two Vrancea earthquakes with magnitude above 5.0 were selected to this study: one occurred on 1st of May 2011 (MD = 5.3, h = 146 km), and the other one, on 4th October 2011 (MD = 5.2, h = 142 km). The infrasonic signals from the earthquakes have the appearance of the vertical component of seismic signals. Because the mechanism of the infrasonic wave formation is the coupling of seismic waves with the atmosphere, trace velocity values for such signals are compatible with the characteristics of the various seismic phases observed with PLOR array. The study evaluates and characterizes, as well, infrasound and seismic data recorded from the explosion caused by the military accident produced at Evangelos Florakis Naval Base, in Cyprus, on 11th July 2011. Additionally, seismo-acoustic signals presumed to be related to strong mine and quarry blasts were investigated. Ground truth of mine observations provides validation of this interpretation. The combined seismo-acoustic analysis uses two types of detectors for signal identification: one is the automatic detector DFX-PMCC, applied for infrasound detection and characterization, while the other one, which is used for seismic data, is based on array processing techniques (beamforming and frequency-wave number analysis). Spectrograms of the recorded infrasonic and seismic data were examined, showing that an earthquake produces acoustic signals with a high energy in the 1 to 5 Hz frequency range, while, for the explosion, this range lays below 0.6 Hz. Using the combined analysis of the seismic and acoustic data, Plostina array can greatly enhance the event detection and localization in the region. The analysis can be, as well, particularly important in identifying sources of industrial explosion, and therefore, in monitoring of the hazard created both by earthquakes and anthropogenic sources of pollution (chemical factories, nuclear and power plants, refineries, mines).

A review of the developments of radioxenon detectors for nuclear explosion monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sivels, Ciara B.; McIntyre, Justin I.; Bowyer, Theodore W.

Developments in radioxenon monitoring since the implementation of the International Monitoring System are reviewed with emphasis on the most current technologies to improve detector sensitivity and resolution. The nuclear detectors reviewed include combinations of plastic and NaI(Tl) detectors, high purity germanium detectors, silicon detectors, and phoswich detectors. The minimum detectable activity and calibration methods for the various detectors are also discussed.

Direct analysis in real time mass spectrometry of potential by-products from homemade nitrate ester explosive synthesis.

PubMed

Sisco, Edward; Forbes, Thomas P

2016-04-01

This work demonstrates the coupling of direct analysis in real time (DART) ionization with time-of-flight mass spectrometry (MS) in an off-axis configuration for the trace detection and analysis of potential partially nitrated and dimerized by-products of homemade nitrate ester explosive synthesis. Five compounds relating to the synthesis of nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) were examined. Deprotonated ions and adducts with molecular oxygen, nitrite, and nitrate were observed in the mass spectral responses of these compounds. A global optimum temperature of 350 °C for the by-products investigated here enabled single nanogram to sub nanogram trace detection. Matrix effects were examined through a series of mixtures containing one or more compounds (sugar alcohol precursors, by-products, and/or explosives) across a range of mass loadings. The explosives MS responses experienced competitive ionization in the presence of all by-products. The magnitude of this influence corresponded to both the degree of by-product nitration and the relative mass loading of the by-product to the explosive. This work provides a characterization of potential by-products from homemade nitrate ester synthesis, including matrix effects and potential challenges that might arise from the trace detection of homemade explosives (HMEs) containing impurities. Detection and understanding of HME impurities and complex mixtures may provide valuable information for the screening and sourcing of homemade nitrate ester explosives. Published by Elsevier B.V.

Explosives detection using photoneutrons produced by X-rays

NASA Astrophysics Data System (ADS)

Yang, Yigang; Li, Yuanjing; Wang, Haidong; Li, Tiezhu; Wu, Bin

2007-08-01

The detection of explosives has become a critical issue after recent terrorist attacks. This paper describes research on explosives detection using photoneutrons from a photoneutron convertor that consists of 20 kg heavy water in an aluminum container whose shape was optimized to most effectively convert X-rays to photoneutrons. The X-rays were produced by a 9 MeV electron accelerator with an average electron current of 100 μA, resulted in a photoneutron yield of >10 11 n/s. Monte-Carlo simulations show that the radiation field is composed of X-ray pulses, fast neutron pulses and thermal neutrons. Both the X-ray and fast neutron pulses are 5 μs wide with a 300 Hz repetition frequency. The thermal neutron flux, which is higher than 10 4 n/cm 2/s, is essentially time invariant. A time shielding circuit was developed for the spectrometry system to halt the sampling process during the intense X-ray pulses. Paraffin, boron carbide and lead were used to protect the detector from interference from the X-rays, fast neutrons, thermal neutrons and background γ-rays coming from the system materials induced by photoneutrons. 5″×5″ NaI (Tl) scintillators were chosen as the detectors to detect the photoneutrons induced γ-rays from the inspected explosive simulant. Nitrogen (6.01 cps) 10.828 MeV γ-rays were detected with one detector from a 50 kg carbamide block placed 60 cm in front of the detector. A collimator was used to reduce the number of background 10.828 MeV γ-rays coming from the nitrogen in the air to improve the signal to background ratio from 0.136 to 1.81. A detector array of seven 5″×5″ NaI (Tl) detectors was used to measure the 2-D distributions of N and H in the sample. The combination of photoneutron analysis and X-ray imaging shows promise for enhancing explosives detection capabilities.

On-site Rapid Detection of Trace Non-volatile Inorganic Explosives by Stand-alone Ion Mobility Spectrometry via Acid-enhanced Evaporization

PubMed Central

Peng, Liying; Hua, Lei; Wang, Weiguo; Zhou, Qinghua; Li, Haiyang

2014-01-01

New techniques for the field detection of inorganic improvised explosive devices (IEDs) are urgently developed. Although ion mobility spectrometry (IMS) has been proved to be the most effective method for screening organic explosives, it still faces a major challenge to detect inorganic explosives owing to their low volatilities. Herein, we proposed a strategy for detecting trace inorganic explosives by thermal desorption ion mobility spectrometry (TD-IMS) with sample-to-sample analysis time less than 5 s based on in-situ acidification on the sampling swabs. The responses for typical oxidizers in inorganic explosives, such as KNO3, KClO3 and KClO4 were at least enhanced by a factor of 3000 and their limits of detection were found to be subnanogram. The common organic explosives and their mixtures with inorganic oxidizers were detected, indicating that the acidification process did not affect the detection of organic explosives. Moreover, the typical inorganic explosives such as black powders, firecrackers and match head could be sensitively detected as well. These results demonstrated that this method could be easily employed in the current deployed IMS for on-site sensitive detection of either inorganic explosives or organic ones. PMID:25318960

Analysis of different materials subjected to open-air explosions in search of explosive traces by Raman microscopy.

PubMed

Zapata, Félix; García-Ruiz, Carmen

2017-06-01

Post-explosion scenes offer such chaos and destruction that evidence recovery and detection of post-blast residues from the explosive in the surrounding materials is highly challenging and difficult. The suitability of materials to retain explosives residues and their subsequent analysis has been scarcely investigated. Particularly, the use of explosive mixtures containing inorganic oxidizing salts to make improvised explosive devices (IEDs) is a current security concern due to their wide availability and lax control. In this work, a wide variety of materials such as glass, steel, plywood, plastic bag, brick, cardboard or cotton subjected to open-air explosions were examined using confocal Raman microscopy, aiming to detect the inorganic oxidizing salts contained in explosives as black powder, chloratite, dynamite, ammonium nitrate fuel oil and ammonal. Post-blast residues were detected through microscopic examination of materials surfaces. In general, the more homogeneous and smoother the surface was, the less difficulties and better results in terms of identification were obtained. However, those highly irregular surfaces were the most unsuitable collectors for the posterior identification of explosive traces by Raman microscopy. The findings, difficulties and some recommendations related to the identification of post-blast particles in the different materials studied are thoroughly discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Detection and mapping of trace explosives on surfaces under ambient conditions using multiphoton electron extraction spectroscopy (MEES).

PubMed

Tang, Shisong; Vinerot, Nataly; Fisher, Danny; Bulatov, Valery; Yavetz-Chen, Yehuda; Schechter, Israel

2016-08-01

Multiphoton electron extraction spectroscopy (MEES) is an analytical method in which UV laser pulses are utilized for extracting electrons from solid surfaces in multiphoton processes under ambient conditions. Counting the emitted electrons as a function of laser wavelength results in detailed spectral features, which can be used for material identification. The method has been applied to detection of trace explosives on a variety of surfaces. Detection was possible on dusty swabs spiked with explosives and also in the standard dry-transfer contamination procedure. Plastic explosives could also be detected. The analytical limits of detection (LODs) are in the sub pmole range, which indicates that MEES is one of the most sensitive detection methods for solid surface under ambient conditions. Scanning the surface with the laser allows for its imaging, such that explosives (as well as other materials) can be located. The imaging mode is also useful in forensic applications, such as detection of explosives in human fingerprints. Copyright © 2016 Elsevier B.V. All rights reserved.

Universal explosive detection system for homeland security applications

NASA Astrophysics Data System (ADS)

Lee, Vincent Y.; Bromberg, Edward E. A.

2010-04-01

L-3 Communications CyTerra Corporation has developed a high throughput universal explosive detection system (PassPort) to automatically screen the passengers in airports without requiring them to remove their shoes. The technical approach is based on the patented energetic material detection (EMD) technology. By analyzing the results of sample heating with an infrared camera, one can distinguish the deflagration or decomposition of an energetic material from other clutters such as flammables and general background substances. This becomes the basis of a universal explosive detection system that does not require a library and is capable of detecting trace levels of explosives with a low false alarm rate. The PassPort is a simple turnstile type device and integrates a non-intrusive aerodynamic sampling scheme that has been shown capable of detecting trace levels of explosives on shoes. A detailed description of the detection theory and the automated sampling techniques, as well as the field test results, will be presented.

Trace detection of perchlorate in industrial-grade emulsion explosive with portable surface-enhanced Raman spectroscopy.

PubMed

Nuntawong, N; Eiamchai, P; Limwichean, S; Wong-ek, B; Horprathum, M; Patthanasettakul, V; Leelapojanaporn, A; Nakngoenthong, S; Chindaudom, P

2013-12-10

Recent analyses by ion-exchange chromatography (IC) showed that, beside nitrate, the majority of the industrial-grade emulsion explosives, extensively used by most separatists in the southern Thailand insurgency, contained small traces of perchlorate anions. In demand for the faster, reliable, and simple detection methods, the portable detection of nitrate and perchlorate became the great interest for the forensic and field-investigators. This work proposed a unique method to detect the trace amount of perchlorate in seven industrial-grade emulsion explosives under the field tests. We utilized the combination of the portable Raman spectroscope, the developed surfaced-enhanced Raman substrates, and the sample preparation procedures. The portable Raman spectroscope with a laser diode of 785 nm for excitation and a thermoelectric-cooled CCD spectrometer for detection was commercially available. The SERS substrates, with uniformly distributed nanostructured silver nanorods, were fabricated by the DC magnetron sputtering system, based on the oblique-angle deposition technique. The sample preparation procedures were proposed based on (1) pentane extraction technique and (2) combustion technique, prior to being dissolved in the purified water. In comparison to the ion chromatography and the conventional Raman measurements, our proposed methods successfully demonstrated the highly sensitive detectability of the minimal trace amount of perchlorate from five of the explosives with minimal operating time. This work was therefore highly practical to the development for the forensic analyses of the post-blast explosive residues under the field-investigations. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Possible explanation of the correlations between events recorded by underground detectors during the Supernova 1987A explosion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexeyev, E. N., E-mail: alexeyev@ms2.inr.ac.r

A possible explanation of the time correlations between the data from underground detectors (Baksan telescope, LSD, IMB, Kamiokande II) and from the Rome and Maryland gravitational-wave antennas obtained during the Supernova 1987A explosion is proposed. It is shown that the synchronization of the events recorded by various underground facilities could be produced by gravitational radiation from the Supernova.

Detection of explosives, shielded nuclear materials and other hazardous substances in cargo containers

NASA Astrophysics Data System (ADS)

Kuznetsov, Andrey; Evsenin, Alexey; Vakhtin, Dmitry; Gorshkov, Igor; Osetrov, Oleg; Kalinin, Valery

2006-05-01

Nanosecond Neutron Analysis / Associated Particles Technique (NNA/APT) has been used to create devices for detection of explosives, radioactive and heavily shielded nuclear materials in cargo containers. Explosives and other hazardous materials are detected by analyzing secondary high-energy gamma-rays form reactions of fast neutrons with the materials inside the container. Depending on the dimensions of the inspected containers, the detecting system consists of one or several detection modules, each of which contains a small neutron generator with built-in position sensitive detector of associated alpha-particles and several scintillator-based gamma-ray detectors. The same gamma-ray detectors are used to detect unshielded radioactive and nuclear materials. Array of several detectors of fast neutrons is used to detect neutrons from spontaneous and induced fission of nuclear materials. These neutrons can penetrate thick layers of lead shielding, which can be used to conceal gamma-radioactivity from nuclear materials. Coincidence and timing analysis allows one to discriminate between fission neutrons and scattered probing neutrons. Mathematical modeling by MCNP5 code was used to estimate the sensitivity of the device and its optimal configuration. Capability of the device to detect 1 kg of explosive imitator inside container filled with suitcases and other baggage items has been confirmed experimentally. First experiments with heavily shielded nuclear materials have been carried out.

Identification of carbonates as additives in pressure-sensitive adhesive tape substrate with Fourier transform infrared spectroscopy (FTIR) and its application in three explosive cases.

PubMed

Lv, Jungang; Feng, Jimin; Zhang, Wen; Shi, Rongguang; Liu, Yong; Wang, Zhaohong; Zhao, Meng

2013-01-01

Pressure-sensitive tape is often used to bind explosive devices. It can become important trace evidence in many cases. Three types of calcium carbonate (heavy, light, and active CaCO(3)), which were widely used as additives in pressure-sensitive tape substrate, were analyzed with Fourier transform infrared spectroscopy (FTIR) in this study. A Spectrum GX 2000 system with a diamond anvil cell and a deuterated triglycine sulfate detector was employed for IR observation. Background was subtracted for every measurement, and triplicate tests were performed. Differences in positions of main peaks and the corresponding functional groups were investigated. Heavy CaCO(3) could be identified from the two absorptions near 873 and 855/cm, while light CaCO(3) only has one peak near 873/cm because of the low content of aragonite. Active CaCO(3) could be identified from the absorptions in the 2800-2900/cm region because of the existence of organic compounds. Tiny but indicative changes in the 878-853/cm region were found in the spectra of CaCO(3) with different content of aragonite and calcite. CaCO(3) in pressure-sensitive tape, which cannot be differentiated by scanning electron microscope/energy dispersive X-ray spectrometer and thermal analysis, can be easily identified using FTIR. The findings were successfully applied to three specific explosive cases and would be helpful in finding the possible source of explosive devices in future cases. © 2012 American Academy of Forensic Sciences.

30 CFR 22.7 - Specific requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... APPROVAL OF MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.7 Specific requirements. (a) Design. In the... explosion hazard—(1) Detectors. Detectors shall be constructed so that they will not cause external... diameter and are of reasonably thick glass. (4) Battery. If the detector is equipped with a battery, it...

30 CFR 22.7 - Specific requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... APPROVAL OF MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.7 Specific requirements. (a) Design. In the... explosion hazard—(1) Detectors. Detectors shall be constructed so that they will not cause external... diameter and are of reasonably thick glass. (4) Battery. If the detector is equipped with a battery, it...

30 CFR 22.7 - Specific requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... APPROVAL OF MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.7 Specific requirements. (a) Design. In the... explosion hazard—(1) Detectors. Detectors shall be constructed so that they will not cause external... diameter and are of reasonably thick glass. (4) Battery. If the detector is equipped with a battery, it...

30 CFR 22.7 - Specific requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... APPROVAL OF MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.7 Specific requirements. (a) Design. In the... explosion hazard—(1) Detectors. Detectors shall be constructed so that they will not cause external... diameter and are of reasonably thick glass. (4) Battery. If the detector is equipped with a battery, it...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Yue; Gleber, Sophie-Charlotte; Jacobsen, Chris

Trace metals play critical roles in a variety of systems, ranging from cells to photovoltaics. X-Ray Fluorescence (XRF) microscopy using X-ray excitation provides one of the highest sensitivities available for imaging the distribution of trace metals at sub-100 nm resolution. With the growing availability and increasing performance of synchrotron light source based instruments and X-ray nanofocusing optics, and with improvements in energy-dispersive XRF detectors, what are the factors that limit trace element detectability? To address this question, we describe an analytical model for the total signal incident on XRF detectors with various geometries, including the spectral response of energy dispersivemore » detectors. This model agrees well with experimentally recorded X-ray fluorescence spectra, and involves much shorter calculation times than with Monte Carlo simulations. With such a model, one can estimate the signal when a trace element is illuminated with an X-ray beam, and when just the surrounding non-fluorescent material is illuminated. From this signal difference, a contrast parameter can be calculated and this can in turn be used to calculate the signal-to-noise ratio (S/N) for detecting a certain elemental concentration. We apply this model to the detection of trace amounts of zinc in biological materials, and to the detection of small quantities of arsenic in semiconductors. We conclude that increased detector collection solid angle is (nearly) always advantageous even when considering the scattered signal. However, given the choice between a smaller detector at 90° to the beam versus a larger detector at 180° (in a backscatter-like geometry), the 90° detector is better for trace element detection in thick samples, while the larger detector in 180° geometry is better suited to trace element detection in thin samples.« less

Pipeline Processing With an Iterative, Context-Based Detection Model

DTIC Science & Technology

2015-04-19

pattern detectors , correlation detectors , subspace detectors , matched field detectors , nuclear explosion monitoring 16. SECURITY CLASSIFICATION OF: 17...38 13. 3 days of SPAO-BHZ data which is dominated by signals from nearby icequakes. .... 39 14. (Top) 94 detections produced by detector ...92532 and (bottom) 148 detections from detector 92541 produced during the first run of the framework. .................................. 40 15. The 49

Advancing Explosives Detection Capabilities: Vapor Detection

ScienceCinema

Atkinson, David

2018-05-11

A new, PNNL-developed method provides direct, real-time detection of trace amounts of explosives such as RDX, PETN and C-4. The method selectively ionizes a sample before passing the sample through a mass spectrometer to detect explosive vapors. The method could be used at airports to improve aviation security.

Advancing Explosives Detection Capabilities: Vapor Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Atkinson, David

2012-10-15

A new, PNNL-developed method provides direct, real-time detection of trace amounts of explosives such as RDX, PETN and C-4. The method selectively ionizes a sample before passing the sample through a mass spectrometer to detect explosive vapors. The method could be used at airports to improve aviation security.

Integration of CW / Radionucleotide Detection Systems to the Fido XT Explosives Detector

DTIC Science & Technology

2008-07-31

explosives detected by the Fido XT. Additionally, a platform for centralized storage and processing of Fido XT data files collected in house, targeted...fused silica glass wool (obtained from Restek). The fluorescent signal was easily washed out of the flow cell by a nominal amount of buffer...detector with supporting NRE was processed . The Interceptor components were configured to operate under a Windows CE processor environment, and to

Performance of an improved thermal neutron activation detector for buried bulk explosives

NASA Astrophysics Data System (ADS)

McFee, J. E.; Faust, A. A.; Andrews, H. R.; Clifford, E. T. H.; Mosquera, C. M.

2013-06-01

First generation thermal neutron activation (TNA) sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on multi-sensor landmine detection systems. The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr3(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. The sensor is described, with emphasis on the improvements. Experiments to characterize the performance of the second generation TNA in detecting buried landmines and improvised explosive devices (IEDs) hidden in culverts are described. Performance results, including comparisons between the performance of the first and second generation systems are presented.

Origin of a signal detected with the LSD detector after the accident at the chernobyl nuclear power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agafonova, N. Yu., E-mail: natagafonova@gmail.com; Malgin, A. S., E-mail: malgin@lngs.infn.it; Fulgione, W.

A rare signal was detected at 23:53 Moscow time on April 27, 1986 with the LSD low-background scintillation detector located under Mont Blanc at a distance of 1820 km from Chernobyl. To reveal the origin of this signal, we discuss the results obtained with other instruments operating within a similar program, as well as analyze the characteristics of the pulses of the signal and facts referring to the explosion of the Chernobyl reactor. A hypothesis based on detection with the LSD of gamma-quanta from {beta} decays of {sup 135}I nuclei ejected into atmosphere by the reactor explosion and carried inmore » the underground detector camera with air of positive ventilation is considered. The explosion origin of the LSD signal indicates a new technogenic source of the background in the search for neutrino bursts from cores of collapsing stars.« less

Collection of trace evidence of explosive residues from the skin in a death due to a disguised letter bomb. The synergy between confocal laser scanning microscope and inductively coupled plasma atomic emission spectrometer analyses.

PubMed

Turillazzi, Emanuela; Monaci, Fabrizio; Neri, Margherita; Pomara, Cristoforo; Riezzo, Irene; Baroni, Davide; Fineschi, Vittorio

2010-04-15

In most deaths caused by explosive, the victim's body becomes a depot for fragments of explosive materials, so contributing to the collection of trace evidence which may provide clues about the specific type of device used with explosion. Improvised explosive devices are used which contain "homemade" explosives rather than high explosives because of the relative ease with which such components can be procured. Many methods such as chromatography-mass spectrometry, scanning electron microscopy, stereomicroscopy, capillary electrophoresis are available for use in the identification of explosive residues on objects and bomb fragments. Identification and reconstruction of the distribution of explosive residues on the decedent's body may give additional hints in assessing the position of the victim in relation to the device. Traditionally these residues are retrieved by swabbing the body and clothing during the early phase, at autopsy. Gas chromatography-mass spectrometry and other analytical methods may be used to analyze the material swabbed from the victim body. The histological examination of explosive residues on skin samples collected during the autopsy may reveal significant details. The information about type, quantity and particularly about anatomical distribution of explosive residues obtained utilizing confocal laser scanning microscope (CLSM) together with inductively coupled plasma atomic emission spectrometer (ICP-AES), may provide very significant evidence in the clarification and reconstruction of the explosive-related events. Copyright 2009 Elsevier Ireland Ltd. All rights reserved.

Overview: MURI Center on spectroscopic and time domain detection of trace explosives in condensed and vapor phases

NASA Astrophysics Data System (ADS)

Spicer, James B.; Dagdigian, Paul; Osiander, Robert; Miragliotta, Joseph A.; Zhang, Xi-Cheng; Kersting, Roland; Crosley, David R.; Hanson, Ronald K.; Jeffries, Jay

2003-09-01

The research center established by Army Research Office under the Multidisciplinary University Research Initiative program pursues a multidisciplinary approach to investigate and advance the use of complementary analytical techniques for sensing of explosives and/or explosive-related compounds as they occur in the environment. The techniques being investigated include Terahertz (THz) imaging and spectroscopy, Laser-Induced Breakdown Spectroscopy (LIBS), Cavity Ring Down Spectroscopy (CRDS) and Resonance Enhanced Multiphoton Ionization (REMPI). This suite of techniques encompasses a diversity of sensing approaches that can be applied to detection of explosives in condensed phases such as adsorbed species in soil or can be used for vapor phase detection above the source. Some techniques allow for remote detection while others have highly specific and sensitive analysis capabilities. This program is addressing a range of fundamental, technical issues associated with trace detection of explosive related compounds using these techniques. For example, while both LIBS and THz can be used to carry-out remote analysis of condensed phase analyte from a distance in excess several meters, the sensitivities of these techniques to surface adsorbed explosive-related compounds are not currently known. In current implementations, both CRDS and REMPI require sample collection techniques that have not been optimized for environmental applications. Early program elements will pursue the fundamental advances required for these techniques including signature identification for explosive-related compounds/interferents and trace analyte extraction. Later program tasks will explore simultaneous application of two or more techniques to assess the benefits of sensor fusion.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT, EXPLOSIVES DETECTION TECHNOLOGY, SRI INSTRUMENTS, MODEL 8610C, GAS CHROMATOGRAPH/THERMIONIC IONIZATION DETECTION

EPA Science Inventory

The SRI Model 86 1 OC gas chromatograph (GC) is a transportable instrument that can provide on-site analysis of soils for explosives. Coupling this transportable gas chromatograph with a thermionic ionization detector (TID) allows for the determination of explosives in soil matri...

A simulation study of fast neutron interrogation for standoff detection of improvised explosive devices

NASA Astrophysics Data System (ADS)

Heider, S. A.; Dunn, W. L.

2015-11-01

The signature-based radiation-scanning technique utilizes radiation detector responses, called "signatures," and compares these to "templates" in order to differentiate targets that contain certain materials, such as explosives or drugs, from those that do not. Our investigations are aimed at the detection of nitrogen-rich explosives contained in improvised explosive devices. We use the term "clutter" to refer to any non-explosive materials with which the interrogating radiation may interact between source and detector. To deal with the many target types and clutter configurations that may be encountered in the field, the use of "artificial templates" is proposed. The MCNP code was used to simulate 14.1 MeV neutron source beams incident on one type of target containing various clutter and sample materials. Signatures due to inelastic-scatter and prompt-capture gamma rays from hydrogen, carbon, nitrogen, and oxygen and two scattered neutron signatures were considered. Targets containing explosive materials in the presence of clutter were able to be identified from targets that contained only non-explosive ("inert") materials. This study demonstrates that a finite number of artificial templates is sufficient for IED detection with fairly good sensitivity and specificity.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radousky, H B

This months issue has the following articles: (1) Innovative Solutions Reap Rewards--Commentary by George H. Miller; (2) Surveillance on the Fly--An airborne surveillance system can track up to 8,000 moving objects in an area the size of a small city; (3) A Detector Radioactive Particles Can't Evade--An ultrahigh-resolution spectrometer can detect the minute thermal energy deposited by a single gamma ray or neutron; (4) Babel Speeds Communication among Programming Languages--The Babel program allows software applications in different programming languages to communicate quickly; (5) A Gem of a Software Tool--The data-mining software Sapphire allows scientists to analyze enormous data sets generatedmore » by diverse applications; (6) Interferometer Improves the Search for Planets--With externally dispersed interferometry, astronomers can use an inexpensive, compact instrument to search for distant planets; (7) Efficiently Changing the Color of Laser Light--Yttrium-calcium-oxyborate crystals provide an efficient, compact approach to wavelength conversion for high-average-power lasers; (8) Pocket-Sized Test Detects Trace Explosives--A detection kit sensitive to more than 30 explosives provides an inexpensive, easy-to-use tool for security forces everywhere; (9) Tailor-Made Microdevices Serve Big Needs--The Center for Micro- and Nanotechnology develops tiny devices for national security.« less

Method and system for detecting an explosive

DOEpatents

Reber, Edward L.; Rohde, Kenneth W.; Blackwood, Larry G.

2010-12-07

A method and system for detecting at least one explosive in a vehicle using a neutron generator and a plurality of NaI detectors. Spectra read from the detectors is calibrated by performing Gaussian peak fitting to define peak regions, locating a Na peak and an annihilation peak doublet, assigning a predetermined energy level to one peak in the doublet, and predicting a hydrogen peak location based on a location of at least one peak of the doublet. The spectra are gain shifted to a common calibration, summed for respective groups of NaI detectors, and nitrogen detection analysis performed on the summed spectra for each group.

Explosives (and other threats) detection using pulsed neutron interrogation and optimized detectors

NASA Astrophysics Data System (ADS)

Strellis, Dan A.; Elsalim, Mashal; Gozani, Tsahi

2011-06-01

We have previously reported results from a human-portable system using neutron interrogation to detect contraband and explosives. We summarized our methodology for distinguishing threat materials such as narcotics, C4, and mustard gas in the myriad of backgrounds present in the maritime environment. We are expanding our mission for the Domestic Nuclear Detection Office (DNDO) to detect Special Nuclear Material (SNM) through the detection of multiple fission signatures without compromising the conventional threat detection performance. This paper covers our initial investigations into using neutrons from compact pulsed neutron generators via the d(D,n)3He or d(T,n)α reactions with energies of ~2.5 and 14 MeV, respectively, for explosives (and other threats) detection along with a variety of gamma-ray detectors. Fast neutrons and thermal neutrons (after successive collisions) can stimulate the emission of various threat detection signatures. For explosives detection, element-specific gamma-ray signatures via the (n,n'γ) inelastic scattering reaction and the (n,'γ) thermal capture reaction are detected. For SNM, delayed gamma-rays following fission can be measured with the same detector. Our initial trade-off investigations of several gamma-ray detectors types (NaI, CsI, LaBr3, HPGe) for measuring gamma-ray signatures in a pulsed neutron environment for potential application in a human-portable active interrogation system are covered in this paper.

Selective detection of trace nitroaromatic, nitramine, and nitrate ester explosive residues using a three-step fluorimetric sensing process: a tandem turn-off, turn-on sensor.

PubMed

Sanchez, Jason C; Toal, Sarah J; Wang, Zheng; Dugan, Regina E; Trogler, William C

2007-11-01

Detection of trace quantities of explosive residues plays a key role in military, civilian, and counter-terrorism applications. To advance explosives sensor technology, current methods will need to become cheaper and portable while maintaining sensitivity and selectivity. The detection of common explosives including trinitrotoluene (TNT), cyclotrimethylenetrinitramine, cyclotetramethylene-tetranitramine, pentaerythritol tetranitrate, 2,4,6-trinitrophenyl-N-methylnitramine, and trinitroglycerin may be carried out using a three-step process combining "turn-off" and "turn-on" fluorimetric sensing. This process first detects nitroaromatic explosives by their quenching of green luminescence of polymetalloles (lambda em approximately 400-510 nm). The second step places down a thin film of 2,3-diaminonaphthalene (DAN) while "erasing" the polymetallole luminescence. The final step completes the reaction of the nitramines and/or nitrate esters with DAN resulting in the formation of a blue luminescent traizole complex (lambda(em) = 450 nm) providing a "turn-on" response for nitramine and nitrate ester-based explosives. Detection limits as low as 2 ng are observed. Solid-state detection of production line explosives demonstrates the applicability of this method to real world situations. This method offers a sensitive and selective detection process for a diverse group of the most common high explosives used in military and terrorist applications today.

Enhancing forensic science with spectroscopic imaging

NASA Astrophysics Data System (ADS)

Ricci, Camilla; Kazarian, Sergei G.

2006-09-01

This presentation outlines the research we are developing in the area of Fourier Transform Infrared (FTIR) spectroscopic imaging with the focus on materials of forensic interest. FTIR spectroscopic imaging has recently emerged as a powerful tool for characterisation of heterogeneous materials. FTIR imaging relies on the ability of the military-developed infrared array detector to simultaneously measure spectra from thousands of different locations in a sample. Recently developed application of FTIR imaging using an ATR (Attenuated Total Reflection) mode has demonstrated the ability of this method to achieve spatial resolution beyond the diffraction limit of infrared light in air. Chemical visualisation with enhanced spatial resolution in micro-ATR mode broadens the range of materials studied with FTIR imaging with applications to pharmaceutical formulations or biological samples. Macro-ATR imaging has also been developed for chemical imaging analysis of large surface area samples and was applied to analyse the surface of human skin (e.g. finger), counterfeit tablets, textile materials (clothing), etc. This approach demonstrated the ability of this imaging method to detect trace materials attached to the surface of the skin. This may also prove as a valuable tool in detection of traces of explosives left or trapped on the surfaces of different materials. This FTIR imaging method is substantially superior to many of the other imaging methods due to inherent chemical specificity of infrared spectroscopy and fast acquisition times of this technique. Our preliminary data demonstrated that this methodology will provide the means to non-destructive detection method that could relate evidence to its source. This will be important in a wider crime prevention programme. In summary, intrinsic chemical specificity and enhanced visualising capability of FTIR spectroscopic imaging open a window of opportunities for counter-terrorism and crime-fighting, with applications ranging from analysis of trace evidence (e.g. in soil), tablets, drugs, fibres, tape explosives, biological samples to detection of gunshot residues and imaging of fingerprints.

Minutes of the Explosives Safety Seminar (22nd) Held in Anaheim, California on 26-28 August 1986. Volume 2

DTIC Science & Technology

1986-08-01

the U.S. Customs thermionic acetone vapor detector and a non -commercial Gas Chromatograph with electron capture detection as the main types. Each had...detector would only detect RDX or HMX or other explosives that had residual solvent with an alpha keto group like acetone or methylethyl ketone...8217.’=- evaluation for both vapor and non -vapor methods. The NAVSEA was not prepared to engage in r comprehensive study but did fund a reviev of improved

Development of an Electron-capture Technique Specific for Explosives Detection

DOT National Transportation Integrated Search

1974-07-01

This document contains information on the design, fabrication, and testing of a prototype detector specific for explosives which employs electron-capture sensors. The technique used exploits the observation that the electronegative vapors from explos...

Improvements to a Major Digital Archive of Seismic Waveforms from Nuclear Explosions

DTIC Science & Technology

2010-03-23

Semipalatinsk Test site ; Novaya Zemlya (461 traces) in Russia; and Lop Nor (120 traces) in China; and also from many Peaceful Nuclear Explosions (552... Semipalatinsk Test Site (circles) recorded at Borovoye (BRV) during 1966- 1989.The Balapan, Degelen, and Murzhik regions are indicated. 5 3. Locations of... Semipalatinsk Test Site , Kazakhstan; test of 1968 June 19 70 35. Last of seven sets of BRV seismograms on the KOD system for a UNE at the Balapan area

A laser-based FAIMS detector for detection of ultra-low concentrations of explosives

NASA Astrophysics Data System (ADS)

Akmalov, Artem E.; Chistyakov, Alexander A.; Kotkovskii, Gennadii E.; Sychev, Alexey V.; Tugaenko, Anton V.; Bogdanov, Artem S.; Perederiy, Anatoly N.; Spitsyn, Eugene M.

2014-06-01

A non-contact method for analyzing of explosives traces from surfaces was developed. The method is based on the laser desorption of analyzed molecules from the surveyed surfaces followed by the laser ionization of air sample combined with the field asymmetric ion mobility spectrometry (FAIMS). The pulsed radiation of the fourth harmonic of a portable GSGG: Cr3+ :Nd3+ laser (λ = 266 nm) is used. The laser desorption FAIMS analyzer have been developed. The detection limit of the analyzer equals 40 pg for TNT. The results of detection of trinitrotoluene (TNT), cyclotrimethylenetrinitramine (RDX) and cyclotetramethylenetetranitramine (HMX) are presented. It is shown that laser desorption of nitro-compounds from metals is accompanied by their surface decomposition. A method for detecting and analyzing of small concentrations of explosives in air based on the laser ionization and the FAIMS was developed. The method includes a highly efficient multipass optical scheme of the intracavity fourthharmonic generation of pulsed laser radiation (λ = 266 nm) and the field asymmetric ion mobility (FAIM) spectrometer disposed within a resonator. The ions formation and detection proceed inside a resonant cavity. The laser ion source based on the multi-passage of radiation at λ = 266 nm through the ionization region was elaborated. On the basis of the method the laser FAIMS analyzer has been created. The analyzer provides efficient detection of low concentrations of nitro-compounds in air and shows a detection limit of 10-14 - 10-15 g/cm3 both for RDX and TNT.

Piezoelectric trace vapor calibrator

NASA Astrophysics Data System (ADS)

Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.

2006-08-01

The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10°C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver—on demand—continuous vapor concentrations across more than six orders of magnitude (nominally 290fg/lto1.05μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process.

Method for selective detection of explosives in mass spectrometer or ion mobility spectrometer at parts-per-quadrillion level

DOEpatents

Ewing, Robert G.; Atkinson, David A.; Clowers, Brian H.

2015-09-01

A method for selective detection of volatile and non-volatile explosives in a mass spectrometer or ion mobility spectrometer at a parts-per-quadrillion level without preconcentration is disclosed. The method comprises the steps of ionizing a carrier gas with an ionization source to form reactant ions or reactant adduct ions comprising nitrate ions (NO.sub.3.sup.-); selectively reacting the reactant ions or reactant adduct ions with at least one volatile or non-volatile explosive analyte at a carrier gas pressure of at least about 100 Ton in a reaction region disposed between the ionization source and an ion detector, the reaction region having a length which provides a residence time (tr) for reactant ions therein of at least about 0.10 seconds, wherein the selective reaction yields product ions comprising reactant ions or reactant adduct ions that are selectively bound to the at least one explosive analyte when present therein; and detecting product ions with the ion detector to determine presence or absence of the at least one explosive analyte.

Detectors for the gamma-ray resonant absorption (GRA) method of explosives detection in cargo: a comparative study

NASA Astrophysics Data System (ADS)

Vartsky, David; Goldberg, Mark B.; Engler, Gideon; Shor, Asher; Goldschmidt, Aharon; Feldman, Gennady; Bar, Doron; Orion, Itzhak; Wielopolski, Lucian

2004-01-01

Gamma-Ray Resonant Absorption (GRA) is an automatic-decision radiographic screening technique that combines high radiation penetration with very good sensitivity and specificity to nitrogenous explosives. The method is particularly well-suited to inspection of large, massive objects (since the resonant γ-ray probe is at 9.17 MeV) such as aviation and marine containers, heavy vehicles and railroad cars. Two kinds of γ-ray detectors have been employed to date in GRA systems: 1) Resonant-response nitrogen-rich liquid scintillators and 2) BGO detectors. This paper analyses and compares the response of these detector-types to the resonant radiation, in terms of single-pixel figures of merit. The latter are sensitive not only to detector response, but also to accelerator-beam quality, via the properties of the nuclear reaction that produces the resonant-γ-rays. Generally, resonant detectors give rise to much higher nitrogen-contrast sensitivity in the radiographic image than their non-resonant detector counterparts and furthermore, do not require proton beams of high energy-resolution. By comparison, the non-resonant detectors have higher γ-detection efficiency, but their contrast sensitivity is very sensitive to the quality of the accelerator beam. Implications of these detector/accelerator characteristics for eventual GRA field systems are discussed.

Raman scattering spectroscopy for explosives identification

NASA Astrophysics Data System (ADS)

Nagli, L.; Gaft, M.

2007-04-01

Real time detection and identification of explosives at a standoff distance is a major issue in efforts to develop defense against so-called Improvised Explosive Devices (IED). It is recognized that the only technique, which is potentially capable to standoff detection of minimal amounts of explosives is laser-based spectroscopy. LDS technique belongs to trace detection, namely to its micro-particles variety. We applied gated Raman and time-resolved luminescence spectroscopy for detection of main explosive materials, both factory and homemade. Raman system was developed and tested by LDS for field remote detection and identification of minimal amounts of explosives on relevant surfaces at a distance of up to 30 meters.

On the prompt identification of traces of explosives

NASA Astrophysics Data System (ADS)

Trobajo, M. T.; López-Cabeceira, M. M.; Carriegos, M. V.; Díez-Machío, H.

2014-12-01

Some recent results in the use of Raman spectroscopy for recognition of explosives are reviewed. Experimental study using spectra data base has been developed. In order to simulate a more real situation, both blank substances and explosives substances have been considered in this research. Statistic classification techniques have been performed. Estimations of prediction errors were obtained by cross-validation methods. These results can be applied in airport security systems in order to prevent terror acts (by the detection of explosive/flammable substances).

30 CFR 22.7 - Specific requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... APPROVAL OF MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.7 Specific requirements. (a) Design. In the... shall be of such design that it will not produce sparks that will ignite an explosive mixture of methane and air. (5) Detectors of the flame type. Methane detectors of the flame type shall be subject to the...

Detection of trace explosives on relevant substrates using a mobile platform for photothermal infrared imaging spectroscopy (PT-IRIS)

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Byers, Jeff; McGill, R. Andrew

2015-05-01

This manuscript describes the results of recent tests regarding standoff detection of trace explosives on relevant substrates using a mobile platform. We are developing a technology for detection based on photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more microfabricated IR quantum cascade lasers, tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. Increased sensitivity to explosives and selectivity between different analyte types is achieved by narrow bandpass IR filters in the collection path. We have previously demonstrated the technique at several meters of stand-off distance indoors and in field tests, while operating the lasers below the infrared eye-safe intensity limit (100 mW/cm2). Sensitivity to explosive traces as small as a single 10 μm diameter particle (~1 ng) has been demonstrated. Analytes tested here include RDX, TNT, ammonium nitrate and sucrose. The substrates tested in this current work include metal, plastics, glass and painted car panels.

A portable and autonomous multichannel fluorescence detector for on-line and in situ explosive detection in aqueous phase.

PubMed

Xin, Yunhong; Wang, Qi; Liu, Taihong; Wang, Lingling; Li, Jia; Fang, Yu

2012-11-21

A multichannel fluorescence detector used to detect nitroaromatic explosives in aqueous phase has been developed, which is composed of a five-channel sample-sensor unit, a measurement and control unit, a microcontroller, and a communication unit. The characteristics of the detector as developed are mainly embedded in the sensor unit, and each sensor consists of a fluorescent sensing film, a light emitting diode (LED), a multi-pixel photon counter (MPPC), and an optical module with special bandpass optical filters. Due to the high sensitivity of the sensing film, the small size and low cost of LED and MPPC, the developed detector not only has a better detecting performance and small size, but also has a very low cost - it is an alternative to the device made with an expensive high power lamp and photomultiplier tube. The wavelengths of the five sensors covered extend from the upper UV through the visible spectrum, 370-640 nm, and thereby it possesses the potential to detect a variety of explosives and other hazardous materials in aqueous phase. An additional function of the detector is its ability to function via a wireless network, by which the data recorded by the detector can be sent to the host computer, and at the same time the instructions can be sent to the detector from the host computer. By means of the powerful computing ability of the host computer, and utilizing the classical principal component analysis (PCA) algorithm, effective classification of the analytes is achieved. Furthermore, the detector has been tested and evaluated using NB, PA, TNT and DNT as the analytes, and toluene, benzene, methanol and ethanol as interferent compounds (concentration various from 10 and 60 μM). It has been shown that the detector can detect the four nitroaromatics with high sensitivity and selectivity.

Fabrication and testing of a standoff trace explosives detection system

NASA Astrophysics Data System (ADS)

Waterbury, Robert; Rose, Jeremy; Vunck, Darius; Blank, Thomas; Pohl, Ken; Ford, Alan; McVay, Troy; Dottery, Ed

2011-05-01

In order to stop the transportation of materials used for IED manufacture, a standoff checkpoint explosives detection system (CPEDS) has recently been fabricated. The system incorporates multi-wavelength Raman spectroscopy and laser induced breakdown spectroscopy (LIBS) modalities with a LIBS enhancement technique called TEPS to be added later into a single unit for trace detection of explosives at military checkpoints. Newly developed spectrometers and other required sensors all integrated with a custom graphical user interface for producing simplified, real-time detection results are also included in the system. All equipment is housed in a military ruggedized shelter for potential deployment intheater for signature collection. Laboratory and performance data, as well as the construction of the CPEDS system and its potential deployment capabilities, will be presented in the current work.

Integrating preconcentrator heat controller

DOEpatents

Bouchier, Francis A.; Arakaki, Lester H.; Varley, Eric S.

2007-10-16

A method and apparatus for controlling the electric resistance heating of a metallic chemical preconcentrator screen, for example, used in portable trace explosives detectors. The length of the heating time-period is automatically adjusted to compensate for any changes in the voltage driving the heating current across the screen, for example, due to gradual discharge or aging of a battery. The total deposited energy in the screen is proportional to the integral over time of the square of the voltage drop across the screen. Since the net temperature rise, .DELTA.T.sub.s, of the screen, from beginning to end of the heating pulse, is proportional to the total amount of heat energy deposited in the screen during the heating pulse, then this integral can be calculated in real-time and used to terminate the heating current when a pre-set target value has been reached; thereby providing a consistent and reliable screen temperature rise, .DELTA.T.sub.s, from pulse-to-pulse.

Angular dependence of source-target-detector in active mode standoff infrared detection

NASA Astrophysics Data System (ADS)

Pacheco-Londoño, Leonardo C.; Castro-Suarez, John R.; Aparicio-Bolaños, Joaquín. A.; Hernández-Rivera, Samuel P.

2013-06-01

Active mode standoff measurement using infrared spectroscopy were carried out in which the angle between target and the source was varied from 0-70° with respect to the surface normal of substrates containing traces of highly energetic materials (explosives). The experiments were made using three infrared sources: a modulated source (Mod-FTIR), an unmodulated source (UnMod-FTIR) and a scanning quantum cascade laser (QCL), part of a dispersive mid infrared (MIR) spectrometer. The targets consisted of PENT 200 μg/cm2 deposited on aluminum plates placed at 1 m from the sources. The evaluation of the three modalities was aimed at verifying the influence of the highly collimated laser beam in the detection in comparison with the other sources. The Mod-FTIR performed better than QCL source in terms of the MIR signal intensity decrease with increasing angle.

Evaluation of State-of-the-Art High Speed Deluge Systems Presently in Service at Various U.S. Army Ammunition Plants

DTIC Science & Technology

1993-09-01

designed to respond to. No data exists on spectral irradiances in the IR or UV spectral bands where the current detectors operate. A need exists to...appropriate fire/explosion detection spectral bands. Setting a pyrotechnic fire and testing the responses of commercial UV and IR detectors that are designed...PNZ B. DETECTOR BACKGROUND ............... 30 C. UV DETECTORS . . ............ . . . 32 D. IR DETECTORS . . . ......... . . ... 34 E. MACHINE VISION

Raman detection of improvised explosive device (IED) material fabricated using drop-on-demand inkjet technology on several real world surfaces

NASA Astrophysics Data System (ADS)

Farrell, Mikella E.; Holthoff, Ellen L.; Pellegrino, Paul M.

2015-05-01

The requirement to detect hazardous materials (i.e., chemical, biological, and explosive) on a host of materials has led to the development of hazard detection systems. These new technologies and their capabilities could have immediate uses for the US military, national security agencies, and environmental response teams in efforts to keep people secure and safe. In particular, due to the increasing use by terrorists, the detection of common explosives and improvised explosive device (IED) materials have motivated research efforts toward detecting trace (i.e., particle level) quantities on multiple commonly encountered surfaces (e.g., textiles, metals, plastics, natural products, and even people). Non-destructive detection techniques can detect trace quantities of explosive materials; however, it can be challenging in the presence of a complex chemical background. One spectroscopic technique gaining increased attention for detection is Raman. One popular explosive precursor material is ammonium nitrate (AN). The material AN has many agricultural applications, however it can also be used in the fabrication of IEDs or homemade explosives (HMEs). In this paper, known amounts of AN will be deposited using an inkjet printer into several different common material surfaces (e.g., wood, human hair, textiles, metals, plastics). The materials are characterized with microscope images and by collecting Raman spectral data. In this report the detection and identification of AN will be demonstrated.

Improved explosive collection and detection with rationally assembled surface sampling materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chouyyok, Wilaiwan; Bays, J. Timothy; Gerasimenko, Aleksandr A.

Sampling and detection of trace explosives is a key analytical process in modern transportation safety. In this work we have explored some of the fundamental analytical processes for collection and detection of trace level explosive on surfaces with the most widely utilized system, thermal desorption IMS. The performance of the standard muslin swipe material was compared with chemically modified fiberglass cloth. The fiberglass surface was modified to include phenyl functional groups. When compared to standard muslin, the phenyl functionalized fiberglass sampling material showed better analyte release from the sampling material as well as improved response and repeatability from multiple usesmore » of the same swipe. The improved sample release of the functionalized fiberglass swipes resulted in a significant increase in sensitivity. Various physical and chemical properties were systematically explored to determine optimal performance. The results herein have relevance to improving the detection of other explosive compounds and potentially to a wide range of other chemical sampling and field detection challenges.« less

High-throughput trace analysis of explosives in water by laser diode thermal desorption/atmospheric pressure chemical ionization-tandem mass spectrometry.

PubMed

Badjagbo, Koffi; Sauvé, Sébastien

2012-07-03

Harmful explosives can accumulate in natural waters in the long term during their testing, usage, storage, and dumping and can pose a health risk to humans and the environment. For the first time, attachment of small anions to neutral molecules in laser diode thermal desorption/atmospheric pressure chemical ionization was systematically investigated for the direct determination of trace nitroaromatics, nitrate esters, and nitramine explosives in water. Using ammonium chloride as an additive improved the instrument response for all the explosives tested and promoted the formation of several characteristic adduct ions. The method performs well achieving good linearity over at least 2 orders of magnitude, with coefficients of determination greater than 0.995. The resulting limits of detection are in the range of 0.009-0.092 μg/L. River water samples were successfully analyzed by the proposed method with accuracy in the range of 96-98% and a response time of 15 s, without any further pretreatment or chromatographic separation.

Optimization of biological and instrumental detection of explosives and ignitable liquid residues including canines, SPME/ITMS and GC/MSn

NASA Astrophysics Data System (ADS)

Furton, Kenneth G.; Harper, Ross J.; Perr, Jeannette M.; Almirall, Jose R.

2003-09-01

A comprehensive study and comparison is underway using biological detectors and instrumental methods for the rapid detection of ignitable liquid residues (ILR) and high explosives. Headspace solid phase microextraction (SPME) has been demonstrated to be an effective sampling method helping to identify active odor signature chemicals used by detector dogs to locate forensic specimens as well as a rapid pre-concentration technique prior to instrumental detection. Common ignitable liquids and common military and industrial explosives have been studied including trinitrotoluene, tetryl, RDX, HMX, EGDN, PETN and nitroglycerine. This study focuses on identifying volatile odor signature chemicals present, which can be used to enhance the level and reliability of detection of ILR and explosives by canines and instrumental methods. While most instrumental methods currently in use focus on particles and on parent organic compounds, which are often involatile, characteristic volatile organics are generally also present and can be exploited to enhance detection particularly for well-concealed devices. Specific examples include the volatile odor chemicals 2-ethyl-1-hexanol and cyclohexanone, which are readily available in the headspace of the high explosive composition C-4; whereas, the active chemical cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) is not. The analysis and identification of these headspace 'fingerprint' organics is followed by double-blind dog trials of the individual components using certified teams in an attempt to isolate and understand the target compounds to which dogs are sensitive. Studies to compare commonly used training aids with the actual target explosive have also been undertaken to determine their suitability and effectiveness. The optimization of solid phase microextraction (SPME) combined with ion trap mobility spectrometry (ITMS) and gas chromatography/mass spectrometry/mass spectrometry (GC/MSn) is detailed including interface development and comparisons of limits of detection. These instrumental methods are being optimized in order to detect the same target odor chemicals used by detector dogs to reliably locate explosives and ignitable liquids.

Method for position emission mammography image reconstruction

DOEpatents

Smith, Mark Frederick

2004-10-12

An image reconstruction method comprising accepting coincidence datat from either a data file or in real time from a pair of detector heads, culling event data that is outside a desired energy range, optionally saving the desired data for each detector position or for each pair of detector pixels on the two detector heads, and then reconstructing the image either by backprojection image reconstruction or by iterative image reconstruction. In the backprojection image reconstruction mode, rays are traced between centers of lines of response (LOR's), counts are then either allocated by nearest pixel interpolation or allocated by an overlap method and then corrected for geometric effects and attenuation and the data file updated. If the iterative image reconstruction option is selected, one implementation is to compute a grid Siddon retracing, and to perform maximum likelihood expectation maiximization (MLEM) computed by either: a) tracing parallel rays between subpixels on opposite detector heads; or b) tracing rays between randomized endpoint locations on opposite detector heads.

Protection of Public Figures. Symposium Proceedings, May 16-18, 1972

DTIC Science & Technology

1972-01-01

192 EXPLOSIVE TRACE VAPOR DETECTION, Maryland D. Keyrw, USAMERDC.. 194 ATOMIC AND MOLECULAR DETECTION...subject through a doorway, a hallway, a portal, a fence, and thus subject him to co- vert surveillance for weapons or explosives concealed on his person...who has weapons or conceal- ed explosives on his person. So insofar as 4ERDC is concerned, the two broad scenarios that we will be talking about are

Analytical approximations to the Hotelling trace for digital x-ray detectors

NASA Astrophysics Data System (ADS)

Clarkson, Eric; Pineda, Angel R.; Barrett, Harrison H.

2001-06-01

The Hotelling trace is the signal-to-noise ratio for the ideal linear observer in a detection task. We provide an analytical approximation for this figure of merit when the signal is known exactly and the background is generated by a stationary random process, and the imaging system is an ideal digital x-ray detector. This approximation is based on assuming that the detector is infinite in extent. We test this approximation for finite-size detectors by comparing it to exact calculations using matrix inversion of the data covariance matrix. After verifying the validity of the approximation under a variety of circumstances, we use it to generate plots of the Hotelling trace as a function of pairs of parameters of the system, the signal and the background.

Chemical Sensing of Unexploded Ordnance with the Mobile Underwater Survey System (MUDSS)

NASA Technical Reports Server (NTRS)

Chutjian, A.; Darrach, M.

1999-01-01

The ability to sense explosives residues in the marine environment is a critical tool for identification and classification of underwater unexploded ordnance (UXO). Trace explosives signatures of TNT and DNT have been extracted from mulitple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada.

Compton scattering artifacts in electron excited X-ray spectra measured with a silicon drift detector.

PubMed

Ritchie, Nicholas W M; Newbury, Dale E; Lindstrom, Abigail P

2011-12-01

Artifacts are the nemesis of trace element analysis in electron-excited energy dispersive X-ray spectrometry. Peaks that result from nonideal behavior in the detector or sample can fool even an experienced microanalyst into believing that they have trace amounts of an element that is not present. Many artifacts, such as the Si escape peak, absorption edges, and coincidence peaks, can be traced to the detector. Others, such as secondary fluorescence peaks and scatter peaks, can be traced to the sample. We have identified a new sample-dependent artifact that we attribute to Compton scattering of energetic X-rays generated in a small feature and subsequently scattered from a low atomic number matrix. It seems likely that this artifact has not previously been reported because it only occurs under specific conditions and represents a relatively small signal. However, with the advent of silicon drift detectors and their utility for trace element analysis, we anticipate that more people will observe it and possibly misidentify it. Though small, the artifact is not inconsequential. Under some conditions, it is possible to mistakenly identify the Compton scatter artifact as approximately 1% of an element that is not present.

Portable and Reliable Surface-Enhanced Raman Scattering Silicon Chip for Signal-On Detection of Trace Trinitrotoluene Explosive in Real Systems.

PubMed

Chen, Na; Ding, Pan; Shi, Yu; Jin, Tengyu; Su, Yuanyuan; Wang, Houyu; He, Yao

2017-05-02

There is an increasing interest in the development of surface-enhanced Raman scattering (SERS) sensors for rapid and accurate on-site detection of hidden explosives. However, portable SERS methods for trace explosive detection in real systems remain scarce, mainly due to their relatively poor reliability and portability. Herein, we present the first demonstration of a portable silicon-based SERS analytical platform for signal-on detection of trace trinitrotoluene (TNT) explosives, which is made of silver nanoparticle (AgNP)-decorated silicon wafer chip (0.5 cm × 0.5 cm). In principle, under 514 nm excitation, the Raman signals of p-aminobenzenethiol (PABT) modified on the AgNP surface could be largely lit up due to the formation of electronic resonance-active TNT-PABT complex. In addition, the surface of AgNPs and silicon substrate-induced plasmon resonances also contribute the total SERS enhancement. For quantitative evaluation, the as-prepared chip features ultrahigh sensitivity [limit of detection is down to ∼1 pM (∼45.4 fg/cm 2 )] and adaptable reproducibility (relative standard deviation is less than 15%) in the detection of TNT standard solutions. More importantly, the developed chip can couple well with a hand-held Raman spectroscopic device using 785 nm excitation, suitable for qualitative analysis of trace TNT even at ∼10 -8 M level from environmental samples including lake water, soil, envelope, and liquor with a short data acquisition time (∼1 min). Furthermore, TNT vapors diffusing from TNT residues (∼10 -6 M) can be detected by using such a portable device, indicating its feasibility in determination of hidden samples.

Detection of an explosive simulant via electrical impedance spectroscopy utilizing the UiO-66-NH2 metal-organic framework.

PubMed

Peterson, G W; McEntee, M; Harris, C R; Klevitch, A D; Fountain, A W; Soliz, J R; Balboa, A; Hauser, A J

2016-11-01

Electrical impedance spectroscopy, in conjunction with the metal-organic framework (MOF) UiO-66-NH 2 , is used to detect trace levels of the explosive simulant 2,6-dinitrotoluene. The combination of porosity and functionality of the MOF provides an effective dielectric structure, resulting in changes of impedance magnitude and phase angle. The promising data indicate that MOFs may be used in low-cost, robust explosive detection devices.

SWAN - Detection of explosives by means of fast neutron activation analysis

NASA Astrophysics Data System (ADS)

Gierlik, M.; Borsuk, S.; Guzik, Z.; Iwanowska, J.; Kaźmierczak, Ł.; Korolczuk, S.; Kozłowski, T.; Krakowski, T.; Marcinkowski, R.; Swiderski, L.; Szeptycka, M.; Szewiński, J.; Urban, A.

2016-10-01

In this work we report on SWAN, the experimental, portable device for explosives detection. The device was created as part of the EU Structural Funds Project "Accelerators & Detectors" (POIG.01.01.02-14-012/08-00), with the goal to increase beneficiary's expertise and competencies in the field of neutron activation analysis. Previous experiences and budged limitations lead toward a less advanced design based on fast neutron interactions and unsophisticated data analysis with the emphasis on the latest gamma detection and spectrometry solutions. The final device has been designed as a portable, fast neutron activation analyzer, with the software optimized for detection of carbon, nitrogen and oxygen. SWAN's performance in the role of explosives detector is elaborated in this paper. We demonstrate that the unique features offered by neutron activation analysis might not be impressive enough when confronted with practical demands and expectations of a generic homeland security customer.

Hidden explosives detector employing pulsed neutron and x-ray interrogation

DOEpatents

Schultz, F.J.; Caldwell, J.T.

1993-04-06

Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

Hidden explosives detector employing pulsed neutron and x-ray interrogation

DOEpatents

Schultz, Frederick J.; Caldwell, John T.

1993-01-01

Methods and systems for the detection of small amounts of modern, highly-explosive nitrogen-based explosives, such as plastic explosives, hidden in airline baggage. Several techniques are employed either individually or combined in a hybrid system. One technique employed in combination is X-ray imaging. Another technique is interrogation with a pulsed neutron source in a two-phase mode of operation to image both nitrogen and oxygen densities. Another technique employed in combination is neutron interrogation to form a hydrogen density image or three-dimensional map. In addition, deliberately-placed neutron-absorbing materials can be detected.

Nanoporous Substrate with Mixed Nanoclusters for Surface Enhanced Raman Scattering.

NASA Astrophysics Data System (ADS)

Chang, Sehoon; Ko, Hyunhyub; Singamaneni, Srikanth; Gunawidjaja, Ray; Tsukruk, Vladimir

2009-03-01

Rapid detection of plastic and liquid explosives is an urgent need due to various societal and technological reasons. We employed a novel design of surface enhanced Raman scattering (SERS)-active substrate based on porous alumina membranes decorated with mixed nanoclusters of gold nanorods and nanoparticles. We demonstrated trace level detection of several important explosives such as dinitrotolene (DNT), trinitrotoluene (TNT), and hexamethylenetriperoxidediamine (HMTD) by fast, sensitive, reliable Raman spectroscopic method. We achieved near molecular-level detection (about 15˜ 30 molecules) of DNT and TNT utilizing the SERS substrate. However, trace level detection is challenging due to the lack of common optical signatures (fluorescence, absorption in UV-vis range) or chemical functionality of peroxide-based explosives such as HMTD. To overcome this, we employed photochemical decomposition approach and analyzed chemical fragments using SERS. We suggest that tailored polymer coating, mixed nanoclusters, and laser-induced photocatalytic decomposition are all critical for achieving this unprecedented sensitivity level..

Handheld detector using NIR for bottled liquid explosives

NASA Astrophysics Data System (ADS)

Itozaki, Hideo; Sato-Akaba, Hideo

2014-10-01

A handheld bottle checker for detection of liquid explosives is developed using near infrared technology. In order to make it compact, a LED light was used as a light source and a novel circuit board was developed for the device control instead of using a PC. This enables low power consumption and this handheld detector can be powered by a Li-ion battery without an AC power supply. This checker works well to analyze liquids, even using limited bandwidth of NIR by the LED. It is expected that it can be applied not only to airport security but also to wider applications because of its compactness and portability.

Design and field results of a walk-through EDS

NASA Astrophysics Data System (ADS)

Wendel, Gregory J.; Bromberg, Edward E.; Durfee, Memorie K.; Curby, William A.

1997-01-01

A walk-through portal sampling module which incorporates active sampling has been developed. The module uses opposing wands which actively brush the subjects exterior clothing to disturb explosive traces. These traces are entrained in an air stream and transported to a High Speed GC- chemiluminescence explosives detection system. This combination provides automatic screening of passengers at rates of 10 per minute. The system exhibits sensitivity and selectivity which equals or betters that available from commercially available manual equipment. The systems has been developed for deployment at border crossings, airports and other security screening points. Detailed results of laboratory tests and airport field trials are reviewed.

Neutrinos from type Ia supernovae: The gravitationally confined detonation scenario

NASA Astrophysics Data System (ADS)

Wright, Warren P.; Kneller, James P.; Ohlmann, Sebastian T.; Röpke, Friedrich K.; Scholberg, Kate; Seitenzahl, Ivo R.

2017-02-01

Despite their use as cosmological distance indicators and their importance in the chemical evolution of galaxies, the unequivocal identification of the progenitor systems and explosion mechanism of normal type Ia supernovae (SNe Ia) remains elusive. The leading hypothesis is that such a supernova is a thermonuclear explosion of a carbon-oxygen white dwarf, but the exact explosion mechanism is still a matter of debate. Observation of a galactic SN Ia would be of immense value in answering the many open questions related to these events. One potentially useful source of information about the explosion mechanism and progenitor is the neutrino signal because the neutrinos from the different mechanisms possess distinct spectra as a function of time and energy. In this paper, we compute the expected neutrino signal from a gravitationally confined detonation (GCD) explosion scenario for a SN Ia and show how the flux at Earth contains features in time and energy unique to this scenario. We then calculate the expected event rates in the Super-K, Hyper-K, JUNO, DUNE, and IceCube detectors and find both Hyper-K and IceCube will see a few events for a GCD supernova at 1 kpc or closer, while Super-K, JUNO, and DUNE will see events if the supernova is closer than ˜0.3 kpc . The distance and detector criteria needed to resolve the time and spectral features arising from the explosion mechanism, neutrino production, and neutrino oscillation processes are also discussed. The neutrino signal from the GCD is then compared with the signal from a deflagration-to-detonation transition (DDT) explosion model computed previously. We find the overall event rate is the most discriminating feature between the two scenarios followed by the event rate time structure. Using the event rate in the Hyper-K detector alone, the DDT can be distinguished from the GCD at 2 σ if the distance to the supernova is less than 2.3 kpc for a normal mass ordering and 3.6 kpc for an inverted ordering.

UV gated Raman spectroscopy for standoff detection of explosives

NASA Astrophysics Data System (ADS)

Gaft, M.; Nagli, L.

2008-07-01

Real-time detection and identification of explosives at a standoff distance is a major issue in efforts to develop defense against so-called improvised explosive devices (IED). It is recognized that the only method, which is potentially capable to standoff detection of minimal amounts of explosives is laser-based spectroscopy. LDS technique belongs to trace detection, namely to its micro-particles variety. It is based on commonly held belief that surface contamination was very difficult to avoid and could be exploited for standoff detection. We have applied gated Raman spectroscopy for detection of main explosive materials, both factory and homemade. We developed and tested a Raman system for the field remote detection and identification of minimal amounts of explosives on relevant surfaces at a distance of up to 30 m.

135Xe measurements with a two-element CZT-based radioxenon detector for nuclear explosion monitoring.

PubMed

Ranjbar, Lily; Farsoni, Abi T; Becker, Eric M

2017-04-01

Measurement of elevated concentrations of xenon radioisotopes ( 131m Xe, 133m Xe, 133 Xe and 135 Xe) in the atmosphere has been shown to be a very powerful method for verifying whether or not a detected explosion is nuclear in nature. These isotopes are among the few with enough mobility and with half-lives long enough to make their detection at long distances realistic. Existing radioxenon detection systems used by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) suffer from problems such as complexity, need for high maintenance and memory effect. To study the response of CdZnTe (CZT) detectors to xenon radioisotopes and investigate whether it is capable of mitigating the aforementioned issues with the current radioxenon detection systems, a prototype detector utilizing two coplanar CZT detectors was built and tested at Oregon State University. The detection system measures xenon radioisotopes through beta-gamma coincidence technique by detecting coincidence events between the two detectors. In this paper, we introduce the detector design and report our measurement results with radioactive lab sources and 135 Xe produced in the OSU TRIGA reactor. Minimum Detectable Concentration (MDC) for 135 Xe was calculated to be 1.47 ± 0.05 mBq/m 3 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of Trace Concentration in TMD Detectors using PGAA

NASA Astrophysics Data System (ADS)

Tomandl, I.; Viererbl, L.; Kudějová, P.; Lahodová, Z.; Klupák, V.; Fikrle, M.

2015-05-01

Transmutation detectors could be alternative to the traditional activation detector method for neutron fluence dosimetry at power nuclear reactors. This new method require an isotopically highly-sensitive, non-destructive in sense of compactness as well as isotopic content, precise and standardly used analytical method for trace concentration determination. The capability of Prompt Gamma-ray Activation Analysis (PGAA) for determination of trace concentrations of transmuted stable nuclides in the metallic foils of Ni, Au, Cu and Nb, which were irradiated for 21 days in the reactor core at the LVR-15 research reactor in Řež, is reported. The PGAA measurements of these activation foils were performed at the PGAA facility at Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRMII) in Garching.

Explosives Detection: Exploitation of the Physical Signatures

NASA Astrophysics Data System (ADS)

Atkinson, David

2010-10-01

Explosives based terrorism is an ongoing threat that is evolving with respect to implementation, configuration and materials used. There are a variety of devices designed to detect explosive devices, however, each technology has limitations and operational constraints. A full understanding of the signatures available for detection coupled with the array of detection choices can be used to develop a conceptual model of an explosives screening operation. Physics based sensors provide a robust approach to explosives detection, typically through the identification of anomalies, and are currently used for screening in airports around the world. The next generation of detectors for explosives detection will need to be more sensitive and selective, as well as integrate seamlessly with devices focused on chemical signatures. An appreciation for the details of the physical signature exploitation in cluttered environments with time, space, and privacy constraints is necessary for effective explosives screening of people, luggage, cargo, and vehicles.

Supersensitive fingerprinting of explosives by chemically modified nanosensors arrays.

PubMed

Lichtenstein, Amir; Havivi, Ehud; Shacham, Ronen; Hahamy, Ehud; Leibovich, Ronit; Pevzner, Alexander; Krivitsky, Vadim; Davivi, Guy; Presman, Igor; Elnathan, Roey; Engel, Yoni; Flaxer, Eli; Patolsky, Fernando

2014-06-24

The capability to detect traces of explosives sensitively, selectively and rapidly could be of great benefit for applications relating to civilian national security and military needs. Here, we show that, when chemically modified in a multiplexed mode, nanoelectrical devices arrays enable the supersensitive discriminative detection of explosive species. The fingerprinting of explosives is achieved by pattern recognizing the inherent kinetics, and thermodynamics, of interaction between the chemically modified nanosensors array and the molecular analytes under test. This platform allows for the rapid detection of explosives, from air collected samples, down to the parts-per-quadrillion concentration range, and represents the first nanotechnology-inspired demonstration on the selective supersensitive detection of explosives, including the nitro- and peroxide-derivatives, on a single electronic platform. Furthermore, the ultrahigh sensitivity displayed by our platform may allow the remote detection of various explosives, a task unachieved by existing detection technologies.

Supersensitive fingerprinting of explosives by chemically modified nanosensors arrays

NASA Astrophysics Data System (ADS)

Lichtenstein, Amir; Havivi, Ehud; Shacham, Ronen; Hahamy, Ehud; Leibovich, Ronit; Pevzner, Alexander; Krivitsky, Vadim; Davivi, Guy; Presman, Igor; Elnathan, Roey; Engel, Yoni; Flaxer, Eli; Patolsky, Fernando

2014-06-01

The capability to detect traces of explosives sensitively, selectively and rapidly could be of great benefit for applications relating to civilian national security and military needs. Here, we show that, when chemically modified in a multiplexed mode, nanoelectrical devices arrays enable the supersensitive discriminative detection of explosive species. The fingerprinting of explosives is achieved by pattern recognizing the inherent kinetics, and thermodynamics, of interaction between the chemically modified nanosensors array and the molecular analytes under test. This platform allows for the rapid detection of explosives, from air collected samples, down to the parts-per-quadrillion concentration range, and represents the first nanotechnology-inspired demonstration on the selective supersensitive detection of explosives, including the nitro- and peroxide-derivatives, on a single electronic platform. Furthermore, the ultrahigh sensitivity displayed by our platform may allow the remote detection of various explosives, a task unachieved by existing detection technologies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Seong-Wook; Tian, Chao; Martini, Rainer, E-mail: rmartini@stevens.edu

We demonstrated highly sensitive detection of explosive dissolved in solvent with a portable spectroscopy system (Q-MACS) by tracing the explosive byproduct, N{sub 2}O, in combination with a pulsed electric discharge system for safe explosive decomposition. Using Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), the gas was monitored and analyzed by Q-MACS and the presence of the dissolved explosive clearly detected. While HMX presence could be identified directly in the air above the solutions even without plasma, much better results were achieved under the decomposition. The experiment results give an estimated detection limit of 10 ppb, which corresponds to a 15 pg of HMX.

Detection device for high explosives

DOEpatents

Grey, Alan E.; Partin, Judy K.; Stone, Mark L.; Von Wandruszka, Ray M.; Reagen, William K.; Ingram, Jani C.; Lancaster, Gregory D.

1992-01-01

A portable fiber optic detector that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator.

Identification of Explosives from Porous Materials: Applications Using Reverse Phase High Performance Liquid Chromatography and Gas Chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

C.J. Miller; G. Elias; N.C. Schmitt

2010-06-01

High performance liquid chromatography and gas chromatography techniques are well documented and widely used for the detection of trace explosives from organic solvents. These techniques were modified to specifically identify and quantify explosives extracted from various materials taken from people who had recently handled explosives. Documented techniques were modified to specifically detect and quantify RDX, TNT, and PETN from denim, colored flannel, vinyl, and canvas extracted in methanol using no sample cleanup prior to analysis. The methanol extracts were injected directly into several different column types and analyzed by HPLC-UV and/or GC-ECD. This paper describes general screening methods that weremore » used to determine the presence of explosives in unknown samples and techniques that have been optimized for quantification of each explosive from the substrate extracts.« less

Preliminary Monte Carlo calculations for the UNCOSS neutron-based explosive detector

NASA Astrophysics Data System (ADS)

Eleon, C.; Perot, B.; Carasco, C.

2010-07-01

The goal of the FP7 UNCOSS project (Underwater Coastal Sea Surveyor) is to develop a non destructive explosive detection system based on the associated particle technique, in view to improve the security of coastal area and naval infrastructures where violent conflicts took place. The end product of the project will be a prototype of a complete coastal survey system, including a neutron-based sensor capable of confirming the presence of explosives on the sea bottom. A 3D analysis of prompt gamma rays induced by 14 MeV neutrons will be performed to identify elements constituting common military explosives, such as C, N and O. This paper presents calculations performed with the MCNPX computer code to support the ongoing design studies performed by the UNCOSS collaboration. Detection efficiencies, time and energy resolutions of the possible gamma-ray detectors are compared, which show NaI(Tl) or LaBr 3(Ce) scintillators will be suitable for this application. The effect of neutron attenuation and scattering in the seawater, influencing the counting statistics and signal-to-noise ratio, are also studied with calculated neutron time-of-flight and gamma-ray spectra for an underwater TNT target.

Infrared photothermal imaging of trace explosives on relevant substrates

NASA Astrophysics Data System (ADS)

Kendziora, Christopher A.; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Borchert, James; Byers, Jeff; McGill, R. Andrew

2013-06-01

We are developing a technique for the stand-off detection of trace explosives on relevant substrate surfaces using photo-thermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more compact IR quantum cascade lasers, tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface and detect small increases in thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral and temporal dimensions as vectors within a detection algorithm. The ability to detect trace analytes on relevant substrates is critical for stand-off applications, but is complicated by the optical and thermal analyte/substrate interactions. This manuscript describes recent PT-IRIS experimental results and analysis for traces of RDX, TNT, ammonium nitrate (AN) and sucrose on relevant substrates (steel, polyethylene, glass and painted steel panels). We demonstrate that these analytes can be detected on these substrates at relevant surface mass loadings (10 μg/cm2 to 100 μg/cm2) even at the single pixel level.

Bomb swab: Can trace explosive particle sampling and detection be improved?

PubMed

Fisher, Danny; Zach, Raya; Matana, Yossef; Elia, Paz; Shustack, Shiran; Sharon, Yarden; Zeiri, Yehuda

2017-11-01

The marked increase in international terror in recent years requires the development of highly efficient methods to detect trace amounts of explosives at airports, border crossings and check points. The preferred analytical method worldwide is the ion mobility spectrometry (IMS) that is capable of detecting most explosives at the nano-gram level. Sample collection for the IMS analysis is based on swabbing of a passenger's belongings to collect possible explosive residues. The present study examines a wide range of issues related to swab-based particle collection and analysis, in the hope of gaining deeper understanding into this technique that will serve to improve the detection process. The adhesion of explosive particles to three typical materials, plastic, metal and glass, were measured using atomic force microscopy (AFM). We found that a strong contribution of capillary forces to adhesion on glass and metal surfaces renders these substrates more promising materials upon which to find and collect explosive residues. The adhesion of explosives to different swipe materials was also examined. Here we found that Muslin, Nomex ® and polyamide membrane surfaces are the most promising materials for use as swipes. Subsequently, the efficiency of multiple swipe use - for collecting explosive residues from a glass surface using Muslin, Nomex ® and Teflon™ swipes - was examined. The study suggests that swipes used in about 5-10 "sampling and analysis cycles" have higher efficiency as compared to new unused swipes. The reason for this behavior was found to be related to the increased roughness of the swipe surface following a few swab measurements. Lastly, GC-MS analysis was employed to examine the nature of contaminants collected by the three types of swipe. The relative amounts of different contaminants are reported. The existence and interference of these contaminants have to be considered in relation to the detection efficiency of the various explosives by the IMS. Copyright © 2017 Elsevier B.V. All rights reserved.

Microcantilever detector for explosives

DOEpatents

Thundat, Thomas G.

1999-01-01

Methods and apparatus for detecting the presence of explosives by analyzing a vapor sample from the suspect vicinity utilize at least one microcantilever. Explosive gas molecules which have been adsorbed onto the microcantilever are subsequently heated to cause combustion. Heat, along with momentum transfer from combustion, causes bending and a transient resonance response of the microcantilever which may be detected by a laser diode which is focused on the microcantilever and a photodetector which detects deflection of the reflected laser beam caused by heat-induced deflection and resonance response of the microcantilever.

Determination of nitroaromatic explosives and their degradation products in unsaturated-zone water samples by high-performance liquid chromatography with photodiode-array, mass spectrometric, and tandem mass spectrometric detection

USGS Publications Warehouse

Gates, Paul M.; Furlong, E.T.; Dorsey, T.F.; Burkhardt, M.R.

1996-01-01

Mass spectrometry and tandem mass spectrometry, coupled by a thermospray interface to a high-performance liguid chromatography system and equipped with a photodiode array detector, were used to determine the presence of nitroaromatic explosives and their degradation products in USA unsaturated-zone water samples. Using this approach, the lower limits of quantitation for explosives determined by mass spectrometry in this study typically ranged from 10 to 100 ng/l.

Microcantilever detector for explosives

DOEpatents

Thundat, T.G.

1999-06-29

Methods and apparatus for detecting the presence of explosives by analyzing a vapor sample from the suspect vicinity utilize at least one microcantilever. Explosive gas molecules which have been adsorbed onto the microcantilever are subsequently heated to cause combustion. Heat, along with momentum transfer from combustion, causes bending and a transient resonance response of the microcantilever which may be detected by a laser diode which is focused on the microcantilever and a photodetector which detects deflection of the reflected laser beam caused by heat-induced deflection and resonance response of the microcantilever. 2 figs.

Urea nitrate, an exceptionally easy-to-make improvised explosive: studies towards trace characterization.

PubMed

Tamiri, Tsippy; Rozin, Rinat; Lemberger, Nitay; Almog, Joseph

2009-09-01

Urea nitrate is a powerful improvised explosive, frequently used by terrorists in the Israeli arena. It was also used in the first World Trade Center bombing in New York in February 1993. It is difficult to identify urea nitrate in post-explosion debris, since only a very small fraction survives the blast. Also, in the presence of water, it readily decomposes to its original components, urea and nitric acid. It is suspected that post-blast debris of urea nitrate can be confused with ammonium nitrate, the main solid product of urea nitrate thermal decomposition. In a comprehensive study towards identification of urea nitrate in post-blast traces, a spectrophotometric technique for quantitative determination of urea nitrate was developed, and conditions were found for extraction and separation of un-exploded traces of urea nitrate with minimal decomposition. Nevertheless, out of 28 samples collected from a series of three controlled firings of urea nitrate charges, only one gave the typical adduct ion by liquid chromatography/mass spectrometry analysis. We found that urea nitrate can be extracted from solid mixtures to organic solvents by using Crown ethers as "host compounds." The adducts thus formed are solid, crystalline compounds that can be characterized by microanalysis and spectroscopic techniques.

A risk-based approach to flammable gas detector spacing.

PubMed

Defriend, Stephen; Dejmek, Mark; Porter, Leisa; Deshotels, Bob; Natvig, Bernt

2008-11-15

Flammable gas detectors allow an operating company to address leaks before they become serious, by automatically alarming and by initiating isolation and safe venting. Without effective gas detection, there is very limited defense against a flammable gas leak developing into a fire or explosion that could cause loss of life or escalate to cascading failures of nearby vessels, piping, and equipment. While it is commonly recognized that some gas detectors are needed in a process plant containing flammable gas or volatile liquids, there is usually a question of how many are needed. The areas that need protection can be determined by dispersion modeling from potential leak sites. Within the areas that must be protected, the spacing of detectors (or alternatively, number of detectors) should be based on risk. Detector design can be characterized by spacing criteria, which is convenient for design - or alternatively by number of detectors, which is convenient for cost reporting. The factors that influence the risk are site-specific, including process conditions, chemical composition, number of potential leak sites, piping design standards, arrangement of plant equipment and structures, design of isolation and depressurization systems, and frequency of detector testing. Site-specific factors such as those just mentioned affect the size of flammable gas cloud that must be detected (within a specified probability) by the gas detection system. A probability of detection must be specified that gives a design with a tolerable risk of fires and explosions. To determine the optimum spacing of detectors, it is important to consider the probability that a detector will fail at some time and be inoperative until replaced or repaired. A cost-effective approach is based on the combined risk from a representative selection of leakage scenarios, rather than a worst-case evaluation. This means that probability and severity of leak consequences must be evaluated together. In marine and offshore facilities, it is conventional to use computational fluid dynamics (CFD) modeling to determine the size of a flammable cloud that would result from a specific leak scenario. Simpler modeling methods can be used, but the results are not very accurate in the region near the release, especially where flow obstructions are present. The results from CFD analyses on several leak scenarios can be plotted to determine the size of a flammable cloud that could result in an explosion that would generate overpressure exceeding the strength of the mechanical design of the plant. A cloud of this size has the potential to produce a blast pressure or flying debris capable of causing a fatality or subsequent damage to vessels or piping containing hazardous material. In cases where the leak results in a fire, rather than explosion, CFD or other modeling methods can estimate the size of a leak that would cause a fire resulting in subsequent damage to the facility, or would prevent the safe escape of personnel. The gas detector system must be capable of detecting a gas release or vapor cloud, and initiating action to prevent the leak from reaching a size that could cause injury or severe damage upon ignition.

Underwater olfaction for real-time detection of submerged unexploded ordnance

NASA Astrophysics Data System (ADS)

Harper, Ross J.; Dock, Matthew L.

2007-04-01

The presence of Underwater Unexploded Ordnance (UUXO) represents a considerable threat in the marine environment. Elevated concentrations of dissolved explosive compounds, such as TNT and RDX, may be produced in the vicinity of degraded UUXO shell casings and are known to have significant toxicant effects on local marine organisms. During World War II and in subsequent years, the US military inadvertently or, in some cases intentionally, deposited many thousands of tons of UUXO in US coastal waters. Much of this material is difficult to locate by magnetometry or sonar imaging techniques, and can be extremely challenging to identify by visual means after lying on the bottom of the ocean for several decades. The present work is focused on advances in underwater olfaction, wherein trace amounts of dissolved explosive compounds may be detected and discriminated from other chemical species found in the marine environment, for the purpose of establishing safe cordons and/or neutralization of the explosives. ICx Nomadics has developed the first known real-time sensor system that is capable of detecting chemical signatures emanating from underwater explosives. The SeaPup sensor, which is based on the fluorescence-quenching transduction mechanism of an amplifying fluorescent polymer (AFP), is capable of real-time detection of the trace chemical signatures emanating from submerged explosive compounds. The SeaPup system has been successfully tested on various marine platforms, including a crawler robot, an autonomous underwater vehicle (AUV), and a remotely operated underwater vehicle (ROV). In one study, the SeaPup was shown to effectively map liquid phase "explosive scent plumes" emanating from an underwater source of TNT. The presented paper will provide an overview of the history, current status, and future development of explosive analyte detection in the underwater environment.

Broad spectrum infrared thermal desorption of wipe-based explosive and narcotic samples for trace mass spectrometric detection.

PubMed

Forbes, Thomas P; Staymates, Matthew; Sisco, Edward

2017-08-07

Wipe collected analytes were thermally desorbed using broad spectrum near infrared heating for mass spectrometric detection. Employing a twin tube filament-based infrared emitter, rapid and efficiently powered thermal desorption and detection of nanogram levels of explosives and narcotics was demonstrated. The infrared thermal desorption (IRTD) platform developed here used multi-mode heating (direct radiation and secondary conduction from substrate and subsequent convection from air) and a temperature ramp to efficiently desorb analytes with vapor pressures across eight orders of magnitude. The wipe substrate experienced heating rates up to (85 ± 2) °C s -1 with a time constant of (3.9 ± 0.2) s for 100% power emission. The detection of trace analytes was also demonstrated from complex mixtures, including plastic-bonded explosives and exogenous narcotics, explosives, and metabolites from collected artificial latent fingerprints. Manipulation of the emission power and duration directly controlled the heating rate and maximum temperature, enabling differential thermal desorption and a level of upstream separation for enhanced specificity. Transitioning from 100% power and 5 s emission duration to 25% power and 30 s emission enabled an order of magnitude increase in the temporal separation (single seconds to tens of seconds) of the desorption of volatile and semi-volatile species within a collected fingerprint. This mode of operation reduced local gas-phase concentrations, reducing matrix effects experienced with high concentration mixtures. IRTD provides a unique platform for the desorption of trace analytes from wipe collections, an area of importance to the security sector, transportation agencies, and customs and border protection.

Digital micromirror devices in Raman trace detection of explosives

NASA Astrophysics Data System (ADS)

Glimtoft, Martin; Svanqvist, Mattias; Ågren, Matilda; Nordberg, Markus; Östmark, Henric

2016-05-01

Imaging Raman spectroscopy based on tunable filters is an established technique for detecting single explosives particles at stand-off distances. However, large light losses are inherent in the design due to sequential imaging at different wavelengths, leading to effective transmission often well below 1 %. The use of digital micromirror devices (DMD) and compressive sensing (CS) in imaging Raman explosives trace detection can improve light throughput and add significant flexibility compared to existing systems. DMDs are based on mature microelectronics technology, and are compact, scalable, and can be customized for specific tasks, including new functions not available with current technologies. This paper has been focusing on investigating how a DMD can be used when applying CS-based imaging Raman spectroscopy on stand-off explosives trace detection, and evaluating the performance in terms of light throughput, image reconstruction ability and potential detection limits. This type of setup also gives the possibility to combine imaging Raman with non-spatially resolved fluorescence suppression techniques, such as Kerr gating. The system used consists of a 2nd harmonics Nd:YAG laser for sample excitation, collection optics, DMD, CMOScamera and a spectrometer with ICCD camera for signal gating and detection. Initial results for compressive sensing imaging Raman shows a stable reconstruction procedure even at low signals and in presence of interfering background signal. It is also shown to give increased effective light transmission without sacrificing molecular specificity or area coverage compared to filter based imaging Raman. At the same time it adds flexibility so the setup can be customized for new functionality.

Detection device for high explosives

DOEpatents

Grey, A.E.; Partin, J.K.; Stone, M.L.; Von Wandruszka, R.M.; Reagen, W.K.; Ingram, J.C.; Lancaster, G.D.

1992-10-20

A portable fiber optic detector is described that senses the presence of specific target chemicals by electrostatically attracting the target chemical to an aromatic compound coating on an optical fiber. Attaching the target chemical to the coated fiber reduces the fluorescence so that a photon sensing detector records the reduced light level and activates an appropriate alarm or indicator. 5 figs.

Modeling of Pixelated Detector in SPECT Pinhole Reconstruction.

PubMed

Feng, Bing; Zeng, Gengsheng L

2014-04-10

A challenge for the pixelated detector is that the detector response of a gamma-ray photon varies with the incident angle and the incident location within a crystal. The normalization map obtained by measuring the flood of a point-source at a large distance can lead to artifacts in reconstructed images. In this work, we investigated a method of generating normalization maps by ray-tracing through the pixelated detector based on the imaging geometry and the photo-peak energy for the specific isotope. The normalization is defined for each pinhole as the normalized detector response for a point-source placed at the focal point of the pinhole. Ray-tracing is used to generate the ideal flood image for a point-source. Each crystal pitch area on the back of the detector is divided into 60 × 60 sub-pixels. Lines are obtained by connecting between a point-source and the centers of sub-pixels inside each crystal pitch area. For each line ray-tracing starts from the entrance point at the detector face and ends at the center of a sub-pixel on the back of the detector. Only the attenuation by NaI(Tl) crystals along each ray is assumed to contribute directly to the flood image. The attenuation by the silica (SiO 2 ) reflector is also included in the ray-tracing. To calculate the normalization for a pinhole, we need to calculate the ideal flood for a point-source at 360 mm distance (where the point-source was placed for the regular flood measurement) and the ideal flood image for the point-source at the pinhole focal point, together with the flood measurement at 360 mm distance. The normalizations are incorporated in the iterative OSEM reconstruction as a component of the projection matrix. Applications to single-pinhole and multi-pinhole imaging showed that this method greatly reduced the reconstruction artifacts.

Comparing performances of a CdTe X-ray spectroscopic detector and an X-ray dual-energy sandwich detector

NASA Astrophysics Data System (ADS)

Gorecki, A.; Brambilla, A.; Moulin, V.; Gaborieau, E.; Radisson, P.; Verger, L.

2013-11-01

Multi-energy (ME) detectors are becoming a serious alternative to classical dual-energy sandwich (DE-S) detectors for X-ray applications such as medical imaging or explosive detection. They can use the full X-ray spectrum of irradiated materials, rather than disposing only of low and high energy measurements, which may be mixed. In this article, we intend to compare both simulated and real industrial detection systems, operating at a high count rate, independently of the dimensions of the measurements and independently of any signal processing methods. Simulations or prototypes of similar detectors have already been compared (see [1] for instance), but never independently of estimation methods and never with real detectors. We have simulated both an ME detector made of CdTe - based on the characteristics of the MultiX ME100 and - a DE-S detector - based on the characteristics of the Detection Technology's X-Card 1.5-64DE model. These detectors were compared to a perfect spectroscopic detector and an optimal DE-S detector. For comparison purposes, two approaches were investigated. The first approach addresses how to distinguise signals, while the second relates to identifying materials. Performance criteria were defined and comparisons were made over a range of material thicknesses and with different photon statistics. Experimental measurements in a specific configuration were acquired to checks simulations. Results showed good agreement between the ME simulation and the ME100 detector. Both criteria seem to be equivalent, and the ME detector performs 3.5 times better than the DE-S detector with same photon statistics based on simulations and experimental measurements. Regardless of the photon statistics ME detectors appeared more efficient than DE-S detectors for all material thicknesses between 1 and 9 cm when measuring plastics with an attenuation signature close that of explosive materials. This translates into an improved false detection rate (FDR): DE-S detectors have an FDR 2.87±0.03-fold higher than ME detectors for 4 cm of POM with 20 000 incident photons, when identifications are screened against a two-material base.

Standoff laser-based spectroscopy for explosives detection

NASA Astrophysics Data System (ADS)

Gaft, M.; Nagli, L.

2007-10-01

Real time detection and identification of explosives at a standoff distance is a major issue in efforts to develop defense against so-called Improvised Explosive Devices (IED). It is recognized that the only technique, which is potentially capable to standoff detection of minimal amounts of explosives is laser-based spectroscopy. LDS activity is based on a combination of laser-based spectroscopic methods with orthogonal capabilities. Our technique belongs to trace detection, namely to its micro-particles variety. It is based on commonly held belief that surface contamination was very difficult to avoid and could be exploited for standoff detection. We has applied optical techniques including gated Raman and time-resolved luminescence spectroscopy for detection of main explosive materials, both factory and homemade. We developed and tested a Raman system for the field remote detection and identification of minimal amounts of explosives on relevant surfaces at a distance of up to 30 meters.

Applications of Quantum Cascade Laser Scanners for Remote Detection of Chemical and Biological Threats and Weapons of Mass Destruction

DTIC Science & Technology

2014-07-09

Rivera. Highly Sensitive Filter Paper Substrate for SERS Trace Explosives Detection , International Journal of Spectroscopy, (09 2012): 0. doi: 10.1155...Highly Sensitive Filter Paper Substrate for SERS Field Detection of Trace Threat Chemicals”, PITTCON-2013: Forensic Analysis in the Lab and Crime Scene...the surface. In addition, built-in algorithms were used for nearly real-time sample detection . Trace and bulk concentrations of the other substances

Methodology to Improve Aviation Security With Terrorist Using Aircraft as a Weapon

DTIC Science & Technology

2013-09-01

STATEMENT Approval for public release;distribution is unlimited 12b. DISTRIBUTION CODE 13. ABSTRACT (maximum 200 words ) The aviation industry... Electronic Baggage Screening Program EDS Explosive Detection System EMMI Energy, Matter, Material wealth, and Information ETD Explosives Trace...12 All checked baggage in the United States has been subjected to 100% screening since December 2003 under TSA’s Electronic Baggage Screening

Quantum Cascade Laser (QCL) based sensor for the detection of explosive compounds

NASA Astrophysics Data System (ADS)

Normand, Erwan; Howieson, Iain; McCulloch, Michael; Black, Paul

2006-09-01

Following Cascade Technologies first success at using Quantum Cascade Lasers (QCL) for trace gas detection in the continuous emission monitoring market, the core technology platform is now being developed towards homeland security applications. This paper will highlight the potential of QCL based trace gas sensor for detecting vapours of explosives. Furthermore we will present results that let foresee the use of such technologies at addressing security gaps for protection against terrorism in infrastructures where high throughput screening of individuals or items is required. Preliminary measurements have shown that rapid identification, or fingerprinting, of explosive is achievable in 10ms at extrapolated sensitivities in the sub-part per billion range. The experiments were carried out with support form the Home Office Scientific Development Branch (HOSDB) in the UK and were focused at selecting a variety of explosive compounds and showing their detection using a novel sniffer platform system based on the use of quantum cascade lasers. Preliminary studies on the technology have indicated that direct fingerprinting (detection - identification) of explosive compounds such as NG and tagging agents such as EGDN by sniffing surrounding ambient air is achievable. Furthermore these studies have also indicated that detection of such compounds on packaging used to ship the sealed compounds is possible, making this platform a strong contender for detection through cross contamination on material that have been in contact with each other. Additionally, it was also possible to detect breakdown products associated with sample material NG providing a further capability that could be exploited to enhance the detection and identification of explosive compounds.

Glow discharge detector

DOEpatents

Koo, Jackson C.; Yu, Conrad M.

2002-01-01

A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured.

Pixel CdTe semiconductor module to implement a sub-MeV imaging detector for astrophysics

NASA Astrophysics Data System (ADS)

Gálvez, J.-L.; Hernanz, M.; Álvarez, L.; Artigues, B.; Álvarez, J.-M.; Ullán, M.; Pellegrini, G.; Lozano, M.; Cabruja, E.; Martínez, R.; Chmeissani, M.; Puigdengoles, C.

2017-03-01

Stellar explosions are relevant and interesting astrophysical phenomena. Since long ago we have been working on the characterization of nova and supernova explosions in X and gamma rays, with the use of space missions such as INTEGRAL, XMM-Newton and Swift. We have been also involved in feasibility studies of future instruments in the energy range from several keV up to a few MeV, in collaboration with other research institutes, such as GRI, DUAL and e-ASTROGAM. High sensitivities are essential to perform detailed studies of cosmic explosions and cosmic accelerators, e.g., Supernovae, Classical Novae, Supernova Remnants (SNRs), Gamma-Ray Bursts (GRBs). In order to fulfil the combined requirement of high detection efficiency with good spatial and energy resolution, an initial module prototype based on CdTe pixel detectors is being developed. The detector dimensions are 12.5mm x 12.5mm x 2mm, with a pixel pitch of 1mm x 1mm. Each pixel is bump bonded to a fanout board made of Sapphire substrate and routed to the corresponding input channel of the readout ASIC, to measure pixel position and pulse height for each incident gamma-ray photon. An ohmic CdTe pixel detector has been characterised by means of 57Co, 133Ba and 22Na sources. Based on this, its spectroscopic performance and the influence of charge sharing is reported here. The pixel study is complemented by the simulation of the CdTe module performance using the GEANT 4 and MEGALIB tools, which will help us to optimise the pixel size selection.

Single Broadband Phase-Shaped Pulse Stimulated Raman Spectroscopy for Standoff Trace Explosive Detection.

PubMed

Glenn, Rachel; Dantus, Marcos

2016-01-07

Recent success with trace explosives detection based on the single ultrafast pulse excitation for remote stimulated Raman scattering (SUPER-SRS) prompts us to provide new results and a Perspective that describes the theoretical foundation of the strategy used for achieving the desired sensitivity and selectivity. SUPER-SRS provides fast and selective imaging while being blind to optical properties of the substrate such as color, texture, or laser speckle. We describe the strategy of combining coherent vibrational excitation with a reference pulse in order to detect stimulated Raman gain or loss. A theoretical model is used to reproduce experimental spectra and to determine the ideal pulse parameters for best sensitivity, selectivity, and resolution when detecting one or more compounds simultaneously.

Potential Explosion Hazard of Carbonaceous Nanoparticles: Screening of Allotropes

PubMed Central

Turkevich, Leonid A.; Fernback, Joseph; Dastidar, Ashok G.; Osterberg, Paul

2016-01-01

There is a concern that engineered carbon nanoparticles, when manufactured on an industrial scale, will pose an explosion hazard. Explosion testing has been performed on 20 codes of carbonaceous powders. These include several different codes of SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes) and CNFs (carbon nanofibers), graphene, diamond, fullerene, as well as several different control carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226 protocol), at a concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples typically exhibited overpressures of 5–7 bar, and deflagration index KSt = V1/3 (dP/dt)max ~ 10 – 80 bar-m/s, which places these materials in European Dust Explosion Class St-1. There is minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with primary particle size (BET specific surface area). PMID:27468178

Characterization of high explosive particles using cluster secondary ion mass spectrometry.

PubMed

Gillen, Greg; Mahoney, Christine; Wight, Scott; Lareau, Richard

2006-01-01

The use of secondary ion mass spectrometry (SIMS) for the detection and spatially resolved analysis of individual high explosive particles is described. A C(8) (-) carbon cluster primary ion beam was used in a commercial SIMS instrument to analyze samples of high explosives dispersed as particles on silicon substrates. In comparison with monatomic primary ion bombardment, the carbon cluster primary ion beam was found to greatly enhance characteristic secondary ion signals from the explosive compounds while causing minimal beam-induced degradation. The resistance of these compounds to degradation under ion bombardment allows explosive particles to be analyzed under high primary ion dose bombardment (dynamic SIMS) conditions, facilitating the rapid acquisition of spatially resolved molecular information. The use of cluster SIMS combined with computer control of the sample stage position allows for the automated identification and counting of explosive particle distributions on silicon surfaces. This will be useful for characterizing the efficiency of transfer of particulates in trace explosive detection portal collectors and/or swipes utilized for ion mobility spectrometry applications.

Optoelectronics sensors of hydrocarbons based on NDIR technique

NASA Astrophysics Data System (ADS)

Prokopiuk, Artur

2017-08-01

Saturated hydrocarbons are mainly nontoxic, but as extremely flammable gases forming explosive mixtures with air. The Lower Explosive Level (LEL) for methane is 4.4%, which is very dangerous in the mining industry. Methane is also an asphyxiant gas causing coma or death. Therefore, continuous monitoring of the hydrocarbons concentration is very important. Optoelectronic methods are very attractive for this application, especially nondispersive infrared (NDIR) technique. It enables a direct, fast, and selective measurement of different gas concentrations. NDIR sensors have many advantages, which make them very promising for use as hydrocarbon detectors. Despite a lot of benefits, common used NDIR sensors have some disadvantages. They need periodic calibration and have limited detection range, from 100ppm. These parameters can be improved thanks to modernization detection scheme and use of newest IR sources and detectors. During Analyses selected IR sources and detectors were taken into account. Absorption spectra of analyzed hyrdrocarbons were studied to minimize impact interfering gases like carbon dioxide and water.

Isotope-Labeled Composition B for Tracing Detonation Signatures

NASA Astrophysics Data System (ADS)

Manner, Virginia; Podlesak, David; Huber, Rachel; Amato, Ronald; Giambra, Anna; Bowden, Patrick; Hartline, Ernest; Dattelbaum, Dana

2017-06-01

To better understand how solid carbon forms and evolves during detonation, we have prepared Composition B with 13 C and 15 N-labeled 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) in order to trace the formation of soot from the carbon and nitrogen atoms in these explosives. Isotope-labeling of explosives has been performed in the recent past for a variety of reasons, including environmental remediation and reaction mechanism studies. Because it is expensive and time consuming to prepare these materials, and our detection equipment only requires trace amounts of isotopes, we have prepared fully-labeled materials and substituted them into unlabeled RDX and TNT at less than the 1% level. We will discuss the preparation and full characterization of this labeled Composition B, the detonation tests performed, along with the results of the post-detonation soot analysis. Various detonation models predict differing amounts and forms of carbon and nitrogen; these isotopically-labeled precursors have allowed these models to be tested.

External cavity tunable quantum cascade lasers and their applications to trace gas monitoring.

PubMed

Rao, Gottipaty N; Karpf, Andreas

2011-02-01

Since the first quantum cascade laser (QCL) was demonstrated approximately 16 years ago, we have witnessed an explosion of interesting developments in QCL technology and QCL-based trace gas sensors. QCLs operate in the mid-IR region (3-24 μm) and can directly access the rotational vibrational bands of most molecular species and, therefore, are ideally suited for trace gas detection with high specificity and sensitivity. These sensors have applications in a wide range of fields, including environmental monitoring, atmospheric chemistry, medical diagnostics, homeland security, detection of explosive compounds, and industrial process control, to name a few. Tunable external cavity (EC)-QCLs in particular offer narrow linewidths, wide ranges of tunability, and stable power outputs, which open up new possibilities for sensor development. These features allow for the simultaneous detection of multiple species and the study of large molecules, free radicals, ions, and reaction kinetics. In this article, we review the current status of EC-QCLs and sensor developments based on them and speculate on possible future developments.

Novel Methods for Detecting Buried Explosive Devices

DTIC Science & Technology

2007-04-10

NQR ), and semiotic data fusion. Bioreporter bacteria look promising for third-world humanitarian applications; they are inexpensive, and...demining, NQR is a promising method for detecting explosive substances; of 50,000 substances that have been tested, none has an NQR signature that can be...approach to a cheap mine detector for humanitarian use. Real-time wavelet processing appears to be a key to extending NQR bomb detection into mine

Contributed review: quantum cascade laser based photoacoustic detection of explosives.

PubMed

Li, J S; Yu, B; Fischer, H; Chen, W; Yalin, A P

2015-03-01

Detecting trace explosives and explosive-related compounds has recently become a topic of utmost importance for increasing public security around the world. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. Optical sensing methods, in particular mid-infrared spectrometry techniques, have a great potential to become a more desirable tools for the detection of explosives. The small size, simplicity, high output power, long-term reliability make external cavity quantum cascade lasers (EC-QCLs) the promising spectroscopic sources for developing analytical instrumentation. This work reviews the current technical progress in EC-QCL-based photoacoustic spectroscopy for explosives detection. The potential for both close-contact and standoff configurations using this technique is completely presented over the course of approximately the last one decade.

Contributed Review: Quantum cascade laser based photoacoustic detection of explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, J. S., E-mail: jingsong-li@ahu.edu.cn; Yu, B.; Fischer, H.

2015-03-15

Detecting trace explosives and explosive-related compounds has recently become a topic of utmost importance for increasing public security around the world. A wide variety of detection methods and an even wider range of physical chemistry issues are involved in this very challenging area. Optical sensing methods, in particular mid-infrared spectrometry techniques, have a great potential to become a more desirable tools for the detection of explosives. The small size, simplicity, high output power, long-term reliability make external cavity quantum cascade lasers (EC-QCLs) the promising spectroscopic sources for developing analytical instrumentation. This work reviews the current technical progress in EC-QCL-based photoacousticmore » spectroscopy for explosives detection. The potential for both close-contact and standoff configurations using this technique is completely presented over the course of approximately the last one decade.« less

MCNP Simulation Benchmarks for a Portable Inspection System for Narcotics, Explosives, and Nuclear Material Detection

NASA Astrophysics Data System (ADS)

Alfonso, Krystal; Elsalim, Mashal; King, Michael; Strellis, Dan; Gozani, Tsahi

2013-04-01

MCNPX simulations have been used to guide the development of a portable inspection system for narcotics, explosives, and special nuclear material (SNM) detection. The system seeks to address these threats to national security by utilizing a high-yield, compact neutron source to actively interrogate the threats and produce characteristic signatures that can then be detected by radiation detectors. The portability of the system enables rapid deployment and proximity to threats concealed in small spaces. Both dD and dT electronic neutron generators (ENG) were used to interrogate ammonium nitrate fuel oil (ANFO) and cocaine hydrochloride, and the detector response of NaI, CsI, and LaBr3 were compared. The effect of tungsten shielding on the neutron flux in the gamma ray detectors was investigated, while carbon, beryllium, and polyethylene ENG moderator materials were optimized by determining the reaction rate density in the threats. In order to benchmark the modeling results, experimental measurements are compared with MCNPX simulations. In addition, the efficiency and die-away time of a portable differential die-away analysis (DDAA) detector using 3He proportional counters for SNM detection has been determined.

Ion spectrometric detection technologies for ultra-traces of explosives: a review.

PubMed

Mäkinen, Marko; Nousiainen, Marjaana; Sillanpää, Mika

2011-01-01

In recent years, explosive materials have been widely employed for various military applications and civilian conflicts; their use for hostile purposes has increased considerably. The detection of different kind of explosive agents has become crucially important for protection of human lives, infrastructures, and properties. Moreover, both the environmental aspects such as the risk of soil and water contamination and health risks related to the release of explosive particles need to be taken into account. For these reasons, there is a growing need to develop analyzing methods which are faster and more sensitive for detecting explosives. The detection techniques of the explosive materials should ideally serve fast real-time analysis in high accuracy and resolution from a minimal quantity of explosive without involving complicated sample preparation. The performance of the in-field analysis of extremely hazardous material has to be user-friendly and safe for operators. The two closely related ion spectrometric methods used in explosive analyses include mass spectrometry (MS) and ion mobility spectrometry (IMS). The four requirements-speed, selectivity, sensitivity, and sampling-are fulfilled with both of these methods. Copyright © 2011 Wiley Periodicals, Inc.

Predicting Explosion-Generated SN and LG Coda Using Syntheic Seismograms

DTIC Science & Technology

2008-09-01

velocities in the upper crust are based on borehole data, geologic and gravity data, refraction studies and seismic experiments (McLaughlin et al. 1983...realizations of random media. We have estimated the heterogeneity parameters for the NTS using available seismic and geologic data. Lateral correlation...variance and coherence measures between seismic traces are estimated from clusters of nuclear explosions and well- log data. The horizontal von Karman

Infrared photothermal imaging spectroscopy for detection of trace explosives on surfaces.

PubMed

Kendziora, Christopher A; Furstenberg, Robert; Papantonakis, Michael; Nguyen, Viet; Byers, Jeff; Andrew McGill, R

2015-11-01

We are developing a technique for the standoff detection of trace explosives on relevant substrate surfaces using photothermal infrared (IR) imaging spectroscopy (PT-IRIS). This approach leverages one or more compact IR quantum cascade lasers, which are tuned to strong absorption bands in the analytes and directed to illuminate an area on a surface of interest. An IR focal plane array is used to image the surface and detect increases in thermal emission upon laser illumination. The PT-IRIS signal is processed as a hyperspectral image cube comprised of spatial, spectral, and temporal dimensions as vectors within a detection algorithm. The ability to detect trace analytes at standoff on relevant substrates is critical for security applications but is complicated by the optical and thermal analyte/substrate interactions. This manuscript describes a series of PT-IRIS experimental results and analysis for traces of RDX, TNT, ammonium nitrate, and sucrose on steel, polyethylene, glass, and painted steel panels. We demonstrate detection at surface mass loadings comparable with fingerprint depositions ( 10μg/cm2 to 100μg/cm2) from an area corresponding to a single pixel within the thermal image.

Mid-Infrared Signatures from Type Ia Supernovae Strongly Interacting with a Circumstellar Medium

NASA Astrophysics Data System (ADS)

Fox, Ori

2015-10-01

Type Ia supernovae (SNe Ia) are well-known for their use as precise cosmological distance indicators due to a standardizable peak luminosity resulting from a thermonuclear explosion. A growing subset of SNe Ia, however, show evidence for interaction with a dense circumstellar medium during the first year post-explosion, and sometimes longer (SNe Ia-CSM). The origin of this dense CSM is unknown and suggests either a) the less typical single-degenerate progenitor scenario must be considered or b) the exploding star was not a thermonuclear explosion of a white dwarf at all (i.e., core-collapse). Mid-infrared (IR) observations, in particular, are critical for tracing the density profile of dust (and hence gas) in the surrounding CSM. Yet no Spitzer light curve exists for this subclass within the first year post-expolosion. Here we propose a 'low-impact' (>8 weeks) ToO to obtain 3 epochs of Spitzer imaging of a SN Ia-CSM within 100 Mpc over 1 year post-explosion. The strength of this program is that it will be in conjunction with pre-approved multi-wavelength programs on HST/STIS/UV (GO 13649), Chandra/ASIS-S (Num: 17500672), the Keck/LRIS optical spectrograph (Num: U037LA), and the RATIR visible/infrared robotic imager. Requiring only 2.1 hours of observation total, this program will not only distinguish between the SN explosion mechanisms, but also trace CSM interaction, constrain the progenitor mass loss history, and identify late-time heating mechanisms of warm dust.

Progress on determining the vapor signature of a buried land mine

NASA Astrophysics Data System (ADS)

George, Vivian; Jenkins, Thomas F.; Leggett, Daniel C.; Cragin, James H.; Phelan, James M.; Oxley, Jimmie C.; Pennington, Judy

1999-08-01

The goal of the DARPA 'Dog's Nose' program is to develop a sensor capable of detecting explosives contained in all buried landmines. In support of the DARPA program, the purpose of the Explosives Fate and Transport experiments is to define in detail the accessible trace chemical signature produced by the explosives contained in buried landmines. We intend to determine the partitioning, composition, and quantity of explosive related chemicals which emanate from different kinds of landmines buried in multiple soil types and exposed to various climatic events. We are also developing a computer model that will enable us to predict the composition and quantity of ERC under a much wider range of environmental conditions than we are able to test experimentally.

Miniature Tunable Laser Spectrometer for Detection of a Trace Gas

NASA Technical Reports Server (NTRS)

Christensen, Lance E. (Inventor)

2017-01-01

An open-path laser spectrometer (OPLS) for measuring a concentration of a trace gas, the OPLS including an open-path multi-pass analysis region including a first mirror, a second mirror at a distance and orientation from the first mirror, and a support structure for locating the mirrors, a laser coupled to the analysis region and configured to emit light of a wavelength range and to enable a plurality of reflections of the emitted light between the mirrors, a detector coupled to the analysis region and configured to detect a portion of the emitted light impinging on the detector and to generate a corresponding signal, and an electronic system coupled to the laser and the detector, and configured to adjust the wavelength range of the emitted light from the laser based on the generated signal, and to measure the concentration of the trace gas based on the generated signal.

A SPECT system simulator built on the SolidWorks TM 3D-Design package.

PubMed

Li, Xin; Furenlid, Lars R

2014-08-17

We have developed a GPU-accelerated SPECT system simulator that integrates into instrument-design workflow [1]. This simulator includes a gamma-ray tracing module that can rapidly propagate gamma-ray photons through arbitrary apertures modeled by SolidWorks TM -created stereolithography (.STL) representations with a full complement of physics cross sections [2, 3]. This software also contains a scintillation detector simulation module that can model a scintillation detector with arbitrary scintillation crystal shape and light-sensor arrangement. The gamma-ray tracing module enables us to efficiently model aperture and detector crystals in SolidWorks TM and save them as STL file format, then load the STL-format model into this module to generate list-mode results of interacted gamma-ray photon information (interaction positions and energies) inside the detector crystals. The Monte-Carlo scintillation detector simulation module enables us to simulate how scintillation photons get reflected, refracted and absorbed inside a scintillation detector, which contributes to more accurate simulation of a SPECT system.

A SPECT system simulator built on the SolidWorksTM 3D design package

NASA Astrophysics Data System (ADS)

Li, Xin; Furenlid, Lars R.

2014-09-01

We have developed a GPU-accelerated SPECT system simulator that integrates into instrument-design work flow [1]. This simulator includes a gamma-ray tracing module that can rapidly propagate gamma-ray photons through arbitrary apertures modeled by SolidWorksTM-created stereolithography (.STL) representations with a full com- plement of physics cross sections [2, 3]. This software also contains a scintillation detector simulation module that can model a scintillation detector with arbitrary scintillation crystal shape and light-sensor arrangement. The gamma-ray tracing module enables us to efficiently model aperture and detector crystals in SolidWorksTM and save them as STL file format, then load the STL-format model into this module to generate list-mode results of interacted gamma-ray photon information (interaction positions and energies) inside the detector crystals. The Monte-Carlo scintillation detector simulation module enables us to simulate how scintillation photons get reflected, refracted and absorbed inside a scintillation detector, which contributes to more accurate simulation of a SPECT system.

Cosmic Ray research in Armenia

NASA Astrophysics Data System (ADS)

Chilingarian, A.; Mirzoyan, R.; Zazyan, M.

2009-11-01

Cosmic Ray research on Mt. Aragats began in 1934 with the measurements of East-West anisotropy by the group from Leningrad Physics-Technical Institute and Norair Kocharian from Yerevan State University. Stimulated by the results of their experiments in 1942 Artem and Abraham Alikhanyan brothers organized a scientific expedition to Aragats. Since that time physicists were studying Cosmic Ray fluxes on Mt. Aragats with various particle detectors: mass spectrometers, calorimeters, transition radiation detectors, and huge particle detector arrays detecting protons and nuclei accelerated in most violent explosions in Galaxy. Latest activities at Mt. Aragats include Space Weather research with networks of particle detectors located in Armenia and abroad, and detectors of Space Education center in Yerevan.

The New Maia Detector System: Methods For High Definition Trace Element Imaging Of Natural Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, C. G.; School of Physics, University of Melbourne, Parkville VIC; CODES Centre of Excellence, University of Tasmania, Hobart TAS

2010-04-06

Motivated by the need for megapixel high definition trace element imaging to capture intricate detail in natural material, together with faster acquisition and improved counting statistics in elemental imaging, a large energy-dispersive detector array called Maia has been developed by CSIRO and BNL for SXRF imaging on the XFM beamline at the Australian Synchrotron. A 96 detector prototype demonstrated the capacity of the system for real-time deconvolution of complex spectral data using an embedded implementation of the Dynamic Analysis method and acquiring highly detailed images up to 77 M pixels spanning large areas of complex mineral sample sections.

The New Maia Detector System: Methods For High Definition Trace Element Imaging Of Natural Material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, C.G.; Siddons, D.P.; Kirkham, R.

2010-05-25

Motivated by the need for megapixel high definition trace element imaging to capture intricate detail in natural material, together with faster acquisition and improved counting statistics in elemental imaging, a large energy-dispersive detector array called Maia has been developed by CSIRO and BNL for SXRF imaging on the XFM beamline at the Australian Synchrotron. A 96 detector prototype demonstrated the capacity of the system for real-time deconvolution of complex spectral data using an embedded implementation of the Dynamic Analysis method and acquiring highly detailed images up to 77 M pixels spanning large areas of complex mineral sample sections.

Development and validation of a solid phase extraction sample cleanup procedure for the recovery of trace levels of nitro-organic explosives in soil.

PubMed

Thomas, Jennifer L; Donnelly, Christopher C; Lloyd, Erin W; Mothershead, Robert F; Miller, Mark L

2018-03-01

An improved cleanup method has been developed for the recovery of trace levels of 12 nitro-organic explosives in soil, which is important not only for the forensic community, but also has environmental implications. A wide variety of explosives or explosive-related compounds were evaluated, including nitramines, nitrate esters, nitroaromatics, and a nitroalkane. Fortified soil samples were extracted with acetone, processed via solid phase extraction (SPE), and then analyzed by gas chromatography with electron capture detection. The following three SPE sorbents in cartridge format were compared: Empore™ SDB-XC, Oasis ® HLB, and Bond Elut NEXUS cartridges. The NEXUS cartridges provided the best overall recoveries for the 12 explosives in potting soil (average 48%) and the fastest processing times (<30min). It also rejected matrix components from spent motor oil on potting soil. The SPE method was validated by assessing limit of detection (LOD), processed sample stability, and interferences. All 12 compounds were detectable at 0.02μg explosive/gram of soil or lower in the three matrices tested (potting soil, sand, and loam) over three days. Seven explosives were stable up to seven days at 2μg/g and three were stable at 0.2μg/g, both in processed loam, which was the most challenging matrix. In the interference study, five interferences above the determined LOD for soil were detected in matrices collected across the United States and in purchased all-purpose sand, potting soil, and loam. This represented a 3.2% false positive rate for the 13 matrices processed by the screening method for interferences. The reported SPE cleanup method provides a fast and simple extraction process for separating organic explosives from matrix components, facilitating sample throughput and reducing instrument maintenance. In addition, a comparison study of the validated SPE method versus conventional syringe filtration was completed and highlighted the benefits of sample cleanup for removing matrix interferences, while also providing lower supply cost, order of magnitude lower LODs for most explosives, higher percent recoveries for complex matrices, and fewer instrument maintenance issues. Published by Elsevier B.V.

Gamma-ray spectra and doses from the Little Boy replica

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moss, C.E.; Lucas, M.C.; Tisinger, E.W.

1984-01-01

Most radiation safety guidelines in the nuclear industry are based on the data concerning the survivors of the nuclear explosions at Hiroshima and Nagasaki. Crucial to determining these guidelines is the radiation from the explosions. We have measured gamma-ray pulse-height distributions from an accurate replica of the Little Boy device used at Hiroshima, operated at low power levels near critical. The device was placed outdoors on a stand 4 m from the ground to minimize environmental effects. The power levels were based on a monitor detector calibrated very carefully in independent experiments. High-resolution pulse-height distributions were acquired with a germaniummore » detector to identify the lines and to obtain line intensities. The 7631 to 7645 keV doublet from neutron capture in the heavy steel case was dominant. Low-resolution pulse-height distributions were acquired with bismuth-germanate detectors. We calculated flux spectra from these distributions using accurately measured detector response functions and efficiency curves. We then calculated dose-rate spectra from the flux spectra using a flux-to-dose-rate conversion procedure. The integral of each dose-rate spectrum gave an integral dose rate. The integral doses at 2 m ranged from 0.46 to 1.03 mrem per 10/sup 13/ fissions. The output of the Little Boy replica can be calculated with Monte Carlo codes. Comparison of our experimental spectra, line intensities, and integral doses can be used to verify these calculations at low power levels and give increased confidence to the calculated values from the explosion at Hiroshima. These calculations then can be used to establish better radiation safety guidelines. 7 references, 7 figures, 2 tables.« less

Neutrino signal from pair-instability supernovae

NASA Astrophysics Data System (ADS)

Wright, Warren P.; Gilmer, Matthew S.; Fröhlich, Carla; Kneller, James P.

2017-11-01

A very massive star with a carbon-oxygen core in the range of 64M ⊙

Explosives Detection in a Lasing Plasmon Nanocavity

DTIC Science & Technology

2014-08-01

plasmonic sensors7,13–18 with 2,4-dinitrotoluene and ammonium nitrate . The selectivity between 2,4-dinitrotoluene, ammonium nitrate and nitrobenzene is on a...ammonium nitrate . The selectivity between 2,4-dinitrotoluene, ammoniumnitrate and nitrobenzene is on a par with other state-of-the-art explosives... nitrate (AN) and nitrobenzene (NB). Air was used both to dilute them and as the background reference. Figure 4a–c presents con- tinuous traces of lasing

Atmospheric Pressure Chemical Ionization Sources Used in The Detection of Explosives by Ion Mobility Spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waltman, Melanie J.

2010-05-01

Explosives detection is a necessary and wide spread field of research. From large shipping containers to airline luggage, numerous items are tested for explosives every day. In the area of trace explosives detection, ion mobility spectrometry (IMS) is the technique employed most often because it is a quick, simple, and accurate way to test many items in a short amount of time. Detection by IMS is based on the difference in drift times of product ions through the drift region of an IMS instrument. The product ions are created when the explosive compounds, introduced to the instrument, are chemically ionizedmore » through interactions with the reactant ions. The identity of the reactant ions determines the outcomes of the ionization process. This research investigated the reactant ions created by various ionization sources and looked into ways to manipulate the chemistry occurring in the sources.« less

Chemical Sensing of Unexploded Ordnance with the Mobile Underwater Survey System (MUDSS)

NASA Technical Reports Server (NTRS)

Darrach, M. R.; Chutjian, A.

1995-01-01

The ability to sense explosives residues in the marine environment is a critical tool for identification and classification of underwater unexploded ordnance (UXO). Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion fifty years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater, and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas-chromatography/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance which appeared to be physically intact gave good explosives signatures at the parts-per-billion level, whereas ordnance which had been cracked open during the explosion gave no signatures at the 10 parts-per-trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea UXOs.

Technical note: Headspace analysis of explosive compounds using a novel sampling chamber.

PubMed

DeGreeff, Lauryn; Rogers, Duane A; Katilie, Christopher; Johnson, Kevin; Rose-Pehrsson, Susan

2015-03-01

The development of instruments and methods for explosive vapor detection is a continually evolving field of interest. A thorough understanding of the characteristic vapor signatures of explosive material is imperative for the development and testing of new and current detectors. In this research a headspace sampling chamber was designed to contain explosive materials for the controlled, reproducible sampling and characterization of vapors associated with these materials. In a detonation test, the chamber was shown to contain an explosion equivalent to three grams of trinitrotoluene (TNT) without damage to the chamber. The efficacy of the chamber in controlled headspace sampling was evaluated in laboratory tests with bulk explosive materials. Small quantities of TNT, triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were separately placed in the sampling chamber, and the headspace of each material was analyzed by gas chromatography/mass spectrometry (GC/MS) with online cryogenic trapping to yield characteristic vapor signatures for each explosive compound. Chamber sampling conditions, temperature and sampling time, were varied to demonstrate suitability for precise headspace analysis. Published by Elsevier Ireland Ltd.

Investigation of the Behavioral Characteristics of Dogs Purpose-Bred and Prepared to Perform Vapor Wake® Detection of Person-Borne Explosives.

PubMed

Lazarowski, Lucia; Haney, Pamela Sue; Brock, Jeanne; Fischer, Terry; Rogers, Bart; Angle, Craig; Katz, Jeffrey S; Waggoner, L Paul

2018-01-01

Specialized detector dogs are increasingly being utilized for the detection of modern threats. The Vapor Wake ® (VW) dog was developed to create a dog phenotype ideally suited for detecting hand-carried and body-worn explosives. VW dogs (VWDs) are trained to sample and alert to target odors in the aerodynamic wakes of moving persons, which entrains vapor and small particles from the person. The behavioral characteristics necessary for dogs to be successfully trained and employed for the application of VW are a distinct subset of the desired general characteristics of dogs used for detection tasks due to the dynamic nature of moving targets. The purpose of this study was to examine the behavioral characteristics of candidate detector dogs to determine the particular qualities that set apart VW-capable dogs from others. We assessed 146 candidate detector dogs from a VW breeding and training program. Dogs received identical puppy development and foundational odor training and underwent performance evaluations at 3, 6, 10, and 12 months old, after which they were sold for service. Dogs were categorized based on their final outcome of the training program, independently determined by private vendors, corresponding to three groups: dogs successfully sold for VW, dogs sold for standard explosives detection, and dogs that failed to be placed in any type of detector dog service (Washouts). Comparisons of behavioral evaluations between the groups were made across domains pertaining to search-related behaviors (Performance), reactions to novel stimuli (Environmental), and overall ease of learning new tasks (Trainability). Comparisons were also made at each evaluation to determine any early emergence of differences. VWDs scored significantly higher on Performance characteristics compared to standard explosives detection dogs (EDDs) and Washouts. However, Environmental characteristics did not differentiate VWDs from EDDs, though scores on these measures were significantly lower in the Washouts. Furthermore, differences between groups emerged as early as 3 and 6 months for select measures. We describe the behavioral characteristics targeted for selection in developing the VW phenotype and discuss the relative merit and degree of expression of those characteristics in the success of dogs bred and trained for the VW application.

CMOS-compatible plenoptic detector for LED lighting applications.

PubMed

Neumann, Alexander; Ghasemi, Javad; Nezhadbadeh, Shima; Nie, Xiangyu; Zarkesh-Ha, Payman; Brueck, S R J

2015-09-07

LED lighting systems with large color gamuts, with multiple LEDs spanning the visible spectrum, offer the potential of increased lighting efficiency, improved human health and productivity, and visible light communications addressing the explosive growth in wireless communications. The control of this "smart lighting system" requires a silicon-integrated-circuit-compatible, visible, plenoptic (angle and wavelength) detector. A detector element, based on an offset-grating-coupled dielectric waveguide structure and a silicon photodetector, is demonstrated with an angular resolution of less than 1° and a wavelength resolution of less than 5 nm.

Nuclear Resonance Fluorescence Measurements of High Explosives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caggiano, Joseph A.; Warren, Glen A.; Korbly, Steve

Pacific Northwest National Laboratory and Passport Systems have collaborated to perform Nuclear Resonance Fluorescence experiments using several high quality high-explosive simulant samples. These measurements were conducted to determine the feasibility of finding and characterizing high explosive material by NRF interrogation. Electron beams of 5.1, 5.3, 8, and 10 MeV were used to produce bremsstrahlung photon beams, which irradiated the samples. The gamma-ray spectra were collected using high-purity germanium detectors. Nitrogen-to-carbon ratios of the high-explosive simulants were extracted from the 5.1 and 5.3 MeV data and compare favorably with accepted values. Analysis of the 8 and 10 MeV data is inmore » progress; preliminary isotopic comparisons within the samples are consistent with the expected results.« less

Noncontact optical detection of explosive particles via photodissociation followed by laser-induced fluorescence.

PubMed

Wynn, C M; Palmacci, S; Kunz, R R; Aernecke, M

2011-09-12

High-sensitivity (ng/cm²) optical detection of the explosive 2,4,6-trinitrotoluene (TNT) is demonstrated using photodissociation followed by laser-induced fluorescence (PD-LIF). Detection occurs rapidly, within 6 laser pulses (~7 ns each) at a range of 15 cm. Dropcasting is used to create calibrated samples covering a wide range of TNT concentrations; and a correspondence between fractional area covered by TNT and PD-LIF signal strength is observed. Dropcast data are compared to that of an actual fingerprint. These results demonstrate that PD-LIF could be a viable means of rapidly and remotely scanning surfaces for trace explosive residues.

Pulsating aurora induced by upper atmospheric barium releases

NASA Technical Reports Server (NTRS)

Deehr, C.; Romick, G.

1977-01-01

The paper reports the apparent generation of pulsating aurora by explosive releases of barium vapor near 250 km altitude. This effect occurred only when the explosions were in the path of precipitating electrons associated with the visible aurora. Each explosive charge was a standard 1.5 kg thermite mixture of Ba and CuO with an excess of Ba metal which was vaporized and dispersed by the thermite explosion. Traces of Sr, Na, and Li were added to some of the charges, and monitoring was achieved by ground-based spectrophotometric observations. On March 28, 1976, an increase in emission at 5577 A and at 4278 A was observed in association with the first two bursts, these emissions pulsating with roughly a 10 sec period for approximately 60 to 100 sec after the burst.

Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

PubMed

Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

2014-12-01

An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stable glow discharge detector

DOEpatents

Koo, Jackson C.; Yu, Conrad M.

2004-05-18

A highly sensitive electronic ion cell for the measurement of trace elements in He carrier gas which involves glow discharge. A constant wave (CW) stable glow discharge detector which is controlled through a biased resistor, can detect the change of electron density caused by impurities in the He carrier gas by many orders of magnitude larger than that caused by direct ionization or electron capture. The stable glow discharge detector utilizes a floating pseudo-electrode to form a probe in or near the plasma and a solid rod electrode. By using this probe, the large variation of electron density due to trace amounts of impurities can be directly measured. The solid rod electrode provides greater stability and thus easier alignment.

Gas chromatographic analysis of trace impurities in chlorine trifluoride.

PubMed

Laurens, J B; Swinley, J M; de Coning, J P

2000-03-24

The gas chromatographic determination of trace gaseous impurities in highly reactive fluorinated gaseous matrices presents unique requirements to both equipment and techniques. Especially problematic are the gases normally present in ambient air namely oxygen and nitrogen. Analysing these gases at the low microl/l (ppm) level requires special equipment and this publication describes a custom-designed system utilising backflush column switching to protect the columns and detectors. A thermal conductivity detector with nickel filaments was used to determine ppm levels of impurities in ClF3.

A possibility for standoff bomb detection

NASA Astrophysics Data System (ADS)

Akar Tarim, U.; Ozmutlu, E. N.; Gurler, O.; Yalcin, S.

2015-01-01

The response functions of backscattered photons, which are initially collimated with an energy of 662 keV, were obtained by a Monte Carlo method in an NaI(Tl) scintillation detector using a suitcase or briefcase full of paper, clothing, ammonium nitrate or other generic explosives, as these can be used for terrorism. The results show that characteristic response functions for ammonium nitrate and generic explosives may be found, and using this information, standoff detection of these materials may be possible.

Explosive Detection in Aviation Applications Using CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martz, H E; Crawford, C R

2011-02-15

CT scanners are deployed world-wide to detect explosives in checked and carry-on baggage. Though very similar to single- and dual-energy multi-slice CT scanners used today in medical imaging, some recently developed explosives detection scanners employ multiple sources and detector arrays to eliminate mechanical rotation of a gantry, photon counting detectors for spectral imaging, and limited number of views to reduce cost. For each bag scanned, the resulting reconstructed images are first processed by automated threat recognition algorithms to screen for explosives and other threats. Human operators review the images only when these automated algorithms report the presence of possible threats.more » The US Department of Homeland Security (DHS) has requirements for future scanners that include dealing with a larger number of threats, higher probability of detection, lower false alarm rates and lower operating costs. One tactic that DHS is pursuing to achieve these requirements is to augment the capabilities of the established security vendors with third-party algorithm developers. A third-party in this context refers to academics and companies other than the established vendors. DHS is particularly interested in exploring the model that has been used very successfully by the medical imaging industry, in which university researchers develop algorithms that are eventually deployed in commercial medical imaging equipment. The purpose of this paper is to discuss opportunities for third-parties to develop advanced reconstruction and threat detection algorithms.« less

Detection of Explosive Devices using X-ray Backscatter Radiation

NASA Astrophysics Data System (ADS)

Faust, Anthony A.

2002-09-01

It is our goal to develop a coded aperture based X-ray backscatter imaging detector that will provide sufficient speed, contrast and spatial resolution to detect Antipersonnel Landmines and Improvised Explosive Devices (IED). While our final objective is to field a hand-held detector, we have currently constrained ourselves to a design that can be fielded on a small robotic platform. Coded aperture imaging has been used by the observational gamma astronomy community for a number of years. However, it has been the recent advances in the field of medical nuclear imaging which has allowed for the application of the technique to a backscatter scenario. In addition, driven by requirements in medical applications, advances in X-ray detection are continually being made, and detectors are now being produced that are faster, cheaper and lighter than those only a decade ago. With these advances, a coded aperture hand-held imaging system has only recently become a possibility. This paper will begin with an introduction to the technique, identify recent advances which have made this approach possible, present a simulated example case, and conclude with a discussion on future work.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2014-04-29

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

2013-04-30

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D [Reno, NV; Sulchek, Todd A [Oakland, CA; Feigin, Stuart C [Reno, NV

2012-07-10

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

Cantilevered probe detector with piezoelectric element

DOEpatents

Adams, Jesse D.; Sulchek, Todd A.; Feigin, Stuart C.

2010-04-06

A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

P sub n from the Nevada Test Site

DTIC Science & Technology

1988-12-15

reviewed and is approved for publication" JAMES0- t1IC Z--C J (TEX S C. BAkTIS CnLract Manager Acting Chief Solid Earth Geophysics Branch Solid Earth...high frequency Pn . The data base being used in the development consists of signals from explosions and earthquakes recorded on the western U.S. digital...measured quantitatively by correlating the average explosiorn ?n trace wiLh a data base of explosion and earthquake signals. The populations

Fault-zone guided waves from explosions in the San Andreas fault at Parkfield and Cienega Valley, California

USGS Publications Warehouse

Li, Y.-G.; Ellsworth, W.L.; Thurber, C.H.; Malin, P.E.; Aki, K.

1997-01-01

Fault-zone guided waves were successfully excited by near-surface explosions in the San Andreas fault zone both at Parkfield and Cienega Valley, central California. The guided waves were observed on linear, three-component seismic arrays deployed across the fault trace. These waves were not excited by explosions located outside the fault zone. The amplitude spectra of guided waves show a maximum peak at 2 Hz at Parkfield and 3 Hz at Cienega Valley. The guided wave amplitude decays sharply with observation distance from the fault trace. The explosion-excited fault-zone guided waves are similar to those generated by earthquakes at Parkfield but have lower frequencies and travel more slowly. These observations suggest that the fault-zone wave guide has lower seismic velocities as it approaches the surface at Parkfield. We have modeled the waveforms as S waves trapped in a low-velocity wave guide sandwiched between high-velocity wall rocks, resulting in Love-type fault-zone guided waves. While the results are nonunique, the Parkfield data are adequately fit by a shallow wave guide 170 m wide with an S velocity 0.85 km/sec and an apparent Q ??? 30 to 40. At Cienega Valley, the fault-zone wave guide appears to be about 120 m wide with an S velocity 0.7 km/sec and a Q ??? 30.

SuperCDMS Underground Detector Fabrication Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Platt, M.; Mahapatra, R.; Bunker, Raymond A.

The SuperCDMS SNOLAB dark matter experiment processes Ge and Si crystals into fully tested phonon and ionization detectors at surface fabrication and test facilities. If not mitigated, it is anticipated that trace-level production of radioisotopes in the crystals due to exposure to cosmic rays at (or above) sea level will result in the dominant source of background events in future dark matter searches using the current SuperCDMS detector technology. Fabrication and testing of detectors in underground facilities shielded from cosmic radiation is one way to directly reduce production of trace levels of radioisotopes, thereby improving experimental sensitivity for the discoverymore » of dark matter beyond the level of the current experiment. In this report, we investigate the cost and feasibility to establish a complete detector fabrication processing chain in an underground location to mitigate cosmogenic activation of the Ge and Si detector substrates. For a specific and concrete evaluation, we explore options for such a facility located at SNOLAB, an underground laboratory in Sudbury, Canada hosting the current and future experimental phases of SuperCDMS.« less

Autonomous microexplosives subsurface tracing system final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engler, Bruce Phillip; Nogan, John; Melof, Brian Matthew

The objective of the autonomous micro-explosive subsurface tracing system is to image the location and geometry of hydraulically induced fractures in subsurface petroleum reservoirs. This system is based on the insertion of a swarm of autonomous micro-explosive packages during the fracturing process, with subsequent triggering of the energetic material to create an array of micro-seismic sources that can be detected and analyzed using existing seismic receiver arrays and analysis software. The project included investigations of energetic mixtures, triggering systems, package size and shape, and seismic output. Given the current absence of any technology capable of such high resolution mapping ofmore » subsurface structures, this technology has the potential for major impact on petroleum industry, which spends approximately $1 billion dollar per year on hydraulic fracturing operations in the United States alone.« less

Stand-off imaging Raman spectroscopy for forensic analysis of post-blast scenes: trace detection of ammonium nitrate and 2,4,6-trinitrotoluene

NASA Astrophysics Data System (ADS)

Ceco, Ema; Önnerud, Hans; Menning, Dennis; Gilljam, John L.; Bââth, Petra; Östmark, Henric

2014-05-01

The following paper presents a realistic forensic capability test of an imaging Raman spectroscopy based demonstrator system, developed at FOI, the Swedish Defence Research Agency. The system uses a 532 nm laser to irradiate a surface of 25×25mm. The backscattered radiation from the surface is collected by an 8" telescope with subsequent optical system, and is finally imaged onto an ICCD camera. We present here an explosives trace analysis study of samples collected from a realistic scenario after a detonation. A left-behind 5 kg IED, based on ammonium nitrate with a TNT (2,4,6-trinitrotoluene) booster, was detonated in a plastic garbage bin. Aluminum sample plates were mounted vertically on a holder approximately 6 m from the point of detonation. Minutes after the detonation, the samples were analyzed with stand-off imaging Raman spectroscopy from a distance of 10 m. Trace amounts could be detected from the secondary explosive (ammonium nitrate with an analysis time of 1 min. Measurement results also indicated detection of residues from the booster (TNT). The sample plates were subsequently swabbed and analyzed with HPLC and GC-MS analyses to confirm the results from the stand-off imaging Raman system. The presented findings indicate that it is possible to determine the type of explosive used in an IED from a distance, within minutes after the attack, and without tampering with physical evidence at the crime scene.

Homeland Security and Contraband Detection

NASA Astrophysics Data System (ADS)

Lanza, R. C.

Detection of contraband and illicit materials has become increasingly important, especially since the terrorist attacks in the United States on September 11, 2001. The nature of the detection problem embodies both physics issues and a set of operational constraints that limit the practical application of neutrons. The issue under consideration is detection of materials that are considered serious threats; these may include explosives; radioactive materials, fissile materials, and other materials associated with nuclear weapons, often referred to as special nuclear material (SNM). The overriding constraint is in the physics: systems must be based on clean physics; but unlike physics experiments, detection systems work under the limitation that materials must be identified nonintrusively, without interrupting the normal flow of commerce and with a high probability of detection and a low probability of false alarms. A great deal of work has been reported in the literature on neutron-based techniques for detecting explosives and drugs. The largest impetus by far for detecting explosives comes from aviation industry requirements for inspecting luggage and, to a lesser extent, cargo. The major alternative techniques are either X-ray-based or chemical trace detection methods that look for small traces of explosive residues. The limitations of the X-ray and trace methods in detecting explosives are well known, but currently (2008) it is safe to say that no neutron- or nuclear-based technique is being used routinely for security inspection, despite extensive development of these methods. Smuggling of nuclear materials has become a concern, and neutron techniques are particularly attractive for detecting them. Given the limitations of X-ray techniques and the need for SNM detection, it is now useful to reexamine neutron methodologies, particularly imaging. A significant number of neutron-based techniques have been proposed and are under development for security applications, especially SNM detection, but describing how they work is beyond the scope of the chapter. Instead, one particular approach to neutron imaging, neutron resonance radiography (NRR), is discussed in detail as it illustrates many of the issues connected with imaging and detection.

Optical inspection system for cylindrical objects

DOEpatents

Brenden, Byron B.; Peters, Timothy J.

1989-01-01

In the inspection of cylindrical objects, particularly O-rings, the object is translated through a field of view and a linear light trace is projected on its surface. An image of the light trace is projected on a mask, which has a size and shape corresponding to the size and shape which the image would have if the surface of the object were perfect. If there is a defect, light will pass the mask and be sensed by a detector positioned behind the mask. Preferably, two masks and associated detectors are used, one mask being convex to pass light when the light trace falls on a projection from the surface and the other concave, to pass light when the light trace falls on a depression in the surface. The light trace may be either dynamic, formed by a scanned laser beam, or static, formed by such a beam focussed by a cylindrical lens. Means are provided to automatically keep the illuminating receiving systems properly aligned.

Analysis of stray radiation for infrared optical system

NASA Astrophysics Data System (ADS)

Li, Yang; Zhang, Tingcheng; Liao, Zhibo; Mu, Shengbo; Du, Jianxiang; Wang, Xiangdong

2016-10-01

Based on the theory of radiation energy transfer in the infrared optical system, two methods for stray radiation analysis caused by interior thermal radiation in infrared optical system are proposed, one of which is important sampling method technique using forward ray trace, another of which is integral computation method using reverse ray trace. The two methods are discussed in detail. A concrete infrared optical system is provided. Light-tools is used to simulate the passage of radiation from the mirrors and mounts. Absolute values of internal irradiance on the detector are received. The results shows that the main part of the energy on the detector is due to the critical objects which were consistent with critical objects obtained by reverse ray trace, where mirror self-emission contribution is about 87.5% of the total energy. Corresponding to the results, the irradiance on the detector calculated by the two methods are in good agreement. So the validity and rationality of the two methods are proved.

Accelerator-Detector Complex for Photonuclear Detection of Hidden Explosives Final Report CRADA No. TC2065.0

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowdermilk, W. H.; Brothers, L. J.

This was a collaborative effort by Lawrence Livermore National Security (formerly the University of California)/Lawrence Livermore National Laboratory (LLNL), Valley Forge Composite Technologies, Inc., and the following Russian Institutes: P. N. Lebedev Physical Institute (LPI), Innovative Technologies Center.(AUO CIT), Central Design Bureau-Almas (CDB Almaz), Moscow Instrument Automation Research Institute, and Institute for High Energy Physics (IBEP) to develop equipment and procedures for detecting explosive materials concealed in airline checked baggage and cargo.

Nondestructive inspection of explosive materials using linearly polarized two-colored photon beam

NASA Astrophysics Data System (ADS)

Toyokawa, H.; Hayakawa, T.; Shizuma, T.; Hajima, R.; Masuda, K.; Ohgaki, H.

2011-10-01

A nondestructive inspection method for screening explosive materials that are hidden in passenger vehicles, trucks, and cargo containers with radiation shielding was presented. The method was examined experimentally using linearly polarized two-colored photon beam. A sample object was irradiated with the photon beam, followed by an emission of gamma-rays in nuclear resonance fluorescence. The gamma-rays from oxygen and nitrogen emitted through nuclear resonance fluorescence were measured using high-purity germanium detectors. We were able to evaluate the element concentration ratio.

Remembering Fukushima: PNNL Monitors Radiation from Nuclear Disaster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miley, Harry

Senior Scientist Harry Miley describes how his work in ultra-trace, nuclear detection technology picked up the first reading of radiological materials over the U.S. following the nuclear power plant explosion in Japan.

Remembering Fukushima: PNNL Monitors Radiation from Nuclear Disaster

ScienceCinema

Miley, Harry

2018-02-07

Senior Scientist Harry Miley describes how his work in ultra-trace, nuclear detection technology picked up the first reading of radiological materials over the U.S. following the nuclear power plant explosion in Japan.

A study of the composition of the products of laser-induced breakdown of hexogen, octogen, pentrite and trinitrotoluene using selected ion flow tube mass spectrometry and UV-Vis spectrometry.

PubMed

Sovová, Kristýna; Dryahina, Kseniya; Spanel, Patrik; Kyncl, Martin; Civis, Svatopluk

2010-05-01

Four types of explosives were studied using a combination of Laser Induced Breakdown Spectroscopy (LIBS) and Selected Ion Flow Tube Mass Spectrometry (SIFT-MS). The LIBS technique uses short laser pulses (ArF excimer laser) as the energy source to convert small amounts samples into plasma and to produce the emission from their molecular fragments or atoms. SIFT-MS is a novel method for absolute quantification based on chemical ionization using three precursor ions, with the capability to determine concentrations of trace gases and vapours of volatile organic compounds in real time. This is the first time that SIFT-MS has been used to study the release of NO, NO(2), HCN, HNO(3), HONO, HCHO and C(2)H(2) after a laser-induced breakdown of pure explosive compounds HMX (1,3,5,7-tetranitro-1,3,5,7-tetraazacyclo-octane), RDX (1,3,5-trinitro-2-oxo-1,3,5-triazacyclo-hexane), PETN (pentaerithrityl-tetranitrate) and TNT (2,4,6-trinitrotoluene) in solid form. The radiation emitted after excitation was analysed using a time resolving UV-Vis spectrometer with a ICCD detector. Electronic bands of the CN radical (388 nm), the Swan system of the C(2) radical (512 nm), the NH radical (336 nm), the OH radical (308.4 nm) and atomic lines of oxygen, nitrogen and hydrogen were identified. Vibrational and excitation temperatures were determined from the intensity distributions and a scheme of chemical reactions responsible for the formation of the observed species was proposed.

A multi-channel photometric detector for multi-component analysis in flow injection analysis

PubMed Central

Tan, Aimin; Huang, Jialin; Geng, Liudi; Xu, Jinhua; Zhao, Xinna

1994-01-01

The detector, a multi-channel photometric detector, described in this paper was developed using multi-wavelength LEDs (light emitting diode) and phototransistors for absorbance measurement controlled by an Intel 8031 8-bit single chip microcomputer. Up to four flow cells can be attached to the detector. The LEDs and phototransistors are both inexpensive, and reliable. The results given by the detector for simultaneous determination of trace amounts of cobalt and cadmium in zinc sulphate electrolyte are reported. Because of the newly developed detector, this approach employs much less hardware apparatus than by employing conventional photometric detectors. PMID:18924688

A multi-channel photometric detector for multi-component analysis in flow injection analysis.

PubMed

Tan, A; Huang, J; Geng, L; Xu, J; Zhao, X

1994-01-01

The detector, a multi-channel photometric detector, described in this paper was developed using multi-wavelength LEDs (light emitting diode) and phototransistors for absorbance measurement controlled by an Intel 8031 8-bit single chip microcomputer. Up to four flow cells can be attached to the detector. The LEDs and phototransistors are both inexpensive, and reliable. The results given by the detector for simultaneous determination of trace amounts of cobalt and cadmium in zinc sulphate electrolyte are reported. Because of the newly developed detector, this approach employs much less hardware apparatus than by employing conventional photometric detectors.

Adapting Pipeline Architectures to Track Developing Aftershock Sequences and Recurrent Explosions

DTIC Science & Technology

2014-02-14

Sumatra earthquake was used to study the performance of subspace detectors to detect and classify events from within a very large (Area = ~250,000 km2... detectors to identify and organize repeating waveforms discovered in multichannel seismic data streams. The framework has been tested and evaluated on...a variety of different test cases from mining blasts in Central Asia to moderate and large earthquake aftershock sequences. The framework performs

Liquid-Xe detector for contraband detection

NASA Astrophysics Data System (ADS)

Vartsky, D.; Israelashvili, I.; Cortesi, M.; Arazi, L.; Coimbra, A. E.; Moleri, L.; Erdal, E.; Bar, D.; Rappaport, M.; Shchemelinin, S.; Caspi, E. N.; Aviv, O.; Breskin, A.

2016-07-01

We describe progress made with a liquid-Xe (LXe) detector coupled to a gaseous photomultiplier (GPM), for combined imaging and spectroscopy of fast neutrons and gamma-rays in the MeV range. The purpose of this detector is to enable the detection of hidden explosives and fissile materials in cargo and containers. The expected position resolution is about 2 m and 3.5 mm for fast neutrons and gamma-rays, respectively. Experimental results obtained using an 241Am source yielded energy and time resolutions of 11% and 1.2 ns RMS, respectively. Initial results obtained with the position-sensitive GPM are presented.

REVIEWS OF TOPICAL PROBLEMS: Neutrinos from stellar core collapses: present status of experiments

NASA Astrophysics Data System (ADS)

Ryazhskaya, Ol'ga G.

2006-10-01

The responses of the existing underground detectors to neutrino bursts from collapsing stars evolving in accordance with various models are considered. The interpretation of the results of detecting neutrino radiation from the SN1987A supernova explosion is discussed. A combination of large scintillation counters interlayered with iron slabs (as a target for the electron neutrino interaction) is suggested as a detector for core collapse neutrinos. Bounds for the galactic rate of core collapses based on 28 years of observations by neutrino telescopes of RAS INR, LSD, and LVD detectors are presented.

Biosensor UUV payload for underwater detection

NASA Astrophysics Data System (ADS)

Kusterbeck, Anne W.; Charles, Paul T.; Melde, Brian J.; Trammell, Scott A.; Adams, André A.; Deschamps, Jeffrey R.

2010-04-01

Increased emphasis on maritime domain awareness and port security has led to the development of unmanned underwater vehicles (UUVs) capable of extended missions. These systems rely most frequently on well-developed side scan sonar and acoustic methods to locate potential targets. The Naval Research Laboratory (NRL) is developing biosensors for underwater explosives detection that complement acoustic sensors and can be used as UUV payloads to monitor areas for port and harbor security or in detection of underwater unexploded ordnance (UXO) and biochemical threats. The prototype sensor has recently been demonstrated to detect explosives in seawater at trace levels when run in a continuous sampling mode. To overcome ongoing issues with sample preparation and facilitate rapid detection at trace levels in a marine environment, we have been developing new mesoporous materials for in-line preconcentration of explosives and other small molecules, engineering microfluidic components to improve the signal, and testing alternative signal transduction methods. Additional work is being done to optimize the optical components and sensor response time. Highlights of these current studies and our ongoing efforts to integrate the biosensor with existing detection technologies to reduce false positives are described. In addition, we present the results of field tests that demonstrate the prototype biosensor performance as a UUV payload.

Apparatus and methods for real-time detection of explosives devices

DOEpatents

Blackburn, Brandon W [Idaho Falls, ID; Hunt, Alan W [Pocatello, ID; Chichester, David L [Idaho Falls, ID

2014-01-07

The present disclosure relates, according to some embodiments, to apparatus, devices, systems, and/or methods for real-time detection of a concealed or camouflaged explosive device (e.g., EFPs and IEDs) from a safe stand-off distance. Apparatus, system and/or methods of the disclosure may also be operable to identify and/or spatially locate and/or detect an explosive device. An apparatus or system may comprise an x-ray generator that generates high-energy x-rays and/or electrons operable to contact and activate a metal comprised in an explosive device from a stand-off distance; and a detector operable to detect activation of the metal. Identifying an explosive device may comprise detecting characteristic radiation signatures emitted by metals specific to an EFP, an IED or a landmine. Apparatus and systems of the disclosure may be mounted on vehicles and methods of the disclosure may be performed while moving in the vehicle and from a safe stand-off distance.

Laser-based standoff detection of surface-bound explosive chemicals

NASA Astrophysics Data System (ADS)

Huestis, David L.; Smith, Gregory P.; Oser, Harald

2010-04-01

Avoiding or minimizing potential damage from improvised explosive devices (IEDs) such as suicide, roadside, or vehicle bombs requires that the explosive device be detected and neutralized outside its effective blast radius. Only a few seconds may be available to both identify the device as hazardous and implement a response. As discussed in a study by the National Research Council, current technology is still far from capable of meeting these objectives. Conventional nitrocarbon explosive chemicals have very low vapor pressures, and any vapors are easily dispersed in air. Many pointdetection approaches rely on collecting trace solid residues from dust particles or surfaces. Practical approaches for standoff detection are yet to be developed. For the past 5 years, SRI International has been working toward development of a novel scheme for standoff detection of explosive chemicals that uses infrared (IR) laser evaporation of surfacebound explosive followed by ultraviolet (UV) laser photofragmentation of the explosive chemical vapor, and then UV laser-induced fluorescence (LIF) of nitric oxide. This method offers the potential of long standoff range (up to 100 m or more), high sensitivity (vaporized solid), simplicity (no spectrometer or library of reference spectra), and selectivity (only nitrocompounds).

Applying Bayesian Neural Network to determine neutrino incoming direction in reactor neutrino experiments and supernova explosion location by scintillator detectors

NASA Astrophysics Data System (ADS)

Xu, W. W.; Xu, Y.; Meng, Y. X.; Wu, B.

2009-01-01

In the paper, it is discussed by using Monte-Carlo simulation that the Bayesian Neural Network (BNN) is applied to determine neutrino incoming direction in reactor neutrino experiments and supernova explosion location by scintillator detectors. As a result, compared to the method in ref. [1], the uncertainty on the measurement of the neutrino direction using BNN is significantly improved. The uncertainty on the measurement of the reactor neutrino direction is about 1.0° at the 68.3% C.L., and the one in the case of supernova neutrino is about 0.6° at the 68.3% C.L. . Compared to the method in ref. [1], the uncertainty attainable by using BNN reduces by a factor of about 20. And compared to the Super-Kamiokande experiment (SK), it reduces by a factor of about 8.

New software to model energy dispersive X-ray diffraction in polycrystalline materials

NASA Astrophysics Data System (ADS)

Ghammraoui, B.; Tabary, J.; Pouget, S.; Paulus, C.; Moulin, V.; Verger, L.; Duvauchelle, Ph.

2012-02-01

Detection of illicit materials, such as explosives or drugs, within mixed samples is a major issue, both for general security and as part of forensic analyses. In this paper, we describe a new code simulating energy dispersive X-ray diffraction patterns in polycrystalline materials. This program, SinFullscat, models diffraction of any object in any diffractometer system taking all physical phenomena, including amorphous background, into account. Many system parameters can be tuned: geometry, collimators (slit and cylindrical), sample properties, X-ray source and detector energy resolution. Good agreement between simulations and experimental data was obtained. Simulations using explosive materials indicated that parameters such as the diffraction angle or the energy resolution of the detector have a significant impact on the diffraction signature of the material inspected. This software will be a convenient tool to test many diffractometer configurations, providing information on the one that best restores the spectral diffraction signature of the materials of interest.

Long-wave, infrared laser-induced breakdown (LIBS) spectroscopy emissions from energetic materials.

PubMed

Yang, Clayton S-C; Brown, Ei E; Hommerich, Uwe; Jin, Feng; Trivedi, Sudhir B; Samuels, Alan C; Snyder, A Peter

2012-12-01

Laser-induced breakdown spectroscopy (LIBS) has shown great promise for applications in chemical, biological, and explosives sensing and has significant potential for real-time standoff detection and analysis. In this study, LIBS emissions were obtained in the mid-infrared (MIR) and long-wave infrared (LWIR) spectral regions for potential applications in explosive material sensing. The IR spectroscopy region revealed vibrational and rotational signatures of functional groups in molecules and fragments thereof. The silicon-based detector for conventional ultraviolet-visible LIBS operations was replaced with a mercury-cadmium-telluride detector for MIR-LWIR spectral detection. The IR spectral signature region between 4 and 12 μm was mined for the appearance of MIR and LWIR-LIBS emissions directly indicative of oxygenated breakdown products as well as dissociated, and/or recombined sample molecular fragments. Distinct LWIR-LIBS emission signatures from dissociated-recombination sample molecular fragments between 4 and 12 μm are observed for the first time.

Mass spectrometry detection and imaging of inorganic and organic explosive device signatures using desorption electro-flow focusing ionization.

PubMed

Forbes, Thomas P; Sisco, Edward

2014-08-05

We demonstrate the coupling of desorption electro-flow focusing ionization (DEFFI) with in-source collision induced dissociation (CID) for the mass spectrometric (MS) detection and imaging of explosive device components, including both inorganic and organic explosives and energetic materials. We utilize in-source CID to enhance ion collisions with atmospheric gas, thereby reducing adducts and minimizing organic contaminants. Optimization of the MS signal response as a function of in-source CID potential demonstrated contrasting trends for the detection of inorganic and organic explosive device components. DEFFI-MS and in-source CID enabled isotopic and molecular speciation of inorganic components, providing further physicochemical information. The developed system facilitated the direct detection and chemical mapping of trace analytes collected with Nomex swabs and spatially resolved distributions within artificial fingerprints from forensic lift tape. The results presented here provide the forensic and security sectors a powerful tool for the detection, chemical imaging, and inorganic speciation of explosives device signatures.

Cherenkov water detector NEVOD

NASA Astrophysics Data System (ADS)

Petrukhin, A. A.

2015-05-01

A unique multipurpose Cherenkov water detector, the NEVOD facility, uses quasispherical measuring modules to explore all the basic components of cosmic rays on Earth's surface, including neutrinos. Currently, the experimental complex includes the Cherenkov water detector, a calibration telescope system, and a coordinate detector. This paper traces the basic development stages of NEVOD, examines research directions, presents the results obtained, including the search for the solution to the 'muon puzzle', and discusses possible future development prospects.

Chemical sensing system for classification of minelike objects by explosives detection

NASA Astrophysics Data System (ADS)

Chambers, William B.; Rodacy, Philip J.; Jones, Edwin E.; Gomez, Bernard J.; Woodfin, Ronald L.

1998-09-01

Sandia National Laboratories has conducted research in chemical sensing and analysis of explosives for many years. Recently, that experience has been directed towards detecting mines and unexploded ordnance (UXO) by sensing the low-level explosive signatures associated with these objects. Our focus has been on the classification of UXO in shallow water and anti-personnel/anti tank mines on land. The objective of this work is to develop a field portable chemical sensing system which can be used to examine mine-like objects (MLO) to determine whether there are explosive molecules associated with the MLO. Two sampling subsystems have been designed, one for water collection and one for soil/vapor sampling. The water sampler utilizes a flow-through chemical adsorbent canister to extract and concentrate the explosive molecules. Explosive molecules are thermally desorbed from the concentrator and trapped in a focusing stage for rapid desorption into an ion-mobility spectrometer (IMS). We will describe a prototype system which consists of a sampler, concentrator-focuser, and detector. The soil sampler employs a light-weight probe for extracting and concentrating explosive vapor from the soil in the vicinity of an MLO. The chemical sensing system is capable of sub-part-per-billion detection of TNT and related explosive munition compounds. We will present the results of field and laboratory tests on buried landmines, which demonstrate our ability to detect the explosive signatures associated with these objects.

Discrimination of smokeless powders by headspace SPME-GC-MS and SPME-GC-ECD, and the potential implications upon training canine detection of explosives

NASA Astrophysics Data System (ADS)

Harper, Ross J.; Almirall, Jose R.; Furton, Kenneth G.

2005-05-01

This presentation will provide an odour analysis of a variety of smokeless powders & communicate the rapid SPME-GC-ECD method utilized. This paper will also discuss the implications of the headspace analysis of Smokeless Powders upon the choice of training aids for Explosives Detection Canines. Canine detection of explosives relies upon the dogs" ability to equate finding a given explosive odour with a reward, usually in the form of praise or play. The selection of explosives upon which the dogs are trained thus determines which explosives the canines can and potentially cannot find. Commonly, the training is focussed towards high explosives such as TNT and Composition 4, and the low explosives such as Black and Smokeless Powders are added often only for completeness. Powder explosives constitute a major component of explosive incidents throughout the US, and canines trained to detect explosives must be trained across the entire range of powder products. Given the variability in the manufacture and product make-up many smokeless powders do not share common odour chemicals, giving rise to concerns over the extensiveness of canine training. Headspace analysis of a selection of Smokeless Powders by Solid Phase Microextraction Gas Chromatography using Mass Spectrometry (SPME-GC-MS) and Electron Capture Detectors (SPME-GC-ECD) has highlighted significant differences in the chemical composition of the odour available from different brands. This suggests that greater attention should be paid towards the choice of Powder Explosives when assigning canine training aids.

Direct Write Printing on Thin and Flexible Substrates for Space Applications

NASA Technical Reports Server (NTRS)

Paquette, Beth

2016-01-01

This presentation describes the work done on direct-write printing conductive traces for a flexible detector application. A Repeatability Plan was established to define detector requirements, material and printer selections, printing facilities, and tests to verify requirements are met. Designs were created for the detector, and printed using an aerosol jet printer. Testing for requirement verification is ongoing.

Analytical Support, Characterization, and Optimization of a Canine Training Aid Delivery System: Phase 2

DTIC Science & Technology

2016-01-29

Arlington, Virginia 22203-1995 61-9496-A-2-5 ONR May 2014 – April 2015 *Nova Research, Inc., Alexandria, VA Improvised explosive device Detector dog Canine...37 Figure 30. Mass of MeS collected from three subsequent mock dog sniffs above the MODD. .. 37 Figure 31. Vapor concentration...particularly for the detection of HMEs. In 2012, the Office of Naval Research deployed as many as 280 IED Detector Dogs (IDDs) to Afghanistan [1

Investigation of the Behavioral Characteristics of Dogs Purpose-Bred and Prepared to Perform Vapor Wake® Detection of Person-Borne Explosives

PubMed Central

Lazarowski, Lucia; Haney, Pamela Sue; Brock, Jeanne; Fischer, Terry; Rogers, Bart; Angle, Craig; Katz, Jeffrey S.; Waggoner, L. Paul

2018-01-01

Specialized detector dogs are increasingly being utilized for the detection of modern threats. The Vapor Wake® (VW) dog was developed to create a dog phenotype ideally suited for detecting hand-carried and body-worn explosives. VW dogs (VWDs) are trained to sample and alert to target odors in the aerodynamic wakes of moving persons, which entrains vapor and small particles from the person. The behavioral characteristics necessary for dogs to be successfully trained and employed for the application of VW are a distinct subset of the desired general characteristics of dogs used for detection tasks due to the dynamic nature of moving targets. The purpose of this study was to examine the behavioral characteristics of candidate detector dogs to determine the particular qualities that set apart VW-capable dogs from others. We assessed 146 candidate detector dogs from a VW breeding and training program. Dogs received identical puppy development and foundational odor training and underwent performance evaluations at 3, 6, 10, and 12 months old, after which they were sold for service. Dogs were categorized based on their final outcome of the training program, independently determined by private vendors, corresponding to three groups: dogs successfully sold for VW, dogs sold for standard explosives detection, and dogs that failed to be placed in any type of detector dog service (Washouts). Comparisons of behavioral evaluations between the groups were made across domains pertaining to search-related behaviors (Performance), reactions to novel stimuli (Environmental), and overall ease of learning new tasks (Trainability). Comparisons were also made at each evaluation to determine any early emergence of differences. VWDs scored significantly higher on Performance characteristics compared to standard explosives detection dogs (EDDs) and Washouts. However, Environmental characteristics did not differentiate VWDs from EDDs, though scores on these measures were significantly lower in the Washouts. Furthermore, differences between groups emerged as early as 3 and 6 months for select measures. We describe the behavioral characteristics targeted for selection in developing the VW phenotype and discuss the relative merit and degree of expression of those characteristics in the success of dogs bred and trained for the VW application. PMID:29616229

Spectral signatures for RDX-based explosives in the 3 micron region

NASA Astrophysics Data System (ADS)

Osborn, Tabetha; Kaimal, Sindhu; Reeve, Scott W.; Burns, William

2008-04-01

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.

Optics Research: 1975:2

DTIC Science & Technology

1975-12-31

9. The detectors were numbered as shown. Detector 2 of the HgCdTe array was turned off due to noise considerations. The array traces show an...The probe beam diagnostics were composed of a large area Au:Ge detector to measure the total probe beam transmission, and a five-element HgCdTe array...laser. ...^-J-..:..^il iitiiinnii" --- "-’ ^Ul.ü^^j .. r ■:, >iUj<&k focal spot size. Other shots show larger signals on the outside detectors

Development of a Miniature Mass Spectrometer and an Automated Detector for Sampling Explosive Materials

PubMed Central

Hashimoto, Yuichiro

2017-01-01

The development of a robust ionization source using the counter-flow APCI, miniature mass spectrometer, and an automated sampling system for detecting explosives are described. These development efforts using mass spectrometry were made in order to improve the efficiencies of on-site detection in areas such as security, environmental, and industrial applications. A development team, including the author, has struggled for nearly 20 years to enhance the robustness and reduce the size of mass spectrometers to meet the requirements needed for on-site applications. This article focuses on the recent results related to the detection of explosive materials where automated particle sampling using a cyclone concentrator permitted the inspection time to be successfully reduced to 3 s. PMID:28337396

Challenge of false alarms in nitroaromatic explosive detection--a detection device based on surface-enhanced Raman spectroscopy.

PubMed

Wackerbarth, Hainer; Gundrum, Lars; Salb, Christian; Christou, Konstantin; Viöl, Wolfgang

2010-08-10

A challenge in the detection of explosives is the differentiation between explosives and contaminants. Synthetic musk-containing perfumes can cause false alarms, as these perfumes are nitroaromatic compounds, which can be mistaken for trinitro toluene (TNT) by some detectors. We present a detection principle based on surface-enhanced Raman scattering (SERS). A stream of the airborne compounds is focused and resublimated on a cooled nanostructured gold surface. We recorded high-resolution SERS spectra of TNT, musk xylene, and musk ketone. The nitroaromatic compounds can be identified unambiguously by their SERS spectra. Even the dominant bands containing nitro-group scissoring and symmetric stretching modes are significantly shifted by the difference in molecular structure.

Ultrasensitive detection of explosives and chemical warfare agents by low-pressure photoionization mass spectrometry.

PubMed

Sun, Wanqi; Liang, Miao; Li, Zhen; Shu, Jinian; Yang, Bo; Xu, Ce; Zou, Yao

2016-08-15

On-spot monitoring of threat agents needs high sensitive instrument. In this study, a low-pressure photoionization mass spectrometer (LPPI-MS) was employed to detect trace amounts of vapor-phase explosives and chemical warfare agent mimetics under ambient conditions. Under 10-s detection time, the limits of detection of 2,4-dinitrotoluene, nitrotoluene, nitrobenzene, and dimethyl methyl phosphonate were 30, 0.5, 4, and 1 parts per trillion by volume, respectively. As compared to those obtained previously with PI mass spectrometric techniques, an improvement of 3-4 orders of magnitude was achieved. This study indicates that LPPI-MS will open new opportunities for the sensitive detection of explosives and chemical warfare agents. Copyright © 2016 Elsevier B.V. All rights reserved.

Detection of explosive remnants of war by neutron thermalisation.

PubMed

Brooks, F D; Drosg, M; Smit, F D; Wikner, C

2012-01-01

The HYDAD-D landmine detector (Brooks and Drosg, 2005) has been modified and field-tested for 17 months in a variety of soil conditions. Test objects containing about the same mass of hydrogen (20g) as small explosive remnants of war, such as antipersonnel landmines, were detected with efficiency 100% when buried at cover depths up to 10cm. The false alarm rate under the same conditions was 9%. Plots of detection efficiency versus false alarm rate are presented. Copyright © 2011 Elsevier Ltd. All rights reserved.

Ghostly Remnant of an Explosive Past

NASA Image and Video Library

2007-03-07

This enhanced image from the far-ultraviolet detector on NASA Galaxy Evolution shows a ghostly shell of ionized gas around Z Camelopardalis, a binary, or double-star system featuring a collapsed, dead star known as a white dwarf, and a companion star.

Synthesis and characterization of surrogate nuclear explosion debris: urban glass matrix

DOE PAGES

Campbell, Keri; Judge, Elizabeth J.; Dirmyer, Matthew R.; ...

2017-07-26

Surrogate nuclear explosive debris was synthesized and characterized for major, minor, and trace elemental composition as well as uranium isotopics. The samples consisted of an urban glass matrix, equal masses soda lime and cement, doped with 500 ppm uranium with varying enrichments. The surface and cross section morphology were measured with SEM, and the major elemental composition was determined by XPS. LA-ICP-MS was used to measure the uranium isotopic abundance comparing different sampling techniques. Furthermore, the results provide an example of the utility of LA-ICP-MS for forensics applications.

Ultra-Trace and Vapor Detection of Explosives and Narcotics Finalist for R&D 100 Award

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ewing, Robert

An instrument more sensitive than a canine’s nose identifies explosives and narcotics vapors in real time and at levels previously undetectable than any other sampling technology. The instrument is one among five PNNL-developed technologies in the running for an R&D 100 Award. Known as VP-IDENT, the tool coupled with a mass spectrometer, is ideal for aviation security, cargo screening, and broader counter-terrorism and national security activities where discovering dangerous substances is of utmost importance. Listen as researcher Robert Ewing explains.

Ultra-Trace and Vapor Detection of Explosives and Narcotics Finalist for R&D 100 Award

ScienceCinema

Ewing, Robert

2018-06-13

An instrument more sensitive than a canine’s nose identifies explosives and narcotics vapors in real time and at levels previously undetectable than any other sampling technology. The instrument is one among five PNNL-developed technologies in the running for an R&D 100 Award. Known as VP-IDENT, the tool coupled with a mass spectrometer, is ideal for aviation security, cargo screening, and broader counter-terrorism and national security activities where discovering dangerous substances is of utmost importance. Listen as researcher Robert Ewing explains.

Universal trace pollutant detector for aircraft monitoring of the ozone layer and industrial areas

NASA Technical Reports Server (NTRS)

Filiouguine, I. V.; Kostiouchenko, S. V.; Koudriavtsev, N. N.

1994-01-01

A method of monitoring the trace impurities of nitrogen oxides based on controlling of luminescence of NO molecules excited by nanosecond gas discharge have been developed having pptv-ppbv sensitivity and temporal resolution less than 0.01 s.

Portable NIR bottled liquid explosive detector

NASA Astrophysics Data System (ADS)

Itozaki, Hideo; Ono, Masaki; Ito, Shiori; Uekawa, Keisuke; Miyato, Yuji; Sato-Akaba, Hideo

2016-05-01

A near infrared bottled liquid scanner has been developed for security check at airports for anti-terrorism. A compact handheld liquid scanner has been developed using an LED as a light source, instead of a halogen lamp. An LED has much smaller size, longer life time and lower power consumption than those of the lamp. However, it has narrower wave band. Here, we tried to use LEDs to scan liquids and showed the possibility that LEDs can be used as a light source of liquid detector.

The methodology of the search for a correlated signal from a supernova explosion using the data of gravitational wave detectors and neutrino observatories

NASA Astrophysics Data System (ADS)

Gromov, M. B.

2017-11-01

The proposed methodology developed in cooperation of the LIGO, VIRGO, Borexino, LVD, and IceCube collaborations is based on a joint analysis of data from neutrino and gravitational wave detectors which record corresponding radiations, almost undistorted by the interstellar medium and propagating with similar speeds. This approach allows to increase the reliability of observations, detect the so-called Silent supernovae and explore the properties and generation mechanisms of gravitational waves.

Concept Study of Multi Sensor Detection Imaging and Explosive Confirmation of Mines

DTIC Science & Technology

1998-03-20

surface feature removal can be achieved in LMR images. Small Business Technology Transfer (STTR) Solicitation Topic 97T006 Mufi -Sensor Detection...divided by the applied voltage. This is mathematically given by: 00 Y-I-G+jB = 1o+2E’. COS m4; m1l 1-1 = j120 72(+a) where G = the input conductance...of detector operation that are incorporated into a mathematical algorithm to convert detector impedance characteristics into recognizable indicators

Explosive Characteristics of Carbonaceous Nanoparticles

NASA Astrophysics Data System (ADS)

Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

2013-03-01

Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V1/3 (dp/pt)max ~ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ~ 101 -102 g/m3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ~ 200 bar-m/s, placing it borderline St-1/St-2. Work supported through the NIOSH Nanotechnology Research Center (NTRC)

Small-Scale Thermal Violence Cook Off Test

NASA Astrophysics Data System (ADS)

Cook, Malcolm; Curtis, John; Stennett, Christopher

2015-06-01

The Small-Scale thermal Violence Test (SSVT) is designed to quantify the violence (explosiveness) of test materials by means of observing the velocity history of a metal burst disk that forms one end of a strong thick-walled cylindrical test vehicle. A copper heating block is placed to the rear of, but in contact with, the sample and provides sealing. The difference in thermal conductivity between copper and steel is sufficient that thermal runaway is induced near to the explosive / copper interface in an unlagged test. A series of experiments has been made, in which explosive specimens were confined and heated to explosion. A high-accuracy velocity measurement system was used to record the motion of the bursting disk. These experiments have shown that the early-time motion of the bursting disk corresponds qualitatively to the onset of thermal explosion and growth of reaction within the explosive specimens. However, the velocity history traces are more complex than had been anticipated. In particular, unexplained shoulders were observed in the Phase-Doppler Velocimeter (PDV) data. Some preliminary modelling studies have been carried out in order to shed light on the complex shapes of the projectile velocity histories.

Miniature triaxial metastable ionization detector for gas chromatographic trace analysis of extraterrestrial volatiles

NASA Technical Reports Server (NTRS)

Woeller, F. H.; Kojiro, D. R.; Carle, G. C.

1984-01-01

The present investigation is concerned with a miniature metastable ionization detector featuring an unconventional electrode configuration, whose performance characteristics parallel those of traditional design. The ionization detector is to be incorporated in a flight gas chromatograph (GC) for use in the Space Shuttle. The design of the detector is discussed, taking into account studies which verified the sensitivity of the detector. The triaxial design of the detector is compared with a flat-plate style. The obtained results show that the principal goal of developing a miniature, highly sensitive ionization detector for flight applications was achieved. Improved fabrication techniques will utilize glass-to-metal seals and brazing procedures.

A novel liquid-Xenon detector concept for combined fast-neutrons and gamma imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Breskin, A.; Israelashvili, I.; Cortesi, M.; Arazi, L.; Shchemelinin, S.; Chechik, R.; Dangendorf, V.; Bromberger, B.; Vartsky, D.

2012-06-01

A new detector concept is presented for combined imaging and spectroscopy of fast-neutrons and gamma rays. It comprises a liquid-Xenon (LXe) converter and scintillator coupled to a UV-sensitive gaseous imaging photomultiplier (GPM). Radiation imaging is obtained by localization of the scintillation-light from LXe with the position-sensitive GPM. The latter comprises a cascade of Thick Gas Electron Multipliers (THGEM), where the first element is coated with a CsI UV-photocathode. We present the concept and provide first model-simulation results of the processes involved and the expected performances of a detector having a LXe-filled capillaries converter. The new detector concept has potential applications in combined fast-neutron and gamma-ray screening of hidden explosives and fissile materials with pulsed sources.

Improved thermal neutron activation sensor for detection of bulk explosives

NASA Astrophysics Data System (ADS)

McFee, John E.; Faust, Anthony A.; Andrews, H. Robert; Clifford, Edward T. H.; Mosquera, Cristian M.

2012-06-01

Defence R&D Canada - Suffield and Bubble Technology Industries have been developing thermal neutron activation (TNA) sensors for detection of buried bulk explosives since 1994. First generation sensors, employing an isotopic source and NaI(Tl) gamma ray detectors, were deployed by Canadian Forces in 2002 as confirmation sensors on the ILDS teleoperated, vehicle-mounted, multi-sensor anti-tank landmine detection systems. The first generation TNA could detect anti-tank mines buried 10 cm or less in no more than a minute, but deeper mines and those significantly displaced horizontally required considerably longer times. Mines as deep as 30 cm could be detected with long counting times (1000 s). The second generation TNA detector is being developed with a number of improvements aimed at increasing sensitivity and facilitating ease of operation. Among these are an electronic neutron generator to increase sensitivity for deeper and horizontally displaced explosives; LaBr3(Ce) scintillators, to improve time response and energy resolution; improved thermal and electronic stability; improved sensor head geometry to minimize spatial response nonuniformity; and more robust data processing. This improved sensitivity can translate to either decreased counting times, decreased minimum detectable explosive quantities, increased maximum sensor-to-target displacement, or a trade off among all three. Experiments to characterize the performance of the latest generation TNA in detecting buried landmines and IEDs hidden in culverts were conducted during 2011. This paper describes the second generation system. The experimental setup and methodology are detailed and preliminary comparisons between the performance of first and second generation systems are presented.

Improved gaseous leak detector

DOEpatents

Juravic, F.E. Jr.

1983-10-06

In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the nonlinear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

Gaseous leak detector

DOEpatents

Juravic, Jr., Frank E.

1988-01-01

In a short path length mass-spectrometer type of helium leak detector wherein the helium trace gas is ionized, accelerated and deflected onto a particle counter, an arrangement is provided for converting the detector to neon leak detection. The magnetic field of the deflection system is lowered so as to bring the non linear fringe area of the magnetic field across the ion path, thereby increasing the amount of deflection of the heavier neon ions.

Statistics of the detection rates for tensor and scalar gravitational waves from the Local Galaxy universe

NASA Astrophysics Data System (ADS)

Baryshev, Yu. V.; Paturel, G.

2001-05-01

We use data on the local 3-dimensional galaxy distribution for studying the statistics of the detection rates of gravitational waves (GW) coming from supernova explosions. We consider both tensor and scalar gravitational waves which are possible in a wide range of relativistic and quantum gravity theories. We show that statistics of GW events as a function of sidereal time can be used for distinction between scalar and tensor gravitational waves because of the anisotropy of spatial galaxy distribution. For calculation of the expected amplitudes of GW signals we use the values of the released GW energy, frequency and duration of GW pulse which are consistent with existing scenarios of SN core collapse. The amplitudes of the signals produced by Virgo and the Great Attractor clusters of galaxies is expressed as a function of the sidereal time for resonant bar detectors operating now (IGEC) and for forthcoming laser interferometric detectors (VIRGO). Then, we calculate the expected number of GW events as a function of sidereal time produced by all the galaxies within 100 Mpc. In the case of axisymmetric rotational core collapse which radiates a GW energy of 10-9Msunc2, only the closest explosions can be detected. However, in the case of nonaxisymmetric supernova explosion, due to such phenomena as centrifugal hangup, bar and lump formation, the GW radiation could be as strong as that from a coalescing neutron-star binary. For radiated GW energy higher than 10-6Msunc2 and sensitivity of detectors at the level h ~ 10-23 it is possible to detect Virgo cluster and Great Attractor, and hence to use the statistics of GW events for testing gravity theories.

Analysis of chain saw lubricating oils commonly used in Thailand's southern border provinces for forensic science purpose.

PubMed

Choodum, Aree; Tripuwanard, Kijja; Daeid, Niamh Nic

2014-08-01

In recent years, Thailand's southern border provinces (Malay-Muslim-majority border provinces) have become the scene of violence and insurgency. One of the attack patterns is the blocking of roads with perennial plants followed by planned attacks using improvised explosive devices (IEDs) or weapons on first responders. Containers of viscous dark lubricating oil and traces of lubricants on the felled trees were usually found at the scene. These were suspected to be chain oil lubricant from the chainsaws used to cut down the trees used for the roadblock. This work aimed to differentiate the chromatographic patterns of used lubricating oils available in automobile repair shops from various locations across Thailand's southern border provinces. Lubricating oils were analyzed using gas chromatography/flame ionization detector (GC/FID) every two weeks to study their variation in chemical compositions over time. The results obtained from GC/FID were normalized for differentiation. This included four two-stroke, six four-stroke, and three recycled oils. Two lubricating oils found at an incident scene were also analyzed and the results compared with the chain oil from five seized chainsaws. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Chamber Optics for Testing Passive Remote Sensing Vapor Detectors

DTIC Science & Technology

1993-11-01

BIOLOGICAL A DEFENSE AGENCY Aberden Proving Ground , Maryland 21010-6423 S4 2 18 94-05616 Best Available Copy Disclaimer The findings in this report are...were tried; ray tracing proved to be the most useful. Rays were iteratively traced through every element using the following paraxial equations. 8 U

Localisation of an Unknown Number of Land Mines Using a Network of Vapour Detectors

PubMed Central

Chhadé, Hiba Haj; Abdallah, Fahed; Mougharbel, Imad; Gning, Amadou; Julier, Simon; Mihaylova, Lyudmila

2014-01-01

We consider the problem of localising an unknown number of land mines using concentration information provided by a wireless sensor network. A number of vapour sensors/detectors, deployed in the region of interest, are able to detect the concentration of the explosive vapours, emanating from buried land mines. The collected data is communicated to a fusion centre. Using a model for the transport of the explosive chemicals in the air, we determine the unknown number of sources using a Principal Component Analysis (PCA)-based technique. We also formulate the inverse problem of determining the positions and emission rates of the land mines using concentration measurements provided by the wireless sensor network. We present a solution for this problem based on a probabilistic Bayesian technique using a Markov chain Monte Carlo sampling scheme, and we compare it to the least squares optimisation approach. Experiments conducted on simulated data show the effectiveness of the proposed approach. PMID:25384008

LWIR hyperspectral micro-imager for detection of trace explosive particles

NASA Astrophysics Data System (ADS)

Bingham, Adam L.; Lucey, Paul G.; Akagi, Jason T.; Hinrichs, John L.; Knobbe, Edward T.

2014-05-01

Chemical micro-imaging is a powerful tool for the detection and identification of analytes of interest against a cluttered background (i.e. trace explosive particles left behind in a fingerprint). While a variety of groups have demonstrated the efficacy of Raman instruments for these applications, point by point or line by line acquisition of a targeted field of view (FOV) is a time consuming process if it is to be accomplished with useful spatial resolutions. Spectrum Photonics has developed and demonstrated a prototype system utilizing long wave infrared hyperspectral microscopy, which enables the simultaneous collection of LWIR reflectance spectra from 8-14 μm in a 30 x 7 mm FOV with 30 μm spatial resolution in 30 s. An overview of the uncooled Sagnac-based LWIR HSM system will be given, emphasizing the benefits of this approach. Laboratory Hyperspectral data collected from custom mixtures and fingerprint residues is shown, focusing on the ability of the LWIR chemical micro-imager to detect chemicals of interest out of a cluttered background.

Chemochromic Hydrogen Leak Detectors

NASA Technical Reports Server (NTRS)

Roberson, Luke; Captain, Janine; Williams, Martha; Smith, Trent; Tate, LaNetra; Raissi, Ali; Mohajeri, Nahid; Muradov, Nazim; Bokerman, Gary

2009-01-01

At NASA, hydrogen safety is a key concern for space shuttle processing. Leaks of any level must be quickly recognized and addressed due to hydrogen s lower explosion limit. Chemo - chromic devices have been developed to detect hydrogen gas in several embodiments. Because hydrogen is odorless and colorless and poses an explosion hazard, there is an emerging need for sensors to quickly and accurately detect low levels of leaking hydrogen in fuel cells and other advanced energy- generating systems in which hydrogen is used as fuel. The device incorporates a chemo - chromic pigment into a base polymer. The article can reversibly or irreversibly change color upon exposure to hydrogen. The irreversible pigment changes color from a light beige to a dark gray. The sensitivity of the pigment can be tailored to its application by altering its exposure to gas through the incorporation of one or more additives or polymer matrix. Furthermore, through the incorporation of insulating additives, the chemochromic sensor can operate at cryogenic temperatures as low as 78 K. A chemochromic detector of this type can be manufactured into any feasible polymer part including injection molded plastic parts, fiber-spun textiles, or extruded tapes. The detectors are simple, inexpensive, portable, and do not require an external power source. The chemochromic detectors were installed and removed easily at the KSC launch pad without need for special expertise. These detectors may require an external monitor such as the human eye, camera, or electronic detector; however, they could be left in place, unmonitored, and examined later for color change to determine whether there had been exposure to hydrogen. In one type of envisioned application, chemochromic detectors would be fabricated as outer layers (e.g., casings or coatings) on high-pressure hydrogen storage tanks and other components of hydrogen-handling systems to provide visible indications of hydrogen leaks caused by fatigue failures or other failures in those systems. In another type of envisioned application, chemochromic detectors of this type could be optoelectronically instrumented for monitoring to provide measured digital indications of color changes indicative of the presence of hydrogen.

Analysis of trace impurities in neon by a customized gas chromatography.

PubMed

Yin, Min Kyo; Lim, Jeong Sik; Moon, Dong Min; Lee, Gae Ho; Lee, Jeongsoon

2016-09-09

Excimer lasers, widely used in the semiconductor industry, are crucial for analyzing the purity of premix laser gases for the purpose of controlling stable laser output power. In this study, we designed a system for analyzing impurities in pure neon (Ne) base gas by customized GC. Impurities in pure neon (H2 and He), which cannot be analyzed at the sub-μmol/mol level using commercial GC detectors, were analyzed by a customized pulsed-discharge Ne ionization detector (PDNeD) and a pressurized injection thermal conductivity detector using Ne as the carrier gas (Pres. Inj. Ne-TCD). From the results, trace species in Ne were identified with the following detection limits: H2, 0.378μmol/mol; O2, 0.119μmol/mol; CH4, 0.880μmol/mol; CO, 0.263μmol/mol; CO2, 0.162μmol/mol (PDNeD); and He, 0.190μmol/mol (Pres. Inj. Ne-TCD). This PDNeD and pressurized injection Ne-TCD technique thus developed permit the quantification of trace impurities present in high-purity Ne. Copyright © 2016. Published by Elsevier B.V.

Digital pulse-shape analysis with a TRACE early silicon prototype

NASA Astrophysics Data System (ADS)

Mengoni, D.; Dueñas, J. A.; Assié, M.; Boiano, C.; John, P. R.; Aliaga, R. J.; Beaumel, D.; Capra, S.; Gadea, A.; Gonzáles, V.; Gottardo, A.; Grassi, L.; Herrero-Bosch, V.; Houdy, T.; Martel, I.; Parkar, V. V.; Perez-Vidal, R.; Pullia, A.; Sanchis, E.; Triossi, A.; Valiente Dobón, J. J.

2014-11-01

A highly segmented silicon-pad detector prototype has been tested to explore the performance of the digital pulse shape analysis in the discrimination of the particles reaching the silicon detector. For the first time a 200 μm thin silicon detector, grown using an ordinary floating zone technique, has been shown to exhibit a level discrimination thanks to the fine segmentation. Light-charged particles down to few MeV have been separated, including their punch-through. A coaxial HPGe detector in time coincidence has further confirmed the quality of the particle discrimination.

Increasing the High Voltage Capabilities and Exploring Parameter Space of an Inertial Electrostatic Confinement Fusion Neutron Source for the Detection of Chemical Explosives

NASA Astrophysics Data System (ADS)

Michalak, Matthew K.

The objectives of the work presented here include understanding key operating principles and providing precise data sets that can be used to test inertial electrostatic confinement (IEC) fusion theory and optimize IEC device operation. The underlying physical behavior was separated from superficial trends observed in an IEC device at the University of Wisconsin-Madison (UW). The effects of changing voltage (30-170 kV) and current (30-100 mA) were thoroughly explored, pressure effects (0.15-1.25 mTorr) were mapped, and the effect of impurities in the system was quantified. The most challenging part of this work was designing a high voltage feedthrough that could reliably operate at higher voltages for far longer times than previously attained. A system to detect conventional explosives using fusion neutrons was also designed, constructed, and tested. Precise data sets were created by taking into account and minimizing the effects of short and long term trends in the experiment. Detailed meter current scans were taken that showed a linear relationship of the neutron production rate with current. Cathode voltage scans were slightly greater than linear in the neutron rate from 30 to 170 kV, but the rate increase diminished to near linear as 170 kV was approached. A new high voltage feedthrough was designed that surpassed the performance of past UW IEC lab feedthroughs and shows promise for long duration operation at still higher voltages. Limitations of other equipment in the IEC lab prevented testing the feedthrough to voltages above 175 kV. A more robust construction of the feedthrough and reducing the consequences of a feedthrough failure were also important design criteria that were met. A detector array was made to detect explosives via the 10.8 MeV neutron capture prompt gamma from nitrogen. Signals from four separate detectors were combined to make the individual detectors act similar to one large detector. The detector signals were both summed and combined to compare the performance of the two methods. An overwhelming background radiation signal and insufficient time resolution were two factors that led to the combined signal not performing as well as the summed signal.

Method for remote detection of trace contaminants

DOEpatents

Simonson, Robert J.; Hance, Bradley G.

2003-09-09

A method for remote detection of trace contaminants in a target area comprises applying sensor particles that preconcentrate the trace contaminant to the target area and detecting the contaminant-sensitive fluorescence from the sensor particles. The sensor particles can have contaminant-sensitive and contaminant-insensitive fluorescent compounds to enable the determination of the amount of trace contaminant present in the target are by relative comparison of the emission of the fluorescent compounds by a local or remote fluorescence detector. The method can be used to remotely detect buried minefields.

Dow’s fire and explosion index: a case-study in the process unit of an oil extraction factory

PubMed Central

Nezamodini, Zeynab Sadat; Rezvani, Zahra; Kian, Kumars

2017-01-01

Introduction The incidence of fires and explosions have led to severe damage in many industries, primarily in industries’ financial losses. This study was conducted to estimate losses due to fire and explosion and the impact of control measures on the number of losses applying Dow’s Fire and Explosion Index. Methods This is a case study conducted in one of the process units of an oil extraction factory. Dow’s Fire and Explosion Index Hazard classification guide, 7th edition, issued by the American Institute of Chemical Engineers was applied. Data were obtained mainly through interviews and consultation with experts, as well as reported operating parameters and process documents. Results The Dow Index of the processing unit was estimated to be 243.68, and the most probable base damage was approximately $4.15 million in 2008. The actual damages were estimated to be $2,863,500, and the number of lost work days to be 64.56 days. The interruption losses were estimated to be $15,817,200 and the total losses to the system to be $18.67 million. These results demonstrated that losses resulting from production interruptions are greater than losses due to the destruction of equipment. A series of corrections was then proposed and risk analysis was performed again to examine the effects of reforms. The comparison shows that by applying reforms the FEI can change to 86.62 and the total loss can reduce to $9.03 million. Conclusion This study shows that Dow’s Index is a systematic tool to examine the impact of control measures. It also enhances resource management considering an optimal insurance contract. Considering the priority of reducing damage factors, several correction actions were suggested, such as modifying the drainage system, installation of hexane detectors, an automatic sprinkler system, fire detectors on the cable tray, and finally, using the water spray washing on the tanks. PMID:28465821

Dow's fire and explosion index: a case-study in the process unit of an oil extraction factory.

PubMed

Nezamodini, Zeynab Sadat; Rezvani, Zahra; Kian, Kumars

2017-02-01

The incidence of fires and explosions have led to severe damage in many industries, primarily in industries' financial losses. This study was conducted to estimate losses due to fire and explosion and the impact of control measures on the number of losses applying Dow's Fire and Explosion Index. This is a case study conducted in one of the process units of an oil extraction factory. Dow's Fire and Explosion Index Hazard classification guide, 7 th edition, issued by the American Institute of Chemical Engineers was applied. Data were obtained mainly through interviews and consultation with experts, as well as reported operating parameters and process documents. The Dow Index of the processing unit was estimated to be 243.68, and the most probable base damage was approximately $4.15 million in 2008. The actual damages were estimated to be $2,863,500, and the number of lost work days to be 64.56 days. The interruption losses were estimated to be $15,817,200 and the total losses to the system to be $18.67 million. These results demonstrated that losses resulting from production interruptions are greater than losses due to the destruction of equipment. A series of corrections was then proposed and risk analysis was performed again to examine the effects of reforms. The comparison shows that by applying reforms the FEI can change to 86.62 and the total loss can reduce to $9.03 million. This study shows that Dow's Index is a systematic tool to examine the impact of control measures. It also enhances resource management considering an optimal insurance contract. Considering the priority of reducing damage factors, several correction actions were suggested, such as modifying the drainage system, installation of hexane detectors, an automatic sprinkler system, fire detectors on the cable tray, and finally, using the water spray washing on the tanks.

Design of Microstructured Conducting Polymer Films for Enhanced Trace Explosives Detection

NASA Astrophysics Data System (ADS)

Laster, Jennifer S.

The detection of trace amounts of explosive material is critical to national security. Ion mobility spectrometer (IMS)-based contact sampling continues to be a common method employed for the detection of explosives in high security checkpoint applications, such as airport security. In this process a surface of interest, such as a passenger's hands or luggage, is probed by a swab or particle trap to collect and transfer residue to an IMS for analysis. The collection of residue on a sampling swab has been shown to be a limiting step in this detection process. As such, there is significant need to develop new materials with increased adhesion to explosive analytes and with superior particle removal abilities. Here, the design of novel sampling swabs is presented for the enhanced collection of trace explosive residue from surfaces. First, the influence of the swab microstructure on the ability to remove particles from representative substrates is demonstrated. Free-standing microstructured polypyrrole (PPy) films of a variety of dimensions and form factors are fabricated using a templated electropolymerization process. The removal of polystyrene fluorescent particles from an aluminum substrate of varying surface roughness is examined as a function of the polymer microstructure. PPy microstructured films display enhanced particle removal abilities compared to PPy non-structured and current commercial films. This increase in particle removal is attributed to the increased particle-swab contact from the microstructured films. Next, the influence of the surface chemistry of sampling swabs on the collection of a representative explosive analyte, trinitrotoluene (TNT) is explored. The surface chemistry of PPy films is modified by electropolymerizaton of an N-substituted pyrrole monomer. The surface chemistries examined include a methyl, carboxylic acid, and amino-phenyl functionality. The vapor deposition of TNT on the surface of the functionalized PPy films is quantified through ultraviolet-visible (UV-vis) absorption and compared to commercial swabbing materials of varying chemistry and surface roughness. The PPy modified films with potential sites for hydrogen bonding display the highest deposition of TNT, while the Teflon coated commercial films display the lowest interaction with TNT. Finally, the desorption and release of TNT from sampling swabs is studied as an effect of temperature and of applied bias. For successful analyte detection within an IMS, the residue collected on a sampling swab must be released from the swab, typically through a thermal desorption process. In this work the release of TNT from sampling swabs is determined through solid-phase microextraction-gas chromatography mass spectrometry (SPME-GCMS). The results of this thesis provide important information on the design considerations for the development of novel particle sampling swabs with increased performance.

Predictive Fusion of Geophysical Waveforms using Fisher's Method, under the Alternative Hypothesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carmichael, Joshua Daniel; Nemzek, Robert James; Webster, Jeremy David

2017-05-05

This presentation tries to understand how to combine different signatures from an event or source together in a defensible way. The objective was to build a digital detector that continuously combines detection statistics recording explosions to screen sources of interest from null sources.

Determining the physical and chemical processes behind four caldera-forming eruptions in rapid succession in the San Juan caldera cluster, Colorado, USA

NASA Astrophysics Data System (ADS)

Curry, A. C.; Caricchi, L.; Lipman, P. W.

2017-12-01

A primary goal of volcanology is to understand the frequency and magnitude of large, explosive volcanic eruptions to mitigate their impact on society. Recent studies show that the average magma flux and the time between magma injections into a given magmatic-volcanic system fundamentally control the frequency and magnitude of volcanic eruptions, yet these parameters are unknown for many volcanic regions on Earth. We focus on major and trace element chemistry of individual phases and whole-rock samples, initial zircon ID-TIMS analyses, and zircon SIMS oxygen isotope analyses of four caldera-forming ignimbrites from the San Juan caldera cluster in the Southern Rocky Mountain volcanic field, Colorado, to determine the physical and chemical processes leading to large eruptions. We collected outflow samples along stratigraphy of the three caldera-forming ignimbrites of the San Luis caldera complex: the Rat Creek Tuff ( 150 km3), Cebolla Creek Tuff ( 250 km3), and Nelson Mountain Tuff (>500 km3); and we collected samples of both outflow and intracaldera facies of the Snowshoe Mountain Tuff (>500 km3), which formed the Creede caldera. Single-crystal sanidine 40Ar/39Ar ages show that these large eruptions occurred in rapid succession between 26.91 ± 0.02 Ma (Rat Creek Tuff) and 26.87 ± 0.02 Ma (Snowshoe Mountain Tuff), providing an opportunity to investigate the temporal evolution of magmatic systems feeding large, explosive volcanic eruptions. Major and trace element analyses show that the first and last eruption of the San Luis caldera complex (Rat Creek Tuff and Nelson Mountain Tuff) are rhyolitic to dacitic ignimbrites, whereas the Cebolla Creek Tuff and Snowshoe Mountain Tuff are crystal-rich, dacitic ignimbrites. Trace elements show enrichment in light rare-earth elements (LREEs) over heavy rare-earth elements (HREEs), and whereas the trace element patterns are similar for each caldera cycle, trace element values for each ignimbrite show variability in HREE concentrations. This variability indicates that these large eruptions sampled a magmatic system with some degree of internal heterogeneity. These results have implications for the chemical and physical processes, such as magmatic flux and injection periodicity, leading to the formation of large magmatic systems prior to large, explosive eruptions.

Explosive vapor detection payload for small robots

NASA Astrophysics Data System (ADS)

Stimac, Phil J.; Pettit, Michael; Wetzel, John P.; Haas, John W.

2013-05-01

Detection of explosive hazards is a critical component of enabling and improving operational mobility and protection of US Forces. The Autonomous Mine Detection System (AMDS) developed by the US Army RDECOM CERDEC Night Vision and Electronic Sensors Directorate (NVESD) is addressing this challenge for dismounted soldiers. Under the AMDS program, ARA has developed a vapor sampling system that enhances the detection of explosive residues using commercial-off-the-shelf (COTS) sensors. The Explosives Hazard Trace Detection (EHTD) payload is designed for plug-and-play installation and operation on small robotic platforms, addressing critical Army needs for more safely detecting concealed or exposed explosives in areas such as culverts, walls and vehicles. In this paper, we describe the development, robotic integration and performance of the explosive vapor sampling system, which consists of a sampling "head," a vapor transport tube and an extendable "boom." The sampling head and transport tube are integrated with the boom, allowing samples to be collected from targeted surfaces up to 7-ft away from the robotic platform. During sample collection, an IR lamp in the sampling head is used to heat a suspected object/surface and the vapors are drawn through the heated vapor transport tube to an ion mobility spectrometer (IMS) for detection. The EHTD payload is capable of quickly (less than 30 seconds) detecting explosives such as TNT, PETN, and RDX at nanogram levels on common surfaces (brick, concrete, wood, glass, etc.).

Simple multispectral imaging approach for determining the transfer of explosive residues in consecutive fingerprints.

PubMed

Lees, Heidi; Zapata, Félix; Vaher, Merike; García-Ruiz, Carmen

2018-07-01

This novel investigation focused on studying the transfer of explosive residues (TNT, HMTD, PETN, ANFO, dynamite, black powder, NH 4 NO 3 , KNO 3 , NaClO 3 ) in ten consecutive fingerprints to two different surfaces - cotton fabric and polycarbonate plastic - by using multispectral imaging (MSI). Imaging was performed employing a reflex camera in a purpose-built photo studio. Images were processed in MATLAB to select the most discriminating frame - the one that provided the sharpest contrast between the explosive and the material in the red-green-blue (RGB) visible region. The amount of explosive residues transferred in each fingerprint was determined as the number of pixels containing explosive particles. First, the pattern of PETN transfer by ten different persons in successive fingerprints was studied. No significant differences in the pattern of transfer of PETN between subjects were observed, which was also confirmed by multivariate analysis of variance (MANOVA). Then, the transfer of traces of the nine above explosives in ten consecutive fingerprints to cotton fabric and polycarbonate plastic was investigated. The obtained results demonstrated that the amount of explosive residues deposited on successive fingerprints tended to undergo a power or exponential decrease, with the exception of inorganic salts (NH 4 NO 3 , KNO 3 , NaClO 3 ) and ANFO (consists of 90% NH 4 NO 3 ). Copyright © 2018 Elsevier B.V. All rights reserved.

49 CFR Appendix A to Part 1511 - Aviation Security Infrastructure Fee

Code of Federal Regulations, 2011 CFR

2011-10-01

... final acceptance testing. This includes such equipment as Metal Detection Devices, Hand Wands, X-ray... such equipment as Metal Detection Devices, Hand Wands, X-ray screening machines, Explosives Trace... as test objects and X-ray radiation surveys, electricity costs and maintenance contract costs...

[Ion mobility spectrometer (IMS): a novel online monitor of trace volatile organic compounds].

PubMed

Li, Fang; Xie, Zhi-yong; Schmidt, H; Sielemann, S; Baumbach, J I

2002-12-01

The principle, character and developments of the instrument of ion mobility spectrometry are introduced, the applications of IMS to chemical warfare agents, explosives, drugs, environments monitoring and on-site industrial sensing are discussed, and some work on IMS in ISAS is represented.

Emergency First Responders' Experience with Colorimetric Detection Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandra L. Fox; Keith A. Daum; Carla J. Miller

2007-10-01

Nationwide, first responders from state and federal support teams respond to hazardous materials incidents, industrial chemical spills, and potential weapons of mass destruction (WMD) attacks. Although first responders have sophisticated chemical, biological, radiological, and explosive detectors available for assessment of the incident scene, simple colorimetric detectors have a role in response actions. The large number of colorimetric chemical detection methods available on the market can make the selection of the proper methods difficult. Although each detector has unique aspects to provide qualitative or quantitative data about the unknown chemicals present, not all detectors provide consistent, accurate, and reliable results. Includedmore » here, in a consumer-report-style format, we provide “boots on the ground” information directly from first responders about how well colorimetric chemical detection methods meet their needs in the field and how they procure these methods.« less

Cosmic ray particle dosimetry and trajectory tracing. [cosmic ray track analysis for Apollo 17 BIOCORE

NASA Technical Reports Server (NTRS)

Cruty, M. R.; Benton, E. V.; Turnbill, C. E.; Philpott, D. E.

1975-01-01

Five pocket mice (Perognathus longimembris) were flown on Apollo XVII, each with a solid-state (plastic) nuclear track detector implanted beneath its scalp. The subscalp detectors were sensitive to HZE cosmic ray particles with a LET greater than or approximately equal to 0.15 million electron volts per micrometer (MeV/micron). A critical aspect of the dosimetry of the experiment involved tracing individual particle trajectories through each mouse head from particle tracks registered in the individual subscalp detectors, thereby establishing a one-to-one correspondence between a trajectory location in the tissue and the presence or absence of a lesion. The other major aspect was the identification of each registered particle. An average of 16 particles with Z greater than or equal to 6 and 2.2 particles with Z greater than or equal to 20 were found per detector. The track density, 29 tracks/sq cm, when adjusted for detection volume, was in agreement with the photographic emulsion data from an area dosimeter located next to the flight package.

Direct-Write Printing on Three-Dimensional Geometries for Miniaturized Detector and Electronic Assemblies

NASA Technical Reports Server (NTRS)

Paquette, Beth; Samuels, Margaret; Chen, Peng

2017-01-01

Direct-write printing techniques will enable new detector assemblies that were not previously possible with traditional assembly processes. Detector concepts were manufactured using this technology to validate repeatability. Additional detector applications and printed wires on a 3-dimensional magnetometer bobbin will be designed for print. This effort focuses on evaluating performance for direct-write manufacturing techniques on 3-dimensional surfaces. Direct-write manufacturing has the potential to reduce mass and volume for fabrication and assembly of advanced detector concepts by reducing trace widths down to 10 microns, printing on complex geometries, allowing new electronic concept production, and reduced production times of complex those electronics.

Automatic Whistler Detector and Analyzer system: Implementation of the analyzer algorithm

NASA Astrophysics Data System (ADS)

Lichtenberger, JáNos; Ferencz, Csaba; Hamar, Daniel; Steinbach, Peter; Rodger, Craig J.; Clilverd, Mark A.; Collier, Andrew B.

2010-12-01

The full potential of whistlers for monitoring plasmaspheric electron density variations has not yet been realized. The primary reason is the vast human effort required for the analysis of whistler traces. Recently, the first part of a complete whistler analysis procedure was successfully automated, i.e., the automatic detection of whistler traces from the raw broadband VLF signal was achieved. This study describes a new algorithm developed to determine plasmaspheric electron density measurements from whistler traces, based on a Virtual (Whistler) Trace Transformation, using a 2-D fast Fourier transform transformation. This algorithm can be automated and can thus form the final step to complete an Automatic Whistler Detector and Analyzer (AWDA) system. In this second AWDA paper, the practical implementation of the Automatic Whistler Analyzer (AWA) algorithm is discussed and a feasible solution is presented. The practical implementation of the algorithm is able to track the variations of plasmasphere in quasi real time on a PC cluster with 100 CPU cores. The electron densities obtained by the AWA method can be used in investigations such as plasmasphere dynamics, ionosphere-plasmasphere coupling, or in space weather models.

Explosion Source Location Study Using Collocated Acoustic and Seismic Networks in Israel

NASA Astrophysics Data System (ADS)

Pinsky, V.; Gitterman, Y.; Arrowsmith, S.; Ben-Horin, Y.

2013-12-01

We explore a joined analysis of seismic and infrasonic signals for improvement in automatic monitoring of small local/regional events, such as construction and quarry blasts, military chemical explosions, sonic booms, etc. using collocated seismic and infrasonic networks recently build in Israel (ISIN) in the frame of the project sponsored by the Bi-national USA-Israel Science Foundation (BSF). The general target is to create an automatic system, which will provide detection, location and identification of explosions in real-time or close-to-real time manner. At the moment the network comprises 15 stations hosting a microphone and seismometer (or accelerometer), operated by the Geophysical Institute of Israel (GII), plus two infrasonic arrays, operated by the National Data Center, Soreq: IOB in the South (Negev desert) and IMA in the North of Israel (Upper Galilee),collocated with the IMS seismic array MMAI. The study utilizes a ground-truth data-base of numerous Rotem phosphate quarry blasts, a number of controlled explosions for demolition of outdated ammunitions and experimental surface explosions for a structure protection research, at the Sayarim Military Range. A special event, comprising four military explosions in a neighboring country, that provided both strong seismic (up to 400 km) and infrasound waves (up to 300 km), is also analyzed. For all of these events the ground-truth coordinates and/or the results of seismic location by the Israel Seismic Network (ISN) have been provided. For automatic event detection and phase picking we tested the new recursive picker, based on Statistically optimal detector. The results were compared to the manual picks. Several location techniques have been tested using the ground-truth event recordings and the preliminary results obtained have been compared to the ground-truth locations: 1) a number of events have been located as intersection of azimuths estimated using the wide-band F-K analysis technique applied to the infrasonic phases of the two distant arrays; 2) a standard robust grid-search location procedure based on phase picks and a constant celerity for a phase (tropospheric or stratospheric) was applied; 3) a joint coordinate grid-search procedure using array waveforms and phase picks was tested, 4) the Bayesian Infrasonic Source Localization (BISL) method, incorporating semi-empirical model-based prior information, was modified for array+network configuration and applied to the ground-truth events. For this purpose we accumulated data of the former observations of the air-to-ground infrasonic phases to compute station specific ground-truth Celerity-Range Histograms (ssgtCRH) and/or model-based CRH (mbCRH), which allow to essentially improve the location results. For building the mbCRH the local meteo-data and the ray-tracing modeling in 3 available azimuth ranges, accounting seasonal variations of winds directivity (quadrants North:315-45, South: 135-225, East 45-135) have been used.

Artificial stimulation of auroral electron acceleration by intense field aligned currents

NASA Technical Reports Server (NTRS)

Holmgren, G.; Bostrom, R.; Kelley, M. C.; Kintner, P. M.; Lundin, R.; Bering, E. A.; Sheldon, W. R.; Fahleson, U. V.

1979-01-01

A cesium-doped high explosion was detonated at 165 km altitude in the auroral ionosphere during quiet conditions. An Alfven wave pulse with a 200-mV/m electric field was observed, with the peak occurring 135 ms after the explosion at a distance of about 1 km. The count rate of fixed energy 2-keV electron detectors abruptly increased at 140 ms, peaked at 415 ms, and indicated a downward field-aligned beam of accelerated electrons. An anomalously high-field aligned beam of backscattered electrons was also detected. The acceleration is interpreted as due to production of an electrostatic shock or double layer between 300 and 800 km altitude. The structure was probably formed by an instability of the intense field-aligned currents in the Alfven wave launched by the charge-separation electric field due to the explosion.

Detection of liquid hazardous molecules using linearly focused Raman spectroscopy

NASA Astrophysics Data System (ADS)

Cho, Soo Gyeong; Chung, Jin Hyuk

2013-05-01

In security, it is an important issue to analyze hazardous materials in sealed bottles. Particularly, prompt nondestructive checking of sealed liquid bottles in a very short time at the checkpoints of crowded malls, stadiums, or airports is of particular importance to prevent probable terrorist attack using liquid explosives. Aiming to design and fabricate a detector for liquid explosives, we have used linearly focused Raman spectroscopy to analyze liquid materials in transparent or semi-transparent bottles without opening their caps. Continuous lasers with 532 nm wavelength and 58 mW/130 mW beam energy have been used for the Raman spectroscopy. Various hazardous materials including flammable liquids and explosive materials have successfully been distinguished and identified within a couple of seconds. We believe that our technique will be one of suitable methods for fast screening of liquid materials in sealed bottles.

Neutrino emission from nearby supernova progenitors

NASA Astrophysics Data System (ADS)

Yoshida, Takashi; Takahashi, Koh; Umeda, Hideyuki

2016-05-01

Neutrinos have an important role for energy loss process during advanced evolution of massive stars. Although the luminosity and average energy of neutrinos during the Si burning are much smaller than those of supernova neutrinos, these neutrinos are expected to be detected by the liquid scintillation neutrino detector KamLAND if a supernova explosion occurs at the distance of ~100 parsec. We investigate the neutrino emission from massive stars during advanced evolution. We calculate the evolution of the energy spectra of neutrinos produced through electron-positron pair-annihilation in the supernova progenitors with the initial mass of 12, 15, and 20 M ⊙ during the Si burning and core-collapse stages. The neutrino emission rate increases from ~ 1050 s-1 to ~ 1052 s-1. The average energy of electron-antineutrinos is about 1.25 MeV during the Si burning and gradually increases until the core-collapse. For one week before the supernova explosion, the KamLAND detector is expected to observe 12-24 and 6-13 v¯e events in the normal and inverted mass hierarchies, respectively, if a supernova explosion of a 12-20 M ⊙ star occurs at the distance of 200 parsec, corresponding to the distance to Betelgeuse. Observations of neutrinos from SN progenitors have a possibility to constrain the core structure and the evolution just before the core collapse of massive stars.

Numerical Simulation of Ionospheric Disturbances Generated by the Chelyabinsk and Tunguska Space Body Impacts

NASA Astrophysics Data System (ADS)

Shuvalov, V. V.; Khazins, V. M.

2018-03-01

Numerical simulation of atmospheric disturbances during the first hours after the Chelyabinsk and Tunguska space body impacts has been carried out. The results of detailed calculations, including the stages of destruction, evaporation and deceleration of the cosmic body, the generation of atmospheric disturbances and their propagation over distances of thousands of kilometers, have been compared with the results of spherical explosions with energy equal to the kinetic energy of meteoroids. It has been shown that in the case of the Chelyabinsk meteorite, an explosive analogy provides acceptable dimensions of the perturbed region and the perturbation amplitude. With a more powerful Tunguska fall, the resulting atmospheric flow is very different from the explosive one; an atmospheric plume emerges that releases matter from the meteoric trace to an altitude of the order of a thousand kilometers.

Observations of Twilight Fireballs over Kiev in 2013-2015

NASA Astrophysics Data System (ADS)

Churyumov, Klim; Steklov, Aleksey; Vidmachenko, Anatoliy; Dashkiev, Grigoriy

2016-07-01

The phenomenon of "Chelyabinsk bolide" 15.02.2013, resulted in damage to more than 1000 buildings and injure more than 500 people, after the explosion of fireball's body in the atmosphere over Chelyabinsk. The question about the dangers of such astronomical phenomena for life and health of citizens and for the existence of entire countries, arose with renewed vigor. Normally, bolides leave bright trace from ionized gas and dust. Traces of ionization can be seen particularly well at night. If a meteorite invades at the daytime at the cloudless sky and bright sunshine, the phenomenon of the fireball may not be visible. But if the fireball's track has noticeable angular size, it can be seen even in the daytime. After the flight, bolide remains a noticeable trace of a dust, dark against the light sky. If such a dust trail illuminated by the rays of the Sun, which had just hid behind the horizon (or even in the moonlight), it is visible as bright lanes in the night sky or in twilight. That's why we call it the twilight bolides. Typically, astronomical observations using of meteor patrols, carried out at night after the evening astronomical twilight. But from March 2013 to October 2015, the authors have obtained several thousands of different tracks in the sky over Kiev. Therefore, we have identified a special class of twilight observations of fireballs. We register the traces of invading to atmosphere of meteoroids of natural and artificial origin. At the same time, observe the traces of fireballs at the day-time are also possible. But they are less effective than in the twilight. Night observations of bright meteoric tracks can usually observe some seconds. While traces of the twilight bolides we observed from some minutes up to two hours, before they be scattered by atmospheric currents. It opens the great prospects for low-cost direct experiments probing of these tracks by using, for example, the astronomical aviation. We propose the twilight tracks are classified into the following types: AMT - aero-meteorological tracks, AST - aero-space, ATT - aero-technical, and NST - not yet classified tracks of an unknown nature. In recent years, geostationary satellites often registered flashes in the atmosphere brighter than -17m. The typical initial sizes of the stone bodies have 1-3 meters. If these meteoroids are consist of ice and snow (fragments of cometary nuclei), their size can be increased up to tens of meters. It was a set of fine dust particles with lower average density interconnected by ice of frozen water, carbon dioxide and others. Thus, such a body is actively destroying during the flight through the atmosphere. The mass of Tunguska initial body is estimated at about 2x10^{6} tons. At the speed of entry into the atmosphere 31 km/s, in the way of an explosion, it has passed about 200 km and a lost hundreds of thousands of tons of fine dust. The height of the explosion and flash light, is at a height of maximum braking at altitudes significantly less than the height of the homogeneous atmosphere ( 7.5 km). According to the theory of point explosion in a medium with variable density exponentially if a thermal explosion of the meteoroid will happen at the height of 15 km, the shock wave does not reach the Earth's surface. 06.25.2014 we observed evening twilight bolide in the sky over Kiev. Images were synchronously obtained by Dashkiev G. N. and Steklov A. F. The basic distance between the points of photographing according to GPS data was 8.55 km. A fragment in the atmosphere has moved from the southwest to the northeast. The disintegration of fragment began at a height more of 25 km (it is the highest point of the visible trace, not closed by building and clouds). Traces of disintegration visible at altitudes from 18 to 8.2 km. Therefore, the body is not reached the Earth's surface and disintegrated into finely dispersed particles. Trace was visible for about 20 minutes. Preliminary estimates of the initial mass of this fragment before the atmospheric entry indicates on the mass from 1 to 10 tons. Fragments with a little more mass, formed three bolide phenomena in the sky above the Kyiv 29.03.2013 at 16 hours 22 minutes local time. They arose for about some seconds and been accompanied by flashes, explosions and multiple cascade decays of three fragments, apparently, of the cometary nature, at heights of 35 to 15 km. Thus, we believe that the astronomical studies should be based on a detailed study of the interaction of the planet with the space environment, especially with hazardous meteoroids. During the short period of our observations (from March 2013), was fixed falling at least a dozen fragments of cometary nuclei, at least five of sufficiently large and dozens of smaller fragments of meteoroids. The results of our observations also showed that during the morning and evening twilight over Kiev clearly visible the plume of aerosols of technical nature from the plants, factories and other production facilities.

Self-assembling siloxane bilayer directly on SiO2 surface of micro-cantilevers for long-term highly repeatable sensing to trace explosives.

PubMed

Chen, Ying; Xu, Pengcheng; Li, Xinxin

2010-07-02

This paper presents a novel sensing layer modification technique for static micro-cantilever sensors that detect trace explosives by measuring specific adsorption-induced surface stress. For the first time, a method of directly modifying a siloxane sensing bilayer on an SiO(2) surface is proposed to replace the conventional self-assembled monolayers (SAMs) of thiols on Au to avoid the trouble from long-term unstable Au-S bonds. For modifying the long-term reliable sensing bilayer on the piezoresistor-integrated micro-cantilevers, a siloxane-head bottom layer is self-assembled directly on the SiO(2) cantilever surface, which is followed by grafting another explosive-sensing-group functionalized molecule layer on top of the siloxane layer. The siloxane-modified sensor has experimentally exhibited a highly resoluble response to 0.1 ppb TNT vapor. More importantly, the repeated detection results after 140 days show no obvious attenuation in sensing signal. Also observed experimentally, the specific adsorption of the siloxane sensing bilayer to TNT molecules causes a tensile surface stress on the cantilever. Herein the measured tensile surface stress is in contrast to the compressive surface stress normally measured from conventional cantilever sensors where the sensitive thiol-SAMs are modified on an Au surface. The reason for this newly observed phenomenon is discussed and preliminarily analyzed.

Solid state gas sensors for detection of explosives and explosive precursors

NASA Astrophysics Data System (ADS)

Chu, Yun

The increased number of terrorist attacks using improvised explosive devices (IEDs) over the past few years has made the trace detection of explosives a priority for the Department of Homeland Security. Considerable advances in early detection of trace explosives employing spectroscopic detection systems and other sensing devices have been made and have demonstrated outstanding performance. However, modern IEDs are not easily detectable by conventional methods and terrorists have adapted to avoid using metallic or nitro groups in the manufacturing of IEDs. Instead, more powerful but smaller compounds, such as TATP are being more frequently used. In addition, conventional detection techniques usually require large capital investment, labor costs and energy input and are incapable of real-time identification, limiting their application. Thus, a low cost detection system which is capable of continuous online monitoring in a passive mode is needed for explosive detection. In this dissertation, a thermodynamic based thin film gas sensor which can reliably detect various explosive compounds was developed and demonstrated. The principle of the sensors is based on measuring the heat effect associated with the catalytic decomposition of explosive compounds present in the vapor phase. The decomposition mechanism is complicated and not well known, but it can be affected by many parameters including catalyst, reaction temperature and humidity. Explosives that have relatively high vapor pressure and readily sublime at room temperature, like TATP and 2, 6-DNT, are ideal candidate for vapor phase detection using the thermodynamic gas sensor. ZnO, W2O 3, V2O5 and SnO2 were employed as catalysts. This sensor exhibited promising sensitivity results for TATP, but poor selectivity among peroxide based compounds. In order to improve the sensitivity and selectivity of the thermodynamic sensor, a Pd:SnO2 nanocomposite was fabricated and tested as part of this dissertation. A combinatorial chemistry techniques were used for catalyst discovery. Specially, a series of tin oxide catalysts with continuous varying composition of palladium were fabricated to screen for the optimum Pd loading to maximize specificity. Experimental results suggested that sensors with a 12 wt.% palladium loading generated the highest sensitivity while a 8 wt.% palladium loading provided greatest selectivity. XPS and XRD were used to study how palladium doping level affects the oxidation state and crystal structure of the nanocomposite catalyst. As with any passive detection system, a necessary theme of this dissertation was the mitigation of false positive. Toward this end, an orthogonal detection system comprised of two independent sensing platforms sharing one catalyst was demonstrated using TATP, 2, 6-DNT and ammonium nitrate as target molecules. The orthogonal sensor incorporated a thermodynamic based sensing platform to measure the heat effect associated with the decomposition of explosive molecules, and a conductometric sensing platform that monitors the change in electrical conductivity of the same catalyst when exposed to the explosive substances. Results indicate that the orthogonal sensor generates an effective response to explosives presented at part per billion level. In addition, with two independent sensing platforms, a built-in redundancy of results could be expected to minimize false positive.

An automatic detection software for differential reflection spectroscopy

NASA Astrophysics Data System (ADS)

Yuksel, Seniha Esen; Dubroca, Thierry; Hummel, Rolf E.; Gader, Paul D.

2012-06-01

Recent terrorist attacks have sprung a need for a large scale explosive detector. Our group has developed differential reflection spectroscopy which can detect explosive residue on surfaces such as parcel, cargo and luggage. In short, broad band ultra-violet and visible light is shone onto a material (such as a parcel) moving on a conveyor belt. Upon reflection off the surface, the light intensity is recorded with a spectrograph (spectrometer in combination with a CCD camera). This reflected light intensity is then subtracted and normalized with the next data point collected, resulting in differential reflection spectra in the 200-500 nm range. Explosives show spectral finger-prints at specific wavelengths, for example, the spectrum of 2,4,6, trinitrotoluene (TNT) shows an absorption edge at 420 nm. Additionally, we have developed an automated software which detects the characteristic features of explosives. One of the biggest challenges for the algorithm is to reach a practical limit of detection. In this study, we introduce our automatic detection software which is a combination of principal component analysis and support vector machines. Finally we present the sensitivity and selectivity response of our algorithm as a function of the amount of explosive detected on a given surface.

The End of Youth and Innocence

ERIC Educational Resources Information Center

Wilson, Jane

1975-01-01

The changing role of the physical scientist in society is traced from the first atomic bomb explosion in the New Mexican desert in 1945 to the present. Both the good and bad points of the changes brought upon the world by the rapid development of nuclear energy are discussed. (BT)

Solid-phase microextraction coupled to gas chromatography for the determination of 2,3-dimethyl-2,3-dinitrobutane as a marking agent for explosives.

PubMed

Li, Xiujuan; Zeng, Zhaorui; Zeng, Yi

2007-06-15

This paper investigates the detection of 2,3-dimethyl-2,3-dinitrobutane (DMNB), a marking agent in explosives, by gas chromatography (GC) with electron capture detection using solid-phase microextraction (SPME) as a sample preparation technique. The 25,27-dihydroxy-26,28-oxy (2',7'-dioxo-3',6'-diazaoctyl) oxy-p-tert-butylcalix[4]arene/hydroxy-terminated silicone oil coated fiber was highly sensitive to trap DMNB from ammonium nitrate matrix. The analysis was performed by extracting 2g of explosives for 30s at room temperature and then immediately introducing into the heated GC injector for 1min of thermal desorption. The method showed good linearity in the range from 0.01 to 1.0mug/g. The relative standard deviations for these extractions were <8%. The calculated limit of detection for DMNB (S/N=3) was 4.43x10(-4)mug/g, which illustrates that the proposed systems are suitable for explosive detection at trace level. This is the first report of an SPME-GC system shown to extract marking agent in explosives for subsequent detection in a simple, rapid, sensitive, and inexpensive manner.

Enhanced Raman spectroscopy of 2,4,6-TNT in anatase and rutile titania nanocrystals

NASA Astrophysics Data System (ADS)

De La Cruz-Montoya, Edwin; Jeréz, Jaqueline I.; Balaguera-Gelves, Marcia; Luna-Pineda, Tatiana; Castro, Miguel E.; Hernández-Rivera, Samuel P.

2006-05-01

The majority of explosives found in antipersonnel and antitank landmines contain 2,4,6-trinitrotoluene (TNT). Chemical sensing of landmines and Improvised Explosive Devices (IED) requires detecting the chemical signatures of the explosive components in these devices. Nanotechnology is ideally suited to needs in microsensors development by providing new materials and methods that can be employed for trace explosive detection. This work is focused on modification of nano-scaled colloids of titanium dioxide (Titania: anatase, rutile and brookite) and thin layer of the oxides as substrates for use in Enhanced Raman Scattering (ERS) spectroscopy. Ultrafine particles have been generated by hydrothermally treating the sol-gel derived hydrous oxides. ERS spectra of nanocrystalline anatase Titania samples prepared with different average sizes: 38 nm (without acid), 24 nm (without acid) and 7 nm (with HCl). Bulk phase (commercial) and KBr were also used to prepare mixtures with TNT to look for Enhanced Raman Effect of the nitroaromatic explosive on the test surfaces. The studies clearly indicated that the anatase crystal size affects the enhancement of the TNT Raman signal. This enhancement was highest for the samples with Titania average crystal size of 7 nm.

Gamma ray spectroscopy employing divalent europium-doped alkaline earth halides and digital readout for accurate histogramming

DOEpatents

Cherepy, Nerine Jane; Payne, Stephen Anthony; Drury, Owen B.; Sturm, Benjamin W.

2016-02-09

According to one embodiment, a scintillator radiation detector system includes a scintillator, and a processing device for processing pulse traces corresponding to light pulses from the scintillator, where the processing device is configured to: process each pulse trace over at least two temporal windows and to use pulse digitization to improve energy resolution of the system. According to another embodiment, a scintillator radiation detector system includes a processing device configured to: fit digitized scintillation waveforms to an algorithm, perform a direct integration of fit parameters, process multiple integration windows for each digitized scintillation waveform to determine a correction factor, and apply the correction factor to each digitized scintillation waveform.

Enhancement in sample collection for the detection of MDMA using a novel planar SPME (PSPME) device coupled to ion mobility spectrometry (IMS).

PubMed

Gura, Sigalit; Guerra-Diaz, Patricia; Lai, Hanh; Almirall, José R

2009-07-01

Trace detection of illicit drugs challenges the scientific community to develop improved sensitivity and selectivity in sampling and detection techniques. Ion mobility spectrometry (IMS) is one of the prominent trace detectors for illicit drugs and explosives, mostly due to its portability, high sensitivity and fast analysis. Current sampling methods for IMS rely on wiping suspected surfaces or withdrawing air through filters to collect particulates. These methods depend greatly on the particulates being bound onto surfaces or having sufficient vapour pressure to be airborne. Many of these compounds are not readily available in the headspace due to their low vapour pressure. This research presents a novel SPME device for enhanced air sampling and shows the use of optimized IMS by genetic algorithms to target volatile markers and/or odour signatures of illicit substances. The sampling method was based on unique static samplers, planar substrates coated with sol-gel polydimethyl siloxane (PDMS) nanoparticles, also known as planar solid-phase microextraction (PSPME). Due to its surface chemistry, high surface area and capacity, PSPME provides significant increases in sensitivity over conventional fibre SPME. The results show a 50-400 times increase in the detection capacity for piperonal, the odour signature of 3,4-methylenedioxymethamphetamine (MDMA). The PSPME-IMS technique was able to detect 600 ng of piperonal in a 30 s extraction from a quart-sized can containing 5 MDMA tablets, while detection using fibre SPME-IMS was not attainable. In a blind study of six cases suspected to contain varying amounts of MDMA in the tablets, PSPME-IMS successfully detected five positive cases and also produced no false positives or false negatives. One positive case had minimal amounts of MDMA resulting in a false negative response for fibre SPME-IMS.

A critical review of ion mobility spectrometry for the detection of explosives and explosive related compounds.

PubMed

Ewing, R G; Atkinson, D A; Eiceman, G A; Ewing, G J

2001-05-10

Ion mobility spectrometry has become the most successful and widely used technology for the detection of trace levels of nitro-organic explosives on handbags and carry on-luggage in airports throughout the US. The low detection limits are provided by the efficient ionization process, namely, atmospheric pressure chemical ionization (APCI) reactions in negative polarity. An additional level of confidence in a measurement is imparted by characterization of ions for mobilities in weak electric fields of a drift tube at ambient pressure. Findings from over 30 years of investigations into IMS response to these explosives have been collected and assessed to allow a comprehensive view of the APCI reactions characteristic of nitro-organic explosives. Also, the drift tube conditions needed to obtain particular mobility spectra have been summarized. During the past decade, improvements have occurred in IMS on the understanding of reagent gas chemistries, the influence of temperature on ion stability, and sampling methods. In addition, commercial instruments have been refined to provide fast and reliable measurements for on-site detection of explosives. The gas phase ion chemistry of most explosives is mediated by the fragile CONO(2) bonds or the acidity of protons. Thus, M(-) or M.Cl(-) species are found with only a few explosives and loss of NO(2), NO(3) and proton abstraction reactions are common and complicating pathways. However, once ions are formed, they appear to have stabilities on time scales equal to or longer than ion drift times from 5-20 ms. As such, peak shapes in IMS are suitable for high selectivity and sensitivity.

Progress in standoff surface contaminant detector platform

NASA Astrophysics Data System (ADS)

Dupuis, Julia R.; Giblin, Jay; Dixon, John; Hensley, Joel; Mansur, David; Marinelli, William J.

2017-05-01

Progress towards the development of a longwave infrared quantum cascade laser (QLC) based standoff surface contaminant detection platform is presented. The detection platform utilizes reflectance spectroscopy with application to optically thick and thin materials including solid and liquid phase chemical warfare agents, toxic industrial chemicals and materials, and explosives. The platform employs an ensemble of broadband QCLs with a spectrally selective detector to interrogate target surfaces at 10s of m standoff. A version of the Adaptive Cosine Estimator (ACE) featuring class based screening is used for detection and discrimination in high clutter environments. Detection limits approaching 0.1 μg/cm2 are projected through speckle reduction methods enabling detector noise limited performance. The design, build, and validation of a breadboard version of the QCL-based surface contaminant detector are discussed. Functional test results specific to the QCL illuminator are presented with specific emphasis on speckle reduction.

Design, characterization, and sensitivity of the supernova trigger system at Daya Bay

NASA Astrophysics Data System (ADS)

Wei, Hanyu; Lebanowski, Logan; Li, Fei; Wang, Zhe; Chen, Shaomin

2016-02-01

Providing an early warning of galactic supernova explosions from neutrino signals is important in studying supernova dynamics and neutrino physics. A dedicated supernova trigger system has been designed and installed in the data acquisition system at Daya Bay and integrated into the worldwide Supernova Early Warning System (SNEWS). Daya Bay's unique feature of eight identically-designed detectors deployed in three separate experimental halls makes the trigger system naturally robust against cosmogenic backgrounds, enabling a prompt analysis of online triggers and a tight control of the false-alert rate. The trigger system is estimated to be fully sensitive to 1987A-type supernova bursts throughout most of the Milky Way. The significant gain in sensitivity of the eight-detector configuration over a mass-equivalent single detector is also estimated. The experience of this online trigger system is applicable to future projects with spatially distributed detectors.

Tunguska, 1908: the gas pouch and soil fluidization hypothesis

NASA Astrophysics Data System (ADS)

Nistor, I.

2012-01-01

The Siberian taiga explosion of 30 June 1908 remains one of the great mysteries of the 20th century: millions of trees put down over an area of 2200 km2 without trace of a crater or meteorite fragments. Hundred years of failed searches have followed, resulting in as many flawed hypothesis which could not offer satisfactory explanations: meteorite, comet, UFO, etc. In the author's opinion, the cause is that the energy the explorers looked for was simply not there! The author's hypothesis is that a meteoroid encountered a gas pouch in the atmosphere, producing a devastating explosion, its effects being amplified by soil fluidization.

Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser.

PubMed

Craig, Ian M; Taubman, Matthew S; Lea, A Scott; Phillips, Mark C; Josberger, Erik E; Raschke, Markus B

2013-12-16

Utilizing a broadly-tunable external cavity quantum cascade laser for scattering-type scanning near-field optical microscopy (s-SNOM), we measure infrared spectra of particles of explosives by probing characteristic nitro-group resonances in the 7.1-7.9 µm wavelength range. Measurements are presented with spectral resolution of 0.25 cm(-1), spatial resolution of 25 nm, sensitivity better than 100 attomoles, and at a rapid acquisition time of 90 s per spectrum. We demonstrate high reproducibility of the acquired s-SNOM spectra with very high signal-to-noise ratios and relative noise of <0.02 in self-homodyne detection.

Deep learning algorithms for detecting explosive hazards in ground penetrating radar data

NASA Astrophysics Data System (ADS)

Besaw, Lance E.; Stimac, Philip J.

2014-05-01

Buried explosive hazards (BEHs) have been, and continue to be, one of the most deadly threats in modern conflicts. Current handheld sensors rely on a highly trained operator for them to be effective in detecting BEHs. New algorithms are needed to reduce the burden on the operator and improve the performance of handheld BEH detectors. Traditional anomaly detection and discrimination algorithms use "hand-engineered" feature extraction techniques to characterize and classify threats. In this work we use a Deep Belief Network (DBN) to transcend the traditional approaches of BEH detection (e.g., principal component analysis and real-time novelty detection techniques). DBNs are pretrained using an unsupervised learning algorithm to generate compressed representations of unlabeled input data and form feature detectors. They are then fine-tuned using a supervised learning algorithm to form a predictive model. Using ground penetrating radar (GPR) data collected by a robotic cart swinging a handheld detector, our research demonstrates that relatively small DBNs can learn to model GPR background signals and detect BEHs with an acceptable false alarm rate (FAR). In this work, our DBNs achieved 91% probability of detection (Pd) with 1.4 false alarms per square meter when evaluated on anti-tank and anti-personnel targets at temperate and arid test sites. This research demonstrates that DBNs are a viable approach to detect and classify BEHs.

Crustal structure in Nevada and southern Idaho from nuclear explosions

USGS Publications Warehouse

Pakiser, L.C.; Hill, D.P.

1962-01-01

The time of first arrival of seismic waves generated by 4 underground nuclear explosions at the Nevada Test Site (NTS) and recorded along a line extending north into southern Idaho is expressed as T0 = 0. 00 + Δ/3.0 (assumed), T1 = 0 .40 + Δ/6.03, and T2 = 6.15 + Δ/7.84, where time is in seconds and the shot-detector distance (Δ) is in km. Assuming constant velocities and horizontal layers, crustal thickness in the vicinity of NTS was determined to be 28 km. Delays in the traveltime segment T2, which represents Pn, indicate that the crust may thicken to 32 km in northern Nevada. A third phase, expressed as T3 = 14.48 + Δ/7.84, was also recognized and has arrival times appropriate for SPS. Amplitudes of Pn were determined at 7 places from recordings of seismic waves from one underground nuclear explosion (ANTLER).

Oscillation effects and time variation of the supernova neutrino signal

NASA Astrophysics Data System (ADS)

Kneller, James P.; McLaughlin, Gail C.; Brockman, Justin

2008-02-01

The neutrinos detected from the next galactic core-collapse supernova will contain valuable information on the internal dynamics of the explosion. One mechanism leading to a temporal evolution of the neutrino signal is the variation of the induced neutrino flavor mixing driven by changes in the density profile. With one and two-dimensional hydrodynamical simulations we identify the behavior and properties of prominent features of the explosion. Using these results we demonstrate the time variation of the neutrino crossing probabilities due to changes in the Mikheyev-Smirnov-Wolfenstein (MSW) neutrino transformations as the star explodes by using the S-matrix—Monte Carlo—approach to neutrino propagation. After adopting spectra for the neutrinos emitted from the proto-neutron star we calculate for a galactic supernova the evolution of the positron spectra within a water Cerenkov detector and find that this signal allows us to probe of a number of explosion features.

Galileo versus Aristotle: the case of supernova 1987A

NASA Astrophysics Data System (ADS)

Galeotti, P.; Pizzella, G.

2017-07-01

Most current supernova theories state that this phenomenon lasts a few seconds and ends with a bigfinal explosion.However, these theories do not take into account several experimental results obtained with neutrino and gravitational wave detectors during the explosion of SN1987A, the only supernova observed in a nearby galaxy in modern age. According to these experimental results the phenomenon is much more complex that envisaged by current theories, and has a duration of several hours. Indeed, SN1987A exploded on February 23, 1987, and two neutrino bursts, separated by 4.7 hours were detected: the first one at 2h 52m UT and the second one at 7h 35m UT. Furthermore, correlations between the neutrino and two gravitational wave detectors, ignored by most of the scientific community, were observed during the longer collapse time. Since the current standard theories, based on some rough simplifications, are a clear example of an Aristotelian attitude, still present in our days, we believe that a more Galilean attitude is necessary, being the only correct way for the progress of science.

Combined, solid-state molecular property and gamma spectrometers for CBRNE detection

NASA Astrophysics Data System (ADS)

Rogers, Ben; Grate, Jay; Pearson, Brett; Gallagher, Neal; Wise, Barry; Whitten, Ralph; Adams, Jesse

2013-05-01

Nevada Nanotech Systems, Inc. (Nevada Nano) has developed a multi-sensor solution to Chemical, Biological, Radiological, Nuclear and Explosives (CBRNE) detection that combines the Molecular Property Spectrometer™ (MPS™)—a micro-electro-mechanical chip-based technology capable of measuring a variety of thermodynamic and electrostatic molecular properties of sampled vapors and particles—and a compact, high-resolution, solid-state gamma spectrometer module for identifying radioactive materials, including isotopes used in dirty bombs and nuclear weapons. By conducting multiple measurements, the system can provide a more complete characterization of an unknown sample, leading to a more accurate identification. Positive identifications of threats are communicated using an integrated wireless module. Currently, system development is focused on detection of commercial, military and improvised explosives, radioactive materials, and chemical threats. The system can be configured for a variety of CBRNE applications, including handheld wands and swab-type threat detectors requiring short sample times, and ultra-high sensitivity detectors in which longer sampling times are used. Here we provide an overview of the system design and operation and present results from preliminary testing.

Low-noise mid-IR upconversion detector for improved IR-degenerate four-wave mixing gas sensing.

PubMed

Høgstedt, Lasse; Dam, Jeppe Seidelin; Sahlberg, Anna-Lena; Li, Zhongshan; Aldén, Marcus; Pedersen, Christian; Tidemand-Lichtenberg, Peter

2014-09-15

We compare a nonlinear upconversion detector with a conventional cryogenic InSb detector for the detection of coherent infrared light showing near-shot-noise-limited performance in the upconversion system. The InSb detector is limited by dark noise, which results in a 500 times lower signal-to-noise ratio. The two detectors are compared for the detection of a coherent degenerate four-wave mixing (DFWM) signal in the mid-infrared, and applied to measure trace-level acetylene in a gas flow at atmospheric pressure, probing its fundamental rovibrational transitions. In addition to lower noise, the upconversion system provides image information of the signal, thus adding new functionality compared to standard point detection methods. We further show that the upconversion detector system can be implemented as a simple replacement of the cryogenic detector.

Remote Detection of Explosive Molecules by a Microfluidic SERS Device

NASA Astrophysics Data System (ADS)

Piorek, Brian; Lee, Seung Joon; Moskovits, Martin; Banerjee, Sanjoy; Meinhart, Carl

2007-11-01

Free-surface microfluidics (FSF) is combined with surface-enhanced Raman spectroscopy (SERS) to detect trace explosives vapors at room temperature and pressure. A free surface, with a large surface to volume ratio, is created using an open microchannel. Since surface tension is a dominant force at the microscale, it can be used to confine the fluid in the microchannel and create a pressure gradient to drive the flow with velocities ranging from ˜ 1um/s - 1mm/s. The curvature of the free surface is measured by confocal microscopy in order to determine the local Laplace pressure in the free-surface microchannel flow. The system has been used for the molecular-specific detection of vapor emanated from explosives such as DNT, TNT and picric acid. The system does not show signs of performance degradation from common interferents such as saturated gasoline vapor and perfume.

A portable explosive detector based on fluorescence quenching of pyrene deposited on coloured wax-printed μPADs.

PubMed

Taudte, Regina Verena; Beavis, Alison; Wilson-Wilde, Linzi; Roux, Claude; Doble, Philip; Blanes, Lucas

2013-11-07

A new technique for the detection of explosives has been developed based on fluorescence quenching of pyrene on paper-based analytical devices (μPADs). Wax barriers were generated (150 °C, 5 min) using ten different colours. Magenta was found as the most suitable wax colour for the generation of the hydrophobic barriers with a nominal width of 120 μm resulting in fully functioning hydrophobic barriers. One microliter of 0.5 mg mL(-1) pyrene dissolved in an 80:20 methanol-water solution was deposited on the hydrophobic circle (5 mm diameter) to produce the active microchip device. Under ultra-violet (UV) illumination, ten different organic explosives were detected using the μPAD, with limits of detection ranging from 100-600 ppm. A prototype of a portable battery operated instrument using a 3 W power UV light-emitting-diode (LED) (365 nm) and a photodiode sensor was also built and evaluated for the successful automatic detection of explosives and potential application for field-based screening.

Composition analyzer for microparticles using a spark ion source

NASA Technical Reports Server (NTRS)

Auer, S.; Berg, O. E.

1975-01-01

Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the elements of both detector and particle materials. The total extracted ion current was typically 10 A within a period of 100 nsec, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes or by nuclear bomb explosions.

Particle Detectors Subatomic Bomb Squad

ScienceCinema

Lincoln, Don

2018-01-16

The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

Laser-Induced Breakdown Spectroscopy: A Review of Applied Explosive Detection

DTIC Science & Technology

2013-09-01

Based Techniques ..........................................................................................7 2.5 Ion Mobility and Mass Spectrometry...proximal trace detection. We show that the algorithms for material identification could be improved by including the critical signatures (e.g., C2...IMS), desorption electrospray ionization (DESI), laser electrospray mass spectrometry (LEMS), emerging efforts like antibody/antigen-based efforts

NEW MEDIA AND THE NEW EDUCATION.

ERIC Educational Resources Information Center

MCLUHAN, MARSHALL

THE ELECTRONIC AGE BRINGS WITH IT NEW PATTERNS FOR TEACHING AND LEARNING. EDUCATORS AND LAYMEN NEED TO ORIENT THEMSELVES TO BE ABLE TO GRASP AND BENEFIT FROM THE NEW TECHNIQUES. THE BEGINNINGS OF THE EXPLOSION IN LEARNING ARE TRACED, STARTING WITH THE PRINTING PRESS. PRINTED BOOKS ALTERED PATTERNS OF STUDY MAKING IT POSSIBLE TO READ WIDELY WITHOUT…

Methodologies for Removing/Desorbing and Transporting Particles from Surfaces to Instrumentation

NASA Astrophysics Data System (ADS)

Miller, Carla J.; Cespedes, Ernesto R.

2012-12-01

Explosive trace detection (ETD) continues to be a key technology supporting the fight against terrorist bombing threats. Very selective and sensitive ETD instruments have been developed to detect explosive threats concealed on personnel, in vehicles, in luggage, and in cargo containers, as well as for forensic analysis (e.g. post blast inspection, bomb-maker identification, etc.) in a broad range of homeland security, law enforcement, and military applications. A number of recent studies have highlighted the fact that significant improvements in ETD systems' capabilities will be achieved, not by increasing the selectivity/sensitivity of the sensors, but by improved techniques for particle/vapor sampling, pre-concentration, and transport to the sensors. This review article represents a compilation of studies focused on characterizing the adhesive properties of explosive particles, the methodologies for removing/desorbing these particles from a range of surfaces, and approaches for transporting them to the instrument. The objectives of this review are to summarize fundamental work in explosive particle characterization, to describe experimental work performed in harvesting and transport of these particles, and to highlight those approaches that indicate high potential for improving ETD capabilities.

Rapid Quantitative Analysis of Multiple Explosive Compound Classes on a Single Instrument via Flow-Injection Analysis Tandem Mass Spectrometry.

PubMed

Ostrinskaya, Alla; Kunz, Roderick R; Clark, Michelle; Kingsborough, Richard P; Ong, Ta-Hsuan; Deneault, Sandra

2018-05-24

A flow-injection analysis tandem mass spectrometry (FIA MSMS) method was developed for rapid quantitative analysis of 10 different inorganic and organic explosives. Performance is optimized by tailoring the ionization method (APCI/ESI), de-clustering potentials, and collision energies for each specific analyte. In doing so, a single instrument can be used to detect urea nitrate, potassium chlorate, 2,4,6-trinitrotoluene, 2,4,6-trinitrophenylmethylnitramine, triacetone triperoxide, hexamethylene triperoxide diamine, pentaerythritol tetranitrate, 1,3,5-trinitroperhydro-1,3,5-triazine, nitroglycerin, and octohy-dro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine with sensitivities all in the picogram per milliliter range. In conclusion, FIA APCI/ESI MSMS is a fast (<1 min/sample), sensitive (~pg/mL LOQ), and precise (intraday RSD < 10%) method for trace explosive detection that can play an important role in criminal and attributional forensics, counterterrorism, and environmental protection areas, and has the potential to augment or replace several of the existing explosive detection methods. © 2018 American Academy of Forensic Sciences.

Bomb/no bomb: From multivariate analysis to artificial neural systems

NASA Astrophysics Data System (ADS)

Shea, Patrick; Liu, Felix; Yedidia, Barak

1992-05-01

Systems for the detection of explosives hidden in checked airline baggage have been under development at the Science Applications International Corporation (SAIC) for the FAA since 1985. In May of 1987, the first prototype was fielded for testing at San Francisco International Airport. In 1989, the first production unit was field at JFK Airport in New York. Since than, over 550,000 bags have been screened by SAIC units around the world. The system uses thermal neutron activation (TNA) to detect the presence of explosives. In this technique a suitcase on a conveyor belt moves past a source and an array of detectors. Neutrons from the source easily penetrate the luggage, and are absorbed by all of the materials present. Different elements will emit different energy gamma rays after absorbing these neutrons (much like fluorescence). These gamma rays are of a high enough energy that they easily penetrate the luggage, and are detected by a detector array which surrounds the cavity enclosing the suitcase and conveyor belt. The detectors record the number of gamma rays observed at each energy. The number of gamma rays of a characteristic energy which are observed depends on the amount of the element present, its location, the number of neutrons present, and the probability that the element will capture a thermal neutron and emit the gamma ray. Since this probability is a known constant for any particular element, and the number of neutrons present and the number of characteristic gamma rays are measured, the amount of each element and its location can, in theory, be determined from the array of signals. Commercial and military explosives, such as are used by terrorists, have several characteristics which distinguish them from most objects in luggage. On of these characteristics is a high density of nitrogen. A description of the decision algorithms is presented, and the artificial neural system (ANS) is discussed. On-line experience and decision surfaces are also covered.

The Bayo Canyon/radioactive lanthanum (RaLa) program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dummer, J.E.; Taschner, J.C.; Courtright, C.C.

1996-04-01

LANL conducted 254 radioactive lanthanum (RaLa) implosion experiments Sept. 1944-March 1962, in order to test implosion designs for nuclear weapons. High explosives surrounding common metals (surrogates for Pu) and a radioactive source containing up to several thousand curies of La, were involved in each experiment. The resulting cloud was deposited as fallout, often to distances of several miles. This report was prepared to summarize existing records as an aid in evaluating the off-site impact, if any, of this 18-year program. The report provides a historical setting for the program, which was conducted in Technical Area 10, Bayo Canyon about 3more » miles east of Los Alamos. A description of the site is followed by a discussion of collateral experiments conducted in 1950 by US Air Force for developing an airborne detector for tracking atmospheric nuclear weapons tests. All known off-site data from the RaLa program are tabulated and discussed. Besides the radiolanthanum, other potential trace radioactive material that may have been present in the fallout is discussed and amounts estimated. Off-site safety considerations are discussed; a preliminary off-site dose assessment is made. Bibliographical data on 33 persons important to the program are presented as footnotes.« less

Optimization of the microcable and detector parameters towards low noise in the STS readout system

NASA Astrophysics Data System (ADS)

Kasinski, Krzysztof; Kleczek, Rafal; Schmidt, Christian J.

2015-09-01

Successful operation of the Silicon Tracking System requires charge measurement of each hit with equivalent noise charge lower than 1000 e- rms. Detector channels will not be identical, they will be constructed accordingly to the estimated occupancy, therefore for the readout electronics, detector system will exhibit various parameters. This paper presents the simulation-based study on the required microcable (trace width, dielectric material), detector (aluminum strip resistance) and external passives' (decoupling capacitors) parameters in the Silicon Tracking System. Studies will be performed using a front-end electronics (charge sensitive amplifier with shaper) designed for the power budget of 10 mA/channel.

Atmospheric Transport Modelling assessing radionuclide detection chances after the nuclear test announced by the DPRK in January 2016

NASA Astrophysics Data System (ADS)

Ross, J. Ole; Ceranna, Lars

2016-04-01

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits all kinds of nuclear explosions. The International Monitoring System (IMS) is in place and at about 90% complete to verify compliance with the CTBT. The stations of the waveform technologies are capable to detect seismic, hydro-acoustic and infrasonic signals for detection, localization, and characterization of explosions. The seismic signals of the DPRK event on 6 January 2016 were detected by many seismic stations around the globe and allow for localization of the event and identification as explosion (see poster by G. Hartmann et al.). However, the direct evidence for a nuclear explosion is only possible through the detection of nuclear fission products which may be released. For that 80 Radionuclide (RN) Stations are part of the designed IMS, about 60 are already operational. All RN stations are highly sensitive for tiny traces of particulate radionuclides in large volume air samplers. There are 40 of the RN stations designated to be equipped with noble gas systems detecting traces of radioactive xenon isotopes which are more likely to escape from an underground test cavity than particulates. Already 30 of the noble gas systems are operational. Atmospheric Transport Modelling supports the interpretation of radionuclide detections (and as appropriate non-detections) by connecting the activity concentration measurements with potential source locations and release times. In our study forecasts with the Lagrangian Particle Dispersion Model HYSPLIT (NOAA) and GFS (NCEP) meteorological data are considered to assess the plume propagation patterns for hypothetical releases at the known DPRK nuclear test site. The results show a considerable sensitivity of the IMS station RN 38 Takasaki (Japan) to a potential radionuclide release at the test site in the days and weeks following the explosion in January 2016. In addition, backtracking simulations with ECMWF analysis data in 0.2° horizontal resolution are performed for selected samples to get a complementary estimation of the sensitivities and the connected thresholds for detectable releases.The meteorological situation is compared to the aftermath of the nuclear explosion on 12 February 2013 after which a specific occurrence of an unusual 131mXe signature at RN 38 eight weeks after the test could be very likely attributed to a late release from the DPRK event.

Photoacoustic spectroscopy for trace vapor detection and standoff detection of explosives

NASA Astrophysics Data System (ADS)

Holthoff, Ellen L.; Marcus, Logan S.; Pellegrino, Paul M.

2016-05-01

The Army is investigating several spectroscopic techniques (e.g., infrared spectroscopy) that could allow for an adaptable sensor platform. Current sensor technologies, although reasonably sized, are geared to more classical chemical threats, and the ability to expand their capabilities to a broader range of emerging threats is uncertain. Recently, photoacoustic spectroscopy (PAS), employed in a sensor format, has shown enormous potential to address these ever-changing threats. PAS is one of the more flexible IR spectroscopy variants, and that flexibility allows for the construction of sensors that are designed for specific tasks. PAS is well suited for trace detection of gaseous and condensed media. Recent research has employed quantum cascade lasers (QCLs) in combination with MEMS-scale photoacoustic cell designs. The continuous tuning capability of QCLs over a broad wavelength range in the mid-infrared spectral region greatly expands the number of compounds that can be identified. We will discuss our continuing evaluation of QCL technology as it matures in relation to our ultimate goal of a universal compact chemical sensor platform. Finally, expanding on our previously reported photoacoustic detection of condensed phase samples, we are investigating standoff photoacoustic chemical detection of these materials. We will discuss the evaluation of a PAS sensor that has been designed around increasing operator safety during detection and identification of explosive materials by performing sensing operations at a standoff distance. We investigate a standoff variant of PAS based upon an interferometric sensor by examining the characteristic absorption spectra of explosive hazards collected at 1 m.

Detection of explosives using negative ion mobility spectrometry in air based on dopant-assisted thermal ionization.

PubMed

Shahraki, Hassan; Tabrizchi, Mahmoud; Farrokhpor, Hossein

2018-05-26

The ionization source is an essential component of most explosive detectors based on negative ion mobility spectrometry. Conventional ion sources suffer from such inherent limitations as special safety regulations on radioactive sources or generating interfering ions (for non-radioactive sources) such as corona discharge operating in the air. In this study, a new negative ion source is introduced for ion mobility spectrometry that is based on thermal ionization and operates in the air, applicable to explosives detection. Our system consists of a heating filament powered by an isolated power supply connected to negative high voltage. The ionization is assisted by doping chlorinated compounds in the gas phase using chlorinated hydrocarbons in contact with the heating element to yield Cl - reactant ions. Several chlorinated hydrocarbons are evaluated as the reagent chemicals for providing Cl- reactant ions, of which CCl 4 is identified as the best ionizing reagent. The ion source is evaluated by recording the ion mobility spectra of common explosives, including TNT, RDX, and PETN in the air. A detection limit of 150 pg is obtained for TNT. Compared to other ionization sources, the new source is found to be low-cost, simple, and long-lived, making it suited to portable explosives detection devices. Copyright © 2018 Elsevier B.V. All rights reserved.

Flow injection analysis of picric acid explosive using a copper electrode as electrochemical detector.

PubMed

Junqueira, João R C; de Araujo, William R; Salles, Maiara O; Paixão, Thiago R L C

2013-01-30

A simple and fast electrochemical method for quantitative analysis of picric acid explosive (nitro-explosive) based on its electrochemical reduction at copper surfaces is reported. To achieve a higher sample throughput, the electrochemical sensor was adapted in a flow injection system. Under optimal experimental conditions, the peak current response increases linearly with picric acid concentration over the range of 20-300 μmol L(-1). The repeatability of the electrode response in the flow injection analysis (FIA) configuration was evaluated as 3% (n=10), and the detection limit of the method was estimated to be 6.0 μmol L(-1) (S/N=3). The sample throughput under optimised conditions was estimated to be 550 samples h(-1). Peroxide explosives like triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) were tested as potential interfering substances for the proposed method, and no significant interference by these explosives was noticed. The proposed method has interesting analytical parameters, environmental applications, and low cost compared with other electroanalytical methods that have been reported for the quantification of picric acid. Additionally, the possibility to develop an in situ device for the detection of picric acid using a disposable sensor was evaluated. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Validation of the Thematic Mapper radiometric and geometric correction algorithms

NASA Technical Reports Server (NTRS)

Fischel, D.

1984-01-01

The radiometric and geometric correction algorithms for Thematic Mapper are critical to subsequent successful information extraction. Earlier Landsat scanners, known as Multispectral Scanners, produce imagery which exhibits striping due to mismatching of detector gains and biases. Thematic Mapper exhibits the same phenomenon at three levels: detector-to-detector, scan-to-scan, and multiscan striping. The cause of these variations has been traced to variations in the dark current of the detectors. An alternative formulation has been tested and shown to be very satisfactory. Unfortunately, the Thematic Mapper detectors exhibit saturation effects suffered while viewing extensive cloud areas, and is not easily correctable. The geometric correction algorithm has been shown to be remarkably reliable. Only minor and modest improvements are indicated and shown to be effective.

Observations on military exploitation of explosives detection technologies

NASA Astrophysics Data System (ADS)

Faust, Anthony A.; de Ruiter, C. J.; Ehlerding, Anneli; McFee, John E.; Svinsås, Eirik; van Rheenen, Arthur D.

2011-06-01

Accurate and timely detection of explosives, energetic materials, and their associated compounds would provide valuable information to military commanders in a wide range of military operations: protection of fast moving convoys from mobile or static IED threats; more deliberate countermine and counter-IED operations during route or area clearance; and static roles such as hasty or deliberate checkpoints, critical infrastructure protection and support to public security. The detection of hidden explosive hazards is an extremely challenging problem, as evidenced by the fact that related research has been ongoing in many countries for at least seven decades and no general purpose solution has yet been found. Technologies investigated have spanned all major scientific fields, with emphasis on the physical sciences, life sciences, engineering, robotics, computer technology and mathematics. This paper will present a limited, operationally-focused overview of the current status of detection technologies. Emphasis will be on those technologies that directly detect the explosive hazard, as opposed to those that detect secondary properties of the threat, such as the casing, associated wires or electronics. Technologies that detect explosives include those based on nuclear radiation and terahertz radiation, as well as trace and biological detection techniques. Current research areas of the authors will be used to illustrate the practical applications.

Monte Carlo Simulations for the Detection of Buried Objects Using Single Sided Backscattered Radiation.

PubMed

Yip, Mary; Saripan, M Iqbal; Wells, Kevin; Bradley, David A

2015-01-01

Detection of buried improvised explosive devices (IEDs) is a delicate task, leading to a need to develop sensitive stand-off detection technology. The shape, composition and size of the IEDs can be expected to be revised over time in an effort to overcome increasingly sophisticated detection methods. As an example, for the most part, landmines are found through metal detection which has led to increasing use of non-ferrous materials such as wood or plastic containers for chemical based explosives being developed. Monte Carlo simulations have been undertaken considering three different commercially available detector materials (hyperpure-Ge (HPGe), lanthanum(III) bromide (LaBr) and thallium activated sodium iodide (NaI(Tl)), applied at a stand-off distance of 50 cm from the surface and burial depths of 0, 5 and 10 cm, with sand as the obfuscating medium. Target materials representing medium density wood and mild steel have been considered. Each detector has been modelled as a 10 cm thick cylinder with a 20 cm diameter. It appears that HPGe represents the most promising detector for this application. Although it was not the highest density material studied, its excellent energy resolving capability leads to the highest quality spectra from which detection decisions can be inferred. The simulation work undertaken here suggests that a vehicle-born threat detection system could be envisaged using a single betatron and a series of detectors operating in parallel observing the space directly in front of the vehicle path. Furthermore, results show that non-ferrous materials such as wood can be effectively discerned in such remote-operated detection system, with the potential to apply a signature analysis template matching technique for real-time analysis of such data.

Traceable terahertz power measurement from 1 THz to 5 THz.

PubMed

Steiger, Andreas; Kehrt, Mathias; Monte, Christian; Müller, Ralf

2013-06-17

The metrology institute in Germany, the Physikalisch-Technische Bundesanstalt (PTB), calibrates the spectral responsivity of THz detectors at 2.52 THz traceable to International System of Units. The Terahertz detector calibration facility is equipped with a standard detector calibrated against a cryogenic radiometer at this frequency. In order to extend this service to a broader spectral range in the THz region a new standard detector was developed. This detector is based on a commercial thermopile detector. Its absorber was modified and characterized by spectroscopic methods with respect to its absorptance and reflectance from 1 THz to 5 THz and at the wavelength of a helium-neon laser in the visible spectral range. This offers the possibility of tracing back the THz power responsivity scale to the more accurate responsivity scale in the visible spectral range and thereby to reduce the uncertainty of detector calibrations in the THz range significantly.

Rapid identification and desorption mechanisms of nitrogen-based explosives by ambient micro-fabricated glow discharge plasma desorption/ionization (MFGDP) mass spectrometry.

PubMed

Tian, CaiYan; Yin, JinWei; Zhao, ZhongJun; Zhang, Yinchenxi; Duan, YiXiang

2017-05-15

A novel technique of micro-fabricated glow discharge plasma desorption/ionization mass spectrometry was investigated for the first time in negative ion mode in this study. Negative ion micro-fabricated glow discharge plasma desorption/ionization mass spectrometry (NI-MFGDP-MS) was successfully applied to identify trace explosives in open air. Six explosives and explosives-related compounds were directly analyzed in seconds with this ion source. The ions of [M-H] - were predominant for 2-methyl-1,3,5-trinitrobenzene (trinitrotoluene, TNT) and 2,4,6-trinitrophenol (picric acid), and [M+NO 3 ] - were dominant ions for 1,3,5-trinitro-perhydro-1,3,5-triazine (cyclonite, RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (octogen, HMX), 1,2,3-trinitroxypropane (nitroglycerin, NG), and pentaerythritol tetranitrate (PETN). The limits of detection (LOD) were from 87.5pgmm -2 to 0.4 fg mm -2 and the relative standard deviation (RSD) ranged between 5.8% and 16.8% for the explosives involved in this study. The reliability of NI-MFGDP-MS was characterized by the analysis of a picric acid-RDX-PETN mixture and a mixture of RDX-pond water. NI-MFGDP-MS and ESI-MS were compared with these explosives and along with collision induced dissociation (CID) experiments. The results showed that electron capture, proton abstraction reaction, nucleophilic attack, ion-molecule attachment, decomposition and anion attachment took place during the NI-MFGDP-MS measurement. These findings provide a guideline and a supplement to the chemical libraries for rapid and accurate detection of explosives. The method shows great potential for fast, in situ, on-line and high throughput detection of explosives in the field of antiterrorism. Copyright © 2017 Elsevier B.V. All rights reserved.

High-Sensitivity Ionization Trace-Species Detector

NASA Technical Reports Server (NTRS)

Bernius, Mark T.; Chutjian, Ara

1990-01-01

Features include high ion-extraction efficiency, compactness, and light weight. Improved version of previous ionization detector features in-line geometry that enables extraction of almost every ion from region of formation. Focusing electrodes arranged and shaped into compact system of space-charge-limited reversal electron optics and ion-extraction optics. Provides controllability of ionizing electron energies, greater efficiency of ionization, and nearly 100 percent ion-collection efficiency.

NEW LENSLET BASED IFS WITH HIGH DETECTOR PIXEL EFFICIENCY

NASA Astrophysics Data System (ADS)

Gong, Qian

2018-01-01

Three IFS types currently used for optical design are: lenslet array, imager slicer, and lenslet array and fiber combined. Lenslet array based Integral Field Spectroscopy (IFS) is very popular for many astrophysics applications due to its compactness, simplicity, as well as cost and mass savings. The disadvantage of lenslet based IFS is its low detector pixel efficiency. Enough spacing is needed between adjacent spectral traces in cross dispersion direction to avoid wavelength cross-talk, because the same wavelength is not aligned to the same column on detector. Such as on a recent exoplanet coronagraph instrument study to support the coming astrophysics decadal survey (LUVOIR), to cover a 45 λ/D Field of View (FOV) with a spectral resolving power of 200 at shortest wavelength, a 4k x 4k detector array is needed. This large format EMCCD pushes the detector into technology development area with a low TRL. Besides the future mission, it will help WFIRST coronagraph IFS by packing all spectra into a smaller area on detector, which will reduce the chance for electrons to be trapped in pixels, and slow the detector degradation during the mission.The innovation we propose here is to increase the detector packing efficiency by grouping a number of lenslets together to form many mini slits. In other words, a number of spots (Point Spread Function at lenslet focus) are aligned into a line to resemble a mini slit. Therefore, wavelength cross-talk is no longer a concern anymore. This combines the advantage of lenslet array and imager slicer together. The isolation rows between spectral traces in cross dispersion direction can be reduced or removed. So the packing efficiency is greatly increased. Furthermore, the today’s microlithography and etching technique is capable of making such a lenslet array, which will relax the detector demand significantly. It will finally contribute to the habitable exoplanets study to analyzing their spectra from direct images. Detailed theory, design, analysis, and fabrication status will be presented.

Characterization and Thermal Decomposition of Nanometer 2,2', 4,4', 6,6'-Hexanitro-Stilbene and 1,3,5-Triamino-2,4,6-Trinitrobenzene Fabricated by a Mechanical Milling Method

NASA Astrophysics Data System (ADS)

Song, Xiaolan; Wang, Yi; Zhao, Shanshan; An, Chongwei; Wang, Jingyu; Zhang, Jinglin

2018-04-01

Nanometer 2,2', 4,4', 6,6'-hexanitro-stilbene (HNS) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) were fabricated on a high-energy ball mill. The particle sizes of nano-HNS and nano-TATB were 98.4 and 57.8 nm, respectively. An SEM analysis was employed to image the micron morphology of nano-explosives. The particle size distribution was calculated by measuring the size of 300 particles in SEM images. XRD, IR, and XPS analyses were used to confirm whether the crystal phase, molecule structure, and surface elements were changed by the milling process. Thermal decomposition of nano-HNS and nano-TATB was investigated by differential scanning calorimetry (DSC) and thermal-infrared spectrometry online (DSC-IR) analyses. Using DSC traces collected from different heating rates, the kinetic and thermodynamic parameters of thermolysis of raw and nano-explosives were calculated (activation energy (EK), pre-exponential factor (lnAK), rate constant (k), activation heat (ΔH≠), activation free energy (ΔG≠), activation entropy (ΔS≠), critical temperature of thermal explosion (Tb), and critical heating rate of thermal explosion (dT/dt)Tb). The results indicated that nano-explosives were of different kinetic and thermodynamic properties from starting explosives. In addition, the gas products for thermal decomposition of nano-HNS and nano-TATB were detected. Although HNS and TATB are both nitro explosives, the decomposition products of the two were different. A mechanism to explain the difference is proposed.

Sensor Feasibility Report: Survey of the Capabilities and Limitations of Chemical, Biological, Radiological, Nuclear and Explosive (CBRNE) Sensor Technologies Relevant to Vehicle Inspection Systems

DTIC Science & Technology

2007-10-01

Nitro Compounds High Grade Military TNT – 99% 2,4,6-trinitrotoluene and trace amounts of 2,4-DNT (Nitroaromatic) Picric Acid Nitrate Esters...tetrazacyclooctane) Salts of Inorganic Acids Ammonium Nitrate Organic Peroxides TATP triacetone-triperoxide Mixtures Dynamites Composition B

Observing the Next Galactic Supernova with the NOvA Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vasel, Justin A.; Sheshukov, Andrey; Habig, Alec

The next galactic core-collapse supernova will deliver a wealth of neutrinos which for the first time we are well-situated to measure. These explosions produce neutrinos with energies between 10 and 100 MeV over a period of tens of seconds. Galactic supernovae are relatively rare events, occurring with a frequency of just a few per century. It is therefore essential that all neutrino detectors capable of detecting these neutrinos are ready to trigger on this signal when it occurs. This poster describes a data-driven trigger which is designed to detect the neutrino signal from a galactic core-collapse supernova with the NOvAmore » detectors. The trigger analyzes 5ms blocks of detector activity and applies background rejection algorithms to detect the signal time structure over the background. This background reduction is an essential part of the process, as the NOvA detectors are designed to detect neutrinos from Fermilab's NuMI beam which have an average energy of 2GeV--well above the average energy of supernova neutrinos.« less

A Wolf-Rayet-like progenitor of SN 2013cu from spectral observations of a stellar wind.

PubMed

Gal-Yam, Avishay; Arcavi, I; Ofek, E O; Ben-Ami, S; Cenko, S B; Kasliwal, M M; Cao, Y; Yaron, O; Tal, D; Silverman, J M; Horesh, A; De Cia, A; Taddia, F; Sollerman, J; Perley, D; Vreeswijk, P M; Kulkarni, S R; Nugent, P E; Filippenko, A V; Wheeler, J C

2014-05-22

The explosive fate of massive Wolf-Rayet stars (WRSs) is a key open question in stellar physics. An appealing option is that hydrogen-deficient WRSs are the progenitors of some hydrogen-poor supernova explosions of types IIb, Ib and Ic (ref. 2). A blue object, having luminosity and colours consistent with those of some WRSs, has recently been identified in pre-explosion images at the location of a supernova of type Ib (ref. 3), but has not yet been conclusively determined to have been the progenitor. Similar work has so far only resulted in non-detections. Comparison of early photometric observations of type Ic supernovae with theoretical models suggests that the progenitor stars had radii of less than 10(12) centimetres, as expected for some WRSs. The signature of WRSs, their emission line spectra, cannot be probed by such studies. Here we report the detection of strong emission lines in a spectrum of type IIb supernova 2013cu (iPTF13ast) obtained approximately 15.5 hours after explosion (by 'flash spectroscopy', which captures the effects of the supernova explosion shock breakout flash on material surrounding the progenitor star). We identify Wolf-Rayet-like wind signatures, suggesting a progenitor of the WN(h) subclass (those WRSs with winds dominated by helium and nitrogen, with traces of hydrogen). The extent of this dense wind may indicate increased mass loss from the progenitor shortly before its explosion, consistent with recent theoretical predictions.

A Wolf-Rayet-Like Progenitor of SN 2013cu from Spectral Observations of a Stellar Wind

NASA Technical Reports Server (NTRS)

Gal-Yam, Avishay; Arcavi, I.; Ofek, E. O.; Ben-Ami, S.; Cenko, S. B.; Kasliwal, M. M.; Cao, Y.; Yaron, O.; Tal, D.; Silverman, J. M.;

Hand-held microwave search detector

NASA Astrophysics Data System (ADS)

Daniels, David J.; Philippakis, Mike

2005-05-01

This paper describes the further development of a patented, novel, low cost, microwave search detector using noise radar technology operating in the 27-40GHz range of frequencies, initially reported in SPIE 2004. Initial experiments have shown that plastic explosives, ceramics and plastic material hidden on the body can be detected with the system. This paper considers the basic physics of the technique and reports on the development of a initial prototype system for hand search of suspects and addresses the work carried out on optimisation of PD and FAR. The radar uses a novel lens system and the design and modelling of this for optimum depth of field of focus will be reported.

System of radiographic control or an imaging system for personal radiographic inspection

NASA Astrophysics Data System (ADS)

Babichev, E. A.; Baru, S. E.; Neustroev, V. A.; Leonov, V. V.; Porosev, V. V.; Savinov, G. A.; Ukraintsev, Yu. G.

2004-06-01

The security system of personal radiographic inspection for detection of explosive materials and plastic weapons was developed in BINP recently. Basic system parameters are: maximum scanning height— 2000 mm, image width— 800 mm, number of detector channels—768, channel size— 1.05×1 mm, charge collecting time for one line—2, 5 ms, scanning speed— 40 cm/s, maximum scanning time— 5 s, radiation dose per one inspection <5 μSv. The detector is a multichannel ionization Xe chamber. The image of inspected person will appear on the display just after scanning. The pilot sample of this system was put into operation in March, 2003.b

Scanning Electron Microscopy (SEM) Procedure for HE Powders on a Zeiss Sigma HD VP SEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zaka, F.

This method describes the characterization of inert and HE materials by the Zeiss Sigma HD VP field emission Scanning Electron Microscope (SEM). The SEM uses an accelerated electron beam to generate high-magnification images of explosives and other materials. It is fitted with five detectors (SE, Inlens, STEM, VPSE, HDBSD) to enable imaging of the sample via different secondary electron signatures, angles, and energies. In addition to imaging through electron detection, the microscope is also fitted with two Oxford Instrument Energy Dispersive Spectrometer (EDS) 80 mm detectors to generate elemental constituent spectra and two-dimensional maps of the material being scanned.

A composition analyzer for microparticles using a spark ion source. [using time of flight spectrometers

NASA Technical Reports Server (NTRS)

Auer, S. O.; Berg, O. E.

1975-01-01

Iron microparticles were fired onto a capacitor-type microparticle detector which responded to an impact with a spark discharge. Ion currents were extracted from the spark and analyzed in a time-of-flight mass spectrometer. The mass spectra showed the element of both detector and particle materials. The total extracted ion currents was typically 10A within a period of 100ns, indicating very efficient vaporization of the particle and ionization of the vapor. Potential applications include research on cosmic dust, atmospheric aerosols and cloud droplets, particles ejected by rocket or jet engines, by machining processes, or by nuclear bomb explosions.

Raman Laser Spectrometer internal Optical Head current status: opto-mechanical redesign to minimize the excitation laser trace

NASA Astrophysics Data System (ADS)

Sanz, Miguel; Ramos, Gonzalo; Moral, Andoni; Pérez, Carlos; Belenguer, Tomás; del Rosario Canchal, María; Zuluaga, Pablo; Rodriguez, Jose Antonio; Santiago, Amaia; Rull, Fernando; Instituto Nacional de Técnica Aeroespacial (INTA); Ingeniería de Sistemas para la Defesa de España S.A. (ISDEFE)

2016-10-01

Raman Laser Spectrometer (RLS) is the Pasteur Payload instruments of the ExoMars mission, within the ESA's Aurora Exploration Programme, that will perform for the first time in an out planetary mission Raman spectroscopy. RLS is composed by SPU (Spectrometer Unit), iOH (Internal Optical Head), and ICEU (Instrument Control and Excitation Unit). iOH focuses the excitation laser on the samples (excitation path), and collects the Raman emission from the sample (collection path, composed on collimation system and filtering system). The original design presented a high laser trace reaching to the detector, and although a certain level of laser trace was required for calibration purposes, the high level degrades the Signal to Noise Ratio confounding some Raman peaks.The investigation revealing that the laser trace was not properly filtered as well as the iOH opto-mechanical redesign are reported on. After the study of the Long Pass Filters Optical Density (OD) as a function of the filtering stage to the detector distance, a new set of filters (Notch filters) was decided to be evaluated. Finally, and in order to minimize the laser trace, a new collection path design (mainly consisting on that the collimation and filtering stages are now separated in two barrels, and on the kind of filters to be used) was required. Distance between filters and collimation stage first lens was increased, increasing the OD. With this new design and using two Notch filters, the laser trace was reduced to assumable values, as can be observed in the functional test comparison also reported on this paper.

Problematic projection to the in-sample subspace for a kernelized anomaly detector

DOE PAGES

Theiler, James; Grosklos, Guen

2016-03-07

We examine the properties and performance of kernelized anomaly detectors, with an emphasis on the Mahalanobis-distance-based kernel RX (KRX) algorithm. Although the detector generally performs well for high-bandwidth Gaussian kernels, it exhibits problematic (in some cases, catastrophic) performance for distances that are large compared to the bandwidth. By comparing KRX to two other anomaly detectors, we can trace the problem to a projection in feature space, which arises when a pseudoinverse is used on the covariance matrix in that feature space. Here, we show that a regularized variant of KRX overcomes this difficulty and achieves superior performance over a widemore » range of bandwidths.« less

Assessment of soil and water contaminants from selected locations in and near the Idaho Army National Guard Orchard Training Area, Ada County, Idaho, 2001-2003

USGS Publications Warehouse

Parliman, D.J.

2004-01-01

In 2001, the National Guard Bureau and the U.S. Geological Survey began a project to compile hydrogeologic data and determine presence or absence of soil, surface-water, and ground-water contamination at the Idaho Army National Guard Orchard Training Area in southwestern Idaho. Between June 2002 and April 2003, a total of 114 soil, surface-water, ground-water, precipitation, or dust samples were collected from 68 sample sites (65 different locations) in the Orchard Training Area (OTA) or along the vehicle corridor to the OTA. Soil and water samples were analyzed for concentrations of selected total trace metals, major ions, nutrients, explosive compounds, semivolatile organics, and petroleum hydrocarbons. Water samples also were analyzed for concentrations of selected dissolved trace metals and major ions. Distinguishing naturally occurring large concentrations of trace metals, major ions, and nutrients from contamination related to land and water uses at the OTA was difficult. There were no historical analyses for this area to compare with modern data, and although samples were collected from 65 locations in and near the OTA, sampled areas represented only a small part of the complex OTA land-use areas and soil types. For naturally occurring compounds, several assumptions were made?anomalously large concentrations, when tied to known land uses, may indicate presence of contamination; naturally occurring concentrations cannot be separated from contamination concentrations in mid- and lower ranges of data; and smallest concentrations may represent the lowest naturally occurring range of concentrations and (or) the absence of contaminants related to land and water uses. Presence of explosive, semivolatile organic (SVOC), and petroleum hydrocarbon compounds in samples indicates contamination from land and water uses. In areas along the vehicle corridor and major access roads within the OTA, most trace metal, major ion, and nutrient concentrations in soil samples were not in the upper 10th percentile of data, but concentrations of 25 metals, ions, or nutrients were in the upper 10th percentile in a puddle sample near the heavy equipment maneuvering area, MPRC-H. The largest concentrations of tin, ammonia, and nitrite plus nitrate (as nitrogen) in water from the OTA were detected in a sample from this puddle. Petroleum hydrocarbons were the most common contaminant, detected in all soil and surface-water samples. An SVOC, bis (2-ethylhexyl) phthalate, a plasticizer, was detected at a site along the vehicle corridor. In Maneuver Areas within the OTA, many soil samples contained at least one trace metal, major ion, or nutrient in the upper 10th percentile of data, and the largest concentrations of cobalt, iron, mercury, titanium, sodium, ammonia, or total phosphorus were detected in 6 of 13 soil samples outside the Tadpole Lake area. The largest concentrations of aluminum, arsenic, beryllium, nickel, selenium, silver, strontium, thallium, vanadium, chloride, potassium, sulfate, and nitrite plus nitrate were detected in soil samples from the Tadpole Lake area. Water from Tadpole Lake contained the largest total concentrations of 19 trace metals, 4 major ions, and 1 nutrient. Petroleum hydrocarbons were detected in 5 soil samples and water from Tadpole Lake. SVOCs related to combustion of fuel or plasticizers were detected in 1 soil sample. Explosive compounds were detected in 1 precipitation sample.In the Impact Area within the OTA, most soil samples contained at least one trace metal, major ion, or nutrient in the upper 10th percentile of data, and the largest concentrations of barium, chromium, copper, manganese, lead, or orthophosphate were detected in 6 of the 18 soil samples. Petroleum hydrocarbons were detected in 4 soil samples, SVOCs in 6 samples, and explosive compounds in 4 samples. In the mobilization and training equipment site (MATES) compound adjacent to the OTA, all soil and water samples contained at lea

The Era of Kilometer-Scale Neutrino Detectors

DOE PAGES

Halzen, Francis; Katz, Uli

2013-01-01

Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by the 1970s, it was realized that kilometer-scale neutrino detectors were required. The first such instrument, IceCube, transforms a cubic kilometer of deep and ultra-transparent Antarctic ice into a particle detector. KM3NeT, an instrument that aims to exploit several cubic kilometers of the deep Mediterranean sea as its detector medium, is in its final design stages. The scientific missions of these instruments include searching for sources of cosmic rays and for dark matter, observing Galactic supernova explosions, and studying the neutrinos themselves. Identifying the accelerators that produce Galacticmore » and extragalactic cosmic rays has been a priority mission of several generations of high-energy gamma-ray and neutrino telescopes; success has been elusive so far. Detecting the gamma-ray and neutrino fluxes associated with cosmic rays reaches a new watershed with the completion of IceCube, the first neutrino detector with sensitivity to the anticipated fluxes. In this paper, we will first revisit the rationale for constructing kilometer-scale neutrino detectors. We will subsequently recall the methods for determining the arrival direction, energy and flavor of neutrinos, and will subsequently describe the architecture of the IceCube and KM3NeT detectors.« less

QCL-based standoff and proximal chemical detectors

NASA Astrophysics Data System (ADS)

Dupuis, Julia R.; Hensley, Joel; Cosofret, Bogdan R.; Konno, Daisei; Mulhall, Phillip; Schmit, Thomas; Chang, Shing; Allen, Mark; Marinelli, William J.

2016-05-01

The development of two longwave infrared quantum cascade laser (QCL) based surface contaminant detection platforms supporting government programs will be discussed. The detection platforms utilize reflectance spectroscopy with application to optically thick and thin materials including solid and liquid phase chemical warfare agents, toxic industrial chemicals and materials, and explosives. Operation at standoff (10s of m) and proximal (1 m) ranges will be reviewed with consideration given to the spectral signatures contained in the specular and diffusely reflected components of the signal. The platforms comprise two variants: Variant 1 employs a spectrally tunable QCL source with a broadband imaging detector, and Variant 2 employs an ensemble of broadband QCLs with a spectrally selective detector. Each variant employs a version of the Adaptive Cosine Estimator for detection and discrimination in high clutter environments. Detection limits of 5 μg/cm2 have been achieved through speckle reduction methods enabling detector noise limited performance. Design considerations for QCL-based standoff and proximal surface contaminant detectors are discussed with specific emphasis on speckle-mitigated and detector noise limited performance sufficient for accurate detection and discrimination regardless of the surface coverage morphology or underlying surface reflectivity. Prototype sensors and developmental test results will be reviewed for a range of application scenarios. Future development and transition plans for the QCL-based surface detector platforms are discussed.

Comparing FDTD and Ray-Tracing Models in Numerical Simulation of HgCdTe LWIR Photodetectors

NASA Astrophysics Data System (ADS)

Vallone, Marco; Goano, Michele; Bertazzi, Francesco; Ghione, Giovanni; Schirmacher, Wilhelm; Hanna, Stefan; Figgemeier, Heinrich

2016-09-01

We present a simulation study of HgCdTe-based long-wavelength infrared detectors, focusing on methodological comparisons between the finite-difference time-domain (FDTD) and ray-tracing optical models. We performed three-dimensional simulations to determine the absorbed photon density distributions and the corresponding photocurrent and quantum efficiency spectra of isolated n-on- p uniform-composition pixels, systematically comparing the results obtained with FDTD and ray tracing. Since ray tracing is a classical optics approach, unable to describe interference effects, its applicability has been found to be strongly wavelength dependent, especially when reflections from metallic layers are relevant. Interesting cavity effects around the material cutoff wavelength are described, and the cases where ray tracing can be considered a viable approximation are discussed.

Mercuric iodide detector systems for identifying substances by x-ray energy dispersive diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iwanczyk, J.S.; Patt, B.E.; Wang, Y.J.

The use of mercuric iodide arrays for energy-dispersive x-ray diffraction (EDXRD) spectroscopy is now being investigated by the authors for inspection of specific crystalline powders in substances ranging from explosives to illicit drugs. Mercuric iodide has been identified as the leading candidate for replacing the Ge detectors previously employed in the development of this technique because HgI{sub 2} detectors: operate at or near room temperature; without the bulky apparatus associated with cryogenic cooling; and offer excellent spectroscopy performance with extremely high efficiency. Furthermore, they provide the practicality of constructing optimal array geometries necessary for these measurements. Proof of principle experimentsmore » have been performed using a single-HgI{sub 2} detector spectrometer. An energy resolution of 655 eV (FWHM) has been obtained for 60 keV gamma line from an {sup 241}Am source. The EDXRD signatures of various crystalline powdered compounds have been measured and the spectra obtained show the excellent potential of mercuric iodide for this application.« less

Liquid Chromatographic Analysis of Hydraulic Fluids.

DTIC Science & Technology

1979-11-01

chemical mixtures of a petroleum- or nonpetroleum-base stock component formulated with various additives which may be present in trace amounts or...absorb UV radiation near the monitoring wavelength may swamp the detector signal and therefore should be avoided in 1JV detection. The recorder trace of...Also, organic phosphites , thiophosphates, and sulfides are used to inhibit oxidative catalysis by metal ions. The oxidation inhibitor in 6083D-0 is BPC

Microshell-tipped optical fibers as sensors of high-pressure pulses in adverse environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benjamin, R.F.; Mayer, F.J.; Maynard, R.L.

1984-01-01

An optical-fiber sensor for detecting the arrival of strong pressure pulses was developed. The sensor consists of an optical fiber, tipped with a gas-filled microballoon. They have been used successfully in adverse environments including explosives, ballistics and electromagnetic pulses (EMP). The sensor produces a bright optical pulse caused by the rapid shock-heating of a gas, typically argon or xenon, which is confined in the spherical glass or plastic microballoon. The light pulse is transmitted via the optical fiber to a photo detector, usually a streak camera or photomultiplier tube. The microballoon optical sensor (called an optical pin by analogy tomore » standard electrical pins), was originally developed for diagnosing an explosive, pulsed-power generator. Optical pins are required due to the EMP. The optical pins are economical arrival-time indicators because many channels can be recorded by one streak camera. The generator tests and related experiments, involving projectile velocities and detonation velocities of several kilometers per sec have demonstrated the usefulness of the sensors in explosives and ballistics applications. The technical and cost advantages of this optical pin make it potentially useful for many electromagnetic, explosive, and ballistics applications.« less

A new miniature hand-held solar-blind reagentless standoff chemical, biological, and explosives (CBE) sensor

NASA Astrophysics Data System (ADS)

Hug, W. F.; Reid, R. D.; Bhartia, R.; Lane, A. L.

2008-04-01

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.

Initiation of Coronal Mass Ejections

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Sterling, Alphonse C.

2005-01-01

This paper is a synopsis of the initiation of the strong-field magnetic explosions that produce large, fast coronal mass ejections. Cartoons based on observations are used to describe the inferred basic physical processes and sequences that trigger and drive the explosion. The magnetic field that explodes is a sheared-core bipole that may or may not be embedded in surrounding strong magnetic field, and may or may not contain a flux rope before it starts to explode. We describe three different mechanisms that singly or in combination trigger the explosion: (1) runaway internal tether-cutting reconnection, (2) runaway external tether-cutting reconnection, and (3) ideal MHD instability or loss or equilibrium. For most eruptions, high-resolution, high-cadence magnetograms and chromospheric and coronal movies (such as from TRACE and/or Solar-B) of the pre-eruption region and of the onset of the eruption and flare are needed to tell which one or which combination of these mechanisms is the trigger. Whatever the trigger, it leads to the production of an erupting flux rope. Using a simple model flux rope, we demonstrate that the explosion can be driven by the magnetic pressure of the expanding flux rope, provided the shape of the expansion is "fat" enough.

Method for combined biometric and chemical analysis of human fingerprints.

PubMed

Staymates, Jessica L; Orandi, Shahram; Staymates, Matthew E; Gillen, Greg

This paper describes a method for combining direct chemical analysis of latent fingerprints with subsequent biometric analysis within a single sample. The method described here uses ion mobility spectrometry (IMS) as a chemical detection method for explosives and narcotics trace contamination. A collection swab coated with a high-temperature adhesive has been developed to lift latent fingerprints from various surfaces. The swab is then directly inserted into an IMS instrument for a quick chemical analysis. After the IMS analysis, the lifted print remains intact for subsequent biometric scanning and analysis using matching algorithms. Several samples of explosive-laden fingerprints were successfully lifted and the explosives detected with IMS. Following explosive detection, the lifted fingerprints remained of sufficient quality for positive match scores using a prepared gallery consisting of 60 fingerprints. Based on our results ( n  = 1200), there was no significant decrease in the quality of the lifted print post IMS analysis. In fact, for a small subset of lifted prints, the quality was improved after IMS analysis. The described method can be readily applied to domestic criminal investigations, transportation security, terrorist and bombing threats, and military in-theatre settings.

Physical and environmental factors affecting the persistence of explosives particles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Papantonakis, Michael R.; Nguyen, Viet K.; Furstenberg, Robert; White, Caitlyn; Shuey, Melissa; Kendziora, Christopher A.; McGill, R. Andrew

2017-05-01

Knowledge of the persistence of trace explosives materials is critical to aid the security community in designing detection methods and equipment. The physical and environmental factors affecting the lifetimes of particles include temperature, airflow, interparticle distance, adlayers, humidity, particle field size and vapor pressure. We are working towards a complete particle persistence model that captures the relative importance of these effects to allow the user, with known environmental conditions, to predict particle lifetimes for explosives or other chemicals. In this work, particles of explosives are sieved onto smooth glass substrates using particle sizes and loadings relevant to those deposited by fingerprint deposition. The coupon is introduced into a custom flow cell and monitored under controlled airflow, humidity and temperature. Photomicroscopy images of the sample taken at fixed time intervals are analyzed to monitor particle sublimation and characterized as a size-independent radial sublimation velocity for each particle in the ensemble. In this paper we build on previous work by comparing the relationship between sublimation of different materials and their vapor pressures. We also describe the influence of a sebum adlayer on particle sublimation, allowing us to better model `real world' samples.

New, high-efficiency ion trap mobility detection system for narcotics and explosives

NASA Astrophysics Data System (ADS)

McGann, William J.; Bradley, V.; Borsody, A.; Lepine, S.

1994-10-01

A new patented Ion Trap Mobility Spectrometer (ITMS) design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electric field driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC and LSD are reported.

New high-efficiency ion trap mobility detection system for narcotics and explosives

NASA Astrophysics Data System (ADS)

McGann, William J.; Jenkins, Anthony; Ribiero, K.; Napoli, J.

1994-03-01

A new patented ion trap mobility spectrometer design is presented. Conventional IMS designs typically operate below 0.1% efficiency. This is due primarily to electrical-field-driven, sample ion discharge on a shutter grid. Since 99.9% of the sample ions generated in the reaction region are lost in this discharge process, the sensitivity of conventional systems is limited. The new design provides greater detection efficiency than conventional designs through the use of an `ion trap' concept. The paper describes the plasma and sample ion dynamics in the reaction region of the new detector and discusses the advantages of utilizing a `field-free' space to generate sample ions with high efficiency. Fast electronic switching is described which is used to perturb the field-free space and pulse the sample ions into the drift region for separation and subsequent detection using pseudo real-time software for analysis and display of the data. Many applications for this new detector are now being considered including the detection of narcotics and explosives. Preliminary ion spectra, reduced mobility data and sensitivity data are presented for fifteen narcotics, including cocaine, THC, and LSD are reported.

National Security Science and Technology Initiative: Air Cargo Screening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bingham, Philip R; White, Tim; Cespedes, Ernesto

The non-intrusive inspection (NII) of consolidated air cargo carried on commercial passenger aircraft continues to be a technically challenging, high-priority requirement of the Department of Homeland Security's Science and Technology Directorate (DHS S&T), the Transportation Security Agency and the Federal Aviation Administration. The goal of deploying a screening system that can reliably and cost-effectively detect explosive threats in consolidated cargo without adversely affecting the flow of commerce will require significant technical advances that will take years to develop. To address this critical National Security need, the Battelle Memorial Institute (Battelle), under a Cooperative Research and Development Agreement (CRADA) with fourmore » of its associated US Department of Energy (DOE) National Laboratories (Oak Ridge, Pacific Northwest, Idaho, and Brookhaven), conducted a research and development initiative focused on identifying, evaluating, and integrating technologies for screening consolidated air cargo for the presence of explosive threats. Battelle invested $8.5M of internal research and development funds during fiscal years 2007 through 2009. The primary results of this effort are described in this document and can be summarized as follows: (1) Completed a gap analysis that identified threat signatures and observables, candidate technologies for detection, their current state of development, and provided recommendations for improvements to meet air cargo screening requirements. (2) Defined a Commodity/Threat/Detection matrix that focuses modeling and experimental efforts, identifies technology gaps and game-changing opportunities, and provides a means of summarizing current and emerging capabilities. (3) Defined key properties (e.g., elemental composition, average density, effective atomic weight) for basic commodity and explosive benchmarks, developed virtual models of the physical distributions (pallets) of three commodity types and three explosive benchmarks combinations, and conducted modeling and simulation studies to begin populating the matrix of commodities, threats, and detection technologies. (4) Designed and fabricated basic (homogeneous) commodity test pallets and fabricated inert stimulants to support experiments and to validate modeling/simulation results. (5) Developed/expanded the team's capabilities to conduct full-scale imaging (neutron and x-ray) experiments of air cargo commodities and explosive benchmarks. (6) Conducted experiments to improve the collection of trace particles of explosives from a variety of surfaces representative of air cargo materials by means of mechanical (air/vibration/pressure), thermal, and electrostatic methods. Air cargo screening is a difficult challenge that will require significant investment in both research and development to find a suitable solution to ensure the safety of passengers without significantly hindering the flow of commodities. The initiative funded by Battelle has positioned this group to make major contributions in meeting the air cargo challenge by developing collaborations, developing laboratory test systems, improving knowledge of the challenges (both technical and business) for air cargo screening, and increasing the understanding of the capabilities for current inspection methods (x-ray radiography, x-ray backscatter, etc.) and potential future inspection methods (neutron radiography, fusion of detector modalities, advanced trace detection, etc.). Lastly, air cargo screening is still an issue that will benefit from collaboration between Department of Energy Laboratories and Battelle. On January 7, 2010, DHS Secretary Napolitano joined White House Press Secretary Robert Gibbs and Assistant to the President for Counterterrorism and Homeland Security John Brennan to announce several recommendations DHS has made to the President for improving the technology and procedures used to protect air travel from acts of terrorism. (This announcement followed the 25 Dec'09 Delta/Northwest Airlines Flight 253 terror attack.) Secretary Napolitano outlined five recommendations DHS will pursue to enhance the safety of the traveling public. One of the five recommendations, read as follows: 'Establish a partnership on aviation security between DHS and the Department of Energy and its National Laboratories in order to develop new and more effective technologies to deter and disrupt known threats and proactively anticipate and protect against new ways by which terrorists could seek to board an aircraft.' In conclusion, it appears very timely that Battelle and its DOE lab partners initiated a serious collaboration on the air cargo topic, and that we should continue to work toward future collaboration in response to the government's needs.« less

Detection of explosive substances by tomographic inspection using neutron and gamma-ray spectroscopy

NASA Astrophysics Data System (ADS)

Farahmand, M.; Boston, A. J.; Grint, A. N.; Nolan, P. J.; Joyce, M. J.; Mackin, R. O.; D'Mellow, B.; Aspinall, M.; Peyton, A. J.; van Silfhout, R.

2007-08-01

In recent years the detection and identification of hazardous materials has become increasingly important. This work discusses research and development of a technique which is capable of detecting and imaging hidden explosives. It is proposed to utilise neutron interrogation of the substances under investigation facilitating the detection of emitted gamma radiation and scattered neutrons. Pulsed fast neutron techniques are attractive because they can be used to determine the concentrations of the light elements (hydrogen, carbon, nitrogen, and oxygen) which can be the primary components of explosive materials. Using segmented High Purity Ge (HPGe) detectors and digital pulse processing [R.J. Cooper, G. Turk, A.J. Boston, H.C. Boston, J.R. Cresswell, A.R. Mather, P.J. Nolan, C.J. Hall, I. Lazarus, J. Simpson, A. Berry, T. Beveridge, J. Gillam, R.A. Lewis, in: Proceedings of the 7th International Conference on Position Sensitive Detectors, Nuclear Instruments and Methods A, in press; I. Lazarus, D.E. Appelbe, A. J. Boston, P.J. Coleman-Smith, J.R. Cresswell, M. Descovich, S.A.A. Gros, M. Lauer, J. Norman, C.J. Pearson, V.F.E. Pucknell, J.A. Sampson, G. Turk, J.J. Valiente-Dobón, IEEE Trans. Nucl. Sci., 51 (2004) 1353; R.J. Cooper, A.J. Boston, H.C. Boston, J.R. Cresswell, A.N. Grint, A.R. Mather, P.J. Nolan, D.P. Scraggs, G. Turk, C.J. Hall, I. Lazarus, A. Berry, T. Beveridge, J. Gillam, R.A. Lewis, in: Proceedings of the 11th International Symposium on Radiation Measurements and Application, 2006. [1-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Theiler, James; Grosklos, Guen

We examine the properties and performance of kernelized anomaly detectors, with an emphasis on the Mahalanobis-distance-based kernel RX (KRX) algorithm. Although the detector generally performs well for high-bandwidth Gaussian kernels, it exhibits problematic (in some cases, catastrophic) performance for distances that are large compared to the bandwidth. By comparing KRX to two other anomaly detectors, we can trace the problem to a projection in feature space, which arises when a pseudoinverse is used on the covariance matrix in that feature space. Here, we show that a regularized variant of KRX overcomes this difficulty and achieves superior performance over a widemore » range of bandwidths.« less

Development of a software based automatic exposure control system for use in image guided radiation therapy

NASA Astrophysics Data System (ADS)

Morton, Daniel R.

Modern image guided radiation therapy involves the use of an isocentrically mounted imaging system to take radiographs of a patient's position before the start of each treatment. Image guidance helps to minimize errors associated with a patients setup, but the radiation dose received by patients from imaging must be managed to ensure no additional risks. The Varian On-Board Imager (OBI) (Varian Medical Systems, Inc., Palo Alto, CA) does not have an automatic exposure control system and therefore requires exposure factors to be manually selected. Without patient specific exposure factors, images may become saturated and require multiple unnecessary exposures. A software based automatic exposure control system has been developed to predict optimal, patient specific exposure factors. The OBI system was modelled in terms of the x-ray tube output and detector response in order to calculate the level of detector saturation for any exposure situation. Digitally reconstructed radiographs are produced via ray-tracing through the patients' volumetric datasets that are acquired for treatment planning. The ray-trace determines the attenuation of the patient and subsequent x-ray spectra incident on the imaging detector. The resulting spectra are used in the detector response model to determine the exposure levels required to minimize detector saturation. Images calculated for various phantoms showed good agreement with the images that were acquired on the OBI. Overall, regions of detector saturation were accurately predicted and the detector response for non-saturated regions in images of an anthropomorphic phantom were calculated to generally be within 5 to 10 % of the measured values. Calculations were performed on patient data and found similar results as the phantom images, with the calculated images being able to determine detector saturation with close agreement to images that were acquired during treatment. Overall, it was shown that the system model and calculation method could potentially be used to predict patients' exposure factors before their treatment begins, thus preventing the need for multiple exposures.

Ar39 Detection at the 10-16 Isotopic Abundance Level with Atom Trap Trace Analysis

NASA Astrophysics Data System (ADS)

Jiang, W.; Williams, W.; Bailey, K.; Davis, A. M.; Hu, S.-M.; Lu, Z.-T.; O'Connor, T. P.; Purtschert, R.; Sturchio, N. C.; Sun, Y. R.; Mueller, P.

2011-03-01

Atom trap trace analysis, a laser-based atom counting method, has been applied to analyze atmospheric Ar39 (half-life=269yr), a cosmogenic isotope with an isotopic abundance of 8×10-16. In addition to the superior selectivity demonstrated in this work, the counting rate and efficiency of atom trap trace analysis have been improved by 2 orders of magnitude over prior results. The significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the development of dark matter detectors.

Sensitivity Comparison of Vapor Trace Detection of Explosives Based on Chemo-Mechanical Sensing with Optical Detection and Capacitive Sensing with Electronic Detection

PubMed Central

Strle, Drago; Štefane, Bogdan; Zupanič, Erik; Trifkovič, Mario; Maček, Marijan; Jakša, Gregor; Kvasič, Ivan; Muševič, Igor

2014-01-01

The article offers a comparison of the sensitivities for vapour trace detection of Trinitrotoluene (TNT) explosives of two different sensor systems: a chemo-mechanical sensor based on chemically modified Atomic Force Microscope (AFM) cantilevers based on Micro Electro Mechanical System (MEMS) technology with optical detection (CMO), and a miniature system based on capacitive detection of chemically functionalized planar capacitors with interdigitated electrodes with a comb-like structure with electronic detection (CE). In both cases (either CMO or CE), the sensor surfaces are chemically functionalized with a layer of APhS (trimethoxyphenylsilane) molecules, which give the strongest sensor response for TNT. The construction and calibration of a vapour generator is also presented. The measurements of the sensor response to TNT are performed under equal conditions for both systems, and the results show that CE system with ultrasensitive electronics is far superior to optical detection using MEMS. Using CMO system, we can detect 300 molecules of TNT in 10+12 molecules of N2 carrier gas, whereas the CE system can detect three molecules of TNT in 10+12 molecules of carrier N2. PMID:24977388

Surface enhanced Raman scattering (SERS) spectra of trinitrotoluene in silver colloids prepared by microwave heating method.

PubMed

Zhang, Chunling; Wang, Kaijun; Han, Dejun; Pang, Qing

2014-03-25

Surface enhanced Raman spectroscopy (SERS) has been demonstrated for the detection of trace levels of explosives due to its high sensitivity, speed of detection and fingerprint feature. 2,4,6-Trinitrotoluene (TNT), a leading example of nitroaromatic explosives, is causing wide concern. In this study, SERS spectra of TNT solution in silver colloids have been successfully measured and a comparison was drawn with the normal Raman spectra of bulk TNT. The silver colloids were prepared by the microwave heating method and characterized by UV-Vis spectra and the scanning electron microscopy (SEM). NaCl and pH value have a great impact on SERS intensity of TNT, the corresponding experimental research results and theoretical interpretations were further illustrated to a certain extent. Moreover, the detection limit of TNT in aqueous solution was achieved as low as 10(-10) mol L(-1) and some preliminary experiments of detecting TNT vapor (about 10 μg/L) using SERS have been carried out. Our results demonstrated the potential of SERS for probing TNT with high sensitivity, and suggest SERS as a powerful method for detection of TNT and similar species at trace levels. Copyright © 2013 Elsevier B.V. All rights reserved.

Trace material detection of surfaces via single-beam femtosecond MCARS

NASA Astrophysics Data System (ADS)

Bowman Pilkington, Sherrie S.; Roberson, Stephen D.; Pellegrino, Paul M.

2016-05-01

There is a significant need for the development of optical diagnostics for rapid and accurate detection of chemical species in convoluted systems. In particular, chemical warfare agents and explosive materials are of interest, however, identification of these species is difficult for a wide variety of reasons. Low vapor pressures, for example, cause traditional Raman scattering to be ineffective due to the incredibly long signal collection times that are required. Multiplex Coherent Anti-Stokes Raman Scattering (MCARS) spectroscopy generates a complete Raman spectrum from the material of interest using a combination of a broadband pulse which drives multiple molecular vibrations simultaneously and a narrow band probe pulse. For most species, the complete Raman spectrum can be detected in milliseconds; this makes MCARS an excellent technique for trace material detection in complex systems. In this paper, we present experimental MCARS results on solid state chemical species in complex systems. The 40fs Ti:Sapphire laser used in this study has sufficient output power to produce both the broadband continuum pulse and narrow band probe pulse simultaneously. A series of explosive materials of interest have been identified and compared with spontaneous Raman spectra, showing the specificity and stability of this system.

Imaging standoff trace detection of explosives using IR-laser based backscattering

NASA Astrophysics Data System (ADS)

Fuchs, F.; Hugger, S.; Jarvis, J.; Yang, Q. K.; Ostendorf, R.; Schilling, Ch.; Bronner, W.; Driad, R.; Aidam, R.; Wagner, J.

2016-05-01

We perform active hyperspectral imaging using tunable mid-infrared (MIR) quantum cascade lasers for contactless identification of solid and liquid contaminations on surfaces. By collecting the backscattered laser radiation with a camera, a hyperspectral data cube, containing the spatially resolved spectral information of the scene is obtained. Data is analyzed using appropriate algorithms to find the target substances even on substrates with a priori unknown spectra. Eye-save standoff detection of residues of explosives and precursors over extended distances is demonstrated and the main purpose of our system. Using a MIR EC-QCL with a tuning range from 7.5 μm to 10 μm, detection of a large variety of explosives, e.g. TNT, PETN and RDX and precursor materials such as Ammonium Nitrate could be demonstrated. In a real world scenario stand-off detection over distances of up to 20 m could be successfully performed. This includes measurements in a post blast scenario demonstrating the potential of the technique for forensic investigations.

Advances in quantum cascade lasers for security and crime-fighting

NASA Astrophysics Data System (ADS)

Normand, Erwan L.; Stokes, Robert J.; Hay, Kenneth; Foulger, Brian; Lewis, Colin

2010-10-01

Advances in the application of Quantum Cascade Lasers (QCL) to trace gas detection will be presented. The solution is real time (~1 μsec per scan), is insensitive to turbulence and vibration, and performs multiple measurements in one sweep. The QCL provides a large dynamic range, which is a linear response from ppt to % level. The concentration can be derived with excellent immunity from cross interference. Point sensing sensors developed by Cascade for home made and commercial explosives operate by monitoring key constituents in real time and matching this to a spatial event (i.e. sniffer device placed close to an object or person walking through portal (overt or covert). Programmable signature detection capability allows for detection of multiple chemical compounds along the most likely array of explosive chemical formulation. The advantages of configuration as "point sensing" or "stand off" will be discussed. In addition to explosives this method is highly applicable to the detection of mobile drugs labs through volatile chemical release.

SU-F-T-555: Accurate Stereotactic Cone TMRs Converted from PDDs Scanned with Ray Trace

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, H; Zhong, H; Qin, Y

Purpose: To investigate whether the accuracy of TMRs for stereotactic cones converted from PDDs scanned with Ray Trace can be improved, when compared against the TMRs converted from the traditional PDDs. Methods: Ray Trace measurement in Sun Nuclear 3D Scanner is for accurate scan of small field PDDs. The system detects the center of field at two depths, for example, at 3 and 20 cm in our study, and then performs scan along the line passing the two centers. With both Ray Trace and the traditional method, PDDs for conical cones of 4, 5, 7.5, 10, 12.5, 15, and 17.5more » mm diameter (jaws set to 5×5 cm) were obtained for 6X FFF and 10X FFF energies on a Varian Edge linac, using Edge detectors. The formalism of converting PDD to TMR given in Khan’s book (4th Edition, p.161) was applied. Sp values at dmax were obtained by measuring cone Scp and Sc. Continuous direct measurement of TMR by filling/draining water to/from the tank and spot measurement by moving the tank and detector were also performed with the same equipment, using 100 cm SDD. Results: For 6XFFF energy and all the cones, TMRs converted from Ray Trace were very close to the continuous and spot measurement, while TMRs converted from traditional PDDs had larger deviation. Along the central axis beyond dmax, 1.7% of TMR data points calculated from Ray Trace had more 3% deviation from measurement, with maximal deviation of 5.2%. Whereas, 34% of TMR points calculated from traditional PDDs had more than 3% deviation, with maximum of 5.7%. In this initial study, Ray Trace scans for 10XFFF beam were noisy, further measurement is warranted. Conclusion: The Ray Trace could improve the accuracy of PDDs measurement and the calculated TMRs for stereotactic cones, which was within 3% of the measured TMRs.« less

Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry.

PubMed

Romolo, Francesco Saverio; Cassioli, Luigi; Grossi, Silvana; Cinelli, Giuseppe; Russo, Mario Vincenzo

2013-01-10

The method of sample recovery for trace detection and identification of explosives plays a critical role in several criminal investigations. After bombing, there can be difficulties in sending big objects to a laboratory for analysis. Traces can also be searched for on large surfaces, on hands of suspects or on surfaces where the explosive was placed during preparatory phases (e.g. places where an IED was assembled, vehicles used for transportation, etc.). In this work, triacetone triperoxide (TATP) was synthesized from commercial precursors following reported methods. Several portions of about 6mg of TATP were then spread on different surfaces (e.g. floors, tables, etc.) or used in handling tests. Three different swabbing systems were used: a commercial swab, pre-wetted with propan-2-ol (isopropanol) and water (7:3), dry paper swabs, and cotton swabs wetted with propan-2-ol. Paper and commercial swabs were also used to sample a metal plate, where a small charge of about 4g of TATP was detonated. Swabs were sealed in small glass jars with screw caps and Parafilm(®) M and sent to the laboratory for analysis. Swabs were extracted and analysed several weeks later by gas chromatography/mass spectrometry. All the three systems gave positive results, but wetted swabs collected higher amounts of TATP. The developed procedure showed its suitability for use in real cases, allowing TATP detection in several simulations, including a situation in which people wash their hands after handling the explosive. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Negative-ion formation in the explosives RDX, PETN, and TNT using the Reversal Electron Attachment Detection (READ) technique

NASA Technical Reports Server (NTRS)

Chutijian, Ara; Boumsellek, S.; Alajajian, S. H.

1992-01-01

In the search for high sensitivity and direct atmospheric sampling of trace species, techniques have been developed such as atmospheric-sampling, glow-discharge ionization (ASGDI), corona discharge, atmospheric pressure ionization (API), electron-capture detection (ECD), and negative-ion chemical ionization (NICI) that are capable of detecting parts-per-billion to parts-per-trillion concentrations of trace species. These techniques are based on positive- or negative-ion formation via charge-transfer to the target, or electron capture under multiple-collision conditions in a Maxwellian distribution of electron energies at the source temperature. One drawback of the high-pressure, corona- or glow-discharge devices is that they are susceptible to interferences either through indistinguishable product masses, or through undesired ion-molecule reactions. The ASGDI technique is relatively immune from such interferences, since at target concentrations of less than 1 ppm the majority of negative ions arises via electron capture rather than through ion-molecule chemistry. A drawback of the conventional ECD, and possibly of the ASGDI, is that they exhibit vanishingly small densities of electrons with energies in the range 0-10 millielectron volts (meV), as can be seen from a typical Maxwellian electron energy distribution function at T = 300 K. Slowing the electrons to these subthermal (less than 10 meV) energies is crucial, since the cross section for attachment of several large classes of molecules is known to increase to values larger than 10(exp -12) sq cm at near-zero electron energies. In the limit of zero energy these cross sections are predicted to diverge as epsilon(exp -1/2), where epsilon is the electron energy. In order to provide a better 'match' between the electron energy distribution function and attachment cross section, a new concept of attachment in an electrostatic mirror was developed. In this scheme, electrons are brought to a momentary halt by reversing their direction with electrostatic fields. At this turning point the electrons have zero or near-zero energy. A beam of target molecules is introduced, and the resultant negative ions extracted. This basic idea has been recently improved to allow for better reversal geometry, higher electron currents, lower backgrounds, and increased negative-ion extraction efficiency. We present herein application of the so-called reversal electron attachment detector (READ) to the study of negative-ion formation in the explosives molecules RDX, PETN, and TNT under single-collision conditions.

Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source.

PubMed

Usmanov, D T; Chen, L C; Yu, Z; Yamabe, S; Sakaki, S; Hiraoka, K

2015-04-01

The high-sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NOx (-) (x = 2,3), O3 and HNO3 originating from plasma-excited air were suggested to contribute to the formation of [TNT - H](-) (m/z 226), [TNT - NO](-) (m/z 197) and [TNT - NO + HNO3 ](-) (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

AllamehZadeh, Mostafa, E-mail: dibaparima@yahoo.com

A Quadratic Neural Networks (QNNs) model has been developed for identifying seismic source classification problem at regional distances using ARMA coefficients determination by Artificial Neural Networks (ANNs). We have devised a supervised neural system to discriminate between earthquakes and chemical explosions with filter coefficients obtained by windowed P-wave phase spectra (15 s). First, we preprocess the recording's signals to cancel out instrumental and attenuation site effects and obtain a compact representation of seismic records. Second, we use a QNNs system to obtain ARMA coefficients for feature extraction in the discrimination problem. The derived coefficients are then applied to the neuralmore » system to train and classification. In this study, we explore the possibility of using single station three-component (3C) covariance matrix traces from a priori-known explosion sites (learning) for automatically recognizing subsequent explosions from the same site. The results have shown that this feature extraction gives the best classifier for seismic signals and performs significantly better than other classification methods. The events have been tested, which include 36 chemical explosions at the Semipalatinsk test site in Kazakhstan and 61 earthquakes (mb = 5.0-6.5) recorded by the Iranian National Seismic Network (INSN). The 100% correct decisions were obtained between site explosions and some of non-site events. The above approach to event discrimination is very flexible as we can combine several 3C stations.« less

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques using RDX and C-4

DOE Office of Scientific and Technical Information (OSTI.GOV)

C.J. Miller; T.S. Yoder

The amount of time that an explosive is present on the surface of a material is dependent upon the original amount of explosive on the surface, temperature, humidity, rain, etc. This laboratory study focused on looking at similarities and differences in three different surface contamination techniques that are used when performance testing explosive trace detection equipment in an attempt to determine how effective the techniques are at replicating actual field samples. The three techniques used were dry transfer deposition of solutions using the Transportation Security Laboratory (TSL) patented dry transfer techniques (US patent 6470730), direct deposition of explosive standards, andmore » fingerprinting of actual explosives. Explosives were deposited on the surface of one of five substrates using one of the three different deposition techniques. The process was repeated for each surface type using each contamination technique. The surface types used were: 50% cotton/50% polyester as found in T-shirts, 100% cotton with a smooth surface such as that found in a cotton dress shirt, 100% cotton on a rough surface such as that found on canvas or denim, suede leather such as might be found on jackets, purses, or shoes, and metal obtained from a car hood at a junk yard. The samples were not pre-cleaned prior to testing and contained sizing agents, and in the case of the metal, oil and dirt. The substrates were photographed using a Zeiss Discover V12 stereoscope with Axiocam ICc1 3 megapixel digital camera to determine the difference in the crystalline structure and surface contamination in an attempt to determine differences and similarities associated with current contamination techniques.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Tushar, E-mail: tushar@barc.gov.in; Kashyap, Yogesh; Shukla, Mayank

Associated particle technique (APT) for detection of explosives is well established but has been implemented mostly for fixed portal systems. In certain situations, a portable system is required where the suspect object cannot be moved from site. This paper discusses the development of a portable APT system in single-sided geometry which can be transported to site and requires only one-sided access to the object. The system comprised D-T neutron source and bismuth germanate (BGO) detectors fixed on a portable module. Different aspects of the system have been discussed such as background contribution, time selection, and elemental signatures. The system wasmore » used to detect benign samples and explosive simulants under laboratory condition. The elemental ratios obtained by analyzing the gamma spectra show good match with the theoretical ratios.« less

The Bright Future of Gravitational Wave Astronomy

NASA Astrophysics Data System (ADS)

Gonzalez, Gabriela

2008-04-01

These are exciting times in the search for gravitational waves. Gravitational waves are expected from many different astrophysical sources: brief transients from violent events like supernova explosions and collisions of neutron stars and black holes, coalescence of compact binary systems, continuous waves from rotating systems, and stochastic signals from cosmological origin or unresolved transients. The LIGO gravitational wave detectors have achieved unprecedented sensitivity to gravitational waves, and other detectors around the world are expected to reach similar sensitivities. The LIGO Scientific Collaboration (LSC) has recently completed their most sensitive observation run to date with LIGO and GEO detectors, including several months of joint observations with the European VIRGO detector. The LIGO Laboratory and the LSC, as well as the Virgo Collaboration, are actively preparing for operating enhanced detectors in the very near future. The next decade will see the construction and commissioning of Advanced LIGO and VIRGO, and quite possibly the launch of the space-based LISA mission, starting for sure then, if not earlier, a new era for gravitational wave astronomy. Plans for a world-wide network of ground based detectors involving more detectors in Europe, Japan and Australia are becoming more concrete. The future of gravitational wave astronomy is bright indeed! In this talk, will briefly describe the present status of the ground and space based detector projects and discuss the science we may expect to do with the detectors (and detections!) we will have in the upcoming era of gravitational wave astronomy.

Trace gas detection from fermentation processes in apples; an intercomparison study between proton-transfer-reaction mass spectrometry and laser photoacoustics

NASA Astrophysics Data System (ADS)

Boamfa, E. I.; Steeghs, M. M. L.; Cristescu, S. M.; Harren, F. J. M.

2004-12-01

A custom-built proton-transfer-reaction mass spectrometry (PTR-MS) instrument was used to monitor the emission of various compounds (aldehydes, alcohols, acids, acetates and C-6 compounds) related to fermentation, aroma and flavour, released by four apple cultivars (Elstar, Jonaglod, Granny Smith and Pink Lady) under short anaerobic (24 h) and post-anaerobic conditions. The novel feature of our instrument is the new design of the collisional dissociation chamber, which separates the high pressure in the drift tube (2 mbar) from the high vacuum pressure in the detection region (10-6 mbar). The geometry of this chamber was changed and a second turbo pump was added to reduce the influence of collisional loss of ions, background signals and cluster ions, which facilitates the interpretation of the mass spectra and increases the signal intensity at the mass of the original protonated compound. With this system, detection limits of similar magnitude to the ones reported in literature are reached. An intercomparison study between PTR-MS and a CO laser-based photoacoustic trace gas detector is presented. The alcoholic fermentation products (acetaldehyde and ethanol) from young rice plants were simultaneously monitored by both methods. A very good agreement was observed for acetaldehyde production. The photoacoustic detector showed about two times lower ethanol concentration as compared to PTR-MS, caused by memory effects due to sticking of compounds to the walls of the nylon tube used to transport the trace gases to the detector.

Inclusion of Scatter in HADES: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aufderheide, M B

Covert nuclear attack is one of the foremost threats facing the United States and is a primary focus of the War on Terror. The Domestic Nuclear Detection Office (DNDO), within the Department of Homeland Security (DHS), is chartered to develop, and improve domestic systems to detect and interdict smuggling for the illicit use of a nuclear explosive device, fissile material or radiologica1 material. The CAARS (Cargo Advanced Automated Radiography System) program is a major part of the DHS effort to enhance US security by harnessing cutting-edge technologies to detect radiological and nuclear threats at points of entry to the Unitedmore » States. DNDO has selected vendors to develop complete radiographic systems. It is crucial that the initial design and testing concepts for the systems be validated and compared prior to the substantial efforts to build and deploy prototypes and subsequent large-scale production. An important aspect of these systems is the scatter which interferes with imaging. Monte Carlo codes, such as MCNP (X-5 Monte Carlo Team, 2005 Revision) allow scatter to be calculatied, but these calculations are very time consuming. It would be useful to have a fast scatter estimation algorithm in a fast ray tracing code. We have been extending the HADES ray-tracing radiographic simulation code to model vendor systems in a flexible and quick fashion and to use this tool to study a variety of questions involving system performance and the comparative value of surrogates. To enable this work, HADES has been linked to the BRL-CAD library (BRL-CAD Open Source Project, 2010), in order to enable the inclusion of complex CAD geometries in simulations, scanner geometries have been implemented in HADES, and the novel detector responses have been included in HADES. A major extension of HADES which has been required by this effort is the inclusion of scatter in these radiographic simulations. Ray tracing codes generally do not easily allow the inclusion of scatter, because these codes define a source and a grid of detector pixels and only compute the attenuation along rays between these points. Scatter is an extremely complex set of processes which can involve rays which change directions many times between the source and detector. Scatter from outside the field of view of the imaging system, as well as within the field of view, can have an important role in image formation. In this report, we will describe how we implemented a treatment of scatter in HADES. We begin with a discussion of how we define scatter in Section 2, followed by a description of how single Compton scatter is now included in HADES in Section 3. In Section 4 we report a set of verification tests against MCNP and tests of how the technique scales with image size, number of scatters allowed and number of processors used in the calculations. In Section 5, we describe how we plan to extend this approach to other forms of scatter and conclude in Section 6. It should be emphasized that the purpose of this report is to show that a form of scatter has been implemented in HADES and has been verified against MCNP. Validation, the process of comparing simulation and experiment, is a future task.« less

Optimization of the design of Gas Cherenkov Detectors for ICF diagnosis

NASA Astrophysics Data System (ADS)

Liu, Bin; Hu, Huasi; Han, Hetong; Lv, Huanwen; Li, Lan

2018-07-01

A design method, which combines a genetic algorithm (GA) with Monte-Carlo simulation, is established and applied to two different types of Cherenkov detectors, namely, Gas Cherenkov Detector (GCD) and Gamma Reaction History (GRH). For accelerating the optimization program, open Message Passing Interface (MPI) is used in the Geant4 simulation. Compared with the traditional optical ray-tracing method, the performances of these detectors have been improved with the optimization method. The efficiency for GCD system, with a threshold of 6.3 MeV, is enhanced by ∼20% and time response improved by ∼7.2%. For the GRH system, with threshold of 10 MeV, the efficiency is enhanced by ∼76% in comparison with previously published results.

Gamma signatures of the C-BORD Tagged Neutron Inspection System

NASA Astrophysics Data System (ADS)

Sardet, A.; Pérot, B.; Carasco, C.; Sannié, G.; Moretto, S.; Nebbia, G.; Fontana, C.; Pino, F.; Iovene, A.; Tintori, C.

2018-01-01

In the frame of C-BORD project (H2020 program of the EU), a Rapidly relocatable Tagged Neutron Inspection System (RRTNIS) is being developed to non-intrusively detect explosives, chemical threats, and other illicit goods in cargo containers. Material identification is performed through gamma spectroscopy, using twenty NaI detectors and four LaBr3 detectors, to determine the different elements composing the inspected item from their specific gamma signatures induced by fast neutrons. This is performed using an unfolding algorithm to decompose the energy spectrum of a suspect item, selected by X-ray radiography and on which the RRTNIS inspection is focused, on a database of pure element gamma signatures. This paper reports on simulated signatures for the NaI and LaBr3 detectors, constructed using the MCNP6 code. First experimental spectra of a few elements of interest are also presented.

DSSD detectors development PACT, a new space Compton telescope at the horizon 2025

NASA Astrophysics Data System (ADS)

Laurent, P.; Khalil, M.; Dolgorouki, Y.; Bertoli, W.; Oger, R.; Bréelle, E.

2015-07-01

PACT is a Pair and Compton telescope that aims to make a sensitive survey of the gamma-ray sky between 100 keV and 100 MeV . It will be devoted to the detection of radioactivity lines from present and past supernova explosions, the observation of thousands of new blazars, and the study of polarized radiations from gamma-ray bursts, pulsars and accreting black holes. It will reach a sensitivity of one to two orders of magnitude lower than COMPTEL/CGRO (e.g. about 50 times lower for the broad-band, survey sensitivity at 1 MeV after 5 years). The PACT telescope is based upon three main components: a silicon-based gamma-ray tracker, a crystal-based calorimeter (e.g. CeBr3), and an anticoincidence detector made of plastic scintillator panels. Prototypes of the Silicon detector planes have been optimized and are currently tested in the APC laboratory.

Fluid Interactions with Explosion-Induced Fractures

NASA Astrophysics Data System (ADS)

Swanson, E.; Sussman, A. J.; Wilson, J.; Broome, S.

2016-12-01

Fluids can chemically interact with the fractures they flow through, a process that may affect the movement of fluids in the subsurface. This is a topic of interest to a large variety of research areas, including (but not limited to) production of oil and gas, contaminant tracking, geothermal energy production, CO2 sequestration, and nuclear test monitoring. A study performed as part of the Source Physics Experiment, designed to look at the effects of underground chemical explosions, provides a rare opportunity to compare cores from pre-shot and post-shot rock, from damage created in situ. We present data on the variability of microfracture density with distance from the explosion, as well as the occurrence of fractures that either open or contain clay infill. We find that both open and filled fractures occur more frequently within the post-shot samples (by a factor of up to 4x), with similar spatial distributions. This calls into question the validity of the commonly made assumption that all filled fractures were present prior to the explosive shot, and only open fractures can represent explosion-induced damage. These results suggest that fluid-rock interactions might have a significant influence on the permeabilities that result from explosions, even within a few weeks. Additional data on the mechanical properties of the pre-shot and post-shot core samples show an unexpected pattern during unconfined compressive strength tests: the samples retrieved following 2 successive shots failed at higher stresses than did samples retrieved after 1 shot. We present these results, along with some evidence this behavior may arise from trace differences in water content during testing.

Fiber optic fluid detector

DOEpatents

Angel, S.M.

1987-02-27

Particular gases or liquids are detected with a fiber optic element having a cladding or coating of a material which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses. 10 figs.

SN 1987A - The impact of greater than 50 MeV gamma-ray luminosity limits on theories of particle acceleration

NASA Astrophysics Data System (ADS)

Sood, R. K.; Waldron, L.; Rochester, G. K.; Sumner, T. J.; Frye, G.; Jenkins, T.; Staubert, R.; Kendziorra, E.; Ubertini, P.; Bazzano, A.

1992-08-01

Analysis of the data obtained from two flights of a balloonborne gamma-ray detector to observe SN 1987A was completed. The detector, which included a spark chamber to determine the arrival directions of the photons, was sensitive in the energy range 50-500 MeV. The 95 percent confidence upper limit to the flux on day 55 after the explosion has been established to be 1.1 x 10 exp -5 photons/sq cm/s and on day 407 to be 3.4 x 10 exp -5 photons/sq cm/s. These limits are compared with various theoretical predictions.

Developing the Second Generation of Improvised Explosive Device Detector Dog

DTIC Science & Technology

2013-04-15

improvement, we obtained a consult from Dr. Thierry Olivry, a veterinary dermatologist, who recommended further treatment for bacterial dermatitis ...cefovecin (Convenia) long-acting injectable, 8 mg/kg for two doses, plus medicated baths) but also suggested possibility of atopic dermatitis . After...presumptive diagnosis of atopic dermatitis , we started a novel protein diet trial in April (Iams kangaroo/potato), and most clinical signs were resolved

Seismo-Acoustic Generation by Earthquakes and Explosions and Near-Regional Propagation

DTIC Science & Technology

2009-09-30

earthquakes generate infrasound . Three infrasonic arrays in Utah (BGU, EPU, and NOQ), one in Nevada (NVIAR), and one in Wyoming (PDIAR) recorded...Katz, and C. Hayward (2009b). The F-detector Revisited: An Improved Strategy for Signal Detection at Seismic and Infrasound Arrays , Bull. Seism. Soc...sources. RESEARCH ACCOMPLISHED Infrasound Observations of the Wells Earthquake Most studies documenting earthquake - generated infrasound are based

Optimizing substance detection by integration of canine-human team with machine technology

NASA Astrophysics Data System (ADS)

Prestrude, Al M.; Ternes, J. W.

1994-02-01

There are several promising methods and technologies for substance detection. The oldest of these methods is the trained detector or `sniffer' dog. We summarize what is known about the capabilities of dogs in substance detection and recommend comparative testing of the canine- human team with current technology to identify the optimum combination of methods to maximize the detection of explosives and contraband.

Quantitative carbon detector for enhanced detection of molecules in foods, pharmaceuticals, cosmetics, flavors, and fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beach, Connor A.; Krumm, Christoph; Spanjers, Charles S.

Analysis of trace compounds, such as pesticides and other contaminants, within consumer products, fuels, and the environment requires quantification of increasingly complex mixtures of difficult-to-quantify compounds.

Future Long-Baseline Neutrino Facilities and Detectors

DOE PAGES

Diwan, Milind; Edgecock, Rob; Hasegawa, Takuya; ...

2013-01-01

We review the ongoing effort in the US, Japan, and Europe of the scientific community to study the location and the detector performance of the next-generation long-baseline neutrino facility. For many decades, research on the properties of neutrinos and the use of neutrinos to study the fundamental building blocks of matter has unveiled new, unexpected laws of nature. Results of neutrino experiments have triggered a tremendous amount of development in theory: theories beyond the standard model or at least extensions of it and development of the standard solar model and modeling of supernova explosions as well as the development ofmore » theories to explain the matter-antimatter asymmetry in the universe. Neutrino physics is one of the most dynamic and exciting fields of research in fundamental particle physics and astrophysics. The next-generation neutrino detector will address two aspects: fundamental properties of the neutrino like mass hierarchy, mixing angles, and the CP phase, and low-energy neutrino astronomy with solar, atmospheric, and supernova neutrinos. Such a new detector naturally allows for major improvements in the search for nucleon decay. A next-generation neutrino observatory needs a huge, megaton scale detector which in turn has to be installed in a new, international underground laboratory, capable of hosting such a huge detector.« less

Development of the focal plane system for the SEparator for CApture Reactions

NASA Astrophysics Data System (ADS)

Hood, A. A. D.; Blackmon, J. C.; Cottingham, R.; Deibel, C. M.; Good, E.; Joerres, K.; Laminack, A.; Garrity, A.; Secar Collaboration

2017-09-01

The SEparator for CApture Reactions (SECAR) is currently under construction for the National Superconducting Cyclotron Laboratory and future Facility for Rare Isotope Beams. SECAR is designed to conduct sensitive measurements of capture reactions critical to understanding stellar explosions. We have developed a versatile focal plane system that will differentiate reaction recoils from unreacted scattered beam particles in measurements covering a large range of energies and masses. The elements of the focal plane system include two metal-foil, micro-channel plate (MCP) detectors, a variety of diagnostics, and two alternative recoil stopping detectors. The MCP detectors will measure the time-of-flight (and therefore velocity) as well as the position of the recoils. Our primary heavy ion recoil detector is a gas ionization chamber that measures position, total energy and relative energy loss and provides good atomic number discrimination at energies greater than about 0.5 MeV/u. For some cases, this gas counter will be replaced by silicon strip detectors to provide superior energy resolution. We will describe the overall design and report on construction and testing of the detector systems. Supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Awards DE-SC0014384 and DE-FG02-96ER40978.

High-z Universe with Gamma Ray Bursts

NASA Technical Reports Server (NTRS)

Kouveliotou, C.

2011-01-01

Gamma-Ray Bursts (GRBs) are the most luminous explosions in space and trace the cosmic star formation history back to the first generations of stars. Their bright afterglows allow us to trace the abundances of heavy elements to large distances, thereby measuring cosmic chemical evolution. To date GRBs have been detected up to distances of z=8.23 and possibly even beyond z9. This makes GRBs a unique and powerful tool to probe the high-z Universe up to the re-ionization era. We discuss the current status of the field, place it in context with other probes, and also discuss new mission concepts that have been planned to utilize GRBs as probes.

Collection and Analysis of Ground Truth Infrasound Data in Kazakhstan and Russia

DTIC Science & Technology

2006-05-01

Infrasound signals generated by large mining explosions at Ekibastuz coal mines in Northern Kazakstan have been detected by a 4-element infrasound array ...380 km) and Kokchetav (distance=74 km). Detection of infrasound signals at these distance ranges at mid-latitude (50 degrees N), suggests the... infrasound array , contour plot of beam power and array beam trace .............................. 9 5 Infrasound signals from the

Characterization and source term assessments of radioactive particles from Marshall Islands using non-destructive analytical techniques

NASA Astrophysics Data System (ADS)

Jernström, J.; Eriksson, M.; Simon, R.; Tamborini, G.; Bildstein, O.; Marquez, R. Carlos; Kehl, S. R.; Hamilton, T. F.; Ranebo, Y.; Betti, M.

2006-08-01

Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized by non-destructive analytical and microanalytical methods. Composition and elemental distribution in the particles were studied with synchrotron radiation based micro X-ray fluorescence spectrometry. Scanning electron microscope equipped with energy dispersive X-ray detector and with wavelength dispersive system as well as a secondary ion mass spectrometer were used to examine particle surfaces. Based on the elemental composition the particles were divided into two groups: particles with pure Pu matrix, and particles where the plutonium is included in Si/O-rich matrix being more heterogenously distributed. All of the particles were identified as nuclear fuel fragments of exploded weapon components. As containing plutonium with low 240Pu/ 239Pu atomic ratio, less than 0.065, which corresponds to weapons-grade plutonium or a detonation with low fission yield, the particles were identified to originate from the safety test and low-yield tests conducted in the history of Runit Island. The Si/O-rich particles contained traces of 137Cs ( 239 + 240 Pu/ 137Cs activity ratio higher than 2500), which indicated that a minor fission process occurred during the explosion. The average 241Am/ 239Pu atomic ratio in the six particles was 3.7 × 10 - 3 ± 0.2 × 10 - 3 (February 2006), which indicated that plutonium in the different particles had similar age.

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

NASA Astrophysics Data System (ADS)

Fisher, Mark E.; la Grone, Marcus; Sikes, John

2003-09-01

A sensor (known as Fido) that utilizes amplification of fluorescence quenching as the transduction mechanism for ultra-trace detection of nitroaromatic compounds associated with landmines has been described previously. Previous sensor prototypes utilized a single band of amplifying polymer deployed inside a capillary waveguide to form the sensing element of the detector. A new prototype has been developed that incorporates multiple, discrete bands of different amplifying polymers deployed in a linear array inside the capillary. Vapor-phase samples are introduced into the sensor as a sharp pulse via a gated inlet. As the vapor pulse is swept through the capillary by flow of a carrier gas, the pulse of analyte encounters the bands of polymer sequentially. If the sample contains nitroaromatic explosives, the bands of polymer will respond with a reduction in emission intensity proportional to the mass of analyte in the sample. Because the polymer bands are deployed serially, the analyte pulse does not reach the bands of polymer simultaneously. Hence, a temporal response pattern will be observed as the analyte pulse traverses the length of the capillary. In addition, the intensity of response for each band will vary, producing a ratiometric response. The temporal and ratiometric responses are characteristic of a given analyte, enhancing discrimination of target analytes from potential interferents. This should translate into a reduction in sensor false alarm rates.

Supernova neutrino physics with xenon dark matter detectors: A timely perspective

NASA Astrophysics Data System (ADS)

Lang, Rafael F.; McCabe, Christopher; Reichard, Shayne; Selvi, Marco; Tamborra, Irene

2016-11-01

Dark matter detectors that utilize liquid xenon have now achieved tonne-scale targets, giving them sensitivity to all flavors of supernova neutrinos via coherent elastic neutrino-nucleus scattering. Considering for the first time a realistic detector model, we simulate the expected supernova neutrino signal for different progenitor masses and nuclear equations of state in existing and upcoming dual-phase liquid xenon experiments. We show that the proportional scintillation signal (S2) of a dual-phase detector allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the supernova burst. XENON1T (XENONnT and LZ; DARWIN) experiments will be sensitive to a supernova burst up to 25 (35; 65) kpc from Earth at a significance of more than 5 σ , observing approximately 35 (123; 704) events from a 27 M⊙ supernova progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of all flavors, to constrain the total explosion energy, and to reconstruct the supernova neutrino light curve. Our results suggest that a large xenon detector such as DARWIN will be competitive with dedicated neutrino telescopes, while providing complementary information that is not otherwise accessible.

Initial results from a multi-point mapping observation of thundercloud high-energy radiation in coastal area of Japan sea

NASA Astrophysics Data System (ADS)

Wada, Y.; Enoto, T.; Furuta, Y.; Nakazawa, K.; Yuasa, T.; Okuda, K.; Makishima, K.; Nakano, T.; Umemoto, D.; Tsuchiya, H.

2017-12-01

On-ground detections of Thunderstorm Radiation Bursts (TRB) which mainly consist of bremsstrahlung gamma rays with energy extending up to 20 MeV indicate powerful electron accelerations inside thunderclouds or along lightning discharge paths (e.g. Torii et al., 2002, Tsuchiya et al., 2007, Dwyer et al., 2004). In order to resolve time variation and structure of the electron accelerators, we have constructed a multi-point mapping observation network with the aim of tracing gamma rays from moving thunderclouds since 2015. In fiscal 2016, we developed low cost and small size detectors dedicated to our observation. The data acquisition system records energy and timing of individual gamma-ray photons by 4-ch and 50 MHz sampling electrical boards (9.5 cm x 9.5 cm), coupled with BGO scintillator crystals. The systems were installed in portable water-proof boxes. We operated 10 detectors in two areas (Ishikawa and Niigata) along the coast of Japan Sea from October 2016 to April 2017. During this period, detectors in Ishikawa detected in total 10 TRBs lasting for several minutes associated with passage of a thundercloud. Our previous single-site measurement at Niigata, has recorded 1.4 TRBs per year on average in 2006-2015. Therefore, our new multi-point observation detected 7 times as many events as the previous system. One of the TRB gamma-ray spectra was fitted well by a cutoff power-law model. We performed a Monte Carlo simulation, and revealed that this spectrum was explained as bremsstrahlung of a monochromatic 15 MeV electron beam generated at an altitude of 500 m. We also succeeded in tracing gamma rays from an identical moving thundercloud with two detectors, demonstrating performance of the multi-point observation. In addition, we detected "short TRBs" lasting for a few hundred milliseconds associated with lightning discharges from four independent detectors placed 500 m apart simultaneously, in January and February 2017 at Niigata. The results in 2016-2017 winter season are proving that our multi-point observation can firmly detect a large number of TRBs and trace gamma rays from thunderstorms.

Near-Source Mechanism for Creating Shear Content from Buried Explosions

NASA Astrophysics Data System (ADS)

Steedman, D. W.; Bradley, C. R.

2017-12-01

The Source Physics Experiment (SPE) has the goal of developing a greater understanding of explosion phenomenology at various spatial scales, from near-source to the far-field. SPE Phase I accomplished a series of six chemical explosive tests of varying scaled depth of burial within a borehole in granite. The testbed included an extensive array of triaxial accelerometers. Velocity traces derived from these accelerometers allow for detailed study of the shock environment close in to the explosion. A specific goal of SPE is to identify various mechanisms for generating shear within the propagation environment and how this might be informative on the identification of explosive events that otherwise fail historic compression wave energy/shear wave energy (P/S) event discrimination. One of these sources was hypothesized to derive from slippage along joint sets near to the source. Velocity traces from SPE Phase I events indicate that motion tangential to a theoretically spherical shock wave are initially quiescent after shock arrival. But this period of quiescence is followed by a sudden increase in amplitude that consistently occurs just after the peak of the radial velocity (i.e., onset of shock unloading). The likelihood of occurrence of this response is related to yield-scaled depth-of-burial (SDOB). We describe a mechanism where unloading facilitates dilation of closed joints accompanied by a release of shear energy stored during compression. However, occurrence of this mechanism relies on relative amplitudes between the shock loading caused at a point and the in situ stress: at too large a SDOB the stored energy is insufficient to overcome the combination of the overburden stress and traction on the joint. On the other hand, too small of a SDOB provides that the in situ stress is insufficient to keep joints from storing stress, thus overriding the release mechanism and mitigating rupture-like slippage. We develop a notional relationship between SPE Phase I SDOB and the likelihood of shear release. We then compare this to the six recorded DPRK events in terms of where these events fall in relation to the accepted mb:MS discriminant using estimated SDOB values for those events. To first order SPE SDOBs resulting in shear release appear to map to estimated DPRK SDOBs which display excessive shear magnitude. LA-UR-17-29528.

Trace vapor detection of hydrogen peroxide: An effective approach to identification of improvised explosive devices

NASA Astrophysics Data System (ADS)

Xu, Miao

Vapor detection has been proven as one of the practical, noninvasive methods suitable for explosives detection among current explosive detection technologies. Optical methods (especially colorimetric and fluorescence spectral methods) are low in cost, provide simple instrumentation alignment, while still maintaining high sensitivity and selectivity, these factors combined facilitate broad field applications. Trace vapor detection of hydrogen peroxide (H2O2) represents an effective approach to noninvasive detection of peroxide-based explosives, though development of such a sensor system with high reliability and sufficient sensitivity (reactivity) still remains challenging. Three vapor sensor systems for H2O2 were proposed and developed in this study, which exploited specific chemical reaction towards H2O2 to ensure the selectivity, and materials surface engineering to afford efficient air sampling. The combination of these features enables expedient, cost effective, reliable detection of peroxide explosives. First, an expedient colorimetric sensor for H2O2 vapor was developed, which utilized the specific interaction between Ti(oxo) and H2O2 to offer a yellow color development. The Ti(oxo) salt can be blended into a cellulose microfibril network to produce tunable interface that can react with H2O2. The vapor detection limit can reach 400 ppb. To further improve the detection sensitivity, a naphthalimide based fluorescence turn-on sensor was designed and developed. The sensor mechanism was based on H2O2-mediated oxidation of a boronate fluorophore, which is nonfluorescent in ICT band, but becomes strongly fluorescent upon conversion into the phenol state. The detection limit of this sensory material was improved to be below 10 ppb. However, some technical factors such as sensor concentration, local environment, and excitation intensity were found difficult to control to make the sensor system sufficiently reproducible. To solve the problem, we developed a ratiometric fluorescence sensor, which allows for dual-band emission monitoring and thus enhances the detection reliability. Moreover, the significant spectral overlap between the fluorescence of the pristine sensor and the absorption of the reacted state enables effective Foster Resonance Energy Transfer (FRET). This FRET process can significantly enhance the fluorescence sensing efficiency in comparison to the normal single-band sensor system, for which the sensing efficiency is solely determined by the stoichiometric conversion of sensor molecules.

Biomimetic Sniffing with an Artificial Dogs Nose Leads to Improvements in VaporSampling and Detection

DTIC Science & Technology

2016-07-25

and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD Abstract Unlike current chemical trace detection technology, dogs...mm vertically from the flat surface. The vapor source consisted of a 10 mm diameter and 10 mm tall can with approximately 10 g of gelatin with 0.1...Fabrication and characterization of gelatin -based test materials for verification of trace contraband vapor detectors. Analyst 135, 2573-2578 (2010

(U) Second-Order Sensitivity Analysis of Uncollided Particle Contributions to Radiation Detector Responses Using Ray-Tracing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Favorite, Jeffrey A.

The Second-Level Adjoint Sensitivity System (2nd-LASS) that yields the second-order sensitivities of a response of uncollided particles with respect to isotope densities, cross sections, and source emission rates is derived in Refs. 1 and 2. In Ref. 2, we solved problems for the uncollided leakage from a homogeneous sphere and a multiregion cylinder using the PARTISN multigroup discrete-ordinates code. In this memo, we derive solutions of the 2nd-LASS for the particular case when the response is a flux or partial current density computed at a single point on the boundary, and the inner products are computed using ray-tracing. Both themore » PARTISN approach and the ray-tracing approach are implemented in a computer code, SENSPG. The next section of this report presents the equations of the 1st- and 2nd-LASS for uncollided particles and the first- and second-order sensitivities that use the solutions of the 1st- and 2nd-LASS. Section III presents solutions of the 1st- and 2nd-LASS equations for the case of ray-tracing from a detector point. Section IV presents specific solutions of the 2nd-LASS and derives the ray-trace form of the inner products needed for second-order sensitivities. Numerical results for the total leakage from a homogeneous sphere are presented in Sec. V and for the leakage from one side of a two-region slab in Sec. VI. Section VII is a summary and conclusions.« less

Gamma ray spectroscopy employing divalent europium-doped alkaline earth halides and digital readout for accurate histogramming

DOEpatents

Cherepy, Nerine Jane; Payne, Stephen Anthony; Drury, Owen B; Sturm, Benjamin W

2014-11-11

A scintillator radiation detector system according to one embodiment includes a scintillator; and a processing device for processing pulse traces corresponding to light pulses from the scintillator, wherein pulse digitization is used to improve energy resolution of the system. A scintillator radiation detector system according to another embodiment includes a processing device for fitting digitized scintillation waveforms to an algorithm based on identifying rise and decay times and performing a direct integration of fit parameters. A method according to yet another embodiment includes processing pulse traces corresponding to light pulses from a scintillator, wherein pulse digitization is used to improve energy resolution of the system. A method in a further embodiment includes fitting digitized scintillation waveforms to an algorithm based on identifying rise and decay times; and performing a direct integration of fit parameters. Additional systems and methods are also presented.

A three-dimensional spacecraft-charging computer code

NASA Technical Reports Server (NTRS)

Rubin, A. G.; Katz, I.; Mandell, M.; Schnuelle, G.; Steen, P.; Parks, D.; Cassidy, J.; Roche, J.

1980-01-01

A computer code is described which simulates the interaction of the space environment with a satellite at geosynchronous altitude. Employing finite elements, a three-dimensional satellite model has been constructed with more than 1000 surface cells and 15 different surface materials. Free space around the satellite is modeled by nesting grids within grids. Applications of this NASA Spacecraft Charging Analyzer Program (NASCAP) code to the study of a satellite photosheath and the differential charging of the SCATHA (satellite charging at high altitudes) satellite in eclipse and in sunlight are discussed. In order to understand detector response when the satellite is charged, the code is used to trace the trajectories of particles reaching the SCATHA detectors. Particle trajectories from positive and negative emitters on SCATHA also are traced to determine the location of returning particles, to estimate the escaping flux, and to simulate active control of satellite potentials.

Next generation fire suppressants

NASA Technical Reports Server (NTRS)

Brown, Jerry A.

1995-01-01

Spectrex, Inc., located in Cedar Grove, NJ is a manufacturer of fire detection and suppression equipment. Spectrex is one of the original pioneers in high speed fire detection and suppression systems for combat vehicles. Spectrex has installed fire suppressions systems in thousands of combat vehicles and ships throughout the world. Additionally, they manufacture flame explosion detectors, ship damage control systems, and optical gas and vapor detectors. The culmination of several years of research and development has recently produced an innovative electro-optical continuous monitoring systems called SharpEye 20/20I IR(sup 3) and SAFEYE that provide fast and reliable gas, vapor, aerosol, flame, and explosion detection. SharpEye 20/20I IR(sup 3) is a self-contained triple spectrum flame detector which scans for oscillating IR radiation (1 to 10 Hz) in the spectral bands ranging from 4.0 to 5.0 microns and uses programmed algorithms to check the ratio and correlation of data received by the three sensors to make the system highly immune to false alarms. It is extremely sensitive as it can detect a 1 x 1 square foot gasoline pan fire at 200 feet in less than 3 seconds. The sensitivity is user programmable, offering 4 ranges of detection. SAFEYE is comprised of a selected number of multispectral ban microprocessors controlled detectors which are in communication with one or more radiation sources that is projected along a 600 feet optical path. The signals from the selected narrow bands are processed and analyzed by highly sophisticated algorithms. It is ideal for high risk, remote, large areas such as petroleum and chemical manufacturing sites, waste dumps, aircraft cargo bays, and ship compartments. The SAFEYE will perform direct readings of the presence or rate of rise of concentrations of gases, vapors, or aerosols at the range of parts per million and provide alarms at various set points at different levels of concentrations.

Astigmatism correction of a non-imaging double spectrometer fitted with a 2D array detector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yaney, P.P.; Ernst, S.L.; Blackshire, J.

1992-12-01

A SPEX 1401 double spectrometer was adapted for a liquid nitrogen cooled CCD detector to permit both spectral and spatial analysis of ceramic specimens in a laser Raman microprobe system. The exit image of the spectrometer suffers from astigmatism due to off-axis spherical mirrors. A cylindrical lens was added before the CCD to correct for the astigmatism. The spectrometer and several lenses were modeled using an optical ray tracing program to characterize the astigmatism and to optimize the locations of the lens and the detector. The astigmatism and the spot pattern sizes determined by the model were in good agreementmore » with he observed performance of the modified spectrometer-detector system. Typical spot patterns fell within the 23 {mu}m square pixel size.« less

Photon and neutron interrogation techniques for chemical explosives detection in air cargo: A critical review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Runkle, Robert C.; White, Timothy A.; Miller, Erin A.

Scanning cargo transported via aircraft ("air cargo") for explosive threats is a problem that, at present, lacks a comprehensive technical solution. While explosives detection in the baggage-scanning domain has a rich history that sheds light on potential solutions for air cargo, baggage scanning differs in several ways and thus one cannot look to the present array of technologies. Some contemporary solutions, like trace analysis, are not readily applied to cargo due to sampling challenges while the larger geometry of air cargo makes others less effective. This review article examines an array of interrogation techniques using photons and neutrons as incidentmore » particles. We first present a summary of the signatures and observables explosives provide and review how they have been exploited in baggage scanning. Following this is a description of the challenges posed by the air cargo application space. After considering interrogation sources, methods focused on transmission imaging, sub-surface examination and elemental characterization are described. It is our goal to shed light on the technical promise of each method while largely deferring questions that revolve around footprint, safety and conduct of operations. Our overarching intent is that a comprehensive understanding of potential techniques will foster development of a comprehensive solution.« less

An explosion of a CNG fuel vessel in an urban bus.

PubMed

Park, Chan-Seong; Jeon, Seung-Won; Moon, Jung-Eun; Lee, Kyu-Jung

2010-03-01

An investigation is presented of the explosion of a CNG (compressed natural gas) fuel vessel, called a liner, in an urban bus. The explosion happened at a gas station 10 min after filling was completed. There were no traces of soot and flames at the failed liner, which would be indicative of explosion by ignition of the gas. The filling process of the station was automatically monitored and recorded in a computer. There was no unusual record of the filling system that indicated excess pressure at the time of the accident. There were cracks on the liner that were initiated at the outer surface of the cylindrical shell located at a point 4 cm above the lower dome where cracks did not originate easily as a result of overload. Chemical analysis was performed on a specimen that was cut from the liner, and there was no peculiarity in the mix. Mechanical analysis was performed on the specimens and showed that the hardness was not in the specified range because of inadequate heat treatment of the metal. The hardness of the liner was strictly controlled in the manufacturing process. All the liners that were manufactured at the same period with the failed liner were recalled for examination.

Advanced recognition of explosives in traces on polymer surfaces using LIBS and supervised learning classifiers.

PubMed

Serrano, Jorge; Moros, Javier; Sánchez, Carlos; Macías, Jorge; Laserna, J Javier

2014-01-02

The large similarity existing in the spectral emissions collected from organic compounds by laser-induced breakdown spectroscopy (LIBS) is a limiting factor for the use of this technology in the real world. Specifically, among the most ambitious challenges of today's LIBS involves the recognition of an organic residue when neglected on the surface of an object of identical nature. Under these circumstances, the development of an efficient algorithm to disclose the minute differences within this highly complex spectral information is crucial for a realistic application of LIBS in countering explosive threats. An approach cemented on scatter plots of characteristic emission features has been developed to identify organic explosives when located on polymeric surfaces (teflon, nylon and polyethylene). By using selected spectral variables, the approach allows to design a concise classifier for alerting when one of four explosives (DNT, TNT, RDX and PETN) is present on the surface of the polymer. Ordinary products (butter, fuel oil, hand cream, olive oil and motor oil) cause no confusion in the decisions taken by the classifier. With rates of false negatives and false positives below 5%, results demonstrate that the classification algorithm enables to label residues according to their harmful nature in the most demanding scenario for a LIBS sensor. Copyright © 2013 Elsevier B.V. All rights reserved.

Time dependent 14 MeV neutrons measurement using a polycrystalline chemical vapor deposited diamond detector at the JET tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angelone, M.; Pillon, M.; Bertalot, L.

A polycrystalline chemical vapor deposited (CVD) diamond detector was installed on a JET tokamak in order to monitor the time dependent 14 MeV neutron emission produced by D-T plasma pulses during the Trace Tritium Experiment (TTE) performed in October 2003. This was the first tentative ever attempted to use a CVD diamond detector as neutron monitor in a tokamak environment. Despite its small active volume, the detector was able to detect the 14 MeV neutron emission (>1.0x10{sup 15} n/shot) with good reliability and stability during the experimental campaign that lasted five weeks. The comparison with standard silicon detectors presently usedmore » at JET as 14 MeV neutron monitors is reported, showing excellent correlation between the measurements. The results prove that CVD diamond detectors can be reliably used in a tokamak environment and therefore confirm the potential of this technology for next step machines like ITER.« less

Measurement of Trace Constituents by Electron-Excited X-Ray Microanalysis with Energy-Dispersive Spectrometry.

PubMed

Newbury, Dale E; Ritchie, Nicholas W M

2016-06-01

Electron-excited X-ray microanalysis performed with scanning electron microscopy and energy-dispersive spectrometry (EDS) has been used to measure trace elemental constituents of complex multielement materials, where "trace" refers to constituents present at concentrations below 0.01 (mass fraction). High count spectra measured with silicon drift detector EDS were quantified using the standards/matrix correction protocol embedded in the NIST DTSA-II software engine. Robust quantitative analytical results for trace constituents were obtained from concentrations as low as 0.000500 (mass fraction), even in the presence of significant peak interferences from minor (concentration 0.01≤C≤0.1) and major (C>0.1) constituents. Limits of detection as low as 0.000200 were achieved in the absence of peak interference.

Mapping of explosive contamination using GC/chemiluminescence and ion mobility spectrometry techniques

NASA Astrophysics Data System (ADS)

Miller, Carla J.; Glenn, D. F.; Hartenstein, Steven D.; Hallowell, Susan F.

1998-12-01

Recent efforts at the Idaho National Engineering and Environmental Laboratory (INEEL) have included mapping explosive contamination resulting from manufacturing and carrying improvised explosive devices (IEDs). Two types of trace detection equipment were used to determine levels of contamination from designated sampling areas. A total of twenty IEDs were constructed: ten using TNT and ten using C-4. Two test scenarios were used. The first scenario tracked the activities of a manufacturer who straps the device onto an independent courier. The courier then performed a series of activities to simulate waiting in an airport. The second scenario tracked the activities of a manufacturer who also served as the courier. A sample set for each test consisted of thirty samples from various locations on each IED manufacturer, thirty from each IED courier, twenty-five from the manufacturing area, and twenty-five from the courier area. Pre-samples and post-samples were collected for analysis with each detection technique. Samples analyzed by gc/chemiluminescence were taken by swiping a teflon- coated sampling swipe across the surface of the sampling area to pick up any explosive particles. Samples analyzed by ion mobility spectrometry (IMS) were taken from the clothing of the manufacturer and courier by vacuuming the surface and collecting particulates on a fiberglass filter. Samples for IMS analysis from the manufacturing and courier rooms were taken by wiping a cotton sampling swipe across the surface area. Currently, building IEDs and monitoring the explosive contamination is being directed toward detection with portal monitors.

Fabrication of a self-assembled and flexible SERS nanosensor for explosive detection at parts-per-quadrillion levels from fingerprints.

PubMed

Liyanage, Thakshila; Rael, Ashur; Shaffer, Sidney; Zaidi, Shozaf; Goodpaster, John V; Sardar, Rajesh

2018-04-30

Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film. Our SERS nanosensor provides excellent SERS activity (enhancement factor = ∼6.0 × 106) and limit of detection (as low as 56 parts-per-quadrillions) with high selectivity by chemometric analyses among three commonly military high explosives (TNT, RDX, and PETN). Furthermore, the SERS nanosensors present excellent reproducibility (<4.0% relative standard deviation at 1.0 μM concentration) and unprecedentedly high stability with a "shelf life" of at least 5 months. Finally, TNT and PETN were analyzed and quantified by transferring solid explosive residues from fingerprints left on solid surfaces to the SERS nanosensor. Taken together, the demonstrated sensitivity, selectivity, and reliability of the measurements as well as with the excellent shelf life of our SERS nanosensors obviate the need for complicated sample processing steps required for other analytical techniques, and thus these nanosensors have tremendous potential not only in the field of measurement science but also for homeland security applications to combat acts of terror and military threats.

Imaging standoff detection of explosives using widely tunable midinfrared quantum cascade lasers

NASA Astrophysics Data System (ADS)

Fuchs, Frank; Hugger, Stefan; Kinzer, Michel; Aidam, Rolf; Bronner, Wolfgang; Lösch, Rainer; Yang, Quankui; Degreif, Kai; Schnürer, Frank

2010-11-01

The use of a tunable midinfrared external cavity quantum cascade laser for the standoff detection of explosives at medium distances between 2 and 5 m is presented. For the collection of the diffusely backscattered light, a high-performance infrared imager was used. Illumination and wavelength tuning of the laser source was synchronized with the image acquisition, establishing a hyperspectral data cube. Sampling of the backscattered radiation from the test samples was performed in a noncooperative geometry at angles of incidence far away from specular reflection. We show sensitive detection of traces of trinitrotoluene and pentaerythritol tetranitrate on real-world materials, such as standard car paint, polyacrylics from backpacks, and jeans fabric. Concentrations corresponding to fingerprints were detected, while concepts for false alarm suppression due to cross-contaminations were presented.

Laser-induced plasma chemistry of the explosive RDX with various metallic nanoparticles.

PubMed

Gottfried, Jennifer L

2012-03-01

The feasibility of exploiting plasma chemistry to study the chemical reactions between metallic nanoparticles and molecular explosives such as cyclotrimethylenetrinitramine (RDX) has been demonstrated. This method, based on laser-induced breakdown spectroscopy, involves the production of nanoparticles in a laser-induced plasma and the simultaneous observation of time-resolved atomic and molecular emission characteristic of the species involved in the intermediate chemical reactions of the nanoenergetic material in the plasma. Using this method, it has been confirmed that the presence of aluminum promotes the ejection process of carbon from the intermediate products of RDX. The time evolution of species formation, the effects of laser pulse energy, and the effects of trace metal content on the chemical reactions were also studied. © 2012 Optical Society of America

Eye-safe UV Raman spectroscopy for remote detection of explosives and their precursors in fingerprint concentration

NASA Astrophysics Data System (ADS)

Almaviva, S.; Angelini, F.; Chirico, R.; Palucci, A.; Nuvoli, M.; Schnuerer, F.; Schweikert, W.; Romolo, F. S.

2014-10-01

We report the results of Raman investigation performed at stand-off distance between 6-10 m with a new apparatus, capable to detect traces of explosives with surface concentrations similar to those of a single fingerprint. The device was developed as part of the RADEX prototype (RAman Detection of EXplosives) and is capable of detecting the Raman signal with a single laser shot of few ns (10-9 s) in the UV range (wavelength 266 nm), in conditions of safety for the human eye. This is because the maximum permissible exposure (MPE) for the human eye is established to be 3 mJ/cm2 in this wavelength region and pulse duration. Samples of explosives (PETN, TNT, Urea Nitrate, Ammonium Nitrate) were prepared starting from solutions deposited on samples of common fabrics or clothing materials such as blue jeans, leather, polyester or polyamide. The deposition process takes place via a piezoelectric-controlled plotter device, capable of producing drops of welldefined volume, down to nanoliters, on a surface of several cm2, in order to carefully control the amount of explosive released to the tissue and thus simulate a slight stain on a garment of a potential terrorist. Depending on the type of explosive sampled, the detected density ranges from 0.1 to 1 mg/cm2 and is comparable to the density measured in a spot on a dress or a bag due to the contact with hands contaminated with explosives, as it could happen in the preparation of an improvised explosive device (IED) by a terrorist. To our knowledge the developed device is at the highest detection limits nowadays achievable in the field of eyesafe, stand-off Raman instruments. The signals obtained show some vibrational bands of the Raman spectra of our samples with high signal-to-noise ratio (SNR), allowing us to identify with high sensitivity (high number of True Positives) and selectivity (low number of False Positives) the explosives, so that the instrument could represent the basis for an automated and remote monitoring device.

Improving Infrasound Signal Detection and Event Location in the Western US Using Atmospheric Modeling

NASA Astrophysics Data System (ADS)

Dannemann, F. K.; Park, J.; Marcillo, O. E.; Blom, P. S.; Stump, B. W.; Hayward, C.

2016-12-01

Data from five infrasound arrays in the western US jointly operated by University of Utah Seismograph Station and Southern Methodist University are used to test a database-centric processing pipeline, InfraPy, for automated event detection, association and location. Infrasonic array data from a one-year time period (January 1 2012 to December 31 2012) are used. This study focuses on the identification and location of 53 ground-truth verified events produced from near surface military explosions at the Utah Test and Training Range (UTTR). Signals are detected using an adaptive F-detector, which accounts for correlated and uncorrelated time-varying noise in order to reduce false detections due to the presence of coherent noise. Variations in detection azimuth and correlation are found to be consistent with seasonal changes in atmospheric winds. The Bayesian infrasonic source location (BISL) method is used to produce source location and time credibility contours based on posterior probability density functions. Updates to the previous BISL methodology include the application of celerity range and azimuth deviation distributions in order to accurately account for the spatial and temporal variability of infrasound propagation through the atmosphere. These priors are estimated by ray tracing through Ground-to-Space (G2S) atmospheric models as a function of season and time of day using historic atmospheric characterizations from 2007 to 2013. Out of the 53 events, 31 are successfully located using the InfraPy pipeline. Confidence contour areas for maximum a posteriori event locations produce error estimates which are reduced a maximum of 98% and an average of 25% from location estimates utilizing a simple time independent uniform atmosphere. We compare real-time ray tracing results with the statistical atmospheric priors used in this study to examine large time differences between known origin times and estimated origin times that might be due to the misidentification of infrasonic phases. This work provides an opportunity to improve atmospheric model predictions by understanding atmospheric variability at a station-level.

Interaction of Electron Neutrinos with {sup 56}Fe in the LSD for E{sub {nu}{sub e}} {<=} 50 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaponov, Yu.V.; Ryazhskaya, O.G.; Semenov, S.V.

The neutrino pulses detected by the LSD (Liquid Scintillator Detector) on February 23, 1987, are analyzed on the basis of a two-stage model of supernova explosion. The number of events due to the electron-neutrino interaction with {sup 56}Fe in the LSD is calculated. The obtained number of signals is in agreement with experimental data.

Detectability of galactic supernova neutrinos coherently scattered on xenon nuclei in XMASS

NASA Astrophysics Data System (ADS)

Abe, K.; Hiraide, K.; Ichimura, K.; Kishimoto, Y.; Kobayashi, K.; Kobayashi, M.; Moriyama, S.; Nakagawa, K.; Nakahata, M.; Norita, T.; Ogawa, H.; Sekiya, H.; Takachio, O.; Takeda, A.; Yamashita, M.; Yang, B. S.; Kim, N. Y.; Kim, Y. D.; Tasaka, S.; Liu, J.; Martens, K.; Suzuki, Y.; Fujita, R.; Hosokawa, K.; Miuchi, K.; Oka, N.; Onishi, Y.; Takeuchi, Y.; Kim, Y. H.; Lee, J. S.; Lee, K. B.; Lee, M. K.; Fukuda, Y.; Itow, Y.; Kegasa, R.; Kobayashi, K.; Masuda, K.; Takiya, H.; Uchida, H.; Nishijima, K.; Fujii, K.; Murayama, I.; Nakamura, S.; Xmass Collaboration

2017-03-01

The coherent elastic neutrino-nucleus scattering (CEvNS) plays a crucial role at the final evolution of stars. The detection of it would be of importance in astroparticle physics. Among all available neutrino sources, galactic supernovae give the highest neutrino flux in the MeV range. Among all liquid xenon dark matter experiments, XMASS has the largest sensitive volume and light yield. The possibility to detect galactic supernova via the CEvNS-process on xenon nuclei in the current XMASS detector was investigated. The total number of events integrated in about 18 s after the explosion of a supernova 10 kpc away from the Earth was expected to be from 3.5 to 21.1, depending on the supernova model used to predict the neutrino flux, while the number of background events in the same time window was measured to be negligible. All lead to very high possibility to detect CEvNS experimentally for the first time utilizing the combination of galactic supernovae and the XMASS detector. In case of a supernova explosion as close as Betelgeuse, the total observable events can be more than ∼ 104, making it possible to distinguish different supernova models by examining the evolution of neutrino event rate in XMASS.

Background Equatorial Astronomical Measurements Focal Plane Assembly (Refurbished HI STAR SOUTH)

DTIC Science & Technology

1984-09-01

Subassembly RPT41412 MOSFETs during assembly and test. The old and new designs are shown in Fig- ure 7. The copper webs between the first and second and...machined in the remaining webs be- tween the detector recesses and through a small hole drilled through the frame to connect the traces of all four...gold wirebond routed through a notch machined in the frame web between one of the detector recesses and the board recess. The sap- phire support

Evolution of Trace Gases and Particles Emitted by a Chaparral Fire in California

DTIC Science & Technology

2012-02-07

length of 78 m and was then focused onto an MCT detector . The cell exchange time was about ten seconds when the flow con- trol valves were open and IR...through a 1064 nm Nd:YAG laser cavity where light scattered by the particles was measured by two avalanche photodiode detectors . Sufficiently light...collected with higher signal-to- noise . Smoke samples collected more than 1.8 km from the source showed signs of aging (O3 for- mation) and were not

Characterization of Nitrated Sugar Alcohols by Atmospheric-Pressure Chemical-Ionization Mass Spectrometry

DTIC Science & Technology

2016-07-27

disclosed here will benefit the area of explosives trace detection for counterterrorism and forensics . INTRODUCTION The military-grade...plasticizer formulation.[4] As a result, methods to detect MHN, SHN, and XPN should be pursued for the same security and forensics applications as...with ion mobility mass spectrometry (IMS) provide direct detection of molecular ions,[8] and thus are preferred for most security and forensic

MIT Lincoln Laboratory Annual Report 2009

DTIC Science & Technology

2009-01-01

unclassified c. THIS PAGE unclassified Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 MIt lincoln laboratory Massachusetts Institute...Climate-change monitoring that will be conducted by assessing the utility of using very-long-wave infrared radiation for space-based sensing and by... radiation to detect trace explosives on a person’s hair were investigated. An ultrasensitive THz receiver leverages mature technology at the near-infrared

Novel Concept of Frequency-Combs Interferometric Spectroscopy in the Mid-IR for Significantly Enhanced Detection of Explosives

DTIC Science & Technology

2015-12-01

frequency combs. Ultrasensitive detection of methane, isotopic carbon dioxide, carbon monoxide, formaldehyde, acetylene, and ethylene was performed in...rmaldehyde, acetylene, and ethylene was perfo rmed in the spectral range 2.5- 5 11111 using intracav ity spectroscopy in broadband optical parametric osc...trace point detection of methane, carbon dioxide, isotopic (13C02) carbon dioxide, carbon monoxide, ethylene , acetylene, and formaldehyde and

Entrepreneurship Studies--An Ascending Academic Discipline in the Twenty-First Century. Entrepreneurial Studies in Higher Education

ERIC Educational Resources Information Center

Volkmann, Christine

2004-01-01

Entrepreneurship is relatively new as a subject of formal study in universities. Its teaching can be traced back to 1947. Since then, the subject has caught on, and in the 1980s and 1990s, there was a veritable explosion in such offerings at universities in the United States. The subject came to Europe rather late, but here, too, courses and…

Improved detection of highly energetic materials traces on surfaces by standoff laser-induced thermal emission incorporating neural networks

NASA Astrophysics Data System (ADS)

Figueroa-Navedo, Amanda; Galán-Freyle, Nataly Y.; Pacheco-Londoño, Leonardo C.; Hernández-Rivera, Samuel P.

2013-05-01

Terrorists conceal highly energetic materials (HEM) as Improvised Explosive Devices (IED) in various types of materials such as PVC, wood, Teflon, aluminum, acrylic, carton and rubber to disguise them from detection equipment used by military and security agency personnel. Infrared emissions (IREs) of substrates, with and without HEM, were measured to generate models for detection and discrimination. Multivariable analysis techniques such as principal component analysis (PCA), soft independent modeling by class analogy (SIMCA), partial least squares-discriminant analysis (PLS-DA), support vector machine (SVM) and neural networks (NN) were employed to generate models, in which the emission of IR light from heated samples was stimulated using a CO2 laser giving rise to laser induced thermal emission (LITE) of HEMs. Traces of a specific target threat chemical explosive: PETN in surface concentrations of 10 to 300 ug/cm2 were studied on the surfaces mentioned. Custom built experimental setup used a CO2 laser as a heating source positioned with a telescope, where a minimal loss in reflective optics was reported, for the Mid-IR at a distance of 4 m and 32 scans at 10 s. SVM-DA resulted in the best statistical technique for a discrimination performance of 97%. PLS-DA accurately predicted over 94% and NN 88%.

Potential for portal detection of human chemical and biological contamination

NASA Astrophysics Data System (ADS)

Settles, Gary S.; McGann, William J.

2001-08-01

The walk-through metal-detection portal is a paradigm of non-intrusive passenger screening in aviation security. Modern explosive detection portals based on this paradigm will soon appear in airports. This paper suggests that the airborne trace detection technology developed for that purpose can also be adapted to human chemical and biological contamination. The waste heat of the human body produces a rising warm-air sheath of 50-80 liters/sec known as the human thermal plume. Contained within this plume are hundreds of bioeffluents from perspiration and breath, and millions of skin flakes. Since early medicine, the airborne human scent was used in the diagnosis of disease. Recent examples also include toxicity and substance abuse, but this approach has never been quantified. The appearance of new bioeffluents or subtle changes in the steady-state may signal the onset of a chemical/biological attack. Portal sampling of the human thermal plume is suggested, followed by a pre-concentration step and the detection of the attacking agent or the early human response. The ability to detect nanogram levels of explosive trace contamination this way was already demonstrated. Key advantages of the portal approach are its rapidity and non-intrusiveness, and the advantage that it does not require the traditional bodily fluid or tissue sampling.

Coherent anti-stokes Raman spectroscopy for detecting explosives in real time

NASA Astrophysics Data System (ADS)

Dogariu, Arthur; Pidwerbetsky, Alex

2012-06-01

We demonstrate real-time stand-off detection and imaging of trace explosives using collinear, backscattered Coherent Anti-Stokes Raman Spectroscopy (CARS). Using a hybrid time-resolved broad-band CARS we identify nanograms of explosives on the millisecond time scale. The broad-band excitation in the near-mid-infrared region excites the vibrational modes in the fingerprint region, and the time-delayed probe beam ensures the reduction of any non-resonant contributions to the CARS signal. The strong coherent enhancement allows for recording Raman spectra in real-time. We demonstrate stand-off detection by acquiring, analyzing, and identifying vibrational fingerprints in real-time with very high sensitivity and selectivity. By extending the focused region from a 100-micron sized spot to a 5mm long line we can obtain the spectral information from an extended region of the remote target with high spatial resolution. We demonstrate fast hyperspectral imaging by one-dimensional scanning of the Line-CARS. The three-dimensional data structure contains the vibrational spectra of the target at each sampled location, which allows for chemical mapping of the remote target.

Threat detection of liquid explosives and precursors from their x-ray scattering pattern using energy dispersive detector technology

NASA Astrophysics Data System (ADS)

Kehres, Jan; Lyksborg, Mark; Olsen, Ulrik L.

2017-09-01

Energy dispersive X-ray diffraction (EDXRD) can be applied for identification of liquid threats in luggage scanning in security applications. To define the instrumental design, the framework for data reduction and analysis and test the performance of the threat detection in various scenarios, a flexible laboratory EDXRD test setup was build. A data set of overall 570 EDXRD spectra has been acquired for training and testing of threat identification algorithms. The EDXRD data was acquired with limited count statistics and at multiple detector angles and merged after correction and normalization. Initial testing of the threat detection algorithms with this data set indicate the feasibility of detection levels of > 95 % true positive with < 6 % false positive alarms.

Frequency selective detection of nuclear quadrupole resonance (NQR) spin echoes

NASA Astrophysics Data System (ADS)

Somasundaram, Samuel D.; Jakobsson, Andreas; Smith, John A. S.; Althoefer, Kaspar A.

2006-05-01

Nuclear Quadrupole Resonance (NQR) is a radio frequency (RF) technique that can be used to detect the presence of quadrupolar nuclei, such as the 14N nucleus prevalent in many explosives and narcotics. The technique has been hampered by low signal-to-noise ratios and is further aggravated by the presence of RF interference (RFI). To ensure accurate detection, proposed detectors should exploit the rich form of the NQR signal. Furthermore, the detectors should also be robust to any remaining residual interference, left after suitable RFI mitigation has been employed. In this paper, we propose a new NQR data model, particularly for the realistic case where multiple pulse sequences are used to generate trains of spin echoes. Furthermore, we refine two recently proposed approximative maximum likelihood (AML) detectors, enabling the algorithm to optimally exploit the data model of the entire echo train and also incorporate knowledge of the temperature dependent spin-echo decay time. The AML-based detectors ensure accurate detection and robustness against residual RFI, even when the temperature of the sample is not precisely known, by exploiting the dependencies of the NQR resonant lines on temperature. Further robustness against residual interference is gained as the proposed detector is frequency selective; exploiting only those regions of the spectrum where the NQR signal is expected. Extensive numerical evaluations based on both simulated and measured NQR data indicate that the proposed Frequency selective Echo Train AML (FETAML) detector offers a significant improvement as compared to other existing detectors.

Study of run time errors of the ATLAS pixel detector in the 2012 data taking period

NASA Astrophysics Data System (ADS)

Gandrajula, Reddy Pratap

The high resolution silicon Pixel detector is critical in event vertex reconstruction and in particle track reconstruction in the ATLAS detector. During the pixel data taking operation, some modules (Silicon Pixel sensor +Front End Chip+ Module Control Chip (MCC)) go to an auto-disable state, where the Modules don't send the data for storage. Modules become operational again after reconfiguration. The source of the problem is not fully understood. One possible source of the problem is traced to the occurrence of single event upset (SEU) in the MCC. Such a module goes to either a Timeout or Busy state. This report is the study of different types and rates of errors occurring in the Pixel data taking operation. Also, the study includes the error rate dependency on Pixel detector geometry.

Proceedings of the First International Symposium on Explosive Detection Technology

DTIC Science & Technology

1992-05-01

of these per unit volume is C, = 2.0 ct /cm 3/sec. For the 10 metals make the activity concentration significantly seconds that the bag is in the...Hopfield Network CI Chemical Ionization CL Chemiluminescence CLD Chemiluminescence Detector CPU Central Processing Unit CT Computed Tomography CW...NOTICE This document is disseminated under the sponsorship of the U.S. Department of Transportation in the Interest of Information exchange. The United

Ion mobility spectrometry for food quality and safety.

PubMed

Vautz, W; Zimmermann, D; Hartmann, M; Baumbach, J I; Nolte, J; Jung, J

2006-11-01

Ion mobility spectrometry is known to be a fast and sensitive technique for the detection of trace substances, and it is increasingly in demand not only for protection against explosives and chemical warfare agents, but also for new applications in medical diagnosis or process control. Generally, a gas phase sample is ionized by help of ultraviolet light, ss-radiation or partial discharges. The ions move in a weak electrical field towards a detector. During their drift they collide with a drift gas flowing in the opposite direction and, therefore, are slowed down depending on their size, shape and charge. As a result, different ions reach the detector at different drift times, which are characteristic for the ions considered. The number of ions reaching the detector are a measure of the concentration of the analyte. The method enables the identification and quantification of analytes with high sensitivity (ng l(-1) range). The selectivity can even be increased - as necessary for the analyses of complex mixtures - using pre-separation techniques such as gas chromatography or multi-capillary columns. No pre-concentration of the sample is necessary. Those characteristics of the method are preserved even in air with up to a 100% relative humidity rate. The suitability of the method for application in the field of food quality and safety - including storage, process and quality control as well as the characterization of food stuffs - was investigated in recent years for a number of representative examples, which are summarized in the following, including new studies as well: (1) the detection of metabolites from bacteria for the identification and control of their growth; (2) process control in food production - beer fermentation being an example; (3) the detection of the metabolites of mould for process control during cheese production, for quality control of raw materials or for the control of storage conditions; (4) the quality control of packaging materials during the production of polymeric materials; and (5) the characterization of products - wine being an example. The challenges of such applications were operation in humid air, fast on-line analyses of complex mixtures, high sensitivity - detection limits have to be, for example, in the range of the odour limits - and, in some cases, the necessity of mobile instrumentation. It can be shown that ion mobility spectrometry is optimally capable of fulfilling those challenges for many applications.

Advanced protection technology for ground combat vehicles.

PubMed

Bosse, Timothy G

2012-01-01

Just as highway drivers use radar detectors to attempt to stay ahead of police armed with the latest radar technology, the Armed Forces are locked in a spiral to protect combat vehicles and their crews against the latest threats in both the contemporary operating environment and the anticipated operating environment (ie, beyond 2020). In response to bigger, heavier, or better-protected vehicles, adversaries build and deploy larger explosive devices or bombs. However, making improvements to combat vehicles is much more expensive than deploying larger explosives. In addition, demand is increasing for lighter-weight vehicles capable of rapid deployment. Together, these two facts give the threat a clear advantage in the future. To protect vehicles and crews, technologies focusing on detection and hit avoidance, denial of penetration, and crew survivability must be combined synergistically to provide the best chance of survival on the modern battlefield.

Tracker Mindset for Explosive Device Emplacement Indicator Detection

DTIC Science & Technology

2014-09-01

NOTES 14. ABSTRACT While investigating landmine detection training for the AN/PSS-14, we noticed operators were so focused on the detector’s auditory ...traces? 1.1.1 How Humans See Basically speaking, when light from the environment enters the eye, it stimulates the rod and cone photoreceptors on...contours or edges more visible. 31 Intuition Can targets, in some way, be detected at a level below conscious awareness? Can stimulation , of which

Improved Infrasound Event Location

DTIC Science & Technology

2007-09-01

Bolide (20) —— 1 signal —— 5-8 signals Mine Explosion (112) Volcano (20) —— 2 signals —— >8 signals Rocket Motor Test (1) Landslide (1) —— 3-4...significant bookkeeping, since the ray-tracing programs must be executed separately for each source-receiver-model scenario, each producing multiple...Infrasound monitoring of volcanoes to probe high-altitude winds, J. Geophys. Res. 110, D13106, doi: 10.1029/2004JD005587. Le Pichon, A., K

Photochemical Degradation of Composition B and Its Components

DTIC Science & Technology

2007-09-01

recorded on the toluene (5.7 mg yield ), ether I (35 mg), and aceto- nitrile (17.8 mg) fractions. Irradiation of solution explosives in soils A...the soil was Soxhlet extracted with acetonitrile for 93 hours. The acetonitrile was removed with a rotary evaporator and the residue redissolved in...ionization to yield an anion of m/z 226. The traces show differences observed in samples with different initial preparation protocols at 15 days. Distance

An array of antenna-coupled superconducting microbolometers for passive indoors real-time THz imaging

NASA Astrophysics Data System (ADS)

Luukanen, A.; Grönberg, L.; Helistö, P.; Penttilä, J. S.; Seppä, H.; Sipola, H.; Dietlein, C. R.; Grossman, E. N.

2006-05-01

The temperature resolving power (NETD) of millimeter wave imagers based on InP HEMT MMIC radiometers is typically about 1 K (30 ms), but the MMIC technology is limited to operating frequencies below ~ 150 GHz. In this paper we report the first results from a pixel developed for an eight pixel sub-array of superconducting antenna-coupled microbolometers, a first step towards a real-time imaging system, with frequency coverage of 0.2 - 3.6 THz. These detectors have demonstrated video-rate NETDs in the millikelvin range, close to the fundamental photon noise limit, when operated at a bath temperature of ~ 4K. The detectors will be operated within a turn-key cryogen-free pulse tube refrigerator, which allows for continuous operation without the need for liquid cryogens. The outstanding frequency agility of bolometric detectors allows for multi-frequency imaging, which greatly enhances the discrimination of e.g. explosives against innoncuous items concealed underneath clothing.

Adsorption and Detection of Hazardous Trace Gases by Metal-Organic Frameworks.

PubMed

Woellner, Michelle; Hausdorf, Steffen; Klein, Nicole; Mueller, Philipp; Smith, Martin W; Kaskel, Stefan

2018-06-19

The quest for advanced designer adsorbents for air filtration and monitoring hazardous trace gases has recently been more and more driven by the need to ensure clean air in indoor, outdoor, and industrial environments. How to increase safety with regard to personal protection in the event of hazardous gas exposure is a critical question for an ever-growing population spending most of their lifetime indoors, but is also crucial for the chemical industry in order to protect future generations of employees from potential hazards. Metal-organic frameworks (MOFs) are already quite advanced and promising in terms of capacity and specific affinity to overcome limitations of current adsorbent materials for trace and toxic gas adsorption. Due to their advantageous features (e.g., high specific surface area, catalytic activity, tailorable pore sizes, structural diversity, and range of chemical and physical properties), MOFs offer a high potential as adsorbents for air filtration and monitoring of hazardous trace gases. Three advanced topics are considered here, in applying MOFs for selective adsorption: (i) toxic gas adsorption toward filtration for respiratory protection as well as indoor and cabin air, (ii) enrichment of hazardous gases using MOFs, and (iii) MOFs as sensors for toxic trace gases and explosives. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Finding the First Cosmic Explosions: Hypernovae and Pair-Instability Supernovae

NASA Astrophysics Data System (ADS)

Wiggins, Brandon; Whalen, D. J.; Migenes, V.; Astrophysics Research Group at Los Alamos National Laboratory

2014-01-01

The cosmic Dark Ages ended with the formation of the first stars at z ~ 20, or ~ 200 Myr after the Big Bang. Because they literally lie at the edge of the observable universe Pop III stars will be beyond the reach of even next generation observatories like JWST and the Thirty-Meter Telescope. But primordial supernovae could soon directly probe the properties of the first stars because they can be observed at high redshifts and their masses can be inferred from their light curves. I will present numerical simulations of Pop III hypernovae and pair-instability supernovae and their light curves done with the Los Alamos RAGE and SPECTRUM codes. We find that these two types of explosions will be visible at z ~ 10 - 15, revealing the positions of ancient dim galaxies on the sky and tracing their star formation rates.

Methane Explosion Mitigation in Coal Mines by Water Mist

NASA Astrophysics Data System (ADS)

Chikhradze, Nikoloz; Mataradze, Edgar; Chikhradze, Mikheil; Krauthammer, Ted; Mansurov, Zulkhair; Alyiev, Erhan

2017-12-01

Statistics shows that the majority of accidents with fatal outcome are caused by methane and/or coal dust explosion. This leads to assume that contemporary counter-explosion systems of various designs cannot be considered effective. Considering the growing threat of methane explosion in the coming years along with the development of deeper levels, the improvement of a system for protecting people in underground opening appears urgent. This paper focuses on technical solutions to be used in designing a protective system for minimizing the consequences of methane explosions in coalmines. The new protective system consists of three main modules: i) a high-speed shock wave suppression section; ii) a suppression section with a long-term action and iii) a system activating device. The shock wave suppressor contains a 200 litre volume water tank with a built-in gas generator and nozzles. It is activated after 12ms from the blast moment, the duration of discharge is 40 s. The suppression section with a long-term action contains a 2000 litre volume water tank, a high-pressure pump, a hydraulic accumulator, solenoid valves, and a system of pipes with built-in nozzles. It is activated after 4 s from the blast moment, the duration of discharge is 8 min. The activation device includes a detection block containing sensors, an emergency signal generation module, a signal transmission module, a signal receiving module and a power supply module. The system operates in a waiting mode and activates immediately upon the receipt of the start signal generated by the detector. The paper also addresses the preliminary results of the system prototype testing in the tunnel.

Differential-optoacoustic absorption detector

NASA Technical Reports Server (NTRS)

Shumate, M. S.

1977-01-01

Two-cell spectrophone detects trace amounts of atmospheric pollutants by measuring absorption coefficients of gases with various laser sources. Device measures pressure difference between two tapered cells with differential manometer. Background signal is reduced by balanced window heating and balanced carrier gas absorption in two cells.

Detection of land mines by amplified fluorescence quenching of polymer films: a man-portable chemical sniffer for detection of ultratrace concentrations of explosives emanating from land mines

NASA Astrophysics Data System (ADS)

la Grone, Marcus J.; Cumming, Colin J.; Fisher, Mark E.; Fox, Michael J.; Jacob, Sheena; Reust, Dennis; Rockley, Mark G.; Towers, Eric

2000-08-01

The explosive charge within a landmine is the source for a mixture of chemical vapors that form a distinctive 'chemical signature' indicative of a landmine. The concentration of these compounds in the air over landmines is extremely low, well below the minimum detection limits of most field- portable chemical sensors. Described in this paper is a man- portable landmine detection system that has for the first time demonstrated the ability to detect landmines by direct sensing of the vapors of signature compounds in the air over landmines. The system utilizes fluorescent polymers developed by collaborators at the MIT. The sensor can detect ultra-trace concentrations of TNT vapor and other nitroaromatic compounds found in many landmine explosives. Thin films of the polymers exhibit intense fluorescence, but when exposed to vapors of nitroaromatic explosives the intensity of the light emitted from the films decreases. A single molecule of TNT binding to a receptor site quenches the fluorescence from many polymer repeat units, increasing the sensitivity by orders of magnitude. A sensor prototype has been develop that response in near real-time to low femtogram quantities of nitroaromatic explosives. The prototype is portable, lightweight, has low power consumption, is simple to operate, and is relatively inexpensive. Simultaneous field testing of the sensor and experienced canine landmine detection teams was recently completed. Although the testing was limited in scope, the performance of the senor met or exceeded that of the canines against buried landmines.

Remote laser drilling and sampling system for the detection of concealed explosives

NASA Astrophysics Data System (ADS)

Wild, D.; Pschyklenk, L.; Theiß, C.; Holl, G.

2017-05-01

The detection of hazardous materials like explosives is a central issue in national security in the field of counterterrorism. One major task includes the development of new methods and sensor systems for the detection. Many existing remote or standoff methods like infrared or raman spectroscopy find their limits, if the hazardous material is concealed in an object. Imaging technologies using x-ray or terahertz radiation usually yield no information about the chemical content itself. However, the exact knowledge of the real threat potential of a suspicious object is crucial for disarming the device. A new approach deals with a laser drilling and sampling system for the use as verification detector for suspicious objects. Central part of the system is a miniaturised, diode pumped Nd:YAG laser oscillator-amplifier. The system allows drilling into most materials like metals, synthetics or textiles with bore hole diameters in the micron scale. During the drilling process, the hazardous material can be sampled for further investigation with suitable detection methods. In the reported work, laser induced breakdown spectroscopy (LIBS) is used to monitor the drilling process and to classify the drilled material. Also experiments were carried out to show the system's ability to not ignite even sensitive explosives like triacetone triperoxide (TATP). The detection of concealed hazardous material is shown for different explosives using liquid chromatography and ion mobility spectrometry.

Short communication: simultaneous analysis of reducing sugars and 5-hydroxymethyl-2-furaldehyde at a low concentration by high performance anion exchange chromatography with electrochemical detector, compared with HPLC with refractive index detector.

PubMed

Guan, Y-G; Yu, P; Yu, S-J; Xu, X-B; Wu, X-L

2012-11-01

A simultaneous analysis of reducing sugars and 5-hydroxymethyl-2-furaldehyde of the Maillard reaction products was detailed. It was based on a high performance anion exchange chromatography with electrochemical detector system and an HPLC with refractive index detector. Results showed that high performance anion exchange chromatography with electrochemical detector using a CarboPac PA-1 column (Dionex Corp., Sunnyvale, CA) was more suitable for reducing sugars and 5-hydroxymethyl-2-furaldehyde determination, especially for trace analysis. The lowest detectable limit of reducing sugars and 5-hydroxymethyl-2-furaldehyde was 0.00005 mol/L in this experiment. However, HPLC with a refractive index detector always produces a tailing peak for 5-hydroxymethyl-2-furaldehyde, and mannose and fructose cannot be absolutely separated. The results of the present study could provide a more sensitive means for 5-hydroxymethyl-2-furaldehyde and reducing sugar detection. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Fossils, molecules and embryos: new perspectives on the Cambrian explosion

NASA Technical Reports Server (NTRS)

Valentine, J. W.; Jablonski, D.; Erwin, D. H.

1999-01-01

The Cambrian explosion is named for the geologically sudden appearance of numerous metazoan body plans (many of living phyla) between about 530 and 520 million years ago, only 1.7% of the duration of the fossil record of animals. Earlier indications of metazoans are found in the Neoproterozic; minute trails suggesting bilaterian activity date from about 600 million years ago. Larger and more elaborate fossil burrows appear near 543 million years ago, the beginning of the Cambrian Period. Evidence of metazoan activity in both trace and body fossils then increased during the 13 million years leading to the explosion. All living phyla may have originated by the end of the explosion. Molecular divergences among lineages leading to phyla record speciation events that have been earlier than the origins of the new body plans, which can arise many tens of millions of years after an initial branching. Various attempts to date those branchings by using molecular clocks have disagreed widely. While the timing of the evolution of the developmental systems of living metazoan body plans is still uncertain, the distribution of Hox and other developmental control genes among metazoans indicates that an extensive patterning system was in place prior to the Cambrian. However, it is likely that much genomic repatterning occurred during the Early Cambrian, involving both key control genes and regulators within their downstream cascades, as novel body plans evolved.

Femtosecond Laser Fabricated Ag@Au and Cu@Au Alloy Nanoparticles for Surface Enhaned Raman Spectrosocpy Based Trace Explosives Detection

NASA Astrophysics Data System (ADS)

Sree Satya Bharati, Moram; Byram, Chandu; Soma, Venugopal R.

2018-03-01

Herein we present results from our detailed studies on the fabrication of Ag@Au and Cu@Au alloy nanoparticles (NPs) using the femtosecond laser ablation in liquid technique. The NPs were obtained by ablating the pure Ag, Cu targets (bulk) in HAuCl4 (5 mM) solution. The absorption properties of the obtained NPs colloids were characterized using UV-Visible absorption spectrometer and their size, shape, and crystallinity were investigated using the XRD, FESEM and TEM techniques. The fabricated NPs were utilized for sensing of explosive molecules such as 2, 4, 6-trinitrophenol (PA), 2, 4-dinitrotoluene (DNT) and a common dye methylene blue (MB) using the surface enhanced Raman spectroscopy (SERS) technique. The detection limit in terms of weight was as low as few nano-grams in the case of nitroaromatic explosive compounds (PA, DNT) and few picograms in the case of a common dye molecule (MB). Typical enhancement factors achieved were estimated to be 104, 105 and 107, respectively, for PA, DNT, and MB. The significance of the present work lies in exploring the performance of the prepared NPs being used as SERS substrates for explosives detection using a portable Raman instrument. Such capability enables one to carry the spectrometer to the point of interest in the field and evaluate any hazardous samples within a short period of time.

An automated approach to detecting signals in electroantennogram data

USGS Publications Warehouse

Slone, D.H.; Sullivan, B.T.

2007-01-01

Coupled gas chromatography/electroantennographic detection (GC-EAD) is a widely used method for identifying insect olfactory stimulants present in mixtures of volatiles, and it can greatly accelerate the identification of insect semiochemicals. In GC-EAD, voltage changes across an insect's antenna are measured while the antenna is exposed to compounds eluting from a gas chromatograph. The antenna thus serves as a selective GC detector whose output can be compared to that of a "general" GC detector, commonly a flame ionization detector. Appropriate interpretation of GC-EAD results requires that olfaction-related voltage changes in the antenna be distinguishable from background noise that arises inevitably from antennal preparations and the GC-EAD-associated hardware. In this paper, we describe and compare mathematical algorithms for discriminating olfaction-generated signals in an EAD trace from background noise. The algorithms amplify signals by recognizing their characteristic shape and wavelength while suppressing unstructured noise. We have found these algorithms to be both powerful and highly discriminatory even when applied to noisy traces where the signals would be difficult to discriminate by eye. This new methodology removes operator bias as a factor in signal identification, can improve realized sensitivity of the EAD system, and reduces the number of runs required to confirm the identity of an olfactory stimulant. ?? 2007 Springer Science+Business Media, LLC.

Shot-Noise-Limited Dual-Beam Detector for Atmospheric Trace-Gas Monitoring with Near-Infrared Diode Lasers

NASA Astrophysics Data System (ADS)

Durry, Georges; Pouchet, Ivan; Amarouche, Nadir; Danguy, Théodore; Megie, Gerard

2000-10-01

A dual-beam detector is used to measure atmospheric trace species by differential absorption spectroscopy with commercial near-infrared InGaAs laser diodes. It is implemented on the Spectrom tre Diodes Laser Accordables, a balloonborne tunable diode laser spectrometer devoted to the in situ monitoring of CH 4 and H 2 O. The dual-beam detector is made of simple analogical subtractor circuits combined with InGaAs photodiodes. The detection strategy consists in taking the balanced analogical difference between the reference and the sample signals detected at the input and the output of an open optical multipass cell to apply the full dynamic range of the measurements (16 digits) to the weak molecular absorption information. The obtained sensitivity approaches the shot-noise limit. With a 56-m optical cell, the detection limit obtained when the spectra is recorded within 8 ms is 10 4 (expressed in absorbance units). The design and performances of both a simple substractor and an upgraded feedback substractor circuit are discussed with regard to atmospheric in situ CH 4 absorption spectra measured in the 1.653- m region. Mixing ratios are obtained from the absorption spectra by application of a nonlinear least-squares fit to the full molecular line shape in conjunction with in situ P and T measurements.

Trace: a high-throughput tomographic reconstruction engine for large-scale datasets

DOE PAGES

Bicer, Tekin; Gursoy, Doga; Andrade, Vincent De; ...

2017-01-28

Here, synchrotron light source and detector technologies enable scientists to perform advanced experiments. These scientific instruments and experiments produce data at such scale and complexity that large-scale computation is required to unleash their full power. One of the widely used data acquisition technique at light sources is Computed Tomography, which can generate tens of GB/s depending on x-ray range. A large-scale tomographic dataset, such as mouse brain, may require hours of computation time with a medium size workstation. In this paper, we present Trace, a data-intensive computing middleware we developed for implementation and parallelization of iterative tomographic reconstruction algorithms. Tracemore » provides fine-grained reconstruction of tomography datasets using both (thread level) shared memory and (process level) distributed memory parallelization. Trace utilizes a special data structure called replicated reconstruction object to maximize application performance. We also present the optimizations we have done on the replicated reconstruction objects and evaluate them using a shale and a mouse brain sinogram. Our experimental evaluations show that the applied optimizations and parallelization techniques can provide 158x speedup (using 32 compute nodes) over single core configuration, which decreases the reconstruction time of a sinogram (with 4501 projections and 22400 detector resolution) from 12.5 hours to less than 5 minutes per iteration.« less

Trace: a high-throughput tomographic reconstruction engine for large-scale datasets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bicer, Tekin; Gursoy, Doga; Andrade, Vincent De

Here, synchrotron light source and detector technologies enable scientists to perform advanced experiments. These scientific instruments and experiments produce data at such scale and complexity that large-scale computation is required to unleash their full power. One of the widely used data acquisition technique at light sources is Computed Tomography, which can generate tens of GB/s depending on x-ray range. A large-scale tomographic dataset, such as mouse brain, may require hours of computation time with a medium size workstation. In this paper, we present Trace, a data-intensive computing middleware we developed for implementation and parallelization of iterative tomographic reconstruction algorithms. Tracemore » provides fine-grained reconstruction of tomography datasets using both (thread level) shared memory and (process level) distributed memory parallelization. Trace utilizes a special data structure called replicated reconstruction object to maximize application performance. We also present the optimizations we have done on the replicated reconstruction objects and evaluate them using a shale and a mouse brain sinogram. Our experimental evaluations show that the applied optimizations and parallelization techniques can provide 158x speedup (using 32 compute nodes) over single core configuration, which decreases the reconstruction time of a sinogram (with 4501 projections and 22400 detector resolution) from 12.5 hours to less than 5 minutes per iteration.« less

Some Informal Thoughts on Relativity and Limitations on Interstellar Travel

DTIC Science & Technology

1990-12-01

velocities, as quantified by the following: Consider a device made up of a light source, a light detector, and a mirror in the following relationship (after...the source and detector are close enough together so that the value of the cosine of the angle of incidence on the mirror can be taken to be 1, a light ...34 observer will see the light pulse trace a diagonal path with length 2 z4 + (vAt/2)2 at a speed (by Postulate 2) of c. The duration of a transit measured

Low earth orbiting Nadir Etalon Sounding Spectrometer instrument concept for temperature, moisture and trace species, LeoNESS

NASA Technical Reports Server (NTRS)

Kumer, J. B.; Sterritt, L. W.; Roche, A. E.; Rosenberg, W. J.; Morrow, H. E.; Shenk, W. E.; Susskind, J.

1992-01-01

A concept for a low earth orbiting nadir etalon spectrometer sounder (LeoNESS) is described which can achieve retrieval of temperature, H2O, surface, boundary conditions, cloudiness, and trace species with an accuracy that meets or exceeds the AIRS specifications. Options employing 65-K and 30-K detectors are examined; the former may be implemented via passive radiative cooling. The concept, which is derived from the Cryogenic Limb Array Etalon Spectrometer, has the potential for improving the horizontal and vertical resolution.

LLNL Location and Detection Research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, S C; Harris, D B; Anderson, M L

2003-07-16

We present two LLNL research projects in the topical areas of location and detection. The first project assesses epicenter accuracy using a multiple-event location algorithm, and the second project employs waveform subspace Correlation to detect and identify events at Fennoscandian mines. Accurately located seismic events are the bases of location calibration. A well-characterized set of calibration events enables new Earth model development, empirical calibration, and validation of models. In a recent study, Bondar et al. (2003) develop network coverage criteria for assessing the accuracy of event locations that are determined using single-event, linearized inversion methods. These criteria are conservative andmore » are meant for application to large bulletins where emphasis is on catalog completeness and any given event location may be improved through detailed analysis or application of advanced algorithms. Relative event location techniques are touted as advancements that may improve absolute location accuracy by (1) ensuring an internally consistent dataset, (2) constraining a subset of events to known locations, and (3) taking advantage of station and event correlation structure. Here we present the preliminary phase of this work in which we use Nevada Test Site (NTS) nuclear explosions, with known locations, to test the effect of travel-time model accuracy on relative location accuracy. Like previous studies, we find that the reference velocity-model and relative-location accuracy are highly correlated. We also find that metrics based on travel-time residual of relocated events are not a reliable for assessing either velocity-model or relative-location accuracy. In the topical area of detection, we develop specialized correlation (subspace) detectors for the principal mines surrounding the ARCES station located in the European Arctic. Our objective is to provide efficient screens for explosions occurring in the mines of the Kola Peninsula (Kovdor, Zapolyarny, Olenogorsk, Khibiny) and the major iron mines of northern Sweden (Malmberget, Kiruna). In excess of 90% of the events detected by the ARCES station are mining explosions, and a significant fraction are from these northern mining groups. The primary challenge in developing waveform correlation detectors is the degree of variation in the source time histories of the shots, which can result in poor correlation among events even in close proximity. Our approach to solving this problem is to use lagged subspace correlation detectors, which offer some prospect of compensating for variation and uncertainty in source time functions.« less

What can be learned from a future supernova neutrino detection?

NASA Astrophysics Data System (ADS)

Horiuchi, Shunsaku; Kneller, James P.

2018-04-01

This year marks the 30th anniversary of the only supernova from which we have detected neutrinos—SN 1987A. The 20 or so neutrinos that were detected were mined to great depth in order to determine the events that occurred in the explosion and to place limits upon all manner of neutrino properties. Since 1987 the scale and sensitivity of the detectors capable of identifying neutrinos from a Galactic supernova have grown considerably so that current generation detectors are capable of detecting of order 10 000 neutrinos for a supernova at the Galactic Center. Next generation detectors will increase that yield by another order of magnitude. Simultaneous with the growth of neutrino detection capability, our understanding of how massive stars explode and how the neutrino interacts with hot and dense matter has also increased by a tremendous degree. The neutrino signal will contain much information on all manner of physics of interest to a wide community. In this review we describe the expected features of the neutrino signal, the detectors which will detect it, and the signatures one might try to look for in order to get at this physics.

Low level radioactivity measurements with phoswich detectors using coincident techniques and digital pulse processing analysis.

PubMed

de la Fuente, R; de Celis, B; del Canto, V; Lumbreras, J M; de Celis Alonso, B; Martín-Martín, A; Gutierrez-Villanueva, J L

2008-10-01

A new system has been developed for the detection of low radioactivity levels of fission products and actinides using coincidence techniques. The device combines a phoswich detector for alpha/beta/gamma-ray recognition with a fast digital card for electronic pulse analysis. The phoswich can be used in a coincident mode by identifying the composed signal produced by the simultaneous detection of alpha/beta particles and X-rays/gamma particles. The technique of coincidences with phoswich detectors was proposed recently to verify the Nuclear Test Ban Treaty (NTBT) which established the necessity of monitoring low levels of gaseous fission products produced by underground nuclear explosions. With the device proposed here it is possible to identify the coincidence events and determine the energy and type of coincident particles. The sensitivity of the system has been improved by employing liquid scintillators and a high resolution low energy germanium detector. In this case it is possible to identify simultaneously by alpha/gamma coincidence transuranic nuclides present in environmental samples without necessity of performing radiochemical separation. The minimum detectable activity was estimated to be 0.01 Bq kg(-1) for 0.1 kg of soil and 1000 min counting.

Atacama Cosmology Telescope: Polarization calibration analysis for CMB measurements with ACTPol and Advanced ACTPol

NASA Astrophysics Data System (ADS)

Koopman, Brian; ACTPol Collaboration

2015-04-01

The Atacama Cosmology Telescope Polarimeter (ACTPol) is a polarization sensitive upgrade for the Atacama Cosmology Telescope, located at an elevation of 5190 m on Cerro Toco in Chile. Achieving first light in 2013, ACTPol is entering its third observation season. Advanced ACTPol is a next generation upgrade for ACTPol, with additional frequencies, polarization modulation, and new detector arrays, that will begin in 2016. I will first present an overview of the two projects and then focus on describing the methods used for polarization angle calibration of the ACTPol detectors. These methods utilize polarization ray tracing in the optical design software CODEV together with detector positions determined from planet observations and represent a critical input for mapping the polarization of the CMB.

Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts

NASA Technical Reports Server (NTRS)

Elsner, R. F.; O'Dell, S. L.; Ramsey, B. D.; Weisskopf, M. C.

2011-01-01

We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wave vectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

Mathematical Design Optimization of Wide-Field X-ray Telescopes: Mirror Nodal Positions and Detector Tilts

NASA Technical Reports Server (NTRS)

Elsner, Ronald; O'Dell, Stephen; Ramsey, Brian; Weisskopf, Martin

2011-01-01

We describe a mathematical formalism for determining the mirror shell nodal positions and detector tilts that optimize the spatial resolution averaged over a field-of-view for a nested x-ray telescope, assuming known mirror segment surface prescriptions and known detector focal surface. The results are expressed in terms of ensemble averages over variable combinations of the ray positions and wavevectors in the flat focal plane intersecting the optical axis at the nominal on-axis focus, which can be determined by Monte-Carlo ray traces of the individual mirror shells. This work is part of our continuing efforts to provide analytical tools to aid in the design process for wide-field survey x-ray astronomy missions.

First real-time detection of surface dust in a tokamak.

PubMed

Skinner, C H; Rais, B; Roquemore, A L; Kugel, H W; Marsala, R; Provost, T

2010-10-01

The first real-time detection of surface dust inside a tokamak was made using an electrostatic dust detector. A fine grid of interlocking circuit traces was installed in the NSTX vessel and biased to 50 V. Impinging dust particles created a temporary short circuit and the resulting current pulse was recorded by counting electronics. The techniques used to increase the detector sensitivity by a factor of ×10,000 to match NSTX dust levels while suppressing electrical pickup are presented. The results were validated by comparison to laboratory measurements, by the null signal from a covered detector that was only sensitive to pickup, and by the dramatic increase in signal when Li particles were introduced for wall conditioning purposes.

Fiber optic fluid detector

DOEpatents

Angel, S. Michael

1989-01-01

Particular gases or liquids are detected with a fiber optic element (11, 11a to 11j) having a cladding or coating of a material (23, 23a to 23j) which absorbs the fluid or fluids and which exhibits a change of an optical property, such as index of refraction, light transmissiveness or fluoresence emission, for example, in response to absorption of the fluid. The fluid is sensed by directing light into the fiber optic element and detecting changes in the light, such as exit angle changes for example, that result from the changed optical property of the coating material. The fluid detector (24, 24a to 24j) may be used for such purposes as sensing toxic or explosive gases in the atmosphere, measuring ground water contamination or monitoring fluid flows in industrial processes, among other uses.

SELECTIVE TRACE ENRICHMENT BY IMMUNOAFFINITY CAPILLARY ELECTROCHROMATOGRAPHY ON-LINE WITH CAPILLARY ZONE ELECTROPHORESIS - LASER-INDUCED FLUORESCENCE

EPA Science Inventory

Limited by the lack of a sensitive, universal detector, many capillary-based liquid-phase separation techniques might benefit from techniques that overcome modest concentration sensitivity by preconcentrating large injection volumes. The work presented employs selective solid-ph...

The Foggy EUV Corona and Coronal Heating by MHD Waves from Explosive Reconnection Events

NASA Technical Reports Server (NTRS)

Moore, Ron L.; Cirtain, Jonathan W.; Falconer, David A.

2008-01-01

In 0.5 arcsec/pixel TRACE coronal EUV images, the corona rooted in active regions that are at the limb and are not flaring is seen to consist of (1) a complex array of discrete loops and plumes embedded in (2) a diffuse ambient component that shows no fine structure and gradually fades with height. For each of two not-flaring active regions, found that the diffuse component is (1) approximately isothermal and hydrostatic and (2) emits well over half of the total EUV luminosity of the active-region corona. Here, from a TRACE Fe XII coronal image of another not-flaring active region, the large sunspot active region AR 10652 when it was at the west limb on 30 July 2004, we separate the diffuse component from the discrete loop component by spatial filtering, and find that the diffuse component has about 60% of the total luminosity. If under much higher spatial resolution than that of TRACE (e. g., the 0.1 arcsec/pixel resolution of the Hi-C sounding-rocket experiment proposed by J. W. Cirtain et al), most of the diffuse component remains diffuse rather being resolved into very narrow loops and plumes, this will raise the possibility that the EUV corona in active regions consists of two basically different but comparably luminous components: one being the set of discrete bright loops and plumes and the other being a truly diffuse component filling the space between the discrete loops and plumes. This dichotomy would imply that there are two different but comparably powerful coronal heating mechanisms operating in active regions, one for the distinct loops and plumes and another for the diffuse component. We present a scenario in which (1) each discrete bright loop or plume is a flux tube that was recently reconnected in a burst of reconnection, and (2) the diffuse component is heated by MHD waves that are generated by these reconnection events and by other fine-scale explosive reconnection events, most of which occur in and below the base of the corona where they are seen as UV explosive events, EUV blinkers, and type II spicules. These MHD waves propagate across field lines and dissipate, heating the plasma in the field between the bright loops and plumes.

Understanding Hawking radiation in the framework of open quantum systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu Hongwei; Zhang Jialin

2008-01-15

We study the Hawking radiation in the framework of open quantum systems by examining the time evolution of a detector (modeled by a two-level atom) interacting with vacuum massless scalar fields. The dynamics of the detector is governed by a master equation obtained by tracing over the field degrees of freedom from the complete system. The nonunitary effects are studied by analyzing the time behavior of a particular observable of the detector, i.e., its admissible state, in the Unruh, Hartle-Hawking, as well as Boulware vacua outside a Schwarzschild black hole. We find that the detector in both the Unruh andmore » Hartle-Hawking vacua would spontaneously excite with a nonvanishing probability the same as what one would obtain if there is thermal radiation at the Hawking temperature from the black hole, thus reproducing the basic results concerning the Hawking effect in the framework of open quantum systems.« less

Precision measurement of the photon detection efficiency of silicon photomultipliers using two integrating spheres.

PubMed

Yang, Seul Ki; Lee, J; Kim, Sug-Whan; Lee, Hye-Young; Jeon, Jin-A; Park, I H; Yoon, Jae-Ryong; Baek, Yang-Sik

2014-01-13

We report a new and improved photon counting method for the precision PDE measurement of SiPM detectors, utilizing two integrating spheres connected serially and calibrated reference detectors. First, using a ray tracing simulation and irradiance measurement results with a reference photodiode, we investigated irradiance characteristics of the measurement instrument, and analyzed dominating systematic uncertainties in PDE measurement. Two SiPM detectors were then used for PDE measurements between wavelengths of 368 and 850 nm and for bias voltages varying from around 70V. The resulting PDEs of the SiPMs show good agreement with those from other studies, yet with an improved accuracy of 1.57% (1σ). This was achieved by the simultaneous measurement with the NIST calibrated reference detectors, which suppressed the time dependent variation of source light. The technical details of the instrumentation, measurement results and uncertainty analysis are reported together with their implications.

Liquid-absorption preconcentrator sampling instrument

DOEpatents

Zaromb, Solomon

1990-01-01

A system for detecting trace concentrations of an analyte in air and includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container in which is disposed a wettable material extending substantially the entire length of the container. One end of the wettable material is continuously wetted with an analyte-sorbing liquid, which flows to the other end of the container. Sample air is flowed through the container in contact with the wetted material for trapping and preconcentrating the traces of analyte in the sorbing liquid, which is then collected at the other end of the container and discharged to the detector. The wetted material may be a wick comprising a bundle of fibers, one end of which is immersed in a reservoir of the analyte-sorbing liquid, or may be a liner disposed on the inner surface of the container, with the sorbing liquid being centrifugally dispersed onto the liner at one end thereof. The container is preferably vertically oriented so that gravity effects the liquid flow.

Liquid-absorption preconcentrator sampling instrument

DOEpatents

Zaromb, S.

1990-12-11

A system is described for detecting trace concentrations of an analyte in air and includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container in which is disposed a wettable material extending substantially the entire length of the container. One end of the wettable material is continuously wetted with an analyte-sorbing liquid, which flows to the other end of the container. Sample air is flowed through the container in contact with the wetted material for trapping and preconcentrating the traces of analyte in the sorbing liquid, which is then collected at the other end of the container and discharged to the detector. The wetted material may be a wick comprising a bundle of fibers, one end of which is immersed in a reservoir of the analyte-sorbing liquid, or may be a liner disposed on the inner surface of the container, with the sorbing liquid being centrifugally dispersed onto the liner at one end thereof. The container is preferably vertically oriented so that gravity effects the liquid flow. 4 figs.

High throughput liquid absorption preconcentrator sampling instrument

DOEpatents

Zaromb, Solomon; Bozen, Ralph M.

1992-01-01

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

High-throughput liquid-absorption preconcentrator sampling methods

DOEpatents

Zaromb, Solomon

1994-01-01

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis.

High throughput liquid absorption preconcentrator sampling instrument

DOEpatents

Zaromb, S.; Bozen, R.M.

1992-12-22

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

High-throughput liquid-absorption preconcentrator sampling methods

DOEpatents

Zaromb, S.

1994-07-12

A system for detecting trace concentrations of an analyte in air includes a preconcentrator for the analyte and an analyte detector. The preconcentrator includes an elongated tubular container comprising a wettable material. The wettable material is continuously wetted with an analyte-sorbing liquid which flows from one part of the container to a lower end. Sampled air flows through the container in contact with the wetted material with a swirling motion which results in efficient transfer of analyte vapors or aerosol particles to the sorbing liquid and preconcentration of traces of analyte in the liquid. The preconcentrated traces of analyte may be either detected within the container or removed therefrom for injection into a separate detection means or for subsequent analysis. 12 figs.

Microfabricated thermionic detector

DOEpatents

Lewis, Patrick R; Manginell, Ronald P; Wheeler, David R; Trudell, Daniel E

2012-10-30

A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

Optimization of Composting for Explosives Contaminated Soil

DTIC Science & Technology

1991-09-30

undesirable and essentially economically unfeasible for the remediation of small sites due to the large expenditures required for the mobilization and...mm, 5 micron. * Detector: UV absorbance at 250 nm. " Mobile phase: 52% methanol/48% water. " Flow rate: 1.5 mL/min. * Injection volume: 50 1&L. The...and lOx calibration standards. 4-21 57SC/2hif 12/02/91 Samples were diluted with mobile phase as necessary to bring target analytes into the

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lincoln, Don

The manner in which particle physicists investigate collisions in particle accelerators is a puzzling process. Using vaguely-defined “detectors,” scientists are able to somehow reconstruct the collisions and convert that information into physics measurements. In this video, Fermilab’s Dr. Don Lincoln sheds light on this mysterious technique. In a surprising analogy, he draws a parallel between experimental particle physics and bomb squad investigators and uses an explosive example to illustrate his points. Be sure to watch this video… it’s totally the bomb.

Warhead verification as inverse problem: Applications of neutron spectrum unfolding from organic-scintillator measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence, Chris C.; Flaska, Marek; Pozzi, Sara A.

2016-08-14

Verification of future warhead-dismantlement treaties will require detection of certain warhead attributes without the disclosure of sensitive design information, and this presents an unusual measurement challenge. Neutron spectroscopy—commonly eschewed as an ill-posed inverse problem—may hold special advantages for warhead verification by virtue of its insensitivity to certain neutron-source parameters like plutonium isotopics. In this article, we investigate the usefulness of unfolded neutron spectra obtained from organic-scintillator data for verifying a particular treaty-relevant warhead attribute: the presence of high-explosive and neutron-reflecting materials. Toward this end, several improvements on current unfolding capabilities are demonstrated: deuterated detectors are shown to have superior response-matrixmore » condition to that of standard hydrogen-base scintintillators; a novel data-discretization scheme is proposed which removes important detector nonlinearities; and a technique is described for re-parameterizing the unfolding problem in order to constrain the parameter space of solutions sought, sidestepping the inverse problem altogether. These improvements are demonstrated with trial measurements and verified using accelerator-based time-of-flight calculation of reference spectra. Then, a demonstration is presented in which the elemental compositions of low-Z neutron-attenuating materials are estimated to within 10%. These techniques could have direct application in verifying the presence of high-explosive materials in a neutron-emitting test item, as well as other for treaty verification challenges.« less

Warhead verification as inverse problem: Applications of neutron spectrum unfolding from organic-scintillator measurements

NASA Astrophysics Data System (ADS)

Lawrence, Chris C.; Febbraro, Michael; Flaska, Marek; Pozzi, Sara A.; Becchetti, F. D.

2016-08-01

Verification of future warhead-dismantlement treaties will require detection of certain warhead attributes without the disclosure of sensitive design information, and this presents an unusual measurement challenge. Neutron spectroscopy—commonly eschewed as an ill-posed inverse problem—may hold special advantages for warhead verification by virtue of its insensitivity to certain neutron-source parameters like plutonium isotopics. In this article, we investigate the usefulness of unfolded neutron spectra obtained from organic-scintillator data for verifying a particular treaty-relevant warhead attribute: the presence of high-explosive and neutron-reflecting materials. Toward this end, several improvements on current unfolding capabilities are demonstrated: deuterated detectors are shown to have superior response-matrix condition to that of standard hydrogen-base scintintillators; a novel data-discretization scheme is proposed which removes important detector nonlinearities; and a technique is described for re-parameterizing the unfolding problem in order to constrain the parameter space of solutions sought, sidestepping the inverse problem altogether. These improvements are demonstrated with trial measurements and verified using accelerator-based time-of-flight calculation of reference spectra. Then, a demonstration is presented in which the elemental compositions of low-Z neutron-attenuating materials are estimated to within 10%. These techniques could have direct application in verifying the presence of high-explosive materials in a neutron-emitting test item, as well as other for treaty verification challenges.

Understanding Chemical Sensitivity and Surface Response in Detecting Trace Levels of Explosives Using Vibrational Sum Frequency Spectroscopy

DTIC Science & Technology

2013-11-04

coated with enamel paint containing black, blue, red, and yellow pigment. The chemical compositions of the pigments are not known, but they show... enamel paint containing black pigment. VSFS signal intensities, ISFG,, has been normalized to constant incident laser power for each spectra. RDX...surface that has been coated with a 1 mm thick layer of enamel paint containing blue pigment. VSFS signal intensities, ISFG,, has been normalized to

Distinct molecular underpinnings of Drosophila olfactory trace conditioning

PubMed Central

Shuai, Yichun; Hu, Ying; Qin, Hongtao; Campbell, Robert A. A.; Zhong, Yi

2011-01-01

Trace conditioning is valued as a simple experimental model to assess how the brain associates events that are discrete in time. Here, we adapted an olfactory trace conditioning procedure in Drosophila melanogaster by training fruit flies to avoid an odor that is followed by foot shock many seconds later. The molecular underpinnings of the learning are distinct from the well-characterized simultaneous conditioning, where odor and punishment temporally overlap. First, Rutabaga adenylyl cyclase (Rut-AC), a putative molecular coincidence detector vital for simultaneous conditioning, is dispensable in trace conditioning. Second, dominant-negative Rac expression, thought to sustain early labile memory, significantly enhances learning of trace conditioning, but leaves simultaneous conditioning unaffected. We further show that targeting Rac inhibition to the mushroom body (MB) but not the antennal lobe (AL) suffices to achieve the enhancement effect. Moreover, the absence of trace conditioning learning in D1 dopamine receptor mutants is rescued by restoration of expression specifically in the adult MB. These results suggest the MB as a crucial neuroanatomical locus for trace conditioning, which may harbor a Rac activity-sensitive olfactory “sensory buffer” that later converges with the punishment signal carried by dopamine signaling. The distinct molecular signature of trace conditioning revealed here shall contribute to the understanding of how the brain overcomes a temporal gap in potentially related events. PMID:22123966

Redesigned β γ radioxenon detector

NASA Astrophysics Data System (ADS)

Cooper, Matthew W.; McIntyre, Justin I.; Bowyer, Ted W.; Carman, April J.; Hayes, James C.; Heimbigner, Tom R.; Hubbard, Charles W.; Lidey, Lance; Litke, Kevin E.; Morris, Scott J.; Ripplinger, Michael D.; Suarez, Reynold; Thompson, Robert

2007-08-01

The Automated Radio-xenon Sampler/Analyzer (ARSA), designed by Pacific Northwest National Laboratory (PNNL) collects and detects several radioxenon isotopes, and is used to monitor underground nuclear explosions. The ARSA is very sensitive to 133Xe, 131mXe, 133mXe, and 135Xe (<1 mBq/SCM) [M. Auera et al., Wernspergera, Appl. Radiat. 6 (2004) 60] through use of its compact high efficiency β-γ coincidence detector. For this reason, it is an excellent treaty monitoring system and it can be used as an environmental sampling device as well. Field testing of the ARSA has shown it to be both robust and reliable, but the nuclear detector requires a detailed photomultiplier tube (PMT) gain matching regime difficult to implement in a field environment. Complexity is a problem from a maintenance and quality assurance/quality control (QA/QC) standpoint, and efforts to reduce these issues have led to development of a simplified β-γ coincident detector. The new design reduces the number of PMT's and the complexity of the calibration needed in comparison to the old design. New scintillation materials (NaI(Tl), CsI(Na), and CsI(Tl)) were investigated and a comparison of three different gamma sensitive well detectors has been completed. A new plastic-scintillator gas cell was constructed and a new method of forming the scintillator gas cell was developed. The simplified detector system compares favorably with the original ARSA design in spectral resolution and efficiency and is significantly easier to set up and calibrate. The new materials and configuration allow the resulting β-γ coincidence detector to maintain the overall performance of the ARSA type β-γ detector while simplifying the design.