Progress on determining the vapor signature of a buried land mine

George, Vivian; Jenkins, Thomas F.; Phelan, James M.; Leggett, Daniel C.; Oxley, Jimmie C.; Webb, Stephen W.; Miyares, Paul H.; Cragin, James H.; Smith, James L.; Berry, Thomas E.

doi:10.1117/12.357034

Cited by 46 publications

(40 citation statements)

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“…The four compounds in the reference standard mix (1,3-dinitrobenzene (1,3-DNB), 2,6-dinitrotoluene (2,6-DNT), 2,4-dinitrotoluene (2,4-DNT), and 2,4,6-trinitrotoluene (2,4,6-TNT)) are commonly found in the environment near landmines. Other nitroaromatic compounds have been identified in the chemical signature of landmines, but these four were selected as targets since they are the analytes most commonly found in the vapor signature of TNT-containing landmines 5 . Responses due to a few unknown compounds are also seen in the chromatogram, but the responses are weak.…”

Section: Receptors Wired In Seriesmentioning

confidence: 99%

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Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

Fisher¹,

Grone²,

Sikes³

2003

SPIE Proceedings

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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 1-3 . 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.

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Section: Receptors Wired In Seriesmentioning

confidence: 99%

“…Of particular concern is post-blast explosive residue that may occur after detonation of munitions. While more study of post-blast residue is needed, there is evidence that TNT quickly degrades when released into the environment 5 .…”

Section: Introductionmentioning

confidence: 99%

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

Fisher¹,

Grone²,

Sikes³

2003

SPIE Proceedings

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“…The concentration of signature compounds like TNT and 2,4-DNT adsorbed on soils has been found to far exceed the equilibrium vapor concentration, while most of the transport of these explosives through soil occurs in the aqueous phase [6][7]. The maximum measured concentrations of nitroaromatics in surface soils above buried landmines have been reported to be as high as a part per million (~1 microgram/g) [4]. Laboratory measurements of vapor concentrations above similarly doped soils are many orders of magnitude lower [7].…”

Section: Introductionmentioning

confidence: 98%

“…Trace chemical methods are limited by environmental fate and transport of explosive compounds in the minefield environment [4]. It has been estimated that more than 80% of the landmines emplaced worldwide contain some fraction of TNT in their main explosive charge [5].…”

Section: Introductionmentioning

confidence: 99%

Remote detection of nitroaromatic explosives in soil using distributed sensor particles

et al. 2001

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Environmental fate and transport studies of explosives in soil indicate that 2,4,6-trinitrotoluene (TNT) and similar products such as dinitrotoluene (DNT) are major contributors to the trace chemical signature emanating from buried landmines. Chemical analysis methods are under development that have great potential to detect mines, or to rapidly classify electromagnetically detected anomalies as mines vs. "mine-like objects". However, these chemical methods are currently confined to point sensors. In contrast, we have developed a method that can remotely determine the presence of nitroaromatic explosives in surface soil. This method utilizes a novel distributed granular sensor approach in combination with uv-visible fluorescence LIDAR (Light Detection and Ranging) technology. We have produced prototype sensor particles that combine sample preconcentration, explosives sensing, signal amplification, and optical signal output functions. These particles can be sprayed onto soil areas that are suspected of explosives contamination. By design, the fluorescence emission spectrum of the distributed particles is strongly affected by absorption of nitroaromatic explosives from the surrounding environment. Using ~1mg/cm 2 coverage of the sensor particles on natural soil, we have observed significant spectral changes due to TNT concentrations in the ppm range (µg TNT/g soil) on 2-inch diameter targets at a standoff distance of 0.5 km. These field measurements have also been used to validate calculations of fluorescent signal/noise for the granular sensor particles as a function of several variables, including particle and receiver characteristics, standoff range, pump laser characteristics, and particle coverage. Some implications of these measurements and calculations for field deployment of the sensor particles are discussed.

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“…Vapor-contaminated materials, themselves, remain a source of vapors for many days (Bender et al 1992). These emitted vapors are sorbed and concentrated on soil around buried landmines (George et al 1999). The success with which canines locate buried landmines suggests an olfactory process: chemical sensing of airborne vapors or vaporcontaminated particles.…”

Section: Tablesmentioning

confidence: 99%

Diffusion and Flux of Explosive-Related Compounds in Plastic Mine Surrogates

Cragin¹,

Leggett²

2003

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Canine detection of buried landmines is thought to be an olfactory process and efforts are now underway to develop electronic sensing of explosives vapors. The quantity of these vapors is critical to any chemical-sensing-based procedure for detecting landmines. Plastic-cased mines release vapors of explosive-related compounds (ERC) by permeation through the casing as well as through holes and cracks. Measurement of permeation contributions to the release flux was reported previously for a few intact mines. Here we determine permeation-driven fluxes and difiusivities by analysis of ERC release into water as a function of time. The solubility of TNT and diffusivities of TNT, 2,4-DNT, and 1,3-DNB in five polymeric materials potentially used in mine casings are reported for the first time. This information can be used to estimate ERC fluxes from TNT-filled mines encased in any of these materials. Direct measurement of the release fluxes from intact mines are feasible and were described previously. Calculated difiusivities of the nitroaromatics in these materials were similar to those reported in the hterature for other aromatic vapors. Diffusion was generally non-Fickian (concentration-dependent). TNT fluxes into Tedlar bags were also measured at 3,13, and 22° C for the five materials. The temperature dependence is well described by simple exponential relations of the van't HoflE/Arrhenius type, and an activation energy was calculated for the process. The temperature dependence of the fluxes was similar for all five materials. Fluxes of individual ERC components were also determined at 22° C and reflected their abundance in the headspace of the source explosive. Plastic/air partition coefficients of the contaminants ranged from 1 x 10^ to 3 x 10^ and were about an order of magnitude higher for TNT than for DNB and were intermediate for DNT.DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. AH product names and trademarks cited are the property of their respective owners.

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Progress on determining the vapor signature of a buried land mine

Cited by 46 publications

References 0 publications

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

Remote detection of nitroaromatic explosives in soil using distributed sensor particles

Diffusion and Flux of Explosive-Related Compounds in Plastic Mine Surrogates

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