Mr. Mike E. Fisher Profile

Mike E. Fisher

Lead Scientist at FLIR Systems Inc

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Publications (9)

Proceedings Article | 5 May 2010 Paper

Intricacies of comparative testing of explosives detectors at the ultra-trace level

Ross Harper, Mark Fisher

Proceedings Volume 7665, 76650R (2010) https://doi.org/10.1117/12.850373

KEYWORDS: Explosives, Sensors, Palladium, Statistical analysis, Contamination, Chemical analysis, Explosives detection, Failure analysis, Glasses, Standards development

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This paper shall demonstrate the reduced lifetime of ultra-trace explosive residues when subjected to standard laboratory conditions, citing examples of flawed experimental design. The traditional view of "trace" level residue may lie within the detection limit capabilities of bench-top instrumentation. Gas chromatography / mass spectrometry, often the main stay of many trace evidence analysis laboratories can readily deliver nanogram and now potentially upper picogram detection limits. Today, emerging technologies continue to push the limits of detection, and sub-nanogram restrictions give way to picogram and femtogram opportunities. As instrument technologies become more sensitive, the need to work at continually lower detection levels is expressed. Generation of reliable, reproducible ultra-trace samples for the testing, analysis and evaluation of those technologies is challenged by the chemical properties of the very samples under investigation. Unlike testing against bulk quantities of explosives, at the picogram level unforeseen sublimation and sorption phenomena may potentially disrupt an otherwise well-planned test. While it may be valid to assume that the properties of bulk samples of most explosives are relatively constant with respect to time, it may not be safe to assume the same is true of ultra-trace level deposits of explosive residue. The vapor pressures of many common military explosives are low, but they are not zero. This fact cannot be ignored when working with trace levels of explosive residue. Failure of an inexperienced technician to consider these factors when conducting an evaluation may unnecessarily introduce bias into the data, and may result in the misrepresentation of a sensor's capabilities. The analyst is now faced with the complication of working with amounts of explosive so potentially low, that loss of a few picograms of material due to evaporation, air currents, poor laboratory technique or some other diluting factor represents a significant percentage of the total sample mass. Added to the complication are sample and substrate matrix, carry-over, and potential cross contamination effects that may now pose a significant effect rather than a slight background nuisance.

Proceedings Article | 20 May 2005 Paper

Detection of vehicle-based improvised explosives using ultra-trace detection equipment

Mark Fisher, John Sikes, Mark Prather, Clint Wichert

Proceedings Volume 5778, (2005) https://doi.org/10.1117/12.606668

KEYWORDS: Explosives, Sensors, Improvised explosive devices, Contamination, Explosives detection, Polymers, Statistical analysis, Luminescence, Target detection, Land mines

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Proceedings Article | 15 September 2004 Paper

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

Mark Fisher, John Sikes, Mark Prather

Proceedings Volume 5403, (2004) https://doi.org/10.1117/12.542900

KEYWORDS: Sensors, Explosives, Explosives detection, Statistical analysis, Particles, Sensor performance, Land mines, Nose, Target detection, Detector development

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Proceedings Article | 11 September 2003 Paper

Minefield edge detection using a novel chemical vapor sensing technique

Mark Fisher, John Sikes

Proceedings Volume 5089, (2003) https://doi.org/10.1117/12.487879

KEYWORDS: Sensors, Land mines, Explosives, Mining, Polymers, Edge detection, Contamination, Statistical analysis, Biological and chemical sensing, Chemical analysis

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Proceedings Article | 11 September 2003 Paper

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

Mark Fisher, Marcus la Grone, John Sikes

Proceedings Volume 5089, (2003) https://doi.org/10.1117/12.487902

KEYWORDS: Sensors, Polymers, Land mines, Capillaries, Prototyping, Chemical analysis, Molecules, Polymeric sensors, Luminescence, Polymer thin films

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Proceedings Article | 13 August 2002 Paper

Investigation of an area reduction method for suspected minefields using an ultrasensitive chemical vapor detector

Marcus la Grone, Mark Fisher, Colin Cumming, Eric Towers

Proceedings Volume 4742, (2002) https://doi.org/10.1117/12.479079

KEYWORDS: Land mines, Sensors, Mining, Explosives, Polymers, Soil science, Particles, Soil contamination, Statistical analysis, Electrodes

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Proceedings Article | 22 August 2000 Paper

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

Marcus la Grone, Colin Cumming, Mark Fisher, Michael Fox, Sheena Jacob, Dennis Reust, Mark Rockley, Eric Towers

Proceedings Volume 4038, (2000) https://doi.org/10.1117/12.396225

KEYWORDS: Land mines, Sensors, Polymers, Luminescence, Explosives, Polymer thin films, Chromophores, Molecules, Sensor performance, Receptors

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Proceedings Article | 2 August 1999 Paper

Landmine detection by chemical signature: detection of vapors of nitroaromatic compounds by fluorescence quenching of novel polymer materials

Marcus la Grone, Colin Cumming, Mark Fisher, Dennis Reust, Robert Taylor

Proceedings Volume 3710, (1999) https://doi.org/10.1117/12.357064

KEYWORDS: Sensors, Polymers, Polymer thin films, Land mines, Luminescence, Statistical analysis, Molecules, Polymeric sensors, Light, Explosives

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Proceedings Article | 4 September 1998 Paper

Electrostatic particle sampler and chemical sensor system for land mine detection by chemical signature

Mike Fisher, Colin Cumming, Marcus la Grone, Robert Taylor

Proceedings Volume 3392, (1998) https://doi.org/10.1117/12.324229

KEYWORDS: Particles, Explosives, Land mines, Soil science, Sensors, Electrodes, Soil contamination, Molecules, Statistical analysis, Chemical analysis

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Locating landmines and UXO by detection of the chemical signature emanating from these devices is extremely challenging due to several of the physical properties of explosives. Because the explosives used in landmines and UXO have extremely low vapor pressures, the concentration of explosive vapors escaping from the ordnance is very low. Fate and transport studies of explosives in soil over buried ordnance have indicated that once released into the soil, virtually all of the explosive vapor is quickly adsorbed onto the surface of soil particles. This behavior is not surprising, since explosives are known to readily adsorb onto most types of surfaces. The adsorption of explosive onto soil particles is to an extent a reversible process, enabling diffusion of explosive through the soil. Unfortunately, because of irreversible adsorption and other processes occurring in the soil that destroy or degrade the explosive, the concentration of explosive reaching the surface of the ground is extremely low. However, dogs are able to locate buried ordnance, indicating that explosive signature compounds are present at or near the surface of the ground at concentrations in excess of the minimum detection limit of canines. Since the fate and transport studies indicate a much higher concentration of explosive adsorbed onto soil particles than in the vapor phase, sampling the explosive adsorbed onto soil particles may be a more efficient approach to sampling explosives than sampling explosive vapor in the air over buried ordnance. An electrostatic particle sampler has been designed which is capable of rapidly and efficiently sampling soil particles. Once the soil particles have been sampled, the explosive is desorbed from the particles, concentrated, and then presented to a sensitive chemical detector for analysis. In its present configuration, the particle sampler delivers a vapor phase sample to the detector, but the device could be adapted to deliver samples in the solvent phase as well. This makes the sampler compatible with a number of sensor technologies.

Showing 5 of 9 publications

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