Better Bomb-Sniffers?

Terrorists and insurgents still love things that go boom. So it's no surprise that the Defense Department is looking for smarter, more accurate ways to detect explosives. Here are a few research contracts Darpa, the Pentagon's bleeding-edge science agency, recently handed out, to build better bomb-sniffers:
EIC LABORATORIES, INC.
111 Downey Street
Norwood, MA 02062
Phone: (781) 769-9450
PI: Jane Bertone
Topic#: DARPA 06-022
Title: Explosives Detection in Residential Building Ventilation Systems

Abstract: One approach to locating illicit bomb factories in Iraq and Afghanistan is analytical monitoring within the ventilation systems of suspect residential buildings. We are proposing a multiple sensor analyzer that sequentially interrogates individual vents or ducts in such buildings and produces fingerprints characteristic of present target substances. The basic premise of this proposal is to locate sensor probes in key ducts or vents and connect them with fiber cabling to a spectral analyzer located in the attic or roof of the building. This setup would monitor a number of different locations within the building with emission of a wireless alarm report to a regional Tactical Operations Center from all online sensors every 10 to 15 minutes. We will achieve reproducible and selective detection of explosives using novel self-assembled structures that create an inherently uniform pattern, leading to rapid, reproducible manufacturing. The specific instrument we propose to analyze the sensors is a field portable spectrograph, with accompanying fiber optic probes, coupled to an accessory containing the sensing elements. Phase I work will focus on the demonstration of reproducible detection of airborne explosives using the sensors in the presence of potentially confusing interfering substances. The Phase II program will focus on quantifying the extent of fouling of the sensors due to long-term exposure to building air, developing a fieldable self-contained and powered instrument including multiplexed probes and wireless communication, and testing the sensors in mock ventilation systems.

Abstract: It has become imperative to counter the escalating threat of improvised explosive device attacks on our armed forces personnel deployed in foreign locations by seeking out and neutralizing local terrorist operated bomb making factories. Such factories are typically located in apartment buildings or other large dwellings, where the level of out-gassed explosive marker vapors is so small and buried within numerous confusers such as common chemicals that current detectors cannot be utilized to aid in their location. Therefore, Lynntech proposes to address this critical DOD need by fabricating three novel TSP based colorimetric sensor elements each selective for DNT, TNB and picrate, and incorporating these into an automated bench scale detector to demonstrate our capability to reagentlessly detect and quantify trace vapor phase explosives markers in the presence of common confusers such as household chemicals and matches. During Phase II, we will fabricate additional selective TSP sensor elements for other molecular explosives markers encompassing groups A through D and integrate these into a prototype compact inexpensive explosives detection device which may be placed in the HVAC system of apartment buildings. The device will be tested for reliable operation with low false positives, multiplex-ability and wireless control during Phase II.

Abstract: Automated vapor sampling detectors could potentially provide a detection capability for high vapor pressure explosives such as nitroglycerine (NG). However, for materials such as HMX and RDX, the equilibrium vapor pressures are at least four orders of magnitude lower than conventional trinitro-toluene (TNT) explosives, making detection based on sampling of airborne vapor difficult for all of the explosives without concentration. MicroStructure Technologies (MicroST) has undertaken a mission to develop small, compact, microstructured array detectors for explosive vapors (both nitrogen and peroxide-based materials). The upstream micropillars on the microstructured array have a high surface area and the vapors are adsorbed. The laser energy is coupled by fiber optic into the microarray to desorb a concentrated pulse of concentrated explosive vapor. A Microstructured Array Sampler (MAS) with an inorganic polymer coating as a sensing element to detect the concentrated vapors. The use of the inorganic polymers for explosive detection on an air-sampling microarray for confirmation is innovative. The key innovation of the proposed approach is to use a chip-based laser to selectively desorb a concentrated energetic sample onto sensing polymers coated onto a microarray. Lastly, the alarm signal from the microarray is sent wirelessly to reveal the type of explosive detected.