There is a renewed interest in the development of chemical and biological agent sensors due to the increased threat of weapons deployment by terrorist organizations and rogue states. Optically based sensors address the needs of military and homeland security forces in that they are reliable, rapidly deployed, and can provide continuous monitoring with little to no operator involvement. Nomadics has developed optically based chemical weapons sensors that utilize reactive fluorescent chromophores initially developed by Professor Tim Swager at MIT. The chromophores provide unprecedented sensitivity and selectivity toward toxic industrial chemicals and certain chemical weapon agents. The selectivity is based upon the reactivity of the G-class nerve agents (phosphorylation of acetylcholinesterase enzyme) that makes them toxic. Because the sensor recognizes the reactivity of strong electrophiles and not molecular weight, chemical affinity or ionizability, our system detects a specific class of reactive agents and will be able to detect newly developed or modified agents that are not currently known. We have recently extended this work to pursue a combined chemical/biological agent sensor system incorporating technologies based upon novel deep ultraviolet (UV) light emitting diodes (LEDs) developed out of the DARPA Semiconductor UV Optical Sources (SUVOS) program.
The United States Army has expressed an interest in developing sensors that are capable of detecting explosives found in buried landmines. Techniques under development often detect explosive molecules that have migrated out of buried landmines, through the soil, and to the soil’s surface. Since the success of detectors using the above method depends on the presence of explosives at the soil surface, it is critical to have an understanding of the nature of the explosive signature that is being detected. Many factors affect the migration of explosives from the landmine through the soil. These factors include, but are not limited to, soil moisture, terrain, mine type, and explosive type. This is a complex system to study. The experiment presented here attempts to monitor the explosive signature above twenty-seven landmines that have been buried for a number of years in a temperate environment. There are nine mine types represented in the experiment. Five of the mine types are anti-tank mines and four of the mine types are anti-personnel mines. Soil samples have been collected above and around these twenty-seven mines and analyzed using gas chromatography coupled with an electron capture detector (GC-ECD). Samples were collected in June 2001, October 2001, February 2002, and June 2002. Results of the GC-ECD analysis of these samples are presented in this paper.
Night Vision Electronic Sensors Directorate (NVESD) has initiated a program for land mine sensor development based upon explosives-related chemical (ERC) detection. As part of the NVESD ERC sensor program, we have sampled soils surrounding buried land mines at the experimental mine lanes, U.S. Army Test Site, with the assistance of the Army Corps of Engineers, Cold Regions Research and Engineering Laboratory. Our goal has been to quantify concentrations of explosive related chemicals found in surface soils above and around nine types of buried land mines and to study their fate over time. This paper will describe the field tests conducted post-DARPA Dog Nose Program, the sampling and analysis protocol and the conclusions drawn from these tests.