Passive standoff detection of chemical warfare agents on surfaces

Abstract

Results are presented on the passive standoff detection and identification of chemical warfare (CW) liquid agents on surfaces by the Fourier-transform IR radiometry. This study was performed during surface contamination trials at Defence Research and Development Canada-Suffield in September 2002. The goal was to verify that passive long-wave IR spectrometric sensors can potentially remotely detect surfaces contaminated with CW agents. The passive sensor, the Compact Atmospheric Sounding Interferometer, was used in the trial to obtain laboratory and field measurements of CW liquid agents, HD and VX. The agents were applied to high-reflectivity surfaces of aluminum, low-reflectivity surfaces of Mylar, and several other materials including an armored personnel carrier. The field measurements were obtained at a standoff distance of 60 m from the target surfaces. Results indicate that liquid contaminant agents deposited on high-reflectivity surfaces can be detected, identified, and possibly quantified with passive sensors. For low-reflectivity surfaces the presence of the contaminants can usually be detected; however, their identification based on simple correlations with the absorption spectrum of the pure contaminant is not possible.

Long range standoff detection of chemical and explosive hazards on surfaces

“…In later work, the authors concentrated on TNT on an aluminum substrate where the CN and C2 molecular emission in the fs-LIBS plasma could be used as a potential marker for explosives detection. [16] In an effort to focus on this molecular opposed to elemental emission, a laser fluence of 200 J/cm-1 was used in this study. Although elemental emission from the aluminum substrate was recorded, there was an absence of atomic emission from the elemental constituents of the TNT in fs-LIBS spectra.…”

“…Other long wave IR systems have also been explored to tackle the standoff surface detection problem [15]. One such system is a modified passive FTIR radiometer developed by Defense Research and Development Canada (DRDC)-Val Cartier [16][17]. The dualbeam compact atmospheric sounding interferometer (CATSI) showed detection of vapor clouds and CW liquids contaminated on surfaces from distances up to 60 meters.…”

Active FTIR-based standoff detection in the 3-4 micron region using broadband femtosecond optical parametric oscillators

“…Typical applications include: environmental pollution diagnosis; non-invasive analysis of paintings; detection of gas leaks or toxic industrial contamination; monitoring chemical reactions; identification of chemical warfare agents on surfaces; analysis of contaminated soils and the remote identification of explosives or hazardous materials. Passive stand-off FTIR spectroscopy [8][9], which relies on the reflected infrared radiation from the cold sky, allows remote detection over a long distance, but identification of molecular species can be complicated and sometimes impossible due to the influence of the background spectrum from the sky. Active stand-off FTIR spectroscopy using a high-temperature blackbody as the light source [10][11][12] facilitates the identification of molecular species, but it is inefficient and only offers short-range remote sensing as a result of the poor spatial coherence and low spectral brightness of the source.…”

Open-Path FTIR Detection of Explosives on Metallic Surfaces

“…Work by Theriault and colleagues (Theriault, et al, 2004), Van Neste and collaborators (Van Neste, et al, 2009), Blake and co-workers (Blake, et al, 2009) and Pacheco-Londoño and colleagues ) have helped to contribute the development of this application of OP/FTIR. Theriault and collaborators made field measurements of liquid contaminants deposited on a number of surfaces at a standoff distance of 60 m using FTIR radiometry (Theriault, et al, 2004). Van Neste and collaborators described standoff detection measurements of trace quantities of surface adsorbed high explosives (Van Neste, et al, 2009).…”