Remote identification of chemicals concealed behind clothing using near infrared spectroscopy
Paper by: C??line M. Canal, Aamer Saleem, Roger J. Green and David A. Hutchins, Anal. Methods, 2011, Advance Article DOI: 10.1039/C0AY00386G , Paper (University of Warwick, UK)
Measurements are presented which demonstrate that near infrared (NIR) spectroscopy can be used to identify chemicals concealed behind clothing. This has been achieved for detector stand-off distances of 3 m.
The optical properties of a range of clothing materials have been investigated, and the transmission of NIR signals found to be sufficient for spectroscopy. The study has shown that granular solid materials can be identified when hidden behind a layer of clothing.
Examples of chemicals used in this study include ammonium nitrate and other ammonium salts.
Details of the current measurements and results are given, together with suggestions for increasing detection sensitivity.
In a related news story by RSC Publishing’s Highlights in Chemical Technology Fay Nolan-Neylan wrote:
‘Identifying materials hidden under clothing is an unsolved challenge for existing security technologies. NIR spectroscopy combined with powerful analysis tools might be a promising answer,’ says J??rgen Popp who develops innovative spectroscopic techniques at Friedrich Schiller University in Jena, Germany. However, he points out that that dealing with influences such as perspiration, scent and pollution will be a challenge.