Non-Subscriber Extract
Raman spectroscopy portends well for standoff explosives detection
By Ben Vogel
29 August 2008
While a number of effective technologies and methods are in use for explosives screening in close proximity to people, packages or vehicles, the problem of detecting explosives at significant standoff distances has proved one of the most difficult - and most important - challenges confronting critical infrastructure security specialists.
A number of techniques for standoff detection have been investigated in recent years. Among the major methods, trace detection has traditionally suffered from the fact that available vapour plumes are normally too diluted for detection at an appreciable standoff range under all but the most favourable conditions, and bulk probing techniques suffer from an intrinsic decline of the signal intensity over distance.
Raman spectroscopy - a technique that analyses changes in laser light bouncing off individual molecules to indicate their chemical composition - has viable potential for explosives detection, according to Swedish threat detection specialist Portendo.
The company, together with Swedish national defence research agency FOI and government innovation agency Vinnovia, has developed a prototype system called P.Eye.
Portendo is developing P.Eye but the technology originates from the Swedish FOI, which has several years' experience in researching standoff explosives detection.
P.Eye functions by using a laser to energise molecules in or on an object, thereby creating Raman scattering that is collected using a telescope. The scattering produces a spectrum that is analysed and matched with a database of selected substances.
Aside from military uses for the product in enabling troops to detect improvised explosive devices from a safe distance, Portendo claims that P.Eye's capability to scan vehicles passing through an airport perimeter makes it suitable for aviation security.