When a 23-year-old Nigerian man allegedly attempted to blow up a trans-Atlantic flight near Detroit on Christmas, the powerful plastic explosive that was sewn into his clothing was not detected before he boarded the plane. Security screenings in airport terminals and other high-traffic sites like government buildings or entertainment venues may soon be better able to detect explosives, narcotics and other illegal contraband hidden on the body.
Officials at Nesch LLC, a firm based at the Purdue Research Park of Northwest Indiana, have developed patented technology called Diffraction-Enhanced X-ray Imaging (DEXI) that detects objects, explosives, narcotics and other contraband better than conventional radiography.
"X-ray absorption is the basis of conventional radiography, but carbon, nitrogen and oxygen do not absorb X-rays well. Explosives and narcotics are typically made of these elements. Conventional radiography detects these objects poorly due to its exclusive reliance on absorption," said Ivan Nesch, CEO. "DEXI is different because it uses X-ray refraction and scattering to construct images, along with absorption. It can detect explosives and narcotics because they noticeably refract and scatter X-rays."
When X-ray beams pass through an object, its density, thickness and material alter the direction of X-rays and produce small, angular variations of the beam. DEXI uses a beam analyzer between the human subject and the detector to introduce sensitivity to X-ray beam angle variations.
"DEXI converts the angle variations to intensity variations, making refraction and scattering effects visible, resulting in highly defined images," Nesch said. "Substances like explosives and narcotics that cause X-ray beams to scatter rather than be absorbed still can be easily detected using the DEXI technology."
Unlike other technology, DEXI is non-invasive. It reveals the internals but does not expose or recreate the contours of a person's body or face. An individual's privacy is maintained during a security screening, an issue that arises with technologies like whole body scanners.
"Those technologies create a topographic map of a person's body. They can see facial and body features," Nesch said. "DEXI looks at what is inside - the clothes and the body. It is almost impossible to recognize a person from such an X-ray image."
DEXI also is safer to use than conventional radiography because it exposes objects to 50 times less radiation.
Nesch and his colleagues' goal in developing DEXI is to provide the public with a solution for a safer world.
"Placing DEXI Security machines at airports' and other buildings' security gates will ensure dangerous materials are taken out of the control of terrorists who seek to inflict grave harm to the general public," he said.
Nesch plans to make DEXI Security machines available as early as the first half of 2010, when the first orders will be accepted. The firm already has received requests for more information about the technology from China, India, Israel, Latin America and Saudi Arabia.
The DEXI technology was discovered by Dean Chapman, Purdue University alumnus and professor at the University of Saskatchewan in Saskatoon. Chapman serves as chief scientific officer at Nesch.
