Washington, DC--A new source of gamma rays produced by the interaction of lower-energy laser photons with high-energy electrons will allow officials to search for hidden reactor fuel/nuclear bomb material.
These gamma rays, called MEGa-rays (for mono-energetic gamma rays), which are incoherent, can be tuned to a specific energy so that they predominantly interact with only one kind of material. A beam of MEGa-rays, for example, might be absorbed by the nuclear fuel uranium-235 while passing through other substances including the more common (but less dangerous) isotope uranium-238. That sort of precision opens the door to “nuclear photonics,” the study of nuclei with light. “It is kind of like tunable laser absorption spectroscopy but with gamma-rays,” says Chris Barty of Lawrence Livermore National Laboratory, who presented on MEGa-rays today at this year's Conference on Lasers and Electro Optics (CLEO 2011, May 1-6, Baltimore, MD) .
In the last couple of years, MEGa-ray prototypes have identified elements like lithium and lead hidden behind metal barriers. The next generation of MEGa-ray machines, which should come on-line in a couple of years, will be a million times brighter, allowing them to see through thick materials to locate specific targets in less than a second.
Barty presented several MEGa-ray applications in use today and described the attributes of next-generation devices. Work is under way on a MEGa-ray technology that could be placed on a truck trailer and carried out into the field to check containers suspected of having bomb material in them. At nuclear reactors, MEGa-rays could be used to quickly identify how enriched a spent fuel rod is in uranium-235. They could also examine nuclear-waste containers to assess their contents without ever opening them up. MEGa-ray technology might also be used in medicine to track drugs that carry specific isotope markers.
The presentation was entitled “Mono-Energetic Gamma-rays (MEGa-rays) and the Dawn of Nuclear Photonics,” by Chris Barty.
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