Low-energy imaging peers through steel containers to spot nuclear material
Detecting nuclear materials whenthey're shielded by steel shipping containers is a difficult task,but a novel low-energy imaging technique might just take away theheadache. The method works by firing a combination of neutrons andhigh-energy photons, and looking for a unique emission signaturereleased in response.
Millions of cargo containers are movedacross the globe every year, and making sure that dangerous nuclearmaterials don't slip through the cracks is an extremely difficulttask. There's been some progress when it comes to detectionmethods, but a new system could make finding nuclear materials mucheasier.
The new technology makes use of an ionaccelerator, which produces heavy isotopes of hydrogen. These aretargeted at boron, resulting in the emission of neutrons andhigh-energy photons, focused in a fan-shaped beam that can be used toscan containers.
Imaging detectors are placed around thecontainer, ready pick up on the emissions caused by the beam. Acombination of the photons and neutrons excite any nuclear materialpresent, causing it to emit gamma rays and neutrons. Thecharacteristics of the different particles provide information aboutthe materials inside the container.
When the particles come into contactwith fissile material, both prompt and delayed neutrons aregenerated. The delayed particles can be detected through the thickmetal of shipping containers, and they aren't generated by non-fissionablematerials such as lead. As such, it's possible to use them anindicator as to whether materials intended for nuclear weapondevelopment are present.
While the technique is yet to be put tothe test out in the real world, it has been put through its pacesunder laboratory conditions. A collaborative team from the GeorgiaInstitute of Technology and MIT found that the particles were able topass through the shielding, with the detectors positioned oppositesuccessfully picking up the tell-tale particles.
If real-world testing of the techniquebacks up the promising lab results, then the newtechnology could have a big security impact, improving abilities todetect the shipping of the dangerous materials. Its low-energy nature should also avoid the scanning process from causing damage to electronics or anything inside the container that's sensitive to radiation.
Full details of the study are publishedonline in the journal Scientific Reports.
Source: Georgia Tech