Washington, D.C. (November 9, 2010) -- Researchers at the University of Maryland have proposed a scheme for detecting a concealed source of radioactive material without searching containers one by one. Detection of radioactive material concealed in shipping containers is important in the early prevention of "dirty" bomb construction. The concept, described in the Journal of Applied Physics, is based on the gamma-ray emission from the radioactive material that would pass through the shipping container walls and ionize the surrounding air.
The facilitated breakdown of the air in a focused beam of high-power, coherent, terahertz or infrared radiation would then be an indicator of the presence of the radioactive material. The gamma rays coming through the container walls could be detected by a pulsed electromagnetic source of duration between 10 ns to microseconds.
The team evaluated several candidate sources for this detection, including a 670-GHz gyrotron oscillator with 200-kW, 10-µs output pulses and a TEA CO2 laser with 30-MW, 100-ns output pulses. A system based on the 670-GHz gyrotron would have enhanced sensitivity and a range exceeding 10 m.
"It is not yet clear whether this approach to detection of nuclear material is practical," says first author professor Victor Granatstein, "but it is worth pursuing since it might impact an important need related to National Security."
The article, "Detecting Excess Ionizing Radiation by Electromagnetic Breakdown of Air" by Victor L. Granatstein and Gregory S. Nusinovich appears in the Journal of Applied Physics. See: http://link.aip.org/link/japiau/v108/i6/p063304/s1
Journalists may request a free PDF of this article by contacting jbardi@aip.org
ABOUT JOURNAL OF APPLIED PHYSICS
Journal of Applied Physics is the American Institute of Physics' (AIP) archival journal for significant new results in applied physics; content is published online daily, collected into two online and printed issues per month (24 issues per year). The journal publishes articles that emphasize understanding of the physics underlying modern technology, but distinguished from technology on the one side and pure physics on the other. See: http://jap.aip.org/
ABOUT AIP
The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.
Journal
Journal of Applied Physics