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-- WITH PHOTO -- TO ENERGY, NATIONAL, AND SCIENCE EDITORS:
Sensitive Detection Method May Help Impede Illicit Nuclear Trafficking
WASHINGTON, April 15, 2014 /PRNewswire-USNewswire/ -- According to the
International Atomic Energy Agency (IAEA) the greatest danger to
nuclear security comes from terrorists acquiring sufficient quantities
of plutonium or highly enriched uranium (HEU) to construct a crude
nuclear explosive device. The IAEA also notes that most cases of
illicit nuclear trafficking have involved gram-level quantities, which
can be challenging to detect with most inspection methods.
According to a new study appearing this week in the Journal of Applied
Physics, coupling commercially available spectral X-ray detectors with
a specialized algorithm can improve the detection of uranium and
plutonium in small, layered objects such as baggage. This approach
enhances the detection powers of X-ray imaging and may provide a new
tool to impede nuclear trafficking.
The study was conducted by a joint research team from the University
of Texas at Austin (UT) and the Department of Energy's Pacific
Northwest National Laboratory (PNNL).
"We first had to develop a computational model for how X-rays move
through materials and how they are detected so that we could predict
what an image will look like once the radiation passed through an
object," said UT's Mark Deinert, one of the authors on the paper.
"With that in hand, we applied an 'inverse algorithm,' varying the
composition of the object until the predicted image matched the
measured one. We also gave our algorithm additional details about
density and other factors-a process called 'regularization'- to
adaptively enhance its ability to discriminate materials."
The new system, Deinert said, expands upon techniques originally
developed for medical applications such as discerning between bone and
iodine contrast agent in an X-ray image. "We wanted to show that
spectrally sensitive detectors can be used to discriminate plutonium
and other high-atomic-number elements from multiple layers of other
materials using a single-view radiograph," said Andrew Gilbert, the
lead author on the paper and a doctoral student of Deinert's working
at PNNL. "In simulated radiographs, we were able to detect the
presence of plutonium with a mass resolution per unit area of at least
0.07 gram/centimeter squared; in other words, we can locate a sample
of plutonium with a thickness of only 0.036 millimeters."
Now that the inverse algorithm method has been shown to help X-rays
detect nuclear materials in luggage and other small objects, Deinert
said that his team will next expand the concept to improve detection
on a larger scale. "We plan to apply the algorithm to high-energy
X-ray systems that could be used for verification of arms-reduction
treaties," he said.
The article, "Non-invasive material discrimination using spectral
X-ray radiography" by A.J. Gilbert, B.S. McDonald, S.M. Robinson, K.D.
Jarman, T.A. White and M.R. Deinert is published in the Journal of
Applied Physics on April 15, 2014 (DOI: 10.1063/1.4870043). After that
date, it can be accessed at:
http://scitation.aip.org/content/aip/journal/jap/115/15/10.1063/1.4870043
ABOUT THE JOURNAL Journal of Applied Physics, published by the
American Institute of Physics, is an influential international journal
publishing significant new experimental and theoretical results of
applied physics research. See: http://jap.aip.org
More Information: Jason Socrates Bardi +1 240-535-4954
jbardi@aip.org @jasonbardi
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SOURCE Journal of Applied Physics
-0- 04/15/2014
/Photo: http://photos.prnewswire.com/prnh/20130627/DC39790LOGO
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