The United Nations estimates that, at present rates, clearing the approximately 110 million landmines buried in seventy countries could take more than 1,000 years. Richard Craig, a physicist at the Department of Energy's (DOE) Pacific Northwest National Laboratory, is developing a new method for detecting landmines. His prototype is called the Timed Neutron Detector. Unlike today's metal detectors, which cannot detect all-plastic landmines, it works by detecting the slowing of neutrons that encounter hydrogen. Hydrogen is found in both explosives and plastics. As neutrons leave the detector, a time-tagging radiation source obtained from the DOE's Oak Ridge National Laboratory records each neutron's exit. Then, neutrons return after either interacting with the soil or with the hydrogen found in landmines. Neutrons that interact with soil will return to the detector at nearly the same speed at which they left. The detector ignores them. Instead, the detector focuses on neutrons that interact with hydrogen. The neutron's speed slows down when it interacts with hydrogen because it has about the same mass as a hydrogen nucleus "It's a little like billiards," says Craig. "When the cue ball strikes another ball of the same mass, the second ball takes some of the energy and the cue ball loses energy and slows down." Additional applications for the neutron detecting technology include forensic and law enforcement applications. For more information, send e-mail to firstname.lastname@example.org. The website for the Oak Ridge National Laboratory is www.ornl.com.
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