Scientists test dirty bomb sensors in Nevada
During a recent test at the Radiological-Nuclear Countermeasures Test and Evaluation Complex in the Nevada desert, scientists waited for a read-out from a hand-held Geiger counter-type machine placed next to a large corrugated metal shipping container. It failed to identify the plutonium in the container, but on a second try, it worked.
Beyond the checkpoints, fences and armed guards, Homeland Security scientists are working on a $33 million program to perfect devices that can more accurately detect such nuclear devices and “dirty bombs,” reports The Associated Press.
The program, a division of the federal Homeland Security Department, was created under a presidential order to refine methods to protect the nation from radiological and nuclear threats.
The complex provides an opportunity for scientists to test for nuclear material, including weapons-grade plutonium, in secure and controlled conditions.
Some of the monitors now used to identify such material do not always work, says Vayl Oxford, director of the federal Domestic Nuclear Detection Office.
The test site, a vast federal reservation the size of Rhode Island, also hosts the National Center for Combating Terrorism, which includes several facilities to improve the nation’s ability to prevent or recover from a terrorist attack.
Technicians are testing pillar-style roadside sensors like those deployed to ports of entry and some highway weigh stations. The sensors detect neutrons and gamma rays emitted by lethal nuclear devices or radioactive isotopes that could be dispersed by less sophisticated explosives in a “dirty bomb.”
The scientists also are testing sensors in vehicles, including white ambulance-style vans, black SUVs and a Jeep loaded with sophisticated radiation sniffers and computers.
The tests aim to see whether the 30 or so devices available commercially can distinguish a bomb from less harmful sources of radioactivity, such as a person who has had a radioactive isotope injected during a medical procedure, or household items like kitty litter and floor tiles that contain natural trace amounts.
Detecting radioactive materials in public places is an evolving science, Oxford says. There are no national standards for devices that range from the size of a steam iron to the two-door prototype “Smart Jeep.”
The next generation of hand-held detectors should be able to identify radiation sources without the need to open shipping containers using what Oxford calls “discrimination capability.”