Passive Radiation Monitors Detect Gamma Rays on State Highways

Radiation detection technology developed at the Lawrence Livermore National Laboratory is now being used to remotely detect the presence of radioactive materials in vehicles driving on highways.

So far, one state in the Western United States has deployed more than a score of the radiation detectors, called the adaptable radiation area monitor (ARAM), and placed them at vehicular entrances to that state to monitor for nuclear materials. The ARAM systems can detect concealed radioactive material about the size of a grain of sand moving at 45 miles per hour, nearly freeway speed.
A second state, New Jersey, has acquired from Textron Defense Systems a fleet of SUV’s outfitted with the ARAM detection technology to patrol its highways and streets for nuclear materials.
New Jersey’s RadTrucks are remarkably simple to use, said state Trooper Dave Gatto, who was quoted in a Philadelphia Inquirer article. Gatto said that after 10 hours of training he could tell the difference between the radioactive signatures emitted by uranium, cesium, and plutonium and even mundane sources such as kitty litter.
ARAM can be deployed in a host of ways — as a portable detector in an SUV, as a vehicle monitor alongside freeways, as a pedestrian portal monitor, as a package or luggage detector, as a fixed maritime detector and as a portable maritime detector.
Operating at room temperatures, ARAM can detect gamma rays and, with the assistance of a helium-3 neutron detector, also can monitor for neutrons.
The system relies on a minimum number of components, including a sodium iodide detector, multi-channel analyzer, computer and sophisticated LLNL control and commercial analysis software. It acquires 1,024 channels of data 10 times per second, which allows the control software a higher probability of detection and provides the commercial analysis software with highest quality data for identification.
“This type of system gives us a better chance of not only picking up that there’s radiation, but the type of radiation, whether it’s a medical isotope or a terrorist device,” said Dave Trombino, a nuclear engineer at LLNL and one of the ARAM developers.

Press release: States use LLNL-developed radiation detection advance for highway monitors, patrolling roads