Georgia Tech graduate student Paul Rose and Assistant Professor Anna Erickson are shown with Cherenkov quartz detectors that would be used to find shielded radioactive materials inside cargo containers. Photo: Rob Felt
Researchers have demonstrated proof-of-concept for a novel monochromatic particle imaging technique based on low-energy nuclear reactions designed to detect the presence of weapons-grade uranium and plutonium in cargo containers arriving at U.S. ports. The method relies on a combination of neutrons and high-energy photons to detect shielded radioactive materials inside the containers.
The technique can simultaneously measure the suspected material’s density and atomic number using mono-energetic gamma ray imaging, while confirming the presence of special nuclear materials by observing their unique delayed neutron emission signature. The mono-energetic nature of the novel radiation source could result in a lower radiation dose compared to conventionally employed methods.
As a result, the technique could increase detection performance while avoiding harm to electronics and other cargo that may be sensitive to radiation. If the technique can be scaled up and proven under real inspection conditions, it could significantly improve the ability to detect — and prevent — the smuggling of dangerous nuclear materials.
Supported by the National Science Foundation and the U.S. Department of Homeland Security, the research was reported in the Nature journal Scientific Reports. Scientists from Georgia Tech, the University of Michigan, and the Pennsylvania State University conducted this research, which is believed to be the first successful effort to identify and image uranium using this approach.
“Once heavy shielding is placed around weapons-grade uranium or plutonium, detecting them passively using radiation detectors surrounding a 40-foot cargo container is very difficult,” said Anna Erickson, an assistant professor in Georgia Tech’s George W. Woodruff School of Mechanical Engineering. “One way to deal with this challenge is to induce the emission of an intense, penetrating radiation signal in the material, which requires an external source of radiation.” — John Toon