Researchers at the Northwestern University have developed new materials that could lead to a handheld device for detecting nuclear weapons and materials, such as a "bomb in a suitcase".
"The terrorist attacks of 9/11 heightened interest in this area of security, but the problem remains a real challenge," said lead researcher Mercouri G. Kanatzidis.
Kanatzidis and his colleagues designed promising semiconductor materials that, once optimized, could be a fast, effective and inexpensive method for detecting dangerous materials such as plutonium and uranium.
They developed the new materials from heavy elements that, when struck by gamma rays, excite the electrons, making them mobile and thus detectable.
Because every element has a particular spectrum, the signal identifies the suspect material.
The problem the researchers faced was that the heavy elements have a lot of mobile electrons, so electrons excited by gamma radiation are hard to detect.
"It's like having a bucket of water and adding one drop-the change is negligible," Kanatzidis said.
"We needed a heavy element material without a lot of electrons. This doesn't exist naturally so we had to design a new material," he added.
The two new semiconductor materials - cesium-mercury-sulfide and cesium-mercury-selenide - operate at room temperature, and the process is scaleable.
"Our materials are very promising and competitive. With further development, they should outperform existing hard radiation detector materials," said Kanatzidis.
The finding will be published in the September 22 issue of the journal Advanced Materials.