Scientists from Northwestern University have succeeded in developing new materials capable of detecting radioactive radiation
Scientists from Northwestern University have succeeded in developing new materials capable of detecting radioactive radiation. The innovative method could lead to the development of a manual device for detecting weapons and nuclear materials, especially in view of the "nuclear bomb in a suitcase" scenario.
"The terrorist attacks of September XNUMXth increased the interest in this security area, but the problem remains a real challenge," said researcher Mercouri G. Kanatzidis, who led the study. We prepared promising semiconductor materials that could lead to the development of a fast, efficient and cheap method for detecting dangerous materials such as plutonium and uranium."
In order to develop an efficient detector, the team of researchers turned to the part of the periodic table where the heavy elements are found. The researchers developed a design concept that enables the preparation of semiconductor materials from heavy elements in which most of the compound's electrons are bound and not mobile. When gamma rays penetrate a compound they excite the electrons and make them mobile, and subsequently measurable. And since each element has its own unique spectrum, the signal identifies the detected material. The method, known as "dimensional reduction" (dimensional reduction) was published in the scientific journal Advanced Materials.
For most materials, gamma rays emitted by nuclear materials will simply pass through them and render them unmeasurable. However, heavy substances, such as mercury, thallium, selenium and cesium absorb the gamma rays to a considerable extent. The problem the researchers faced was that heavy elements have many mobile electrons. This means that the gamma rays that hit the material and excite the electrons do not allow the detection of this change.
"It's like adding one drop of water to a bucket full of water - the change is negligible," explains the researcher. "We needed a material of a heavy element that does not contain many mobile electrons. Such elements do not exist in nature, so we had to design a completely new material." The team of researchers designed their semiconductor materials in the form of crystalline structures, so that the electrons were deprived of their mobility.
The materials that the same researchers were able to develop and demonstrate as effective gamma ray detectors are cesium-mercury-sulfide and cesium-mercury-selenide. Both new semiconductor materials operate at room temperature, and the entire process is scalable to an industrial scale.
Our new materials are very promising and competitive," notes the researcher. "Following their further development, they should outperform existing detection materials for radioactive radiation. They may also be useful in the field of biomedicine as diagnostic imaging agents."
The news about the study
