Scientists from the United States found traces of radioactive elements even after they were removed from surfaces. To do this, they turned building materials into a kind of dosimeters that store information about hazardous substances.

Researchers from North Carolina State University have developed a new methodology for locating radioactive materials. It allows the use of conventional building materials as a source, relying on the residual signals of gamma radiation. Researchers can take pictures of radioactive materials even after they have been removed from the surface.

“This study builds on our previous work, which was an empirical demonstration that we can turn a brick into a gamma-ray spectrometer that characterizes the source energy distribution”, said Robert Hayes, associate professor of nuclear engineering and lead author of the study.

Scientists explained that using the new method they can take almost any array of materials and turn them into a “camera” of gamma radiation, characterizing the location and distribution of the source. In this study, they were able to accurately predict not only the location of plutonium, but even the radius of the source.

Despite the fact that the researchers also used commercial dosimeters, the results of scientists showed that they could do without them – using only building materials. They explained this by the fact that they only need to measure the silicates in the brick – quartz, feldspars, zircon, which contain traces of hazardous substances. Based on these data, they can obtain information on the size and shape of the radiation source, as well as on the nature of the radioactive material itself.