The brick detector

Materials World magazine
9 Mar 2018

Researchers have found a way to determine whether clay bricks have ever been near a radiological source, and identify the specific type of source, such as high enriched uranium or plutonium. 'A major problem with brick material is that there has generally been significant chemical processing to isolate the quartz from the brick. In this study, a simplified treatment process has been tested to lessen the processing burden for retrospective dosimetry studies,’ the researchers from North Carolina (NC) State University, USA, said.

The scientists took samples of bricks and measured the radiation dose 'The technique laid out in our paper can take brick samples the size of a thimble and use them to identify whether a radiological source was plutonium, uranium, and so on, even if the source has been removed,' says Ryan O'Mara, a Ph.D. student at NC State and first author of the paper.

It was found that by using thermoluminescence, so release of light from this material when heated, which is fuelled by previously absorbed energy, the dose deposition profile of a brick sample could be reconstructed without the use of any chemicals for sufficiently large applied doses. This was done by estimating the energy of an 241Am exposure from a source in a brick using actual measured values. 

According to the scientists, this technique has the potential to greatly expedite dose reconstructions in the wake of nuclear accidents or for any related application where doses need to be determined.