Bricks Can Be Used to See Radioactive Presence from the Past

Bricks and other regular materials may be able to tell you where a historical location of radioactive materials was placed, according to a team of nuclear engineers. 

A new technique assembled by a team of researchers from North Carolina State University uses bricks, for instance, as a three-dimensional "camera" to see where radioactive materials such as weapons-grade plutonium used to be located. 

Their study was published in Radiation Measurements.

Snapshot of radioactive gamma radiation

"Our new work effectively shows that we could take an array of bricks and turn them into a gamma ray camera, characterizing the location and distribution of a radiation source," said Robert Hayes, an associate professor of nuclear engineering at NC State, and first author of the study.

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Hayes continued, "In this most recent study, we were able to rather accurately predict not only the location of the weapons-grade plutonium but even the radius of the source, just with passive dosimeters."

As this was a proof of concept study the team did not use bricks but instead relied on commercial dosimeters. "Even though we used commercial dosimeters here, our findings strongly suggest that we could do the same using building materials, such as brick," Hayes said. "That’s because the silicates in brick – such as quartz, feldspars, zircons, and so on – are all individual dosimeters."

What's interesting with their research is that typically you can't find out where past radioactive materials were placed unless using a radiation detector, which requires electricity or battery power, and it only measures the radiation when it's there. 

With its new method, the team is able to essentially see into the past simply by creating a method that captures the nuclear material simply by being next to it. As radiation leaves a mark on these materials, the researchers' method is able to see back in time and detect these spots. 

"This ability for three-dimensional imaging is a novel capability, meaning we can basically see into history in terms of what nuclear material was where or when," said Ryan O’Mara, a Ph.D. student at NC State and co-author of the study.