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Micah Folsom in front of the accelerator at ProVision, a radiation therapy facility in Knoxville.

A recent doctoral graduate in the Tickle College of Engineering has invented a radiation detector design that may one day be used to stop the smuggling of nuclear material or help emergency responders find radiation spread from a dirty bomb.

Micah Folsom, who studied nuclear engineering, took a concept built for gamma ray detection and made it work for neutron scatter imaging technology.

Folsom’s camera design is the first working compact neutron scatter camera, similar to a fast neutron equivalent of the Advanced Compton Telescope used in gamma ray astronomy.

Similar cameras that image neutron sources like plutonium are large and bulky because the neutron must interact at least twice, typically in two well separated planes, and the energies and locations of the neutron scatters must be known.

The camera Folsom designed takes pictures of radiation, fast neutrons, and then shows where those fast neutrons are coming from. The design is compact enough for someone to carry on their person.

The camera uses what’s called coded-aperture imaging, which consists of a very specific shadow pattern and a light source. The source will cast a shadow right through the pattern, similar to how light will go right through fingertips.

There’s a very specific pattern cast onto the photo systems; then the shot is recorded and an unfolding algorithm is used to determine where the light came from.

“This design has very good potential to be able to image neutron sources rather quickly due to high potential for excellent imaging efficiency,” said Jason Hayward, associate nuclear engineering department head and Folsom’s thesis advisor.