Physicists at the University of Maryland have developed a powerful new method of radiation detection by using an infrared laser beam to induce a phenomenon known as an electron avalanche breakdown near the material. The new technique can perform remote detection of shielded material from a distance, and improves on current technologies that require close proximity to the radioactive material. With additional engineering advancements, the remote detection method could be scaled up and used to scan trucks and shipping containers at ports of entry, providing a powerful new tool to detect concealed, dangerous radioactive material. The researchers described their proof-of-concept experiments in a research paper published in the journal Science Advances. As radioactive material emits decay particles, the particles strip electrons from — or ionize — nearby atoms in the air, creating a small number of free electrons that quickly attach to oxygen molecules. By focusing an infrared laser beam into this area, Schwartz and his colleagues easily detached these electrons from their oxygen molecules, seeding an avalanche-like rapid increase in free electrons that is relatively easy to detect.
