A Geiger counter is a type of particle detector that measures Ionizing radiation. They are capable of detecting the emission of nuclear radiation: alpha particles, beta particles or gamma rays. In 2010, Senior Airman O'Donnell used a Geiger counter to scan Homeworld Command for a Naquadria bomb planted by the Lucian Alliance. He was killed when a Tel'tak crashed into the base and the Geiger counter was recovered by Camile Wray and MSgt. Ronald Greer. They used it to locate the Naquadria bomb and also discovered that they had been exposed to lethal levels of radiation. (SGU: "Alliances")