Ionizing radiation, resulting from nuclear reactions or radioactive decay, is invisible to the human eye yet it is all around us. Whether it's coming from space, from radioactive elements in the Earth, or from human activity, ionizing radiation is passing through us everywhere we go, anywhere on the planet. Radioactive decay producing alpha, beta, or gamma radiation is happening all the time, and curiously, some objects in daily life are noticeably more radioactive than others! Welding rods, camping gas mantles, smoke detectors, granite table tops and even bananas, they all produce radiation of different types and different energies.

One instrument to detect ionizing radiation is a Geiger-Müller tube, a simple gas filled tube. When exposed to high energy radiation, the inert gas inside is ionized and able to transport electrical charges. These charges can be detected using an electronic circuit, and visualised or sent to a speaker to produce the typical ticking sound often associated with radioactivity in popular culture.

In this workshop, attendees learn about the different types of ionizing radiation, and proceed to build their own Geiger counter based on an authentic 1970s Soviet Geiger-Müller tube. Because let's be honest: everyone loves a bit of Soviet nostalgia! This requires basic soldering and electronics skills. Once built, attendees calibrate their instrument and test it with different radiation sources. Attendees can choose to take their Geiger counter home after the workshop.