Detecting Nuclear Radiation

Although you can't see, hear, or feel the radioactivity around you, scientific instruments can measure nuclear radiation. Devices that are used to detect nuclear radiation include Geiger counters and film badges. A Geiger counter, shown in Figure 7, uses a gasfilled tube to measure ionizing radiation. When nuclear radiation enters the tube, it ionizes the atoms of the gas. The ions produce an electric current, which can be measured. The greater the amount of nuclear radiation, the greater the electric current produced in the tube is.

Recall that in Becquerel's experiment, nuclear radiation left an image on a photographic plate. Today, many people who work with or near radioactive materials wear film badges to monitor their exposure to nuclear radiation. A film badge contains a piece of photographic film wrapped in paper. The film is developed and replaced with a new piece periodically. The exposure on the film indicates the amount of radiation exposure for the person wearing the badge.

Figure 7 Wearing protective clothing, a firefighter uses a Geiger counter to test the ground for radioactivity. Firefighters sometimes help clean up accidents involving radioactive materials.