However, we can measure and monitor it with simple scientific instruments. Three commonly used devices are dosimeters, film badges, and Geiger counters. People who routinely work with or around radiation sources wear dosimeters or film badges. These include workers in medicine, research, industry, and nuclear energy. Thermoluminescent dosimeters contain a special semiconductor that becomes energized when it is exposed to radiation.
Film badges contain a piece of film that is sensitive to radiation.
These badges are read regularly to determine a worker's total exposure to radiation over a period of time. To measure radiation levels at any given time, a Geiger counter is used. A Geiger counter contains a special gas-filled tube that separates two electrodes. When radiation passes through the tube, it interacts with the gas, causing an electrical pulse that can be measured on a meter or by audible clicks. The number of pulses in a given time is a measure of the intensity of radiation.