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Detecting & Measuring Radiation

Radiation has no odor or property that allows it to be seen. However, there are many types of devices used to measure it. Some devices are qualitative—they simply tell you that radiation is present but don’t tell you the amount of radiation present or the amount of exposure you are receiving. Some are quantitative—they might indicate the rate of radiation exposure, the quantity, or both. Although there are many types of devices, the basic requirement for measurement is that the radiation must be able to interact with the detector. If the radiation cannot get in to the detection chamber because it doesn’t have enough energy or the chamber wall is too thick, then it won’t get measured. This section will discuss only those devices commonly used to measure beta- and gamma-emitting radionuclides.

Local emergency responders will have some of these devices when they respond to incidents that might involve radioactive material. Your local department of health will use one or more of these devices to analyze samples taken from around nuclear power plants to determine if any radioactive materials are being released.