A nuclear gauge is a device used in several construction and industrial applications to perform routine measurements quickly. The device consists of a radioactive source and detector(s) to measure the radiation that interacts with the item being measured. When an item is placed between the source and the detector, the difference in radiation picked up by the detector can provide useful information about the item, such as its thickness, density, or chemical makeup.
There are two main types of nuclear gauges: fixed and portable.
Fixed gauges are permanently mounted in place to analyze an industrial process. The illustrations below show three examples of fixed nuclear gauges, used to measure density, level and thickness:
Nuclear gauges also have portable applications: they can be used to analyze the walls of dug holes to identify mineral deposits, or to search for underground caves or other formations that could make a building site unstable.
Workplaces that use nuclear gauges in Canada do so with operating licenses from the Canadian Nuclear Safety Commission, which requires that the workplaces adhere to strict health and safety regulations. Workers are monitored for radiation exposure from these devices, and are consistently found to be among Canada’s least-exposed users of occupational radiation sources, receiving doses far less than the average background levels.