Background radiation is low intensity ionising radiation which is always present in the environment. Most background radiation comes from natural sources such as cosmic rays and some types of rocks (for example granite in the Earth's crust); the rest - about 13 percent - comes from artificial sources. Of the artificial sources the one that contributes most to the
background radiation is the medical use of radioactive materials: other sources are the nuclear industry and fallout from weapons tests, television screens and luminous paint. When the radiation from a specific source is measured, the background radiation must be deducted from the result to make it accurate. Research Background Radiation
Abbreviations
SciTech
Research Background Radiation