![]() ![]() Radioactive material is found throughout nature. They can be used to visualize the background radiation Industrial, security, medical, educational, and researchĬloud chambers used by early researchers first detected cosmic rays and other background radiation. Up to 0.02 mSv near sites excludes occupational exposure Peak of 0.04 mSv in 1986 and declining since higher near site US is mostly due to medical and aviation workers. Worldwide average to workers only is 0.7 mSv, mostly due to radon in mines Peak of 0.11 mSv in 1963 and declining since higher near sites US figure is mostly CT scans and nuclear medicine.Ĭigarettes, air travel, building materials, etc. Sizeable population groups receive 10–20 mSv Mainly from radon, depends on indoor accumulation However, if no radiation source is specified as being of concern, then the total radiation dose measurement at a location is generally called the background radiation, and this is usually the case where an ambient dose rate is measured for environmental purposes.īackground radiation varies with location and time, and the following table gives examples:Īverage annual human exposure to ionizing radiation in millisieverts (mSv) per year An example would be measurement of radioactive contamination in a gamma radiation background, which could increase the total reading above that expected from the contamination alone. ![]() This is important where radiation measurements are taken of a specified radiation source, where the existing background may affect this measurement. ![]() So a distinction is made between dose which is already in a location, which is defined here as being "background", and the dose due to a deliberately introduced and specified source. These include both cosmic radiation and environmental radioactivity from naturally occurring radioactive materials (such as radon and radium), as well as man-made medical X-rays, fallout from nuclear weapons testing and nuclear accidents.īackground radiation is defined by the International Atomic Energy Agency as "Dose or dose rate (or an observed measure related to the dose or dose rate) attributable to all sources other than the one(s) specified. For background radiation from space, see cosmic background radiation.īackground radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.īackground radiation originates from a variety of sources, both natural and artificial. ![]()
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