Radioactive dating cesium pb 210
By contrast, terrestrial NORM – especially radon – contributes to the majority of natural dose, usually over 1000 microsieverts (1 m Sv) per year.
Some of the main comsogenic nuclides are shown in Table 1, carbon-14 being important for dating early human activities.
Material giving rise to these enhanced exposures has become known as naturally occurring radioactive material (NORM).
NORM is the acronym for Naturally Occurring Radioactive Material, which potentially includes all radioactive elements found in the environment.
However, the term is used more specifically for all naturally occurring radioactive materials where human activities have increased the potential for exposure compared with the unaltered situation.
However from the perspective of radiation doses to people, such a distinction is completely arbitrary.At higher altitudes, the dose due to both increases, meaning that mountain dwellers and frequent flyers are exposed to higher doses than others.For most people, cosmogenic NORM barely contributes to dose – perhaps a few tens of microsieverts per year.A 70 kg person has 4400 Bq of K-40 – and 3000 Bq of carbon-14.) Cosmogenic NORM is formed as a result of interactions between certain gases in the Earth’s atmosphere and cosmic rays, and is only relevant to this paper due to flying being a common mode of transport.
Since most cosmic radiation is deflected by the Earth’s magnetic field or absorbed by the atmosphere, very little reaches the Earth’s surface and cosmogenic radionuclides contribute more to dose at low altitudes than cosmic rays as such.The acronym TENORM, or technologically enhanced NORM, is often used to refer to those materials where the amount of radioactivity has actually been increased or concentrated as a result of industrial processes.This paper addresses some of these industrial sources, and for simplicity the term NORM will be used throughout.For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection.