Radioactive source, natural

Ernest Rutherford was the first person to observe a binuclear reaction, hi 1919, he exposed a sample of nitrogen to a particles from a naturally radioactive source. He observed the production of protons and deduced from the requirements of charge and mass balance that the other product was oxygen-17 ... 

In this context, attention was drawn [11] to quite a number of earlier reports on natural a-particle emitters with energies which do not match with any known natural radioactive source but fall into the ranges expected for superheavy nuclides were the superheavies already there, but unrecognized ... 

Incident Natural Radioactivity - Source Analyses Only. 2886... 

Bombarding the target nuclei with alpha-particles from naturally radioactive sources was the way in which artificial Isotopes were produced initially. An example is afforded by the work of Cockroft, and Walton. In 1931, these workers bombarded lithium target nuclei with hydrogen nuclei and found that many such collisions resulted in the emission of high energy alpha-particles ... 

Radioactivity. Methods based on the measurement of radioactivity belong to the realm of radiochemistry and may involve measurement of the intensity of the radiation from a naturally radioactive material measurement of induced radioactivity arising from exposure of the sample under investigation to a neutron source (activation analysis) or the application of what is known as the isotope dilution technique. 

Robst AL, Lowenstein TK, Jordan TE, Godfrey LV, Ku T-L, Luo S (2001) A 106 ka paleoclimate record from drill core of the Salar de Atacama, northern Chile. Paleogeo Paleoclim Paleoecol 173 21-42 Rosholt JN (1957) Quantitative radiochemical methods for determination of the sources of natural radioactivity. Anal Chem 29 1398-1408... 

The calculation of effective dose equivalent is sometimes used even when reporting values for natural radioactivity. The concept of effective dose equivalent was developed for occupational exposures so that different types of exposure to various organs could be unified in terms of cancer risk. It is highly unlikely that the general population would require summation of risks from several sources of radiation exposure. 

Our exposure to man-made radioactive sources, such as from nuclear power plants, is negligible when compared to the total radiation we receive. Man-made radiation accounts for less than 3% of the total radiation we receive in the United States, but in some countries, this figure is higher. The vast majority of the 3% of man-made doses of radiation we receive in our lifetime results from medical uses, and the vast majority of the 97% of the total exposure to all radiation we receive comes from natural sources. 

Background Radiation amount of natural radiation detected in the absence of nonnatural radioactive sources Base a substance that yields hydroxide ions in solution or accepts protons Becquerel SI unit for activity equal to one disintegration per second, abbreviated Bq... 

In the United States, the average background dose of radiation from natural sources is about 100 mrem/year, but it can be approximately double that amount in some localities. It has been estimated that this background may contribute 4.5 to 45 cancers per million people per year. Minute amounts of radioactivity are found in all drinking waters. Some of this natural radioactivity (tritium) comes from cosmic ray bombardment. 

Archaeologists have long sought methods for obsidian characterization that were rapid, reliable, non-destructive, and low-cost. Among the various methods investigated were visual techniques (79), density measurements (20), magnetic properties (27), thermoluminescence (22), fission-track analysis (25), Mossbauer spectroscopy (24), and natural radioactivity (25). Although some of the methods occasionally identified differences between sources, the overlap between sources was such that their overall reliability was unsatisfactory. The most successful method of characterization for obsidian provenance research has been compositional analysis (26). 

Based on the negligible annual dose to individuals of 10 pSv and assumed scenarios for unrestricted disposal of waste, IAEA has developed recommendations on exemption levels for radionuclides in solid waste (IAEA, 1995) the recommended exempt concentrations have values in the range of about 0.1 to 104 Bq g 1 depending on the radionuclide. IAEA also has issued recommendations on total activities and activity concentrations of radionuclides that could be exempted from any requirements for notification, registration, or licensing of sources or practices, based on the same exemption principles and assumed scenarios for exposure of the public (IAEA, 1996). The recommended exemption levels for naturally occurring radionuclides are limited to their incorporation in consumer products, use as a radioactive source, or use for their elemental properties. 

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