radioactive decay

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radioactive decay

(ray-dee-oh-ak -tiv) The spontaneous transformation of one atomic nucleus into another with the emission of energy. The energy is released in the form of an energetic particle, usually an alpha particle, beta particle (i.e. an electron), or positron, sometimes accompanied by a gamma-ray photon. The unstable isotopes of an element that can undergo such transformations are called radioactive isotopes, or radioisotopes. The emission of a particle from the nucleus of a radioisotope results in the production of an isotope of a different element, as in the beta decay of carbon–14 to nitrogen–14 or the alpha decay of radium–226 to radon–222. The isotope produced is itself often radioactive.

The average time taken for half a given number of nuclei of a particular radioisotope to decay is the half-life of that radioisotope; values range from a fraction of a second to thousands of millions of years. See also radiometric dating.

radioactive decay

[¦rād·ē·ō′ak·tiv di′kā]
(nuclear physics)
The spontaneous transformation of a nuclide into one or more different nuclides, accompanied by either the emission of particles from the nucleus, nuclear capture or ejection of orbital electrons, or fission. Also known as decay; nuclear spontaneous reaction; radioactive disintegration; radioactive transformation; radioactivity.
References in periodicals archive ?
Russell Humphreys, "Young Helium Diffusion Age of Zircons Supports Accelerated Nuclear Decay," in Radioisotopes and the Age of the Earth: Results of a Young-Earth Creationist Research Initiative 2, ed.
Our report carefully applies accepted geochronological practices, discovers new evidence for rapid nuclear decay, points out inconsistencies in conventional interpretations, and calculates alternative, young-earth dates.
However, rather than supposing that there was a burst of accelerated nuclear decay at the time of the Fall or the Flood, I hypothesize that k increases in a regular way with time: Let k = [At.
This double-beta decay is the rarest form of nuclear decay so far observed, says John F.
Physicists then were trying to understand the relationship between the electromagnetic force, which includes the attraction between electrically charged particles, and the weak force, which causes nuclear decay.
For decades, experimenters have tried to find a nuclear decay in which a proton pair sashays right out of the nuclear ballroom, still entwined.
He, the late Abdus Salam, and Steven Weinberg of the University of Texas at Austin won the 1979 physics Nobel for their work, which explains the behavior of the force responsible for nuclear decay.

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