Difference between revisions of "Decay chain"
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A '''decay chain''', also called a '''radioactive series''', is a sequence of [[nuclide]]s in which each nuclide transforms into the next by [[radioactive decay]] until a stable nuclide is reached. There are three "classical" decay chains, which describe the decay of the naturally-occuring [[actinoid]]s; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides. Shorter decay chains describe the decay of the [[transfermium element]]s and lighter non-actinoid radionuclides. | A '''decay chain''', also called a '''radioactive series''', is a sequence of [[nuclide]]s in which each nuclide transforms into the next by [[radioactive decay]] until a stable nuclide is reached. There are three "classical" decay chains, which describe the decay of the naturally-occuring [[actinoid]]s; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides. Shorter decay chains describe the decay of the [[transfermium element]]s and lighter non-actinoid radionuclides. | ||
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| + | The principle of a decay chain comes from the [[radioactive displacement law]], deduced in 1913 by [[Kazimierz Fajans|Fajans]], [[Frederick Soddy|Soddy]] and [[Alexander Russell|Russell]]. The original version of the law, which describes the most common forms of radioactive decay, is that | ||
| + | *[[alpha decay]] leads to a nuclide with an [[atomic number]] two lower than the decaying nuclide, and a [[mass number]] four lower; | ||
| + | *[[beta decay]]<ref group="note">This description applies to β<sup>−</sup> decay, which was the only type of [[beta decay]] known in 1913.</ref> leads to a nuclide with the same mass number as the decaying nuclide but with an atomic number one higher. | ||
==Actinoid decay chains== | ==Actinoid decay chains== | ||
Revision as of 13:03, 17 April 2011
A decay chain, also called a radioactive series, is a sequence of nuclides in which each nuclide transforms into the next by radioactive decay until a stable nuclide is reached. There are three "classical" decay chains, which describe the decay of the naturally-occuring actinoids; a fourth long decay chain has become extinct in natural sources, but is known from artificially-produced radionuclides. Shorter decay chains describe the decay of the transfermium elements and lighter non-actinoid radionuclides.
The principle of a decay chain comes from the radioactive displacement law, deduced in 1913 by Fajans, Soddy and Russell. The original version of the law, which describes the most common forms of radioactive decay, is that
- alpha decay leads to a nuclide with an atomic number two lower than the decaying nuclide, and a mass number four lower;
- beta decay[note 1] leads to a nuclide with the same mass number as the decaying nuclide but with an atomic number one higher.
Actinoid decay chains
Actinium (4n+3) series
| Uranium-235 (α, 7.04 × 108 a) | |
| Thorium-231 (β−, 25.52 h) | |
| Protactinium-231 (α, 3.276 × 104 a) | |
| Actinium-227 (21.772 a) | |
| α, 1.38% | β−, 98.62% |
| Francium-223 (22.00 min) |
Thorium-227 (α, 18.68 d) |
Notes and references
Notes
- ↑ This description applies to β− decay, which was the only type of beta decay known in 1913.
References
External links
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See also the corresponding article on Wikipedia. |
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