Decay Chain

In nuclear science, the decay chain refers to the radioactive decay of different discrete radioactive decay products as a chained series of transformations. Most radioactive elements do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached.

Decay stages are referred to by their relationship to previous or subsequent stages. A parent isotope is one that undergoes decay to form a daughter isotope. The daughter isotope may be stable or it may decay to form a daughter isotope of its own. The daughter of a daughter isotope is sometimes called a granddaughter isotope.

The time it takes for a single parent atom to decay to an atom of its daughter isotope can vary widely, not only for different parent-daughter chains, but also for identical pairings of parent and daughter isotopes. While the decay of a single atom occurs spontaneously, the decay of an initial population of identical atoms over time, t, follows a decaying exponential distribution, e−λt, where λ is called a decay constant. Because of this exponential nature, one of the properties of an isotope is its half-life, the time by which half of an initial number of identical parent radioisotopes have decayed to their daughters. Half-lives have been determined in laboratories for thousands of radioisotopes (or, radionuclides). These can range from nearly instantaneous to as much as 1019 years or more.

The intermediate stages often emit more radioactivity than the original radioisotope. When equilibrium is achieved, a granddaughter isotope is present in proportion to its half-life; but since its activity is inversely proportional to its half-life, any nuclide in the decay chain finally contributes as much as the head of the chain. For example, natural uranium is not significantly radioactive, but pitchblende, a uranium ore, is 13 times more radioactive because of the radium and other daughter isotopes it contains. Not only are unstable radium isotopes significant radioactivity emitters, but as the next stage in the decay chain they also generate radon, a heavy, inert, naturally occurring radioactive gas. Rock containing thorium and/or uranium (such as some granites) emits radon gas that can accumulate in enclosed places such as basements or underground mines. Radon exposure is considered the leading cause of lung cancer in non-smokers.

Read more about Decay ChainTypes, Actinide Alpha Decay Chains, Beta Decay Chains in Uranium & Plutonium Fission Products

Other articles related to "decay, decay chain, decays, chain":

Thorium Fuel Cycle - Nuclear Reactions With Thorium - Uranium-232 Contamination
233U, 233Pa, and 232Th Uranium-232 has a relatively short half-life (68.9 years), and some decay products emit high energy gamma radiation, such as 224Rn, 212Bi and ... The full decay chain, along with half-lives and relevant gamma energies, is 232U decays to 228Th where it joins decay chain of 232Th Thorium-cycle fuels ... chemical separation of thorium from uranium removes the decay product 228Th and the radiation from the rest of the decay chain, which gradually build ...
Isotopes Of Radon
218, 219, 220, 222Rn occur in trace quantities in nature as decay products of, respectively, 218At, 223Ra, 224Ra, and 226Ra. 218Rn and 222Rn are intermediate steps in the decay chain for 238U, 219Rn is an intermediate step in the decay chain for 235U and 220Rn occurs in the decay chain ...
Radium Series
... In nuclear science, the decay chain refers to the radioactive decay of different discrete radioactive decay products as a chained series of transformations ... Most radioactive elements do not decay directly to a stable state, but rather undergo a series of decays until eventually a stable isotope is reached ... Decay stages are referred to by their relationship to previous or subsequent stages ...
Radioactive Source - Mathematics of Radioactive Decay - Universal Law of Radioactive Decay - Chain-decay Processes
... Chain of two decays Now consider the case of a chain of two decays one nuclide A decaying into another B by one process, then B decaying into another C by a second process, i.e ... The previous equation cannot be applied to a decay chain, but can be generalized as follows ... The decay rate of B is proportional to the number of nuclides of B present, so again we have but care must be taken ...
Beta Decay Chains in Uranium & Plutonium Fission Products
... Therefore they undergo multiple beta decays in succession, each converting a neutron to a proton ... The first decays tend to have higher decay energy and shorter half-life ... These last decays may have low decay energy and/or long half-life ...

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