Radioactive decay

Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide.

Types of decay

There are many types of radioactive decay. These include alpha decay, beta decay, gamma decay, neutron emission, cluster decay, proton emission, double beta decay, double electron capture, electron capture, internal conversion, isomeric transition, spontaneous fission, and delayed neutron emission.

Decay chains and multiple modes

The daughter nuclide of a decay event may also be unstable (radioactive). In this case, it will also decay, producing a decay chain. A decay chain refers to the sequential decay of a radioactive parent isotope to a stable daughter isotope through a series of decays of intermediate daughter isotopes.

Decay rate

The decay rate, or activity, of a radioactive substance is characterized by:

• Constant quantities: Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for minuscule samples of atoms.
• Time: The number of decays per time is proportional to the current number of radioactive atoms.

Applications

Radioactive decay has been put to use in the technique of radioisotopic labeling, which is used to track the passage of a chemical substance through a complex system (such as a living organism). A sample of the substance is synthesized with a high concentration of unstable atoms. The presence of the unstable atoms in the sample allows the tracking of the substance's passage through the system.

See also

• Half-life
• Decay product
• Decay scheme
• Decay chain
• Decay energy
• Decay mode
• Decay correct
• Decay heat
• Decay width
• Decay dynamics
• Decay acceleration

References

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