Effective half-life

Time taken for the activity of a radionuclide in a specified place to halve its activity as a result of all relevant processes. Effective half-life Teff may be determined by:

;

[math] \frac{1}{T_{eff}}=\displaystyle \sum_{i} \frac{1}{T_{i}} [/math]

where [math]T_i[/math] is the half-life for process [math]i[/math]. Examples of the processes are physical decay of the radionuclide, physiological removal in the body and weathering in the environment.

ICRP Glossary entry - June 2019

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