secular equilibrium

plural secular equilibria · plural secular equilibriums

1. nuclear physicsThe situation of the quantity of a radioisotope remaining constant because it is produced (by decay of a parent isotope) at the same rate that it decays.

   The ^{₆₈}Ge/^{₆₈}Ga and the ^{₈₂}Sr/^{₈₂}Rb generators represent secular equilibria.

   2016, Tobias L. Ross, Frank Roesch, “Life sciences: Nuclear medicine diagnosis”, in Frank Rösch, editor, Nuclear- and Radiochemistry, Volume 2: Modern Applications, Walter de Gruyter, page 443

   2 more examples

   In decay schemes of this type, the following three conditions may predominate: (1) secular equilibrium, (2) transient equilibrium, and (3) the state of no equilibrium.

   1998, Michael F. L'Annunziata, Handbook of Radioactivity Analysis, Academic Press, page 61

   At the same time, because of differences in the chemistry of the daughter and parent elements involved in such secular equilibria, this parent:daughter ratio may not be equal to 1.

   2020, David J. Burdige, Geochemistry of Marine Sediments, Princeton University Press, page 43

   Synonyms: radioactive equilibrium