secular equilibrium


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secular equilibrium

[′sek·yə·lər ‚ē·kwə′lib·rē·əm]
(nucleonics)
Radioactive equilibrium in which the parent has such a small decay constant that there has been no appreciable change in the quantity of parent present by the time the decay products have reached radioactive equilibrium.
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References in periodicals archive ?
1), the expression 'long-period equilibrium' refers to a secular equilibrium.
ANSTO established that the uranium was in secular equilibrium and therefore not adversely affecting gamma readings, and that thorium concentrations were probably not a major contributing factor to gamma readings.
8 day half-life) in secular equilibrium is the only standard worldwide that provides a National Institute of Standards and Technology (NIST) traceable calibration for F-18 and is the culmination of two years of collaborative research by NIST.