Radioactive equilibrium

{
  "id": "MLC-T-CHM-009865",
  "term": "Radioactive equilibrium",
  "field": "Chemistry",
  "definition": "A state in a radioactive decay chain in which the ratios of the activities of successive members stay constant over time, reached when the parent is longer lived than its daughters. In secular equilibrium the parent half-life is so much longer that parent and daughter activities become equal, while in transient equilibrium the daughter activity stays a fixed factor above the parent activity. It is not a true equilibrium, since radioactive decay is irreversible.",
  "subject": "Analytical Chemistry",
  "see_also": [
    "activity",
    "decay chain",
    "radioactive decay"
  ],
  "references": [
    "PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2519 (https://doi.org/10.1351/pac199466122513)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/radioactive-equilibrium/"
}