IUGS–IUPAC recommendations and status reports on the half-lives of 87Rb, 146Sm, 147Sm, 234U, 235U, and 238U (IUPAC Technical Report)

Autor: Igor M. Villa, Norman E. Holden, Antonio Possolo, Ryan Ben Ickert, David Brynn Hibbert, Paul R. Renne, Mauro L. Bonardi, Paul De Bièvre
Rok vydání: 2022
Předmět:
Zdroj: Villa, Igor M.; Holden, Norman E.; Possolo, Antonio; Ickert, Ryan Ben; Hibbert, David Brynn; Renne, Paul R.; Bonardi, Mauro L.; De Bièvre, Paul (2022). IUGS–IUPAC recommendations and status reports on the half-lives of 87 Rb, 146 Sm, 147 Sm, 234 U, 235 U, and 238 U (IUPAC Technical Report). Pure and applied chemistry, 94(9), pp. 1085-1092. De Gruyter 10.1515/pac-2021-1202
ISSN: 1365-3075
0033-4545
DOI: 10.1515/pac-2021-1202
Popis: The IUPAC–IUGS joint Task Group “Isotopes in Geosciences” (TGIG) has evaluated the published literature on the half-lives of six long-lived, geologically relevant radioactive nuclides. Where conflicting literature estimates are present, it is necessary to first identify any systematic bias in accordance with metrological traceability and to exclude the biased estimates from further consideration. The TGIG recommends three robust half-life estimates: 49.61 ± 0.16 Ga for 87Rb, corresponding to a decay constant λ(87Rb) = (1.3972 ± 0.0045) × 10−11 a−1; 106.25 ± 0.38 Ga for 147Sm, and a corresponding decay constant λ(147Sm) = (6.524 ± 0.024) × 10−12 a−1; 4.4683 ± 0.0096 Ga for 238U, i.e. a decay constant λ(238U) = (1.55125 ± 0.00333) × 10−10 a−1. All cited uncertainties have a coverage factor k = 2. For other radionuclides of Sm and U, no unambiguous consensus value can be endorsed at present by TGIG, which limits its evaluation to a status report highlighting unaccounted-for potential sources of bias. The improved repeatability of mass spectrometric measurements has revealed systematic bias effects that had been dismissed as subordinate in the past. These issues can only be resolved by future dedicated investigations.
Databáze: OpenAIRE
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