1. Activity standardization of two enriched 40K solutions for the determination of decay scheme parameters and the half-life
- Author
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Karsten Kossert, Yuri Amelin, Dirk Arnold, Renaud Merle, Xavier Mougeot, Michael Schmiedel, Daniel Zapata-García, Physikalisch-Technische Bundesanstalt [Braunschweig] (PTB), Australian National University (ANU), Swedish Museum of Natural History (NRM), Uppsala University, Laboratoire National Henri Becquerel (LNHB), Département Métrologie Instrumentation & Information (DM2I), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Département d'instrumentation Numérique (DIN (CEA-LIST)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Australian Research Council Discovery Grant DP140101116
- Subjects
40K ,Radiation ,Decay data measurement ,[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] ,spectrometry ,TDCR ,metrology ,CIEMAT/NIST efficiency tracing ,radioactivity ,activity standardization ,beta-rays ,branching ratio ,ionizing radiation ,liquid scintillation counting ,gamma spectrometry - Abstract
International audience; In this paper we describe experiments on two enriched 40K solutions to accurately determine decay data. The first solution was measured in 2004/2005 by means of a gamma-ray spectrometer with low background and a liquid scintillation (LS) counter to apply the CIEMAT/NIST efficiency tracing method. A combination of results yields an emission probability of the 1461 keV gamma-rays of Pg=0.1030(11) which is lower than current results of data evaluations.The activity concentration of the second solution was also determined by means of LS counting, but here, the CIEMAT/NIST efficiency tracing method as well as the TDCR method were applied. Again, the result was combined with that of independent gamma-ray spectrometry and the gamma-ray emission probability was found to be Pg=0.1029(9) in good agreement with the result obtained from the first solution. A combination of both experiments yields Pg=0.1029(9). The spectra of a TriCarb LS counter were carefully analyzed and a beta minus emission probability Pb- =0.8954(14) was determined. The new results for Pg and Pb- indicate that the overall probability of the decay via electron capture in recent data evaluations is overestimated.The LS counting efficiencies were computed with a stochastic model and up-to-date calculations of the beta spectrum and fractional electron-capture probabilities were used. The final activity result of the second solution is combined with the outcome of a comprehensive isotopic analysis to determine the half-life of 40K which is found to be 1.2536(27) 10^9 years.
- Published
- 2022