%0 Journal Article %T Activity standardization of two enriched 40K solutions for the determination of decay scheme parameters and the half-life %+ Physikalisch-Technische Bundesanstalt [Braunschweig] (PTB) %+ Australian National University (ANU) %+ Swedish Museum of Natural History (NRM) %+ Uppsala University %+ Laboratoire National Henri Becquerel (LNHB) %A Kossert, Karsten %A Amelin, Yuri %A Arnold, Dirk %A Merle, Renaud %A Mougeot, Xavier %A Schmiedel, Michael %A Zapata Garcia, Daniel %Z Australian Research Council Discovery Grant DP140101116 %< avec comité de lecture %@ 0969-8043 %J Applied Radiation and Isotopes %I Elsevier %V 188 %P 110362 %8 2022-10 %D 2022 %R 10.1016/j.apradiso.2022.110362 %K 40K %K activity standardization %K liquid scintillation counting %K TDCR %K CIEMAT/NIST efficiency tracing %K branching ratio %K metrology %K ionizing radiation %K radioactivity %K spectrometry %K Decay data measurement %K gamma spectrometry %K beta-rays %Z Physics [physics]/Nuclear Experiment [nucl-ex]Journal articles %X 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. %G English %2 https://cea.hal.science/cea-03736184/document %2 https://cea.hal.science/cea-03736184/file/k40_lsc_draft_v_10_revised.pdf %L cea-03736184 %U https://cea.hal.science/cea-03736184 %~ CEA %~ DRT %~ CEA-UPSAY %~ UNIV-PARIS-SACLAY %~ LIST %~ DM2I %~ UNIVERSITE-PARIS-SACLAY %~ GS-ENGINEERING %~ GS-COMPUTER-SCIENCE %~ MAP-CEA %~ DIN