Half-life determination and comparison of activity standards of 231Pa

Simon Jerome; Christophe Bobin; Philippe Cassette; Rainer Dersch; Raphael Galea; Haoran Liu; Anja Honig; John Keightley; Karsten Kossert; Juncheng Liang; Maria Marouli; Carine Michotte; Stefaan Pommé; Stefan Röttger; Ross Williams; Ming Zhang

doi:10.1016/j.apradiso.2019.108837

Half-life determination and comparison of activity standards of ²³¹Pa

Appl Radiat Isot. 2020 Jan:155:108837. doi: 10.1016/j.apradiso.2019.108837. Epub 2019 Sep 12.

Authors

Affiliations

¹ National Physical Laboratory (NPL), Teddington, UK; Bureau International des Poids et Mesures (BIPM), Sèvres, France. Electronic address: s.jerome@iaea.org.
² CEA, LIST, Laboratoire National Henri Becquerel, (LNE-LNHB), Gif-sur-Yvette, France.
³ Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany.
⁴ National Research Council of Canada (NRC), Ottawa, Canada.
⁵ National Institute of Metrology of China (NIM), Beijing, China.
⁶ National Physical Laboratory (NPL), Teddington, UK.
⁷ European Commission, Joint Research Centre (JRC), Geel, Belgium.
⁸ Bureau International des Poids et Mesures (BIPM), Sèvres, France.
⁹ Lawrence Livermore National Laboratory (LLNL), Livermore, USA.

PMID: 31655349
DOI: 10.1016/j.apradiso.2019.108837

Abstract

The results of an international comparison of activity measurements of a solution of ²³¹Pa are reported and analysed. Prior to this, no known standardisation of ²³¹Pa by activity measurement had been carried out. The comparison was run in 2017-2018 involving eight laboratories, and returned results with no identifiable inconsistencies between methods or laboratories. The results, including one mass determination, gave a²³¹Pa activity concentration of 41.461(48) kBq g^-1 and a²³¹Pa atom concentration of 61.48(23) × 10¹⁵ atoms g^-1, from which a half-life value of 32 570(130) years was derived.

Keywords: Activity concentration; Half-life; International comparison; Mass spectrometry; Nuclear forensics; Pa-231.