The half-life of 129I

Eduardo García-Toraño (1) , T. Altzitzoglou (2) , P. Auerbach (3) , Marie-Martine Bé (4) , Christophe Bobin (4) , Philippe Cassette (4) , F. Chartier (5) , Rainer Dersch (6) , Marta Fernández (1) , H. Isnard (5) , K. Kossert (6) , Valerie Lourenco (4) , O. Nähle (6) , A. Nonell (5) , V. Peyres (1) , S. Pommé (2) , A. Rozkov (2) , Anabel Sánchez-Cabezudo (1) , Jana Sochorová (3)

1 CIEMAT - Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2 JRC - European Commission - Joint Research Centre [Geel]
3 Czech Metrology Institute
4 LNHB (CEA, LIST) - Laboratoire National Henri Becquerel (CEA, LIST)
5 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
6 PTB - Physikalisch-Technische Bundesanstalt [Braunschweig]

The radionuclide $^{129}$I is a long-lived fission product that decays to $^{129}$Xe by beta-particle emission. It is an important tracer in geological and biological processes and is considered one of the most important radionuclides to be assessed in studies of global circulation. It is also one of the major contributors to radiation dose from nuclear waste in a deep geological repository. Its half-life has been obtained by a combination of activity and mass concentration measurements in the frame of a cooperation of 6 European metrology institutes. The value obtained for the half-life of $^{129}$I is 16.14 (12) × 10$^6$ a, in good agreement with recommended data but with a significant improvement in the uncertainty.

Mots clés: 129I; half-life; activity measurement; beta-particle emission; Primary activity measurement; Decay data measurement; standardization; mass spectrometry; metrology; Ionizing radiation; Radioactivity

Domaines: Physique Nucléaire Expérimentale [nucl-ex]; Physique Nucléaire Théorique [nucl-th]

Eduardo García-Toraño, T. Altzitzoglou, P. Auerbach, Marie-Martine Bé, Christophe Bobin, et al.. The half-life of 129I. Applied Radiation and Isotopes, 2018, 140, pp.157-162. ⟨10.1016/j.apradiso.2018.06.007⟩. ⟨cea-02339672⟩