On decay constants and orbital distance to the Sun—part II: beta minus decay

Research output: Contribution to journalArticlepeer-review


  • Stefaan Pommé
  • H Stroh
  • J Paepen
  • Raf Van Ammel
  • H Marouli
  • T Altzitzoglou
  • M Hult
  • K Kossert
  • O Nähle
  • H Schrader
  • F Juget
  • C Bailat
  • Y Nedjadi
  • F Bochud
  • T Buchillier
  • C Michotte
  • S Courte
  • M W van Rooy
  • M J van Staden
  • J Lubbe
  • B R S Simpson
  • A Fazio
  • P De Felice
  • T W Jackson
  • W M Van Wyngaardt
  • M I Reinhard
  • J Golya
  • S Bourke
  • T Roy
  • R Galea
  • J D Keightley
  • K M Ferreira
  • S M Collins
  • A Ceccatelli
  • Branko Vodenik
  • M Korun
  • V Chisté
  • M N Amiot
  • EC - JRC - European Commission - Joint Research Centre
  • JSI - Jozef Stefan Institute
  • PTB - Physikalisch-Technische Bundesanstalt
  • IRA - Institute of Radiation Physics, University Hospital of Lausanne
  • BIPM - Bureau International des Poids et Mesures
  • NMISA - Radioactivity Standards laboratory - South Africa
  • ENEA - Italian National Agency for New Technologies
  • ANSTO - Australian Nuclear Science and Technology Organisation
  • NRC - National Research Council of Canada - Canada
  • NPL - National Physical Laboratory
  • IAEA - International Atomic Energy Agency
  • CEA Saclay - Commissariat à l'énergie atomique

Documents & links


Claims that proximity to the Sun causes variations of decay constants at the permille level have been investigated for beta-minus decaying nuclides. Repeated activity measurements of 3H, 14C, 60Co, 85Kr, 90Sr, 124Sb, 134Cs, 137Cs, and 154Eu sources were performed over periods of 259 d up to 5 decades at various nuclear metrology institutes. Residuals from the exponential decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ in amplitude and phase from one data set to another and appear attributable to instabilities in the instrumentation and measurement conditions. Oscillations in phase with Earth’s orbital distance to the Sun could not be observed within 10−4–10−5 range precision. The most stable activity measurements of β− decaying sources set an upper limit of 0.003%–0.007% to the amplitude of annual oscillations in the decay rate. There are no apparent indications for systematic oscillations at a level of weeks or months.


Original languageEnglish
Pages (from-to)19-35
Number of pages16
Publication statusPublished - 28 Nov 2016


  • half-life, decay constant, non-exponential decay, adioactivity, Sun, neutrino

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