Application of the most frequent value method for $$^{39}$$Ar half-life determination

Abstract

AbstractAn evaluation method supported by robust statistical analysis was applied to historical measurements of $$^{39}$$ 39 Ar half-life. The method, based on the most frequent value (MFV) approach combined with bootstrap analysis, provides a more robust way to estimate $$^{39}$$ 39 Ar half-life, and results in $$T_{1/2}($$ T 1 / 2 ( MFV$$) = 268.2^{+3.1}_{-2.9}$$ ) = 268 . 2 - 2.9 + 3.1 years with uncertainty corresponding to the 68% confidence level. The uncertainty is a factor of 3 smaller than that of the most precise re-calculated $$^{39}$$ 39 Ar half-life measurements by Stoenner et al. and a factor of 2.7 smaller than that of the adopted half-life value in nuclear data sheets. Recently, the specific activity of the beta decay of $$^{39}$$ 39 Ar in atmospheric argon was measured in several underground facilities. Applying the MFV method to a specific activity of $$^{39}$$ 39 Ar from underground measurements results in $$ SA_{{^{39}\text {Ar}}/\text {Ar}}(\text {MFV}) = 0.966^{+0.010}_{-0.018} \, \, \text {Bq/kg}_{\text {atmAr}}$$ S A 39 Ar / Ar ( MFV ) = 0 . 966 - 0.018 + 0.010 Bq/kg atmAr with uncertainty corresponding to the 68% confidence level. In this paper the method to determine the half-life of $$^{39}$$ 39 Ar using the specific activity of $$^{39}$$ 39 Ar in atmospheric argon is also discussed.