Determination of the 229Th half-life

The paper describes the re-measurement of the half-life of 229Th (ground state). The half-life was obtained by the measurement of amount content of 229Th in the certified 229Th radioactivity standard (SRM 4328C) from National Institute of Standards and Technology. The measurement was performed by isotope dilution inductively coupled plasma mass spectrometry using two independent standards for quantification. From the results the 229Th half-life is determined to be 7917 years with an expanded uncertainty of 48 years using a coverage factor of k = 2. The methodology is traceable to SI and the calculation complies with the recommendations of Bureau International des Poids et Mesures (BIPM) for nuclear data evaluation.JRC.E.7-Nuclear Safeguards and Forensic