S Pommé et al 2009 Metrologia 46 439 doi:10.1088/0026-1394/46/5/007
S Pommé1,5, T Altzitzoglou1, R Van Ammel1, G Sibbens1, R Eykens1, S Richter1, J Camps1, K Kossert2, H Janßen2, E García-Toraño3, T Durán3 and F Jaubert4
Show affiliationsThe half-life of 233U was determined by a specific activity method, in the frame of an international collaboration project of four metrology institutes. A purified, highly enriched 233U solution was prepared with certified concentration of uranium isotopes. The isotopic composition of the uranium material was determined by thermal ionization mass spectrometry. The ingrowth of daughter nuclides was calculated and confirmed by α-particle and γ-ray spectrometry measurements. Quantitative sources were prepared from aliquots of the 233U solution and their disintegration rate was determined by means of α-particle counting at a defined small solid angle, liquid-scintillation counting and 4π counting in a pressurized proportional counter and in a CsI(Tl) sandwich spectrometer. A half-life value of 1.5867 (14) × 105 a was obtained, in which the relative standard uncertainty amounts to 0.09%. The result is lower than the currently recommended value of 1.592 (2) × 105 a and a new best estimate of T1/2(233U) = 1.5903 (13) × 105 a was calculated from a partially weighted mean of a set of published data.
06.20.fb Standards and calibration
29.30.Kv X- and gamma-ray spectroscopy
23.40.-s Beta decay; double beta decay; electron and muon capture
29.30.Aj Charged-particle spectrometers: electric and magnetic
Accelerators, beams and electromagnetism
Issue 5 (October 2009)
Received 29 March 2009, in final form 1 June 2009
Published 26 June 2009
S Pommé et al 2009 Metrologia 46 439
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