New measurement of the 238U decay constant with inductively coupled plasma mass spectrometry

Tashi Parsons-Davis, Josh Wimpenny, C. Brenhin Keller, Keenan Thomas, Kyle M. Samperton, Paul R. Renne, Roland Mundil, Ken Moody, Kim Knight, Michael J. Kristo, and Ross Williams

Journal of Radioanalytical and Nuclear Chemistry, 2018: https://doi.org/10.1007/s10967-018-6148-y


Abstract:
The 238U decay constant (λU-238) is fundamental to radioisotope-based chronometry in the Earth and planetary sciences, yet only a single published λU-238 value (Jaffey et al. in Phys Rev C 4(5):1889–1906, 1971) is widely applied. We have determined λU-238 via the novel approach of measuring of 234Th ingrowth in high-purity 238U solutions, using isotope dilution mass spectrometry (ID-MS). The 234Th decay constant (λTh-234) was measured via decay counting with high-purity Ge (HPGe) γ detectors. Preliminary results for λU-238 agree with the value determined by α-counting within the elevated uncertainty of 0.462% (k = 2). Ongoing efforts to reproduce λU-238 with reduced experimental uncertainties will inform future conclusions.

Suggested citation: Parsons-Davis, T. et al. (2018) New measurement of the 238U decay constant with inductively coupled plasma mass spectrometry. Journal of Radioanalytical and Nuclear Chemistry 4, 1–11.