Age determination of uranium samples by inductively coupled plasma mass spectrometry using direct measurement and spectral deconvolution

A simple and rapid method has been developed for the direct determination of the age (i.e. the production date) of uranium-containing nuclear materials by inductively coupled plasma mass spectrometry based on the measurement of the (230)Th/(234)U radionuclide ratio. The concentration of the trace-level (230)Th in the samples was measured directly without the need for prior chemical separation. The tailing of the highly abundant (238)U peak, which is typically around 10 orders of magnitude higher than that of the (230)Th signal, was eliminated by the mathematical deconvolution of the measured mass spectrum. The (230)Th and (234)U contents were quantified by isotope dilution method. The developed method was validated using reference materials of known production date.