Determinationof Isotope Ratios and Concentration of Trace Uranium in Depleted Uranium Samples by Thermal Ionization Mass Spectrometry

With H3PO4 as the ionization intensifier,the isotope ratios of uranium in the depleted uranium samples with uranium concentration at nanogram-level were determined by thermal ionization mass spectrometry(TIMS) with the precision of 2.9%RSD.With 233U as the diluent,the concentration of uranium in the samples were also determined by isotope dilution mass spectrometry(IDMS) with the expanded uncertainty of 2.4%.The research results showed that in uranium isotope ratio determination for the samples with nanogram-level of uranium,uranium background interference from rhenium filament and other sources should not be ignored,which is needed for further study to remove the background interference.