热表面电离质谱法测定贫化铀样品痕量铀同位素比值及含量

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

选用磷酸为离子流发射剂,热表面电离质谱法分析纳克量级贫化铀样品的铀同位素比值,方法最大相对标准偏差<2.9%。以233U为稀释剂,采用同位素稀释法对铀的含量进行测定,扩展不确定度为2.4%(K=2)。研究表明,在纳克量级的铀同位素比值测定中,来自铼带等铀本底的干扰影响不容忽视,需要进一步研究并扣除。

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.