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

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。

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.