【摘要】 基于高浓铀中235U的衰变子体231Pa的数量随时间而增加,且在一定时间内与高浓铀年龄有很好的线性关系这一原理,用溶剂萃取法从高浓铀中分离出231Pa,回收率达到67.1%以上;用高纯Geγ谱仪测量235U,用α谱仪测量231Pa,并分别计算出235U和231Pa的含量,由此推算出高浓铀的年龄,其结果的不确定度为8%。更多还原

【Abstract】 Based on the linear increase in the amount of 231 Pa with time in a sample of highly enriched uranium (HEU), the HEU age is determined by measurement of the atomic ratio of ~231 Pa to ~235 U. The daughter nuclide ~231 Pa is separated and purified from its parent nuclide ~235 U by solvent extraction with N-benzoyl-N-phenylhydroxylamine (BPHA) with a recovery of higer than 67%. The radioactivity of ~ 231 Pa and ~235 U is measured with an HPGe γ-spectrometer and a large-area gridded ionization chamber α-spectrometer, respectively. The overall uncertainty in HEU age determination is estimated to be ca. 8%.更多还原