Identification and Characteristic of 239Pa
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摘要: 利用60 MeV/u 18O离子束轰击天然铀靶，经多核子转移反应生成重丰中子核素239Pa。用放射化学方法从被照射的靶中分离出镤。借助于239Pa和它的子体239U的γ射线观测和分析，鉴别了239Pa，测得239Pa的半衰期为（106±30） min。长寿命同位素，如232Th和238U，可给出一个测定核合成持续时间的可能性，而中等寿命同位素，如235U，则可给出有关产生函数时间历史的信息。总地说来，通过232Th/238U、235U/238U或244Pu/238U的比率，用公式NA(Δ)/NB(Δ)=（PA/PB）f(λA，λB,S0，λR，Δ)便可推导出宇宙年龄。由239Pa的衰变途径，可简单叙述239Pa的异常长的半衰期对于宇宙年龄估计的影响。Abstract: A nuclide 239Pa was produced via a multinucleon transfer reaction by 60 MeV/u 18O ions bombardment of natural uranium. Protactinium was radiochemically separated from the irradiated targets. 239Pa has been identified by using observation and analysis of γ-rays of 239Pa and 239U as a daughter nucleus of 239Pa. The half-life of 239Pa was determined to be （106±30） min. Long lived isotopes like 232Th and 238U give a possibility of determining the duration of nucleosynthesis whereas intermediate lived nuclei like 235U can give information about the time history of the production function. Generally the universe age is deduced through the ratios of the 232Th/238U, 235U/238U or 244Pu/238U with formular NA(Δ)/NB(Δ)=(PA/PB)f(λA，λB，S0，λR，Δ). The influence of the novel long half-life of 239Pa on the universe age estimate is simply mentioned by 239Pa decay path.
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Keywords:
- identify ,
- 239Pa ,
- universe age
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