5MeV中子诱发~(238)U裂变时几个核素累计产额的绝对测定

    THE ABSOLUTE DETERMINATION OF CUMULATIVE YIELD OF SEVERAL NUCLIDES FROM INDUCED FISSION OF 238U BY 5 MeV NEUTRONS

    • 摘要: <正> 引言 对14MeV中子诱发~(238)U裂变的质量分布已做了很多研究,这是因为氘-氚聚变反应(D+T→n+α)提供了一个极好的14MeV的单能中子源。但对其它单能中子诱发~(238)U裂变的质量分布研究得就不够充分,已报道的结果中有些彼此分歧较大。我们用放化法测量了D(d,n)~3He反应产生的5MeV中子诱发~(238)U裂变时几个核素的绝对产额。

       

      Abstract: The cumulative yields of 95Zr, 97Zr, 99Mo, 103Ru, 106Ru, 140Ba,143Ce and 147Nd in 238U fission induced with 5.00 MeV neutrons are measured absolutely by radiochemical technique. The neutrons of 5.00±0.17 MeV are produced by reaction D (d, n) 3He on a Van de Graaff accelerator. The neutron fluxes range from 4×108 n/s to 1×109 n/s.The sample target is made of depleted uranium. The standard targets are prepared by molecular plating and the sample targets consist of about 3-4 uranium metal disks each weighing 2 to 3 gramms. The absolute fission rate of the sample target is measured by double fission ionization chamber.By means of modified standard radiochemical procedures the nuclides mentioned above are separated, purified and counted.The cumulative yields determined for the nuclides are listed in the table below.The errors given in the table are total errors including both statistic and systematic ones.

       

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