关键词: 
²³³U /
裂变产额 /
质量分布 /
Th/U 循环

摘要: 本模型基于裂变多通道无规颈断裂模型，考虑宏观液滴能、壳效应能以及壳效应与温度的关系，
得到参数化的势能表示形式。通过拟合不同测量方法得到的实验数据(经过评价) 获得3 组模型参数。3 组参数计算的碎片质量分布均很好地再现了不同能点的实验数据，除了基于动能法实验数据得到的参数外，其14 MeV的计算结果与实验数据符合较差。研究发现，不同入射中子能量的裂变碎片质量分布有4 个主要交叉点，在叉点之上的产额随入射中子能量增加减少，之下的产额则随入射中子能量上升；内侧(或外侧) 的两个交叉点质量数之和近似等于裂变复合核的质量数；不同裂变系统的重峰左侧的交叉点都保持在132 附近。Present model was based upon Brosa model, where macro energy，shell effect energy and its decreasing with system temperature were considered and parameterized. 3 sets of model parameters were obtained by fitting to 3 groups of evaluated experimental data, respectively, where the groups were classified by measured method: radiochemistry (RA) method, double kinetic energy (KE) method, and both (ALL). All the 3 sets of parameters could well reproduce the
measured mass distributions on different energies, except the KE set on 14 MeV. The result shows the mass distributions mainly had 4 trend turning points, above which the yield decreasing and below which the yield increasing with energy.The sum of the 1st and 4th (or 2nd and 3rd) point positions was equal to the compound nuclei mass approximately. And the 3rd point was kept at ~132 constantly for different fission systems n+²³³ U, n+²³⁵U, n+²³³Pu.