Prompt neutron multiplicity distribution for ²³⁵ U(n,f) at incident energies up to 20 MeV

Abstract

For the n+235U fission reaction, the total excitation energy partition of the fission fragments, the average neutron kinetic energy ⟨ε⟩(A) and the total average energies Ēγ(A) removed by γ rays as a function of fission fragment mass are given at incident energies up to 20 MeV. The prompt neutron multiplicity as a function of the fragment mass, ν(A), for neutron-induced fission of 235U at different incident neutron energies is calculated. The calculated results are checked with the total average prompt neutron multiplicities ν̄ and compared with the experimental and evaluated data. Some prompt neutron and γ emission mechanisms are discussed.

Monte-Carlo study of pre-neutron emission mass and energy for neutron-induced ²³²Th fission

“…在裂变过程中, 处于激发态的初级裂变碎片会 在极短时间内(<10 -14 s)释放瞬发中子而退激. 裂 变所释放的瞬发中子数目 呈规律性统计分布, 称 之为中子多重性分布 [20,38,39] . 其中, 平均裂变瞬发 中子数与裂变碎片质量数间的物理关系 引起 国内外广泛关注 [40−42] , 它反映了不同质量初始碎片 的激发能大小, 为核裂变机制研究提供重要信息.…”