Prompt fission neutron spectra of n+U-235 above the (n,nf) fission threshold

作者：Shu Neng-Chuan^*; Jia Min; Chen Yong-Jing; Liu Ting-Jin

来源：Chinese Physics C, 2015, 39(5): 054101.

DOI：10.1088/1674-1137/39/5/054101

• U-235(n, f)
• neutron-induced fission
• prompt fission neutron spectrum

Calculations of prompt fission neutron spectra (PFNS) from the U-235(n, f) reaction were performed with a semi-empirical method for E-n = 7.0 and 14.7 MeV neutron energies. The total PFNS were obtained as a superposition of (n,xnf) pre-fission neutron spectra and post-fission spectra of neutrons which were evaporated from fission fragments, and these two kinds of spectra were taken as an expression of the evaporation spectrum. The contributions of (n,xnf) fission neutron spectra on the calculated PFNS were discussed. The results show that emission of one or two neutrons in the (n,nf) or (n,2nf) reactions influences the PFNS shape, and the neutron spectra of the (n,xnf) fission-channel are soft compared with the neutron spectra of the (n,f) fission channel. In addition, analysis of the multiple-chance fission component showed that second-chance fission dominates the PFNS with an incident neutron energy of 14.7 MeV whereas first-chance fission dominates the 7 MeV case.

• 出版日期2015-5
• 单位中国原子能科学研究院