Prompt fission neutron multiplicity and spectra evaluation in the frame of the multi-modal fission model for 237Np(n,f) and 238U(n,f)

Effects of fissioning nuclei distributions on fragment mass distributions for high energy fission

“…There is an apparent puzzle in the conclusions obtained so far, since using the symmetric fission dominance prescription we do not reproduce the results for actinide nuclei, but have much better 125.66 ± 0.05 a 5 14.93 ± 0.05 a 6 3.97 ± 0.05 a 7 5.21 ± 0.05 results for lead. However, the systematics at low energies [6] already shows that for nuclei with mass numbers around 220 the symmetric mode is dominante.…”

“…This method has been used for describing spontaneous fission [3], low-energy induced fission [4][5][6], fission induced by thermal-neutrons [7][8][9] and 12 MeV protons [10], and even for fission induced by intermediate energy probes such as 190 MeV protons [11], neutrons at energies up to 200 MeV [12], and also by heavy-ions [13,14]. A systematic study of the values obtained for the parameters in formula (1) by fitting to experimental data for spontaneous or low energy fission of several nuclei was performed by Böckstiegel et al [6], showing that those parameters can be described by smooth functions of the fissioning nucleus mass number.…”

Statistical study of the prompt-fission γ -ray spectrum for U238(n, f ) in the fast-neutron region

“…Despite the weaker increase of PFG emission relative to PFN emission, our results suggest that the assumption that neutron emission entirely precedes γ emission, is not valid and that competition of both play a considerable role during the deexcitation of fission fragments [4][5][6]. Figure 11 contains-as a function of incident neutron energy-the average values for each quantity from this work, together with results from various fission models, including PbP [42], GEF [41], and FREYA [43], as well as calculations based on systematics [44]. The calculated observables of PFG from GEF and FREYA have reasonable agreement with the experimental results and also exhibit a slightly increasing trend in terms of average γ multiplicity and total energy per fission.…”

Calculation of prompt fission neutron spectrum for 233 U(n, f) reaction by the semi-empirical method

“…The Los Alamos (LA) model [2] is one of the most successful models for predicting the prompt fission neutron spectrum with an assumption of the same triangular-shaped initial nuclear temperature distribution for both light and heavy fragments, and was originally developed for 235 U and 239 Pu. Based on the LA model, the multi-modal random neck-rupture model [3,4] has been applied to some calculations of prompt neutron spectrum of several actinide nuclei isotopes by Ohsawa [5,6], Hambach [7][8][9], Vladuca [10], and Zheng [11] et al But most of these calculations are for 235,238 U(n, f) and 239 Pu(n, f) reactions, only the calculation of Ref. [11] is for 233 U(n, f) reaction, but the nuclear temperature is still an assumption of simple triangular shaped.…”