Fragment-mass distributions in neutron-induced fission ofTh232andU238

Pre-neutron-emission Mass Distributions for Reaction 232 Th( n, f ) up to 60 MeV

“…There are several codes, such as MCFX [8], TALYS [9], UKFY4.1 [10], GEF2012/2.4 [11] and PYF [12], which can calculate the pre-neutron-emission mass distributions for reaction 232 Th(n, f) at low or intermediate energies. Generally, the agreement between the experimental data and the mode calculations mentioned above is good for 238 U but worse for 232 Th at intermediate energies [3,6,7]. It can be obviously seen from the experimental data [3,6,7,13,14] that the pre-neutron-emission mass distributions for reaction 232 Th(n, f) gradually change from double-humped to triple-humped shape with increasing the incident energies.…”

“…Generally, the agreement between the experimental data and the mode calculations mentioned above is good for 238 U but worse for 232 Th at intermediate energies [3,6,7]. It can be obviously seen from the experimental data [3,6,7,13,14] that the pre-neutron-emission mass distributions for reaction 232 Th(n, f) gradually change from double-humped to triple-humped shape with increasing the incident energies. In this work, we attempt to describe quantitatively both the double-humped and triple-humped pre-neutron-emission mass distributions for reaction 232 Th(n, f) up to 60 MeV with an empirical fission potential.…”

“…It is necessary to accurately describe and predict fission yields at different energies for a successful nuclear fission model. Due to the complex of fission process, it is still difficult to microscopically describe the mass splitting for neutroninduced fission at low and intermediate energies [1,2,3], though it is believed that the formation of the fission fragment-mass distribution is closely connected with the potential energy surface in deformation space [4,5]. Nowadays, there is an increasing interest in studying neutroninduced fission of actinides at intermediate energies.…”

“…Recently, the reaction 232 Th(n, f) at intermediate energies was measured by V.D. Simutkin group [3,6,7]. Theoretical calculations for the preneutron-emission mass distributions is of great importance for understanding the fission process and for describing the measured yields of the fission products.…”

“…(2) play an important role. Based on the quasi-monoenergetic experimental data [3,6,7], one can see that the width between the valleys ∆B = B 2 − B 1 increases with the incident energies, and its energy dependence can be reasonably well described with a parameterized formula ∆B = 22.509 − 69.774 exp(−0.114E n ).…”