Experimental Neutron-induced Fission Fragment Mass Yields of 232Th and 238U at Energies from 10 to 33 Me

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.…”

“…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.…”

Study of fission using multi-nucleon transfer reactions

“…The momentum of the target-like fissioning recoil nucleus is determined by the measured momentum of ejectile under the assumption of a binary reaction process. Figure 4 shows the comparison of FFMDs for 239 U * , populated in the 238 U( 18 O, 17 O) 239 U * reaction [9], with n + 238 U [10]. The obtained FFMDs from MNT reactions agree well with the neutron-induced data, particularly the mass asymmetry at the peak positions at the lowest energy data and the increase of the symmetric fission with excitation energy are noteworthy.…”

Study of fission using multi-nucleon transfer reactions

“…The momentum of the target-like fissioning recoil nucleus is determined by the measured momentum of ejectile under the assumption of a binary reaction process. To validate the calibration procedure, Figure 4 shows the comparison of FFMDs for 239 U * , populated in the 238 U( 18 O, 17 O) 239 U * reaction [15], with n + 238 U [16]. The obtained FFMDs from MNT reactions agree well with the neutron-induced data, particularly the mass asymmetry at the peak positions at the lowest energy data and the increase of the symmetric fission with excitation energy are noteworthy.…”

“…One of the possible reasons for the deviation could be in the treatment of the neck parameter (0 < < 1) [24] to define the shape of nucleus. In our work we adopted =0.35 derived as an optimal value in [23] to explain FFMDs of fissioning nucleus of mass of 234-240, which (Color online) Experimental FFMD of 240 U * (blue symbols) measured at the initial excitation energy of 40-50 MeV obtained from the two neutron-transfer channel 238 U( 18 O, 16 O) 240 U * , is compared with the Langevin calculation [23] taking into account multi-chance fission. Thin gray curve is obtained by summing all the fission-chances, which is then broadened with the experimental mass resolution (red curve).…”