Calculation of fission product yields for uranium isotopes by using a semi-empirical model

Semi-empirical model to determine pre- and post-neutron fission product yields and neutron multiplicity

“…Let us begin with a brief description of the model [13]. It is based on the work by Bohr and Wheeler [27], where the compound nucleus formed during the fission process is considered as a microcanonical ensemble.…”

“…In the previous works [13,14], the emission of prompt neutrons were taken into account in the fission barrier V (N) by using the average number of emitted neutrons ν known for each compound nucleus. Therefore, the center of the fission yield distribution and the light fragment peaks were shifted by ν through ÑCN ≡ N CN − ν and Ñj ≡ ÑCN −N j (j = in, out), respectively.…”

“…In other words, in Refs. [13,14], where Eq. ( 3) was applied to describe the POST-FPY, ÑCN and Ñj were used in Eq.…”

“…A simple semi-empirical model was proposed recently for the calculation of the POST-FPY of uranium [13] and plutonium [14] isotopes by taking into account the emission of prompt neutrons through the average number of neutrons emitted for each compound nucleus, whereas the number of emitted neutrons depends on each individual fission fragment. Therefore, in this work we attempt to calculate both PRE-and POST-FPYs with our semi-empirical fission model by taking into account the number of emitted neutrons for each individual fission fragment mass.…”

“…We first apply the semi-empirical FPY model to the pre-neutron emission fission fragment mass distributions instead of the POST-FPY data as was done in Refs. [13,14]. Then, the post-neutron fission fragment mass distributions can be calculated by taking into account the neutron multiplicity for each fission fragment mass.…”