Nuclear shell effect and collinear tripartition of nuclei

TL;DR

This paper theoretically investigates the formation of three nearly equal-mass reaction products in the spontaneous fission of $^{252}$Cf, focusing on the potential energy surface that favors specific fragment combinations.

Contribution

It introduces a detailed calculation of the potential energy surface for collinear tripartition in $^{252}$Cf fission, revealing favorable conditions for certain fragment mass combinations.

Findings

Favorable conditions for forming Ni and Sn clusters with specific masses.

Identification of potential energy minima supporting collinear tripartition.

Correlation with experimental observations of ternary fission products.

Abstract

A possibility of formation of the three reaction products having comparable masses at the spontaneous fission of $^{252}$Cf is theoretically explored. This work is aimed to study the mechanism leading to observation of the reaction products with masses $M_1=$136---140 and $M_2=$68---72 in coincidence by the FOBOS group in JINR. The same type of ternary fission decay has been observed in the reaction $^{235}$U(n$_{\rm th}$,fff). The potential energy surface for the ternary system forming a collinear nuclear chain is calculated for the wide range of mass and charge numbers of constituent nuclei. The results of the PES for the tripartition of $^{252}$Cf(sf,fff) shows, that we have favorable dynamical conditions for the formation of fragments with mass combinations of clusters $^{68-70}$Ni with $^{130-132}$Sn and with missing cluster $^{48-52}$Ca.