Semi-Microscopical Description of the Scission Configuration in the Cold Fission of $^{252}$Cf

This work is focused on even-odd effects on the minimal total fragment excitation energy in thermal neutron induced fission of 233U and 235U as well as in spontaneous fission of 252Cf. In a scission model, taking into account the fragment deformation properties and Coulomb interaction between fragments, the expression of the difference between Q-values referred to even/even and odd/odd charge splits, respectively, on the corresponding difference between the minimal total frag...

In the present work the formal definition of the scission point - the maximal elongation at which the nucleus splits into two fragments - is given. The shape and the deformation energy at the scission point are calculated within the macroscopic-microscopic model. Three minima in the scission point deformation energy are found corresponding to the "standard", "supershort" and "superlong" fission modes. The contribution of each fission mode to the mass distribution of the fis...

The microscopic studies on nuclear fission require the evaluation of the potential energy surface as a function of the collective coordinates. A reasonable choice of constraints on multipole moments should be made to describe the topography of the surface completely within a reasonable amount of computing time. We present a detailed analysis of fission barriers in the self-consistent Hartree-Fock-Bogoliubov approach with the D1S parametrization of the Gogny nucleon-nucleon in...

The time-dependent generator coordinate method with the gaussian overlap approximation (TDGCM+GOA) formalism is applied to describe the fission of $^{252}$Cf. We perform analysis of fission from the initial states laying in the energetic range from the ground state to the state located 4 MeV above the fission barrier. The fission fragment mass distributions, obtained for different parity, energy of levels and types of mixed states, are calculated and compared with experimenta...

The concept of collinear spontaneous true ternary fission of 252Cf is subject to critical analysis. The conclusion is that the collinear flight of the fragments turns out to be a natural and most probable mode. The collinearity arises in the model on the prescission stage as a result of the account of the principles of the collective Bohr's model. It is partly destroyed at the post-scission stage of spreading of the fragments due to their Coulomb interaction, with the allowan...

Within the Unified ternary fission model (UTFM), the alpha accompanied ternary fission of even-even $^{244-260}$Cf isotopes has been studied by taking the interacting barrier as the sum of Coulomb and proximity potential. For the alpha accompanied ternary fission of 244^Cf isotope, the highest yield is obtained for the fragment combination 108^Ru+4^He+132^Te, which contain near doubly magic nuclei 132^Te (N=80, Z=52). In the case of 246^Cf and 248^Cf isotopes, the highest yie...

The fission process is a fascinating phenomenon in which the atomic nucleus, a compact self-bound mesoscopic system, undergoes a spontaneous or induced quantum transition into two or more fragments. A predictive, accurate and precise description of nuclear fission, rooted in a fundamental quantum many-body theory, is one of the biggest challenges in science. Current approaches assume adiabatic motion of the system with internal degrees of freedom at thermal equilibrium. With ...

This paper presents recent experimental results on the yield of prompt fission $\gamma$ rays from the spontaneous fission of $^{252}$Cf. We use an ionization chamber to tag fission events and measure the masses and kinetic energies of the fission fragments and trans-stilbene organic scintillators to measure the neutrons and $\gamma$ rays emitted by the fission fragments. The combination of the ionization chamber and trans-stilbene scintillators allows us to determine the prop...

The saddle-to-scission dynamics of the induced fission process is explored using a microscopic finite-temperature model based on time-dependent nuclear density functional theory (TDDFT), that allows to follow the evolution of local temperature along fission trajectories. Starting from a temperature that corresponds to the experimental excitation energy of the compound system, the model propagates the nucleons along isentropic paths toward scission. For the four illustrative c...

We show that the sharp maximum corresponding to 107Mo in the fragment distribution of the 252Cf cold fission is actually a Sn-like radioactivity, similar to other decay processes in which magic nuclei are involved, namely alpha-decay and heavy cluster emission, also called Pb-like radioactivity. It turns out that the mass asymmetry degree of freedom has a key role in connecting initial Sn with the final Mo isotopes along the fission path. We suppose the cold rearrangement of ...