Three-dimensional potential energy surface for fission of^(236)U within covariant density functional theory

We calculate the three-dimensional potential energy surface(PES)for the fission of the compound nucleus^(236)U using covariant density functional theory with constraints on the axial quadrupole and octupole deformations(β_(2),β_(3))coexistence of the elongated and compact fission modes is predicted for comes shallow across a large range of quadrupole and octupole deformations for small scission line in the(β_(2),β_(3))plane extends to a shallow band,leading to fluctuations of several to ten MeV in the estimated total kinetic energies and of several to approximately ten nucleons in the fragment masses.

Kinetic energy distribution for neutron-induced fission of neptunium isotopes

The mean total kinetic energy as a function of fission fragments,the<TKE>distribution,is presented for neutron-induced fission of ^(235-239)Np using the scission point model.The calculated results of<TKE>for neutron-induced fission of ^(237,238) Np are compared with the available experimental data to obtain the deformation parameters in the scission point model.The deformation parameters of fission fragments are discussed at the scission point.The calculated results are also compared with the results from other methods and with experimental data.The behavior of the<TKE>distribution is then studied for the neutron-induced fission of actinides.This indicates that the<TKE>values for neutron-induced fission of actinides with odd mass numbers are greater than for those with even mass numbers.

Sequential decay analysis of^(235)U(n^(th),f)reaction using fragmentation approach

Numerous experimental and theoretical observations have concluded that the probability of the three fragment emission(ternary fission)or binary fission increases when one proceeds towards the heavy mass region of nuclear periodic table.Many factors affect fragment emission,such as the shell effect,deformation,orientation,and fissility parameter.Binary and ternary fissions are observed for both ground and excited states of the nuclei.The collinear cluster tripartition(CCT)channel of the^(235)U(n^(th),f)reaction is studied,and we observe that the CCT may be a sequential or simultaneous emission phenomenon.To date,different approaches have been introduced to study the CCT process as a simultaneous or sequential process,but the decay dynamics of these modes have not been not fully explored.Identifying the three fragments of the sequential process and exploring their related dynamics using an excitation energy dependent approach would be of further interest.Hence,in this study,we investigate the sequential decay mechanism of the^(235)U(n^(th),f)reaction using quantum mechanical fragmentation theory(QMFT).The decay mechanism is considered in two steps,where initially,the nucleus splits into an asymmetric channel.In the second step,the heavy fragment obtained in the first step divides into two fragments.Stage I analysis is conducted by calculating the fragmentation potential and preformation probability for the spherical and deformed choices of the decaying fragments.The most probable fragment combination of stage I are identified with respect to the dips in the fragmentation structure and the corresponding maxima of the preformation probability(P0).The light fragments of the identified decay channels(obtained in step I)agree closely with the experimentally observed fragments.The excitation energy of the decay channel is calculated using an iteration process.The excitation energy is shared using an excitation energy dependent level density parameter.The obtained excitation energy of the identified heavy fragments is further used to analyze the fragmentation,and the subsequent binary fragments of the sequential process are obtained.The three identified fragments of the sequential process agree with experimental observations and are found near the neutron or proton shell closure.Finally,the kinetic energy of the observed fragments is calculated,and the middle fragment of the CCT mechanism is identified.