Influence of the shell effects on evaporation residue cross section of superheavy nuclei

In order to study the influence of the shell effects on the formation and fission of superheavy elements, we applied multidimensional Langevin equations. The evaporation residue cross sections have been calculated for 3n, 4n, and 5n evaporation channels using three(K = 0)-and four(K ≠ 0)-dimensional Langevin equations. Calculations were done for ^(48)Ca + ^(238)U and ^(48)Ca + ^(244)Pu hot fusion reactions with 3n, An evaporation channels and ^(70)Zn+ ^(208)Pb, and ^(54)Cr + ^(209)Bi cold fusion reactions with In and 2n evaporation channels. The calculations were performed for An and 5n evaporation channels of the ^(26)Mg+ ^(238)U reaction, as well. Our results show that with increasing dimension of Langevin equations the residue cross section increases, whereas the fission cross section decreases. The obtained results with four-dimensional Langevin and considering shell effects are in better agreement with experimental data in comparison with three-and four-dimensional Langevin equations without shell effects.

The entrance channel effect on the synthesis of a superheavy element ^(296)119

In this study,we investigated the entrance channel effect on the evaporation residue cross section of a superheavy element^(296)119.Using 29 projectile-target combinations,we investigated the role of the entrance channel on the 3n and 4n evaporation channels in hot combinations.This effect can be evaluated based on the entrance channel asymmetry and Q value of complete fusion.We calculated the variation of the maximum evaporation residue cross sections(σ^(max)_(3n)andσ^(max)_(4n))with|Q|for the reactions^(49-47)Ti+^(247-249)Bk,^(60-57)Fe+^(236-239)Np,^(44-42)Ca+^(252-254)Es,and^(55,54,52)Mn+^(241,242,244)Pu.With an increase in|Q|,σ^(max)_(3n)andσ^(max)_(4n) increase.In addition,we studied the role of asymmetry and mean fissility parameters in the synthesis of the superheavy element.The obtained results in this study can be utilized in future studies.

Investigation of fission fragments average spin based on four dimensional Langevin dynamical model

We applied the four dimensional Langevin dynamical model to investigate the average spin of fission fragments. Elongation, neck thickness, asymmetry parameter, and the orientation degree of freedom（K coordinate）are the four dimensions of the dynamical model. We assume that the collective modes depend on the emission angle of the fragments, then different parameters related to the average spin of fission fragments are calculated dynamically.The angle dependence of average spin of fission fragments is investigated by calculating the spin at angles 90？and165？. Also, the obtained results based on the transition state model at scission point are presented. One can obtain better agreement between the results of the dynamical model and experimental data in comparison with the results of the transition state model.