Fission of Super-Heavy Nuclei: Fragment Mass Distributions and their Dependence on Excitation Energy
| Autor: | Yu. Ts. Oganessian, Fedir Ivanyuk, N. Carjan |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Nuclear and High Energy Physics
Nuclear Theory SHE Physics and Astronomy (miscellaneous) Fission Materials Science (miscellaneous) FOS: Physical sciences Kinetic energy 01 natural sciences Nuclear Theory (nucl-th) Cn 0103 physical sciences 010306 general physics Nuclear Experiment Spontaneous fission Mass number Physics Radiation Isotope 010308 nuclear & particles physics Fragment (computer graphics) Fl Condensed Matter Physics Potential energy lcsh:QC1-999 nuclear fission Hs Og isotopes symmetric vs asymmetric fission Neutron number Lv Atomic physics excitation energy dependence Ds lcsh:Physics Excitation Energy (signal processing) |
| Zdroj: | Eurasian Journal of Physics and Functional Materials, Vol 3, Iss 1, Pp 10-17 (2019) |
| DOI: | 10.1142/9789811209451_0026 |
| Popis: | The mass and total kinetic energy distributions of the fission fragments in the fission of even-even isotopes of superheavy elements from Hs (Z=108) to Og (Z=118) are estimated using a pre-scission point model. We restrict to nuclei for which spontaneous fission has been experimentally observed. The potential energy surfaces are calculated with Strutinsky's shell correction procedure. The parametrization of the nuclear shapes is based on Cassini ovals. For the just before scission configuration we fix $\alpha$=0.98, what corresponds to $r_{neck}\approx 2$ fm, and take into account another four deformation parameters: $\alpha_1,\alpha_3,\alpha_4,\alpha_6$. The fragment-mass distributions are estimated supposing they are due to thermal fluctuations in the mass asymmetry degree of freedom just before scission. The influence of the excitation energy of the fissioning system on these distributions is studied. The distributions of the total kinetic energy (TKE) of the fragments are also calculated (in the point-charge approximation). In Hs, Ds and Cn isotopes a transition from symmetric to asymmetric fission is predicted with increasing neutron number N (at N$\approx$168). Super-symmetric fission ocurs at N$\approx$160. When the excitation energy increases from 0 to 30 MeV, the peaks (one or two) of the mass distributions become only slightly wider. The first two moments of the TKE distributions are displayed as a function of the mass number A of the fissioning nucleus. A slow decrease of the average energy and a minimum of the width (at N$\approx$162) is found. Comment: 7 pages, 8 figures, submitted to PRC |
| Databáze: | OpenAIRE |
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