Orateur
Description
Fission properties of nuclear matter in the new region of asymmetric fission were investigated using fusion-fission reactions $^{35}$Cl+ $^{141}$Pr $\rightarrow$ $^{176}$Os$_{100}$, $^{35}$Cl+$^{142}$Nd $\rightarrow$ $^{177}$Ir$_{100}$ and $^{35}$Cl+ $^{144}$Sm $\rightarrow$ $^{179}$Au$_{100}$, in the excitation energy interval 40-70 MeV. The studied fission fragment mass distributions (FFMDs) and total kinetic energy(TKE) distributions show deviations from a pure Gaussian distribution indicating the coexistence of both symmetric and asymmetric modes. Fission mode parameters extracted from the FFMDs indicate A$_{L}$~80 and A$_{H}$~A$_{CN}$-A$_{L}$ as fragments hosting the asymmetric mode in the studied nuclei, which is in agreement with the Z=34 and N=46 deformed shells predicted by theory. In contrast to actinides, the symmetric and asymmetric fission modes exhibit very close average TKE which signifies virtually identical scission-point elongations. The width of FFMDs of Os-Hg is analyzed at comparable nuclear temperature and angular momentum, revealing an inverse parabolic shape with atomic number which paves way for border assessment for the new region of asymmetric fission.
| Affiliation de l'auteur principal | LP2i Bordeaux, CNRS/IN2P3-Université de Bordeaux |
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