6533b821fe1ef96bd127ac5b

RESEARCH PRODUCT

Fusion-fission and quasifission of superheavy systems withZ=110–116formed inCa48-induced reactions

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Background: In heavy-ion-induced reactions the mechanism leading to the formation of the compound nucleus and the role of quasifission is still not clear.Purpose: Investigation of the quasifission process of superheavy composite systems with $Z=110\text{\ensuremath{-}}116$ and comparison with properties of fusion-fission and quasifission of lighter composite systems.Method: Mass and energy distributions of fissionlike fragments formed in the reactions $^{48}\mathrm{Ca}+^{232}\mathrm{Th}$, ${}^{238}\mathrm{U}$, ${}^{244}\mathrm{Pu}$, and ${}^{248}\mathrm{Cm}$ at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET at the U-400 cyclotron of the FLNR JINR.Results: The most probable fragment masses as well as total kinetic energies and their dispersions in dependence on the interaction energies and ion-target combinations have been studied for asymmetric and symmetric fragments formed in the reactions. The capture cross sections were obtained for the reactions $^{48}\mathrm{Ca}+^{244}\mathrm{Pu}$ and ${}^{248}\mathrm{Cm}$. The lower limits for fission barriers of ${}^{283\ensuremath{-}286}\mathrm{Cn}$, ${}^{289\ensuremath{-}292}\mathrm{Fl}$, and ${}^{293\ensuremath{-}296}\mathrm{Lv}$ compound nuclei were estimated.Conclusions: Analysis of the properties of symmetric fragments has shown that a significant part of these fragments may be attributed to fusion-fission process for the reactions ${}^{48}\mathrm{Ca}{+}^{238}\mathrm{U}$, ${}^{244}\mathrm{Pu}$, and ${}^{248}\mathrm{Cm}$.