Neutron Emission in Fission And Quasi -Fissionof Hs

摘要

Mass and energy distributions of fission -like fragments obtained in the reactions ~(26)Mg + ~(248)Cm, ~(36)S + ~(238)U and ~(58)Fe + ~(208)Pb leading to the formation of ~(266, 274)Hs are reported.From the analysis of TKE distributions for symmetric fragment it was found that at energies below the Coulomb barrier the bimodal fission of ~(274)Hs, formed in the reaction ~(26)Mg+~(248)Cm, is observed, while in the reaction ~(36)S+~(238)U at these energies the main part of the symmetric fragments arises from the quasi -fission process. At energies above the Coulomb barrier the fusion-fission is a main process leading to the formation of symmetric fragment for the both reactions. In the case of ~(58)Fe+~(208)Pb reaction the quasi-fission process is the main reaction mechanism at all measured energies. The pre- and post-scission neutron multiplicities as a function of the fragment mass have been obtained for all studied reactions.