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This paper presents results of the experiments aimed at producing long-lived superheavy elements located near the spherical-shell closures with Z ⩾ 114 and N ⩾ 172 in the 244Pu + 48Ca and 248Cm + 48Ca reactions. The large measured α-particle energies of the newly observed nuclei, together with the long decay times and spontaneous fission terminating the chains, offer evidence of the decay of nuclei with high atomic numbers. The decay properties of the synthesized nuclei are consistent with the consecutive α-decays originating from the parent nuclides 288, 289114 and 292116, produced in the 3 n and 4 n evaporation channels with cross-sections of about a picobarn. The present observations can be considered as experimental evidence of the existence of the “island of stability” of superheavy elements. [ABSTRACT FROM AUTHOR]

The reaction 48Ca+238U was investigated at the recoil separator VASSILISSA at the Flerov Laboratory of Nuclear Reactions, JINR Dubna, in attempts to synthesize new isotopes of element 112. The experiments were performed at two beam energies resulting in excitation energies of the compound nucleus of 33 and 39 MeV. The collected beam dose was 3.5 × 1018 and 2.2 × 1018, respectively. Two spontaneous fission events were observed at the lower beam energy, which tentatively were assigned to the new neutron rich isotope 283112 produced in the reaction 238U(48Ca,3n)283112. The measured cross-section is (5.0+6.3 −3.2) pb and the half–life is (81+147 −32) s. No event was observed at the higher beam energy resulting in the upper cross–section limit of 7.3 pb. [ABSTRACT FROM AUTHOR]

New results have been obtained for the energy dependence of the total reaction cross section σ[sub R] of [sup 4]He on [sup 28]Si in the energy range E[sub α] ≤ 30 MeV.© 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]