Synthesis and Properties of Even-even Isotopes with Z=110-116 in ⁴⁸Ca Induced Reactions

Abstract

The paper presents results on the synthesis of superheavy nuclides with Z=114 and 116 in the fusion reactions with ⁴⁸Ca ions. In the irradiation of targets made from enriched ²⁴⁴Pu and ²⁴⁸Cm isotopes with beam doses of 1.5×10¹⁹ and 2.3×10¹⁹, respectively, the detector array situated in the focal plaaane of the gas-filled separator registered heavy atoms of new elements undergoing sequential a decays terminated by spontaneous fission. The time of the decay chains is approximately one minute. Decay properties of the synthesized nuclei are consistent the consecutive α decays originating from the parent nuclides ²⁸⁸ 114 and ²⁹⁶ 116 produced in the 4n-evaporation channels with the cross section of about a picobarn. Comparison of T_SF and T_α values for the nuclei with Z=110 and 112 with those obtained earlier for lighter isotopes of these elements points to an enhanced stability of heavy nuclei with an increase in the neutron number. The α-decay energies Q_α measured experimentally in the chains 116-α₁-1l4-α₂-112-α₃-110 are compared with theoretical predictions of different nuclear models. This comparison shows that the difference between the experiment and theory is in the range of ±0.5 MeV. From this it follows that the theoretical models predicting the decisive influence of the nuclear structure on the stability of superheavy elements are well-founded not only qualitatively but in some sense also quantitatively. The prospects of further investigations in the field of superheavy nuclei are discussed briefly.