Shifting the closed proton shell to Z = 122 : a possible scenario to understand the production of superheavy elements Z = 112-118
P. Ambruster (GSI-Darmstadt)
from 11:00 am à 12:00 pm
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The recent experiments at FLNR, Dubna, demonstrated that cross-sections to produce SHEs by
48Ca-induced reactions on actinide targets increase beyond Z = 111, reach a maximum of 5 pb at Z = 114
and fall below the 1 pb level at Z = 118. A scenario is proposed to understand the findings within the
frame of former experimental results of heavy-element production and theoretical predictions about the
stability of the nuclides concerned. New ingredients introduced are: 1) to shift the next proton shell beyond
Pb from Z = 114 to Z = 122; 2) the isotopes of the elements Z = 112 to Z = 118 are deformed and their
nuclei have oblate shapes; 3) the fission barriers around the next nucleus with doubly closed shells
N=184 and Z= 122 are larger than the neutron separation energies and reach values in the range of 10MeV.
The ascent of the flat top at N=184 and Z= 122 is described by the proposed scenario,
which likewise excludes reaching the doubly closed shell region at the top by today’s experimental methods.