D N Poenaru
Horia Hulubei National Institute of Physics and Nuclear Engineering, Romania
Title: Main decay modes of super heavy nuclei
Biography
Biography: D N Poenaru
Abstract
Several laboratories in the world, like GSI Helmholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; JINR Dubna,
Russia; Nat. Livermore Lab., USA and RIKEN Japan are trying to produce super heavy (SH) nuclei with atomic numbers Z>118,
using cold fusion reactions (with just one neutron-evaporation or hot fusion (with 3-4 evaporation neutrons) and 48Ca projectile
beam. Until now the main decay modes of SHs, allowing identifying the new element were alpha decay (AD) and spontaneous fission
(SF), with a clear advantage of using AD chains, leading to a well-known final nucleus. We would like to point out that in some cases
with large atomic number Z (usually Z>120) cluster radioactivity (CR) may compete as well, opening a new opportunity in this
field. In order to illustrate this new finding, we shall present the results of our calculations for the following nuclides: 297,299,300119
and 299,300,301,302120. We are using mainly the following models: ASAF (analytical super-asymmetric fission); UNIV (Universal
formula), and SEMFIS (semi-empirical formula based on fission theory) to study AD. ASAF and UNIV are useful for CR. A dynamical
model based on cranking inertia tensor allows us to calculate SH half-lives. Strutinsky's macroscopic-microscopic method with
Yukawa-plus-exponential (Y+EM) liquid drop and the best two-center shell model are necessary to calculate the total deformation
energy. For pairing we have to solve the BCS system of two equations. For 38Sr CR of 300,302120 we predict a branching ratio
relative to AD of -0.10 and 0.49, respectively, meaning that it is worth trying to detect such kind of decay modes in competition
with AD. Whenever possible we calculate the Q-values by using the latest experimental evaluation of the masses. Otherwise the W4
atomic mass model is our choice.