ISOSPIN DEPENDENCE OF REACTIONS⁴⁸Ca+^243-251Bk

Abstract

The fusion process of 48 Ca induced reactions is studied with the two-step model. In this model, the fusion process is devided into two stages: first, the sticking stage where projectile and target come to the touching point over the Coulomb barrier from infinite distance, and second, the formation stage where the di-nucleus formed with projectile and target evolve to form the spherical compound nucleus from the touching point. By the use of the statistical evaporation model, the residue cross sections for different neutron evaporation channels are analyzed. From the results, optimum reactions are given to synthesize Z = 117 element with 48 Ca induced reactions.

Eleven new heaviest isotopes of elementsZ=105toZ=117identified among the products ofOganessian1, Abdullin2, Bailey3 et al. 2011Phys. Rev. C1255350View full textAdd to dashboardCite

“…This estimate is based on experimentally measured cross sections for the formation of the superheavy nuclides in reactions with 48 Ca, in particular, for the neighboring nuclei with Z = 116 [10,11] and Z = 118 [12]. These extrapolated values agree well with calculated cross sections [23][24][25].…”

“…The measured half-lives for Db isotopes gradually become larger with increase in neutron number on approach to the neutron shell N = −0.6 pb at E*=35 MeV and E*=39 MeV, respectively (see Table III). Error bars correspond to statistical [42] Table III experimental cross sections of the 3n and 4n reaction channels within experimental uncertainties do not contradict the calculated values of [23][24][25].…”

Experimental studies of the249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotopeOganessian1, Abdullin2, Alexander3 et al. 2013Phys. Rev. C1377480View full textAdd to dashboardCite

“…The calculated cross sections are in good agreement with results of experiment. Some other models predict comparable cross-section values but the energies of the maxima of the xn evaporation channels are predicted to be somewhat lower (see, e.g., [17,18]) than those measured in this experiment. [15] and dashed [16] lines.…”

Discovery of the New Element Z=117 and Confirmation of 115

“…by calculations made for the evaporation residues of the reaction 249 Bk + 48 Ca [14][15][16], and by the result of our 249 Bk + 48 Ca experiment performed at lower beam energy (discussed next). The total numbers for random sequences [17] imitating each of the observed five decay chains were calculated to be 6 x 10 A new decay chain with six consecutive -decays and ending in SF was detected, see Fig 2. In this chain, the Z=111 great-granddaughter nucleus emitted an -particle with E  =9.00 MeV instead of undergoing SF, followed by two more -transitions, and after about 33 hours, a fission event.…”