Cross sections for the production of superheavy nuclei

Prospects of heavy and superheavy element production via inelastic nucleus-nucleus collisions – from238U+238U to18O+254Es

“…On the one hand, they exhibit excellent agreement with experimentally determined cross sections [13]. On the other hand, these theory results [28] show a most highly desired but unexpected extension of all isotope distributions towards the neutron rich side, which was never seen before. These isotope distributions have an enormous width of about 10 u (FWHM) and they are -in contrast to all experimental findings so farnot Gaussian in shape anymore.…”

“…This expectation does not solely rely on the 238 248 Cm reaction provide pivotal data challenging results and predictions of recent two-center shell-model calculations; see [28] and references therein. On the one hand, they exhibit excellent agreement with experimentally determined cross sections [13].…”

“…Among these are fascinating isotopes like the ones between 262, 264 Fm and 266, 268 Rf with cross section of more than 1 nb, or 272 Rf and 274 Sg accessible with more than 1 pb. However, as the authors of [28] point out, these cross section essentially depend on the strength of shell effects. Fortunately, the validity of these calculations on the neutron-rich side can be tested in the Fm, Md and No…”

“…Presently, no other nuclear reaction, including radioactive ion beams, provides a competing alternative. Based on current theoretical predictions [28], 248 Cm as a target can provide access to most interesting new isotopes in the heavy actinide and light transactinide region, like the N = 162 nuclei 262 Fm, 264 No and 266 Rf. Moreover, it is essential for putting these theoretical predictions on the synthesis of new isotopes for heavy and superheavy elements on the test bench.…”

Characterizing the mechanism(s) of heavy element synthesis reactions

“…This is an item of some controversy. Some feel the uncertainties in typical predictions are factors of 2-4 [7] while others estimate these uncertainties to be 1-2 orders of magnitude [8,9].…”