Beyond darmstadtium --Status and perspectives of superheavy element research

Abstract.

The search for superheavy elements has yielded exciting results for both the “cold fusion” approach with reactions employing Pb and Bi targets and the “hot fusion” reactions with ⁴⁸Ca beams on actinide targets. In recent years the accelerator laboratories in Berkeley, Dubna and Darmstadt have been joined by new players in the game in France with GANIL, Caen, and in Japan with RIKEN, Tokyo. The latter yielding very encouraging results for the reactions on Pb/Bi targets which confirmed the data obtained at GSI. Beyond the successful synthesis, interesting features of the structure of the very heavy nuclei like the hint for a possible K-isomer in ²⁷⁰Ds or the population of states at a spin of up to 22ℏ in ²⁵⁴No give a flavor of the exciting physics we can expect in the region at the very extreme upper right of the nuclear chart. To get a hand on it, a considerable increase in sensitivity is demanded from future experimental set-ups. High intensity stable beam accelerators, mass measurement in ion traps and mass spectrometers, as well as the possible employment of unstable neutron-rich projectile species, initially certainly only for systematic studies of reaction mechanism and nuclear structure features for lighter exotic neutron-rich isotopes, are some of the technological challenges which have been taken on.