Superheavy elements—Achievements and challenges

The search for superheavy elements (SHE) 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. The most recent activities at GSI were the successful production of a more neutron rich isotope of element 112 in the reaction 48Ca+238U confirming earlier result from FLNR, and the attempt to synthesize an isotope with Z=120 in the reaction 64Ni+238U. Apart from the synthesis of new elements, advanced nuclear structure studies for heavy and superheavy elements promise a detailed insight in the properties of nuclear matter under the extreme conditions of high Z and A. The means are evaporation residue (ER)−α−α and −α−γ coincidence techniques applied after separation of the reaction products from the beam. Recent examples of interesting physics to be discovered in this region of the chart of nuclides are the investigation of K-isomers observed for 252,254No and indicated for 270Ds. Fast chemistry and precision mass measurements deliver in addition valuable information on the fundamental properties of the SHE. In the process of continuous development and improvement of the experimental methods, which is mandatory to address the challenges of ever lower cross-sections asking for ever higher beam intensities, the target technology plays an important role.