The Synthesis of Superheavy Elements

Abstract

The elements with the atomic numbers 107–112 have been synthesized and unambiguously identified at the velocity filter SHIP at GSI. The technique allowing for this successful experimental program is the combination of the detection of correlations between evaporation residues and subsequent a‐decays with a powerful separator. Systematic investigations, the construction of decay chain networks and mass measurements are some of the possible approaches to study the decay chains tentatively attributed to the isotopes of the elements 114 and 116 at Dubna, which are, in contrast to those observed at GSI, not connected to α‐decays of known isotopes. The sensitivity limit of the set‐up at GSI has reached the 1pb level. For systematic investigation in this region of extremely low cross section and to synthesize nuclei of higher Z this limit has to be pushed to even lower values. An extensive development program is pursued at SHIP in order to reach at least an order of magnitude lower cross sections. Apart from target cooling and separator development a super conducting CW linear accelerator is studied to reach this goal. To design a successful experimental program for the possible discovery of new elements the nuclear structure of the heaviest nuclei has to be understood as well as the reaction mechanism which leads to their production in heavy ion reactions. We have initiated series of systematic studies for both subjects.