Abstract
The nuclear shell model predicts that the next doubly magic shell-closure beyond 208Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding aim of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described which allowed for the identification of elements 107 to 112 in studies of cold fusion reactions based on lead and bismuth targets. Also presented are data which were obtained on the synthesis of elements 112, 114, and 116 in investigation of hot fusion reactions using actinide targets. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross-sections arecompared with the results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the exploration of the region of spherical SHEs now seems to become feasible, more than thirty years after its prediction.
