TABLE OF CONTENTS G.M nzenberg
Gesellschaft f r Schwerionenforschung (GSI) mbH, Planckstr. 1, D64291 Darmstadt, Germany and Johannes Gutenberg Universit t, Mainz, Germany
Microscopic nuclear theories predict a region of superheavy elements at the next double magic shell closure above 208Pb. According to recent calculations it is located at Z=120 and N=184. These predictions motivated the search for superheavy elements in nature and in the laboratory and to explore the limits of the chart of nuclides towards its upper end. Recently a new region of shell stabilization has been found for the transactinide elements. It interconnects the transuranium elements and the predicted and still unexplored superheavy elements. Production and investigation of the nuclear properties of the transactinide elements are the subject of this section. The heaviest element known today is Z=112. Evidence for elements 114 and 116 has been reported recently. They are created by complete fusion of heavy ions with rates down to less than one atom per week. All chemical elements at the top of the nuclear table have been discovered on the basis of single-atom decays after separation in-flight. Plans to investigate atomic, chemical and nuclear properties at highest precision will be addressed. The prospects and possibilities for the synthesis of new elements using advanced technologies such as new high-current heavy-ion accelerators or radioactive beams will be outlined.
A fundamental question is how many elements can we find in nature and what are the limits of stability of matter in terms of nuclear mass and charge.
