How does one synthesize a new chemical element? Once made, how does one characterize it? How does a new element gain its name? Finally, how many more elements might there be—or where does the periodic table end? This presentation will discuss these topics and use the synthesis, characterization, and eventual naming of element 116 livermorium and element 117 tennessine as examples. The Dubna/LLNL collaboration has been investigating the nuclear and chemical properties of the heaviest elements since 1989. Elements 113-118 have been synthesized and characterized using fusion-evaporation nuclear reactions of 48Ca beams on actinide targets (237Np, 239,240,242,244Pu, 243Am, 245,248Cm, 249Bk, and 249,251Cf, respectively) at the U400 cyclotron located at the Flerov Laboratory of Nuclear Reactions in Dubna, Russia. This talk will discuss the ramifications of the experimental work during the last 20 years on the synthesis of elements 113 – 118 and the prospects for future new and heavier element synthesis. Experimental and theoretical efforts to locate and access the next region of doubly-magic spherically shaped nuclei, the Island of Stability, will be presented. For some combination of protons (Z > 118) and neutrons, the strong nuclear force which binds nucleons together will not be able to counter the Coulomb repulsion of the protons in a nucleus, and thus nuclei will cease to exist and the periodic table will end.
This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344