Superheavy Element Discovery
Physics Division capabilities for studying the decay of radioactive nuclei are contributing to the discovery and investigation of the heaviest elements and nuclei. Physics Division expertise in digital data acquisition, in combination with unique ORNL facilities for producing actinide target materials at HFIR/REDC, are advancing the field of superheavy nuclei and expanding the Periodic Table. Since 2000, five new heaviest elements, from Z=114 Fl to Z=118 Og including Z=117 Tennessine, have been discovered using ORNL actinide targets including isotopes of Pu, Am, Cm, Bk and Cf. Digital data acquisition capability from ORNL/UTK has contributed to the discoveries of super heavy nuclei, especially for shorter lived activities.
The goal of superheavy (SHE) research is to extend our understanding of nuclei and atoms with the highest numbers of protons, neutrons, and electrons, including the synthesis of new elements not previously observed. While we have reached the shores of the long-sought Island of Stability for heaviest elements, we are just beginning to understand the structure of these heaviest nuclei. There are fascinating phenomena, absent in lighter nuclei, that are at work in these exotic nuclei and atoms. Strong Coulomb fields at the highest charge numbers are trying to split these nuclei, while the strong interaction is stabilizing them. Should repulsive Coulomb forces overcome the attractive nuclear forces in these heaviest nuclei, the resulting will trigger fission and terminate the Segre Chart of Nuclei as well as the Periodic Table of Elements. This competition between fundamental forces can be verified experimentally in future experiments aiming in discoveries of new superheavy elements and nuclei and in studies their ground and isomeric states.
Most recently involved in the co-discovery of elements 115 moscovium and 117 tennessine, ORNL is now engaged in joint experimental programs aiming at the discovery of new elements 119 (RIKEN, Wako, Japan) and 120 (JINR Dubna, Russia). If successful, these studies will push the Nuclear Chart to new frontiers. ORNL actinides and digital detection systems will be essential for this research.
