Superheavy Element Discovery and Chemistry at LLNL
Deputy Director,Heavy Element Discovery Group,
Lawrence Livermore National Laboratory
The heavy element group at Lawrence Livermore National Laboratory (LLNL) has had a long tradition of nuclear and radiochemistry dating back to the 1950’s. Some of the most exciting work has taken place in the last decade (in collaboration with the Flerov Laboratory of Nuclear Reactions in Dubna, Russia) with the discovery of six new elements - 113, 114, 115, 116, 117, and 118. By pushing the boundaries of the periodic table, we can start to answer some of the most fundamental questions of nuclear science, such as the locations of the next “magic numbers” of protons and neutrons, and the possibility of an “Island of Stability” where nuclides would have lifetimes much longer than those currently observed in the heaviest elements. We have already seen evidence of extra-stability in the heaviest nuclides, which leads to half-lives that are long enough for us to perform chemistry on these isotopes one atom at a time. Work is underway on developing an automated chemical system that will be used for studying chemical properties of elements 104 and 105. New chemical separations are being studied that can be deployed using a multi-column automated system. These experiments will provide the ground work for performing aqueous chemistry later on even heavier elements such as element 114 where the chemical properties are completely unknown. In this overview the discovery of these new elements and the chemical experiments in progress will be discussed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This work was funded by the Laboratory Directed Research and Development Program at LLNL under project tracking code 11-ERD-011.
Dawn Shaughnessy received a B.S. in Chemistry from the University of California at Berkeley in May of 1993. After graduating, she decided to remain at Berkeley and pursue a Ph.D. with a focus on nuclear chemistry. She joined the research group of Professor Darleane Hoffman and received a Ph.D. in 2000. Her research focused on the delayed fission properties of isotopes of einsteinium, which were produced at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory. During her tenure at Berkeley, Dawn received an award as one of the top Graduate Student Instructors through the College of Chemistry. After finishing graduate school, Dawn began a postdoctoral appointment at Lawrence Berkeley National Laboratory in the Chemical Sciences Division under Professor Heino Nitsche. Her research was the study of how plutonium interacts with naturally occurring manganese-bearing minerals as part of a DOE Environmental Management Project geared toward clean-up of nuclear materials in the environment. After completing her postdoc in 2002, she accepted a term position at Lawrence Livermore National Laboratory in the Stockpile Radiochemistry Group. She has recently been appointed group leader for the newly created Experimental Nuclear and Radiochemistry Group, which is currently part of the Chemical Sciences Division at LLNL, and is also the Responsible Scientist for radiochemical debris collection at the National Ignition Facility. In addition, she is the project leader of the LLNL heavy element program, which announced discovery of element 117 in April of 2010. In May of 2012, it was also announced by the International Union of Pure and Applied Chemistry that element 116 would be officially known as “livermorium”, an honor granted to the LLNL heavy element program in recognition of their years of research. Dawn’s general research interests include actinide and heavy element chemistry, chemical automation, nuclear forensics methods and radiochemical diagnostics. She has been a staff chemist at LLNL for 12 years. Most recently she was awarded the DOE Office of Science Outstanding Mentor Award (2010), the Gordon Battelle Prize for Scientific Discovery for the discovery of element 117 (2010), and was inducted into the Alameda County Women’s Hall of Fame for Scientific Discovery (2012).