Super Heavy Element Discovery
Searching for the Island of Stability
The Super Heavy Element Research Group, currently led by Seaborg Scientists, Dawn Shaughnessy and Kenton Moody, focuses on investigating the chemical and physical properties of the heaviest elements made by man. The Heavy Elements Group has a long history of accomplishment in fundamental nuclear research, with spectroscopic, chemical, and decay studies dating back to the 1950s.
Periodic table of elements, which includes the 6 most recently discovered elements (yellow).
In 1998 Ken Moody with Livermore scientists collaborated with Russian scientists at the Joint Institute of Nuclear Research in Dubna, Russia, to create element 114. The first atom survived for 30 seconds before it began to decay, a spontaneous process that leads to the creation of another element with a lower number on the periodic table. This lifetime may seem brief, but it is millions of times longer than those of other recently synthesized heavy elements.
In 2000 the team added element 116 to the periodic table with the creation of three atoms of the element in a series of experiments. The creation of elements 116 and 114 involved smashing calcium ions (with 20 protons each) into a curium target (96 protons) to create element 116. Element 116 decayed almost immediately into element 114. These scientists also created element 114 separately by replacing curium with a plutonium target (94 protons). See S&TR; Jan./Feb. 2002, Present at the Creation for further reading.
Heavy elements 113 and 115 were discovered by combining calcium-48 and amercium-243.
In August, 2003, the team of scientists observed atomic decay patterns, that confirm the existence of element 115 and element 113. In these decay chains, element 113 is produced via the alpha decay of element 115.
In February and June 2005, experiments conducted created element 118 by fusing an atom of calcium-48 with an atom of californium-249. Accelerated to nearly 30,000 kilometers per second (or 10 percent the speed of light), the calcium bombarded a spinning target of californium. The californium, which has 98 protons, fused with the calcium, which has 20 protons, creating the new element with 118 protons. See S&TR; April 2007, A New Block on the Periodic Table for further reading.
In 2010, the LLNL-Dubna team established the existence of element 117 from decay patterns observed following the bombardment of a radioactive berkelium target with calcium ions at the JINR U400 cyclotron in Dubna. The experiment depended on the availability of special detection facilities and dedicated accelerator time at Dubna, unique isotope production and separation facilities at Oak Ridge, and distinctive nuclear data analysis capabilities at Livermore.
Recently the LLNL-JINR, Dubna scientists proposed the names as Flerovium for element 114 and Livermorium for element 116. See LLNL; News Releases 12/01/2011 for further reading.
Continuing to collaborate, this international team has discovered up to 6 new elements — 113, 114, 115, 116, 117, and 118. Shaughnessy and Moody, along with LLNL colleagues Jackie Kenneally and Mark Stoyer were critical members of the team along with a team of retired LLNL scientists including John Wild, Ron Lougheed and Jerry Landrum. Former LLNL scientists Nancy Stoyer, Carola Gregorich, Jerry Landrum, Joshua Patin and Philip Wilk also helped in this discovery.