The creation of element 117 took a team of international researchers. Elements 114, 115, 116, and 118 had already been synthesized and the periodic table had a gap for element 117. Russian physicist Yuri Oganessian developed the method that led to the discovery of the surrounding elements, and he reasoned that using that same “hot fusion” method but with a berkelium-249 target would lead to element 117. He would need a lot of it. Oak Ridge National Laboratory is the only place in the world with enough berkelium-249 to support the experiment.
In 2004, Yuri Oganessian proposed the collaborative experiment between the Joint Institute for Nuclear Research (JINR) in Dubna, Russia and Oak Ridge National Laboratory in Tennessee. By January 2009, Oak Ridge had produced enough berkelium-249 for the experiment—a whopping 22 milligrams!
Because of berkelium-249’s 330-day half-life, researchers had to work fast to process, transfer, and bombard the berkelium isotope. The US team sent the isotopes to Russia in what is still the fastest actinide transfer between the two countries. After further preparation at the Research Institute of Atomic Reactors in Ulyanovsk Oblast, Russia, the isotope finally arrived in Dubna on July 28, 2009, to begin bombardment. After 150 days of being irradiated with a beam of 6 trillion calcium-48 ions per second, the berkelium target produced six atoms of element 117.
The team announced the discovery on April 9, 2010 and replicated the results with subsequent experiments in 2012 and 2013. Independent researchers from across the world collaborated to confirm the experiment, independently verifying the discovery of element 117 in May 2014.
In December 2015, the International Union of Pure and Applied Physics (IUPAP) and the International Union of Pure and Applied Chemistry (IUPAC) confirmed the discovery. A year later, in November 2016, the element was officially named tennessine, in recognition of Oak Ridge National Laboratory and contributions by Vanderbilt University and the University of Tennessee.