by Playfuls Staff |
18th October 2006
Scientists from the Chemistry, Materials and
Life Sciences Directorate at Lawrence Livermore National Laboratory, in
collaboration with researchers from Dubna, the Joint Institute for Nuclear
Research (JINR) in Russia
, have discovered the newest superheavy element, element 118. [more]
In experiments conducted at the JINR U400
cyclotron between February and June 2005, the researchers observed atomic decay
patterns, or chains, that establish the existence of element 118. In these
decay chains, previously observed element 116 is produced via the alpha decay
of element 118.
The results are published in the October 2006
edition of the journal Physical Review C.
The experiment produced three atoms of
element 118 when calcium ions bombarded a californium target. The team then
observed the alpha decay from element 118 to element 116 and then to element
114. The Livermore-Dubna team had created the same isotope of element 116 in
earlier experiments.
This discovery brings the total to five new
elements for the Livermore-Dubna collaboration (113, 114, 115, 116 and 118).
“The decay properties of all the isotopes
that we have made so far paint the picture of a large, sort of flat ‘Island of
Stability’ and indicate that we may have luck if we try to go even heavier,”
said Ken Moody, Livermore’s team leader.
The “Island of Stability”
is a term from nuclear physics that describes the possibility of elements which
have particularly stable “magic numbers” of protons and neutrons. This would
allow certain isotopes of some transuranic elements (elements with atomic
numbers greater than 92) to be far more stable than others, and thus decay much
more slowly.
Element 118 is expected to be a noble gas
that lies right below radon on the periodic table of elements.
“The world is made up of about 90 elements,”
Moody said. “Anything more you can learn about the periodic table is exciting.
It can tell us why the world is here and what it is made of.”
Members of the Livermore team include: Moody, Dawn
Shaughnessy, Mark Stoyer, Nancy Stoyer, Philip Wilk, Jacqueline Kenneally,
Jerry Landrum, John Wild, Ron Lougheed and former LLNL employee Joshua Patin.
“This is quite a breakthrough for science,”
said Chemistry, Materials and Life Sciences Associate Director Tomas Diaz de la
Rubia. “We’ve discovered a new element that provides insight into the makeup of
the universe. For our scientists to find another piece of the puzzle is a
testament to the strength and value of the science and technology at this
Laboratory.”
Livermore has had a
long-standing heavy element group since the inception of the Laboratory in
1952. The group has been successful in the discovery of several new elements
over the years because it has access to unique materials to perform the
experiments. In 1999 and 2001, the Laboratory announced the discovery of
elements 114 and 116, respectively. In 2004, the Livermore-Dubna team observed
the existence of elements 113 and 115.
As for the future, the LLNL-Dubna team will
continue to map the region near the “Island
of Stability.” In 2007,
the team plans to look for element 120 by bombarding a plutonium target with
iron isotopes.
“The heavy element community will continue to
search for new elements until the limit of nuclear stability is found,” Mark
Stoyer said. “It is expected that limit will be found.”
Founded in 1952, Lawrence Livermore National
Laboratory has a mission to ensure national security and apply science and
technology to the important issues of our time. Lawrence Livermore National
Laboratory is managed by the University
of California for the
U.S. Department of Energy's National Nuclear Security Administration.
Image Credit: Sabrina Fletcher and
Thomas Tegge/LLNL
