APS April Meeting 2011
Volume 56, Number 4
Saturday–Tuesday, April 30–May 3 2011;
Anaheim, California
Session C5: Nuclear Structure at the Limits of Stability
1:30 PM–3:18 PM,
Saturday, April 30, 2011
Room: Royal AB
Sponsoring
Unit:
DNP
Chair: Dan Bardayan, Oak Ridge National Laboratory
Abstract ID: BAPS.2011.APR.C5.1
Abstract: C5.00001 : Discovery of new superheavy element isotopes*
1:30 PM–2:06 PM
Preview Abstract
Abstract
Author:
Jacklyn Gates
(Lawrence Berkeley National Laboratory)
The first confirmation of element 114 production and decay was
performed in
2009 with the Berkeley Gas-filled Separator at the Lawrence Berkeley
National Laboratory 88-Inch Cyclotron. The $^{48}$Ca~+~$^{242}$Pu
reaction
was used. Compound nucleus evaporation residues were separated
from beam and
other reaction products with the Berkeley Gas-filled separator
and implanted
in the focal plane detector system. Production and decay of one
atom each of
$^{287}$114 (via the $^{242}$Pu($^{48}$Ca,~3$n)^{287}$114
reaction) and
$^{286}$114(via the $^{242}$Pu($^{48}$Ca,~4$n)^{286}$114
reaction) were
observed. Production cross sections, decay modes, decay energies,
and
half-lives and for these element 114 isotopes and their daughters
were
consistent with those reported by the Dubna Gas Filled Recoil
Separator
Group (Yuri Oganessian$,$ J. Phys. G: Nucl. Part. Phys.
\textbf{34 }(2007)
R165--R242).
In 2010, the $^{48}$Ca~+~$^{242}$Pu reaction was used again, at
an increased
beam energy to optimize the production of new isotope,
$^{285}$114, by the
$^{242}$Pu($^{48}$Ca,~5$n)^{285}$114 reaction. The production and
decay of
one atom of $^{286}$114 (via the
$^{242}$Pu($^{48}$Ca,~4$n)^{286}$114
reaction) was observed, re-confirming the properties of this
isotope. In
addition, a single event corresponding to the production and
decay of
$^{285}$114 (via the $^{242}$Pu($^{48}$Ca,~5$n)^{285}$114
reaction) was
observed. The implantation of $^{285}$114 in the detector was
followed by
five \textit{$\alpha $}-decays and a spontaneous fission event,
indicating the \textit{$\alpha $}-decays of new
isotopes, $^{285}$114, $^{281}$Cp, $^{277}$Ds, $^{273}$Hs,
$^{269}$Sg, and
the spontaneous fission of new isotope, $^{265}$Rf. The decay
properties of
all these new isotopes match expectations based on
microscopic-macroscopic
mass models supplemented with extrapolations of previously reported
superheavy element isotope decay properties. However, some
systematic
differences between observed and predicted \textit{$\alpha
$}-decay $Q$-values may be used to
refine models of nuclear shell effects in heavy element isotopes.
*Financial support was provided by the Office of High Energy and Nuclear Physics, Nuclear Physics Division, of the US Department of Energy, under contract DE-AC02-05CH11231.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.APR.C5.1