Speaker
Jason Park
(University of British Columbia/TRIUMF)
Description
The heaviest doubly-magic and self-conjugate nucleus $^{100}$Sn is known for its super-allowed Gamow-Teller decay with the smallest $\log ft$ value
and providing experimental data for quenching effects and $rp$-process path models. In addition, $^{100}$Sn and its
neighbouring species offer valuable insights for nuclear structure.
Gamma-ray spectroscopy of $^{100}$Sn
and nuclei in its vicinity with $N \simeq Z \simeq 50$ will probe single-particle/hole energies near the proton dripline, challenging
current large-scale shell models in this $A$ and $Z$ region.
The nuclei of interest were produced at RIKEN Rare Isotope Beam Factory in June 2013, where
a high-intensity (36 pnA, $2.3 \times 10^{11}$ pps) $^{124}$Xe beam with 345 MeV/u energy was fragmented on a 4-mm Be target. The fragments were identified via energy loss, magnetic rigidity and time-of-flight measurements with BigRIPS and the ZeroDegree Spectrometer. In total, 2035 events of $^{100}$Sn were identified after 8.5 days of beamtime - the largest $^{100}$Sn yield to date by a factor of 8. Many other exotic nuclei with similar $A$ and $Z$ were produced,including previously unobserved species such as $^{98}$Sn and $^{96}$In. These nuclei were implanted in WAS3ABi, a set of position-sensitive silicon strip detectors which measured ion implantation position, $\beta^+$ particles' position and energy. Subsequent $\beta$-delayed gamma-rays were measured with the EURICA spectrometer featuring high-resolution/efficiency HPGe clusters and fast-timing LaBr$_3$ detectors. Of the more abundantly produced nuclei, the level scheme for $^{98}$Ag from the $\beta^+$-decay of $^{98}$Cd has been reproduced with new candidate transitions. Preliminary analysis and level schemes of exotic fragmentation species will be presented.
Primary author
Jason Park
(University of British Columbia/TRIUMF)
