On-line mass separator investigation of the new isotope 2.9-secI116

Abstract

Using on-line mass separation $^{116}\mathrm{I}$ has been identified and its half-life determined to be 2.91 \ifmmode\pm\else\textpm\fi{} 0.15 sec. The activity was produced by the $^{103}\mathrm{Rh}(^{16}\mathrm{O},3n)^{116}\mathrm{I}$ reaction and by the decay of 57-sec $^{116}\mathrm{Xe}$. The $^{116}\mathrm{I}$ decays primarily to the ground state of $^{116}\mathrm{Te}$ and also to excited states at 678.9 and 1219.1 keV. From positron measurements, a decay energy of ${Q}_{\mathrm{EC}}=7.71\ifmmode\pm\else\textpm\fi{}0.20$ MeV is assigned to $^{116}\mathrm{I}$. $\ensuremath{\gamma}$ rays of 540.2 and 678.9 keV are observed in this decay and are assigned to depopulate levels in $^{116}\mathrm{Te}$ at 1219.1 and 678.9 keV, respectively. The former is a new level with a probable spin-parity of either ${2}^{+}$ or ${0}^{+}$. From the $log\mathrm{ft}$ values, a spinparity assignment of ${1}^{+}$ is deduced for the ground state of $^{116}\mathrm{I}$, which is interpreted to have a configuration of [$\ensuremath{\pi}({d}_{\frac{5}{2}})\ensuremath{\nu}({d}_{\frac{3}{2}})$]. A decay energy of ${Q}_{\mathrm{EC}}=4.34\ifmmode\pm\else\textpm\fi{}0.20$ MeV observed from activity produced by the $^{104}\mathrm{Pd}$ + $^{16}\mathrm{O}$ reaction is assigned to $^{116}\mathrm{Xe}$.NUCLEAR REACTIONS $^{103}\mathrm{Rh}(^{16}\mathrm{O},3n\ensuremath{\gamma})$, $E=83$ MeV; $^{104}\mathrm{Pd}(^{16}\mathrm{O},4n\ensuremath{\gamma})$ and $^{104}\mathrm{Pd}(^{16}\mathrm{O},p3n\ensuremath{\gamma})$, $E=91$ MeV. Natural Rh targets and enriched Pd targets. RADIOACTIVITY $^{116}\mathrm{I}$, $^{116}\mathrm{Xe}$; measured ${E}_{\ensuremath{\gamma}}$, ${I}_{\ensuremath{\gamma}}$, ${T}_{\frac{1}{2}}(\ensuremath{\gamma})$, ${T}_{\frac{1}{2}}({\ensuremath{\beta}}^{+})$, ${\ensuremath{\beta}}^{+}\ensuremath{-}\ensuremath{\gamma}$ coin., ${\ensuremath{\beta}}^{+}$ end point; $^{116}\mathrm{Te}$ deduced levels, $J$, $\ensuremath{\pi}$, $log\mathrm{ft}$; $^{116}\mathrm{I}$ deduced ground state $J$, $\ensuremath{\pi}$, $log\mathrm{ft}$; Ge(Li) detectors and plastic scintillators; mass separated sources.