Level Structure of the Low-Lying Excited States ofSn116Populated by the Radiative Capture of Thermal Neutrons

The low-lying excited states of ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ populated by primary and secondary $\gamma$-ray transitions from the reaction ${}_{}{}^{115}{}_{}{}^{}\mathrm{Sn}(n,\gamma ){}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ were studied. Both singles and $\gamma -\gamma$ coincidence techniques were employed with the exclusive use of Ge(Li) detectors. Results obtained from high-energy $\gamma$-ray spectra (∼5.9-10 MeV) were combined with those from low-energy singles spectra (∼100 keV-3.8 MeV) and low-low coincidence spectra in order to infer the excitation energies and branching characteristics of 21 states up to an energy of ∼3.7 keV. A level and decay scheme is proposed including a total of 45 $\gamma$ rays representing ∼90% of the decay intensity. This scheme includes most of the levels having $E_x\le 3$ MeV which were observed previously4 in charged-particle reactions and $\beta$-decay studies. The existence of the $0^{+}$ level having an excitation energy of 2027 keV has been confirmed and a new level at 2545-keV excitation is proposed.