Inelastic Scattering of Iron-Capture Gamma Rays from the 7.64-MeV Level ofCd112

Abstract

In the resonant-scattering experiment of the monochromatic iron-capture gamma rays from natural cadmium, five inelastically scattered photon groups were observed in addition to the 7.64-MeV elastic group. The spectrum of the low-energy cascade photons in coincidence with the scattered photons identifies the inelastic groups to be the transitions to the low-lying levels of ${\mathrm{Cd}}^{112}$, including the three ${2}^{+}$ vibrational levels at 0.61, 1.29, and 1.46 MeV. Angular-distribution measurements show that the 7.64-MeV resonance level in ${\mathrm{Cd}}^{112}$ has angular momentum 1. The average elastic-scattering cross section and the branching ratio for the ground-state transitions are $〈{\ensuremath{\sigma}}_{\ensuremath{\gamma}\ensuremath{\gamma}}〉=0.17\ifmmode\pm\else\textpm\fi{}0.02$ b and $\frac{{\ensuremath{\Gamma}}_{0}}{\ensuremath{\Gamma}}=0.48\ifmmode\pm\else\textpm\fi{}0.06$, respectively. Using these values, the self-absorption measurements determined the ground-state transition width to be ${\ensuremath{\Gamma}}_{0}={{0.6}_{\ensuremath{-}0.1}}^{+0.2}$ eV.