β+−γCoincidence Measurements in the Decay ofGd147

A radioactive source that contained ${}_{}{}^{147}{}_{}{}^{}\mathrm{Gd}$ activity was used in a series of ${\beta }^{+}-\gamma$ (NaI) coincidence measurements. The end-point energy of the ${\beta }^{+}$ component which feeds the 229-keV first excited state in ${}_{}{}^{147}{}_{}{}^{}\mathrm{Eu}$ was measured to be 1077±25 keV, while its intensity was found to be (0.14±0.03)% of all ${}_{}{}^{147}{}_{}{}^{}\mathrm{Gd}$ decays. The corresponding ${}_{}{}^{147}{}_{}{}^{}\mathrm{Gd}$ electron-capture decay energy was used in closed-energy-cycle calculations to predict the ${}_{}{}^{151}{}_{}{}^{}\mathrm{Dy}$ electron-capture energy (3001±35 keV) and the ${}_{}{}^{147}{}_{}{}^{}\mathrm{Gd}$ $\alpha$-decay energy (1847±60 keV).