εβ+decay ofGd145: Resolution ofεβ+decay branching ratio anomalies and evidence for pronounced structures in theβ-decay strength

The $\frac{\epsilon }{{\beta }^{+}}$ decay of 23.0-min ${}_{}{}^{145}{}_{}{}^{}\mathrm{Gd}$ has been thoroughly studied with Ge(Li) and plastic scintillator detectors. A total of 326 $\gamma$ rays deexciting 136 levels in ${}_{}{}^{145}{}_{}{}^{}\mathrm{Eu}$ have been placed by this work. The available decay energy, $Q_{\epsilon }=5.07\mathrm{}\pm 0.06$ MeV, was measured by $\beta -\gamma$ coincidence techniques. $\frac{\epsilon }{{\beta }^{+}}$-decay branching ratios have been measured for several transitions, and a long standing anomaly in those ratios has been resolved by the new $Q_{\epsilon }$ value and the discovery of additional electron-capture decay. We have investigated the $\beta$-strength function for ${}_{}{}^{145}{}_{}{}^{}\mathrm{Gd}$ and discovered pronounced structure with resonances at 1042, 1819, 2584, and 4500 keV. The 1042-keV resonance is proposed to result from a ${\left(\pi d_{\frac{3}{2}}\right)}^2{\left(\nu s_{\frac{1}{2}}\right)}^{-1\mathrm{}}\to {\left(\pi d_{\frac{3}{2}}\right)}^1\beta$ transition, the 1919- and 2584-keV resonances from ${\left(\pi d_{\frac{5}{2}}\right)}^2\to {\left[\right(\pi d_{\frac{5}{2}})\otimes 2^{+}]}_{1,2}$ decays, and the very strong 4500-keV resonance from the ${\left(\pi h_{\frac{11}{2}}\right)}^2\to \left(\pi h_{\frac{11}{2}}\right)\otimes (\nu h_{\frac{9}{2}}+\nu f_{\frac{7}{2}}+\dots )$ transition across the shell closure.