Decay ofNb90

The $\frac{{\beta }^{+}}{\mathrm{EC}}$ decay of 14.6 h ${}_{}{}^{90}{}_{}{}^{}\mathrm{Nb}$ was investigated by Ge(Li) $\gamma$ spectroscopy. Precision energy measurements (±≤ 10 eV) were made on prominent $\gamma$ transitions. Gamma intensities were measured with an escape-suppression $\gamma$ spectrometer, and $\gamma \gamma \mathrm{}\left(t\right)\mathrm{}$ measurements were made with two Ge(Li) detectors. A consistent set of $\gamma$ energies and intensities is presented such that ${}_{}{}^{90}{}_{}{}^{}\mathrm{Nb}$ should be a useful $\gamma$ energy and intensity standard. The import of the ${}_{}{}^{90}{}_{}{}^{}\mathrm{Nb}$ decay scheme on our understanding of the ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ level structure is discussed.