Beta decay ofLu154andYb154

Using mass-separated sources, the $\beta$-decay properties of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Lu}$ and ${}_{}{}^{154}{}_{}{}^{}\mathrm{Yb}$ were investigated. Limits of ${}_{}{}^{154}{}_{}{}^{}\mathrm{Lu}$ decay to the first $8^{+}$ and $6^{+}$ levels in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Yb}$ suggest a $7^{+}$ spin for the odd-odd parent; also delayed proton emission and an indication of delayed $\alpha$-particle emission were observed to follow ${}_{}{}^{154}{}_{}{}^{}\mathrm{Lu}$ $\beta$ decay. The $\beta$-decay branch of the $\alpha$-emitting nucleus ${}_{}{}^{154}{}_{}{}^{}\mathrm{Yb}$ was identified for the first time by the observation of one intense 133.2-keV $\gamma$ ray. This transition deexcites a $1^{+}$ 133.2-keV level in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Tm}$ which is fed by an allowed $0^{+}\to 1^{+}\beta$ transition with a $log\mathrm{ft}$ value of 3.6 ± 0.3.