A 47-min isomer has been identified in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Eu}$. Sources were prepared in ($n,\gamma$) and ($d,p$), ($d,2n$) and ($p,n$), and ($d,\alpha$) reactions on Eu, Sm, and Gd, respectively, and in each case the 47-min activity followed the Eu fraction in the separation of ${\mathrm{EuSO}}_4$. Singles and coincidence $\gamma$-ray studies confirmed a number of the observed $\gamma$ rays in a structure consistent with capture $\gamma$-ray studies. Owing to the high conversion coefficients for low energy $\gamma$ rays a complete decay scheme has not been confirmed for ${}_{}{}^{154}{}_{}{}^{}\mathrm{Eu}_{}^m{}_{}{}^{}$.

RADIOACTIVITY ${}_{}{}^{154}{}_{}{}^{}\mathrm{Eu}_{}^m{}_{}{}^{}$; measured $T_{\frac{1}{2}}$, $E_{\gamma }$, $I_{\gamma }$, $\gamma \gamma$ coin, deduced levels, $J$, $\pi$. Enriched targets. Ge(Li) and Si(Li) detectors, 170 eV at 5.9 keV.

• Received 13 August 1975

DOI:https://doi.org/10.1103/PhysRevC.13.2024