Decay ofEr16168(3.1 hr)

Sources of ${}_{68}{}^{}{}_{}{}^{}\mathrm{Er}_{}^{161}{}_{}{}^{}$(3.1 hr) were produced by the ($n, 2n$) and ($\gamma , n$) reactions. A study of the gamma-ray spectrum by means of scintillation coincidence spectrometry indicated 32 gamma rays. All but three of these are fitted into a tentative decay scheme with levels at 0, 211, 585, 826, 945, 1165, 1253, 1315, 1395, 1450, (1604), 1700, and 1830 kev. The data are consistent with a ${\frac{3}{2}}^{-}$ spin assignment to the Er ground state and ${\frac{7}{2}}^{-}$ and ${\mathrm{½}}^{+}$ assignments to the ground state and 211-kev state of Ho, respectively. The 826-kev level in Ho probably has ${\frac{5}{2}}^{-}$ character.