Compound and Rotational Damping in Warm Deformed Rare-Earth Nuclei

Abstract

The $\ensuremath{\gamma}$ decay in the quasicontinuum from selected configurations of the rotational nucleus $^{163}\mathrm{E}\mathrm{r}$ has been measured with the EUROBALL array. A new analysis technique has allowed for the first time to directly measure the compound and rotational damping widths ${\ensuremath{\Gamma}}_{\ensuremath{\mu}}$ and ${\ensuremath{\Gamma}}_{\mathrm{r}\mathrm{o}\mathrm{t}}$. Values of ${\ensuremath{\Gamma}}_{\ensuremath{\mu}}\ensuremath{\approx}20\text{ }\text{ }\mathrm{k}\mathrm{e}\mathrm{V}$ and ${\ensuremath{\Gamma}}_{\mathrm{r}\mathrm{o}\mathrm{t}}\ensuremath{\approx}200\text{ }\text{ }\mathrm{k}\mathrm{e}\mathrm{V}$ are obtained in the spin region $I\ensuremath{\approx}30--40\mathrm{\ensuremath{\hbar}︀}$, in good agreement with microscopic cranked shell model calculations. A dependence of ${\ensuremath{\Gamma}}_{\ensuremath{\mu}}$ and ${\ensuremath{\Gamma}}_{\mathrm{r}\mathrm{o}\mathrm{t}}$ on the $K$-quantum number of the nuclear states is also presented.