Compound And Rotational Damping In Warm Nuclei

The -decay from excited nuclei is used to study the interplay between rotational motion and compound nucleus formation in deformed nuclei. A new analysis technique is presented which allows for the first time to directly measure the rotational and compound damping widths rot and mu from -coincidence spectra. The method is first tested on simulated spectra and then applied to high-statistics EUROBALL data on the nucleus 163Er. Experimental values of 200 and 20 keV are obtained for rot and mu, respectively, in the spin region I 30-40 , in good agreement with microscopic cranked shell model calculations for the specific nucleus. A dependence of rotational damping on the K-quantum number of the nuclear states is also observed, both in experiment and theory, resulting in a 30% reduction of rot for high-K states. This points to a delayed onset of rotational damping in high-K configurations.