2 AND 3-DIMENSIONAL GAMMA-RAY CORRELATIONS IN ROTATIONAL NUCLEI

Several new methods for the study of nuclear structure at low temperat ure are reviewed. The methods analyze the fluctuations of the intensit y of E(gamma)1 - E(gamma)2 spectra, and the shape and width GAMMA(rot) of the correlated patterns with different characteristics of the rota tional motion in cold and warm nuclei. New results are given for the r otational damping width, and the number of 2-step-paths below and abov e U0 almost-equal-to 800 keV, considered to be the energy of the borde rline between undamped and damped rotational motion. The rotational da mping width GAMMA(rot) is studied as function of rotational frequency for selected regions of entry states in Tm-163, and found to be rather constant almost-equal-to 80 keV, significantly smaller than current t heoretical predictions. The fluctuation analysis supports the damping picture in general, and confirms that a strong branching of the transi tion strength for each step in the E2 cascades exists at high spin. Th is can be taken as evidence for damping of the rotational motion in wa rm nuclei.