Correlation studies of continuum gamma rays

The angular momentum removed by gamma decay of a compound nucleus formed in a heavy ion produced fusion reaction can be as high as 60 h. The higher spin part of this cascade is from the region of higher excitation energy. Due to the high level density, a large number of available decay pathways exist. Therefore, in a one-dimensional spectrum these gamma rays appear as an unresolved quasicontinuum and it is difficult to obtain quantitative nuclear structure information from the spectrum. Fortunately, an ideal rotational cascade emits E2 gamma rays equally spaced in energy and no two gamma rays have the same energy. Thus, in a two dimensional spectrum a ridge-valley structure is observed along the diagonal E1=E2. Quantitative studies of these structures have been carried out. Nuclear properties such as the spreading of the moment of inertia and the rotational damping width have been obtained for the high spin region. Lifetime measurements have also been carried out in a few cases and the nuclear collectivity is determined for a large range of spin values. A measure of the number of pathways can also be obtained from a fluctuation analysis of the spectrum