A description of high-spin phenomena in atomic nuclei is presented from both the experimental and theoretical points of view. The characteristic features of collective nuclear motion, such as rotational bands, band crossings, and backbending, as well as noncollective aspects, like high-spin isomers and irregular decay patterns, are discussed in detail. Recent achievements of the cranking model including the independent quasiparticle and the shell correction methods are reviewed. Changes in the structure of nuclei excited up to the highest possible angular momenta are analyzed; in particular, angular momentum alignment effects, shape changes, possible phase transitions, and sudden rearrangements in the single-particle structure are discussed. Phenomena related to the nuclear quasicontinuum spectra are also examined.

High-spin phenomena in atomic-nuclei

On the formalism of multiplicity measurements

Gamma-ray multiplicity studies for 40Ar and 86Kr induced reactions leading to Er compound nuclei at limiting angular momenta

It is shown how the information on the shape parameters of the multiplicity distribution is contained in the different fold coincidence probabilities. A new non-linear method is proposed to obtain the shape parameters from the experimentalk-fold coincidence probabilities. This method converges much faster than the methods proposed up till now in the literature. The method can also be used with non-normalized coincidence yields. Applications toα and12C induced reactions are presented.

The shape of the multiplicity distribution and the low-fold coincidence probabilities

Optimization of the detector-target geometry for in-beam singles and coincidence γ-ray spectroscopy

An algorithm to extract the multiplicity and the higher moments of a multiplicity distribution from the measured counting rates of multiple coincidences is described. In the statistical averaging process a direct transformation to the central moments is performed which results in a well converging procedure to obtain the moments. Important aspects of error analysis and of numerics are outlined. The generality of the formalism allows applications beyond nuclear physics. Guidelines for optimizing an experimental set-up are given.

I. Giese

Papers

An algorithm for the analysis of multiplicity measurements