Nuclear structure of neutron-rich isotopes with Z from 38--42

摘要

In this report results from a study of the nuclei produced in the spontaneous fission of (sup 248)Cm will be presented. The present paper will concentrate on recent results on neutron-rich Sr, Zr and Mo nuclei with N = 58--64. These isotopes are of particular interest because of the way their shapes change as a function of both proton and neutron number. The basic characteristics of these shape changes have been established for some time by (beta) decay studies of low-spin states. The new data on prompt (gamma) rays extend the knowledge of the behavior of these nuclei quite considerably. The great sensitivity of Ge arrays has lead to the observation of non-yrast bands, providing more detailed information on nuclear structure; the large number of detectors and the geometry of the CLOVER detectors incorporated into EUROGAM II have allowed the measurement of angular correlations and linear polarizations, putting spin and parity assignments on to a firm footing; a further advance in the study of fission fragment spectroscopy is the determination of the lifetimes of yrast states by a new Doppler attenuation technique. These lifetime measurements give new information on the way nuclear shapes change as a function of rotational frequency.