Progress in targets and ion sources for on-line separators

Abstract

The application of on-line mass separation to the study of nuclei far from stability on a broad scale has been made possible by the development of new ion-source and target arrangements. These units often integrated determine together the elements available as well as their yields and chemical purity. The paper summarizes recent developments in this field and the material will be discussed under three main headings according to the types of bombarding particles used for the production of far-unstable nuclei. The selected examples will be given for 1. 1) ion sources and targets for thermal fission; 2. 2) heavy-ion target and ion-source combinations; 3. 3) target and ion-source systems for high-energy proton reactions. The major items of progress include gaseous discharge ion sources and surface ionization sources developed to meet the special requirement of on-line separators. Significant improvements in the delay-time characteristics have been demonstrated with high-temperature targets ( T > 2000°C), consisting of refractory metals or chemical compounds. This technique now permits the study of nuclides with very short half-lives.