ISOLDE Coulex School

Low-energy Coulomb excitation is one of the rare methods available to obtain information on static electromagnetic moments of short-lived excited nuclear states including non-yrast states. In the scattering of two nuclei, the electromagnetic field that acts between them causes their excitation. The process selectively populates low-lying collective states and is therefore ideally suited to study nuclear collectivity. Historically, these experiments were restricted to stable isotopes, however the advent of new facilities, providing intense beams of short-lived radioactive species, has opened the possibility to apply this powerful technique to a much wider range of nuclei. In this course we will introduce the participants to the Coulomb excitation technique and dedicated analysis codes. We will discuss observables that can be measured in a Coulex experiment, their relation to nuclear structure parameters and in particular nuclear shape, as well as assumptions used in data analysis. Some recent examples of complex Coulomb excitation studies will be presented to demonstrate how this method can be applied to investigate phenomena such as shape coexistence and development of exotic deformation (triaxial or octupole shapes). During practical sessions, the participants will learn how to use the GOSIA code in order to estimate counting rates expected in an experiment and to extract electromagnetic matrix elements from experimental data. All participants must have a personal portable computer to take part in the practical sessions.