Exotic Nuclear Beam Facilities

Abstract

The knowledge of exotic nuclei properties is essential for the understanding of the strong interaction and the element synthesis in the cosmos. Exotic nuclides are short lived and therefore, cannot be found on Earth but are still produced in stars. To study such atomic nuclei, one has to produce them with nuclear reactions in the laboratory and to separate them with special tools, from all the inevitable abundant background. The production and separation of these exotic nuclear beams can be performed with in‐flight or isotope separation on line facilities or hybrid systems of these two main scenarios. An exotic nuclear beam facility consists mainly of a combination of the production and the separation part as well as a post‐acceleration unit for the case that the experiment needs beams with kinetic energies and emittances different from that what the separator can provide. The challenge to investigate exotic nuclei is that they are characterized by very low production cross sections and short half‐lives. Different reactions to create exotic nuclei, and the physics and techniques of modern separation methods are discussed. We present the recent progress made in studying exotic nuclei by new accelerator developments, powerful separators combined with high‐resolution spectrometers and storage devices, and efficient detector systems. This chapter ends with the description of some recent discoveries with exotic nuclei and the motivation for the next‐generation facilities.

Mean range bunching of exotic nuclei produced by in-flight fragmentation and fission — Stopped-beam experiments with increased efficiency

“…Projectile fragmentation and fission are the main production methods for exotic nuclei at in-flight separators [1,2]; several of these are worldwide in operation, or under construction [3]. They allow access to the shortest-lived isotopes of all elements for a wide range of experiments [4].…”