Conceptual design of a novel and compact superconducting recoil separator for radioactive isotopes

The recent development of radioactive beam facilities, such as the HIE-ISOLDE facility at CERN, has significantly expanded the capabilities for investigating the structure of the atomic nucleus and the nuclear interaction. All these studies require an efficient and high-resolution recoil separator for the unambiguous identification of medium and large mass reaction fragments. In order to meet such needs, a versatile recoil separator for radioisotopes based on a compact superconducting (SC) Fixed-Field Alternating-Gradient (FFAG) ring has been designed. It is based on a mini-ring of approximately 3.5 m circumference formed by superconducting combined function magnets with both the bending and focusing/defocusing functions. This machine will be able to operate with light and heavy radioisotopes and separate the reaction fragments from the main beam by radiofrequency gymnastics. It also presents the advantage of significantly reducing the size with respect to standard non-SC recoil separator configurations. In this article, the first design of this FFAG based recoil separator is presented, and first beam dynamics simulation results are discussed.