Design study of a pre-separator for the LINAG super separator spectrometer

The Super Separator Spectrometer (S) is a device being designed for experiments with the very high intensity stable beams of LINAG, the superconducting linear accelerator of GANIL, which will be built in the framework of SPIRAL2. These beams, which will be provided in the first phase of SPIRAL2, ions with A/q = 3 can reach intensities exceeding 100 pμA for lighter ones A < 40−50 depending on the final choice of the ECR (Electron Cyclotron Resonance) ion source. These unprecedented intensities open new opportunities in several physics domains, e.g.: super-heavy and very-heavy nuclei, spectroscopy at and beyond the dripline, multi-nucleon transfer and deep-inelastic reactions, isomers, ground state properties and molecular resonances. An international collaboration has been formed for proposing physics experiments and developing technical solutions for this new instrument. All of the experiments mentioned have the common feature of requiring the separation of very rare events from intense backgrounds. Hence, the present study is aimed at finding an appropriate technical solution for a pre-separator stage of S. In this paper we propose some possible approaches and discuss the challenges in addressing the ion optical issues of this device. Three different layouts have been considered to date. These studies are on-going.