Spiral 2 : A high intensity deuteron and ion linear accelerator for exotic beam production

Based on the "LINAG Phase 1" conceptual design, a two years detailed study on a ISOL-type facility for the production of high intensity exotic beams, named SPIRAL2, has been launched. The rare isotope beams are produced via the fission process, with the aim of 10¹³ fissions/s at least, induced either by fast neutrons from a C converter in a UCx target or by direct bombardment of fissile material. The driver, with an acceleration potential of 40 MV, has to be upgradeable and versatile: it will accelerate deuterons (5 mA) and A/q=3 ions (1 mA) and even heavier ions in a later stage. It consists in high-performance ECR sources, an RFQ cavity and independent phase superconducting resonators. The primary beam is transferred towards the production system, including converter, target and ion source. The exotic beam can be directly used in a low energy experimental area or is accelerated by the existing CIME cyclotron after increase of its charge-state by means of an ECR charge booster. The selection of the parameters as well as the technology result from an optimisation of the linac. Systematic beam dynamics calculations with space charge forces, 3-D field maps and alignment errors to check the robustness of the design and the very low loss rate all along the linac are in progress.