The SPIRAL2 Project: Physics and Challenges

The SPIRAL 2 facility, a large extension of the GANIL accelerator complex, has entered in the construction phase in 2005. In the frame of this project, a new superconducting linear accelerator delivering high intensity, up to 20 MeV/nucl., light (proton, deuteron, 3-4He) beams as well as a large variety of heavy-ion beams with mass over charge ratio equal to 3 and energy up to 14.5 MeV/nucl. is under construction. The design-goal intensities of the light and heavy-ions are 5 mA and 1mA respectively. Using a dedicated converter and the deuteron beam, a neutron-induced fission rate is expected to approach 1014 fissions/s for high-density UCx target. The versatility of the SPIRAL 2 driver accelerator will also allow using fusion-evaporation, deep-inelastic or transfer reactions in order to produce very high intensity Rare Isotope Beams and exotic targets. The energies of accelerated RIB will reach up to 7-8 MeV/nucl. for fission fragments and 20 MeV/nucl. for neutron-deficient nuclei. The physics case of SPIRAL 2 based on the use of high intensity Radioactive Ion Beams and stable lightand heavy-ion beams as well as on possibilities to perform several experiments simultaneously will be discussed and illustrated with recent results obtained at GANIL/SPIRAL. In particular, it will be shown that a use of these beams at the low-energy ISOL facility (DESIR) and their acceleration to several MeV/nucl. as well as of high neutron flux at the n-tof like facility will open new possibilities in nuclear structure, nuclear astrophysics and reaction dynamics studies. Several new concepts of the detection systems (PARIS, FAZIA, GASPARD) and a new separator/spectrometer S3 located in dedicated experimental halls are currently under design. The existing detection systems and the experimental area will be adopted to take a full benefit of the high intensity (up to 1011pps) RIB