Physics avenue with the super separator spectrometer (S3) at the SPIRAL2 facility

Abstract : The LINAG accelerator of the SPIRAL2 project in GANIL will produce not only proton and deuteron beams, but also stable heavy ion beams with very high currents, with energies from 0,75 to 14MeV/u. These stable ion beams will enable us to study rare events in the fields of nuclear physics and atomic physics: - Synthesis and decay spectroscopy of fusion evaporation products, notably super heavy elements and nuclei at the proton drip line, - Multi-nucleonic transfer and deep inelastic reactions, - Study of production mechanisms and reaction products distributions, - Study of ground state and isomeric properties of rare nuclei, - Electron capture/ionisation in beam-beam interactions. S3 (Super Separator Spectrometer [1], Figure 1) is a facility designed to handle these high beam currents, combining a high selectivity of the reaction products with a high transmission of the nuclei of interest. It includes: - A rotating target, able to sustain high beam powers, - A separator with two main functions: - Reject the beam ions to prevent them from reaching the detection place, - Select the mass of the different reaction products, - A detection setup at the final focal plane, adapted to the running experiment: - The SIRIUS [2] spectroscopy station to study alpha, electron and gamma decays of the nuclei of interest, - The REGLIS3 [3] low energy branch that stops the products in a gas cell for ingas- jet laser ionisation and spectroscopy and, if required, transmission to other detection systems. S3 is a two-step separator, with a primary selection stage with momentum selection and a secondary mass selection stage combining and electric and a magnetic dipole. It has wide angular, momentum and charge state acceptances, in order to have a large transmission for low energy reaction products. In the present paper, we will present the latest progresses in the construction of the spectrometer and detection setups, and notably full simulations of the transmission and the mass resolution of the device. We will describe some highlight physics cases from the letters of intent and fission spectroscopy in the trans-actinides region.