Designing a Beam Stripper for Fast Ion - Slow Ion Collision (FISIC) Experiments at SPIRAL2

Performing Fast Ion Slow Ion Collision (FISIC) experiments is a long standing project for atomic collision physicists. Whereas such experiments are currently performed by high energy physicists, ion ion collisions for atomic physics have so far been performed only in the case of slow ions, in the context of magnetically confined plasmas. Besides the fundamental interest in understanding the mechanisms involved in ion atom collisions, such studies are also motivated by various aspects of the energy deposition by fast ions in matter, including inertial confinement fusion plasmas, material modifications and biological effects [1]. With the advent of new facilities such as SPIRAL2 at Caen (France) which are able to deliver intense stable ion beams,the INSP team proposes a project named FISIC to explore ion ion collisions and their dynamics for heavy ions in the unknown regime of intermediate velocities. FISIC will use crossed beams of high intensities for which the charge state of both the incoming projectile ions (Fast Ions from SPIRAL2) and the target ionized medium (Slow Ions from an ECR ion source) will be controllable. The ability to produce a high intensity high energy projectile ion beam of the desired charge state makes the process of stripping one of the key parameters to make the project FISIC a success. This requires that the stripper stays stable and survives the impact of the incident ions with a very high repetition rate over an extended period of time. First numerical simulations of the interaction of an oxygen beam with a simple Al stripper target (see Fig. 1) are reported. These calculations are the first step towards designing a viable stripper system for the FISIC experiments.