Two-dimensional thermal simulations of an aluminum beam stripper for experiments at SPIRAL2

Because of the very high ion beam intensities which will become available with the advent of the new large scale facilities like SPIRAL2, the mechanical resistance of targets under beam impact has become a crucial problem due to the large specific power deposition by the projectile ions in the material. For experiments that require production of a specific higher charge state than the one produced by the LINAC, the beam stripper must remain intact during the experimental campaign over a long period of time. Numerical simulations have confirmed that a fixed stripper, which is continuously irradiated at the same spot, cannot be used and we propose an alternative scheme in which a wheel shaped aluminum stripper rotating at a rate of 2000 rpm is used. The thermal load on the material is substantially reduced because a much larger area is now irradiated and our first test of simulations show that a steady state temperature, which is safely below the melting temperature of aluminum, is achieved due to heat conduction and radiation losses from the heated material.