Charge exchange of very heavy ions in carbon foils and in the residual gas of GANIL cyclotrons

The results of several years of operation with heavy to very heavy ions in GANIL accelerators, along with specific measurements concerning stripping through carbon foils, led to a set of valuable recipes for predicting the characteristics required to obtain a desired charge state distribution. The ion species under study range from Ar to U and the energies from 3.8 to 10.6 MeV/nucleon. The experimental method and the fits of the results are presented. A series of measurements was also set up to evaluate the beam losses during acceleration in the three cyclotrons; with the help of existing models for charge exchange cross-sections, it is shown that vacuum requirements can be fairly accurately determined. (orig.)