Beam lifetimes of low-charged ions in storage rings

The beam lifetimes and the charge-changing cross-sections for fast low-char ged ions are calculated for the energy range of 1-100 MeV/u and compared wi th experimental data for Mg1+ and U10+ ions recently measured at SIS GSI, D armstadt. A moderate agreement of calculations with experiment was obtained . The results show that the heavy components of the residual gas (N-2 and A r) play a key role for projectile charge-changing processes in the energy r ange considered.