Improved charge-state formulas

A large set of experimental charge-state distributions is analyzed in this work. Two fit formulas are presented for mean equilibrium charge states of projectiles ranging from protons to uranium. One formula is given for all ions in gas targets and another one for solid targets. The deviation from the experimental data is reduced by roughly a factor of two in comparison with the widely used formula by Nikolaev and Dmitriev as well as with the Bohr stripping criterion as revised by Northcliffe. Finally, the influence of the projectile charge state on the prediction of stopping powers for fast projectiles in carbon is shown and comparison is made with experimental energy-loss data. (C) 2001 Elsevier Science B.V. All rights reserved.