Ionization and Excitation Losses of Charged Particles of Intermediate Energies

A method has been outlined for determining energy losses of charged particles of intermediate energies, i.e. which do not carry bound electrons and have velocities lower than the K shell velocity of the stopping atom. The `free collisions' and the `resonance effects' have been separately evaluated. The number of electrons participating in free collisions has been determined by using the Thomas-Fermi model for the stopping atom, and the energy loss has been evaluated by means of the Rutherford formula. The resonance effects have been calculated by means of an expression derived by Fermi which represents a much better approximation than the usual logarithmic formula. The stopping power of a few elements has been computed and the results compared with experimental data.