Energy loss of protons passing through hydrogen

The cross-sections of processes involving protons and hydrogen atoms calculated by Bates, Dalgarno and Griffing using the Bom approximation are employed to make a detailed analysis of the contributions of excitation, ionization and capture to the stopping power of a gas of atomic hydrogen for a beam consisting initially of protons. A range of beam energies from 10 keV to 3 MeV is covered. The computed total energy loss is compared with experimental data and the accuracy of the Bom approximation for heavy particle collisions is discussed.