  We present convenient formulae for the energy losses of energetic atomic
nuclei over the entire energy range relevant to the physics of cosmic rays.
Results are applied to a leaky-box equation with a complete loss term. Thereby
we derive the equilibrium spectrum of cosmic rays in various types of galaxies.
We emphasize a spectral break energy at 450 MeV independent of the matter
density, resulting from the transition from Coulomb and ionization losses to
pion production losses as the relevant cooling process for the cosmic ray
nuclei . We comment on the possible cosmic ray origin of the cosmic gamma ray
background.
