Charge states of fast protons in solids

It is shown that charge states of high-energy protons in solids may be simply understood in terms of capture into, and subsequent loss from, bound states on the proton within the solid. Both the equilibrium charge states emerging from the solid, and the approach to equilibrium within the solid, may be calculated. At high enough proton velocities gas cross sections may be used to predict the results in solids. This is directly confirmed by experimental results, taken from the literature, on solid carbon and gaseous carbon compounds.