Physical Review A
Ionization, Relativistic quantum theory, Proton beams
The effect due to the polarization of the incident high-energy (~GeV) proton beam on the ionization cross section of heavy atoms is investigated. In particular, with the use of Darwin wave functions for the atomic electron, the effect for hydrogenlike atoms is worked out. A numerical illustration shows that the polarization effect is completely insignificant. The authors also conclude that the K-shell ionization process is completely insensitive to the polarization of the incident beam.
Leung, P. T., & Rustgi, M. L. (1983). Ionization of heavy atoms by polarized relativistic protons. Physical Review A (General Physics), 28(4), 2529-2531.