Model for the production of circular polarization via beam-foil interaction

Electron capture by protons in the tail of the electron density at a metal surface is investigated. The ion velocity is assumed to be large compared to the velocity of an electron in the lowest orbit of hydrogen. Electron transition probabilities into the 2p states of hydrogen are calculated, analogous to the first Born approximation by extending a model of Trubnikov and Yavlinskii 1] to tilted foils and nonzero angular momentum of the captured electron. From the density matrix the Stokes parameters are calculated. The results give partial agreement with experimental data, especially for the sinusoidal dependence of circular polarization on foil tilt angle.