Reflection of a Charged Particle Beam from a Material Medium in 3D Geometry

The concept of flow lines was used in the past to find an analytical solution of the problem of reflection of charged particle beams from a flat interface of a vacuum and an arbitrary material medium. It had been also shown that the stochastic process of multiple Coulomb scattering in the given geometry is described by a distribution function that coincides with the one that is formed when a given beam propagates in an infinite medium. An attempt is made to calculate the coefficient and reflection angle of a charged particle beam when in the case of oblique incidence on the interface between a vacuum and a material medium, taking into account the 3D geometry of the problem.