Channeling of neutral particles in layered structures

The wave equation for neutral particles (including photons) in periodical structure is considered. Its solution gives a general expression describing in two opposite cases Borman effect and the phenomenon of channeling. The channeling of γ-quanta and neutrons is found to be possible as a result of their interaction with either electrons or nuclei of the medium in the layers of different physical or chemical properties. This channeling may occur when the width of the layers is equal to or exceeds several lattice parameters. The critical channeling angles thetac in the cases considered may range from one minute to one degree. The peculiarities of channeling at resonant energies are investigated. The conditions of the ring channeling are obtained. (author)