On the channelling of protons in ionic solids

Publisher Website
Google Scholar
Abstract
This paper is concerned with the theoretical aspects of the channelling of protons in the simple ionic solids of the rock-salt and caesium chloride structures. It is shown that the electrostatic fields occurring between the constituent positive and negative ions can affect the trajectories of protons travelling along certain crystal directions. In particular, the ions surrounding the 〈100〉 direction of the rock-salt structure form a series of electrostatic quadrupole lenses which constrain the proton's path to the central region of the channel. This quadrupole effect is compared to the channelling produced by the interaction with the exponentially screened Coulomb potential of the nuclei, and is shown to be significant only at relatively low proton energies below 10 kev.