Diffraction of low-energy ion-induced secondary electrons emitted in the forward direction from a solid foil.

Abstract

By the measurement of doubly differential distributions of electrons emitted downstream when 170-keV protons pass through thin carbon foils, besides the convoy electron peak and the characteristic ridge, centered in the beam direction and found also in gas targets, a lateral structure is observed at larger angles. The location of this structure can be uniquely and quantitatively attributed to electron diffraction in the three-dimensional reticule of the polycrystalline foil. Electrons in the central ridge are found to diffract, while the convoy electrons do not.