Kikuchi Diffraction

Abstract

In this chapter and the following two, we will discuss two special cases of electron diffraction. In the first we find that inelastically scattered electrons give rise to arrays of lines in DPs known as Kikuchi patterns. In the second, we will form DPs with a convergent rather than a parallel beam. These two techniques have a lot in common. In the first, the electrons are initially being scattered by the atoms in the crystal so that they “lose all memory of direction.” We can then think of these electrons as traveling in different “incident” directions. When the direction is appropriate, these electrons can be scattered again, this time by Bragg diffraction. In the second technique we use a convergent beam intentionally to make the electrons incident on the crystal over a range of different angles. In this case we have another advantage in that we can focus the beam on a much smaller area of the specimen than in SAD.