From Academic Kids
- A LEED system is based on two parts, an Electron gun and a phosphor screen. The electron gun directs an electron beam towards the crystal probe, under normal circumstances impacting vertically into the surface of the crystal.
- Kinematically reflected electrons (the wave-vector k has the same absolute value as the wave-vector of the impacting electron had) differ from the impacting electrons direction by a vector delta g which has to be a vector of the reciprocal lattice. This way the reflected electrons can only have directions which represent the reciprocal lattice of the crystal probe.
- As the reciprocal lattice is a (somehow) simple construction based on the real lattice of the crystal, you can easily make the real crystal structure/lattice visible, even though you'll always just have the top view.
