This technique uses primary electrons in the energy range 0-100eV to form the image. The contrast mechanisms are thus quite different from standard electron microscopes. With LEEM contrast is formed via diffraction and phase effects. LEEM images can be formed very fast as no rastering of the surface is required. Hence time resolved studies can be carried out. The low energy of the electrons impinging on the surface implies that the technique has close connections to LEED. The LEEM technique was invented by Ernst Bauer.