Low-energy electron microscopy
Low-energy electron microscopy, or LEEM, is an analytical surface science technique used to image atomically clean surfaces, atom-surface interactions, and thin (crystalline) films. == Operation == High-energy electrons (15-20 keV) are emitted from an electron gun, focused using a set of condenser optics, and sent through a magnetic beam deflector (usually 60˚ or 90˚).
Source: Wikipedia — Low-energy electron microscopy (CC BY-SA 4.0)