Low energy electron microscope or LEEM is a type of electron microscope that is used to examine the surfaces of materials in mesoscopic dimensions. It is based on the imaging of low energy (0-500 electronvolts) electrons elastically emitted from the surface. It enables the structural and chemical properties of surfaces to be examined at a resolution of up to 10 nanometers. Beyond its importance in studies of thin films, catalytic surfaces, nanotechnological systems, the high signal levels in this microscope allow live monitoring of dynamic changes on the surface at video speed.