Flat electron mirror

Electron beams can be reflected by an electrode that is at a more negative potential than the cathode from which beam emitted. We want to design mirror with flat where electrons are plane very close electrode. The wave front of electron then shaped when contains surface topography or modulated potential. However, mirrors usually characterized high coefficients chromatic and spherical aberration. When combined electrostatic lens form tetrode system, situation deteriorates even further. This places restrictive limit on maximum aperture angle beam, consequently also limits attainable resolution image plane. have numerically studied dependence these aberrations as function parameters consisting ground, lens, cap, electrode, limited ourselves only using electrodes round apertures, fixed spacing. It turns out third order aberration made negative. used partially compensate positive fifth way, system configuration obtained that, 2 keV energy, provides diffraction 7.6 nm 25 mm semi-angles 2.3 mrad, enabling illumination radius 40 ?m mirror. presented could spark innovative use patterned phase plates for microscopy in general, coherent splitters Quantum Microscopy particular. An appendix presents method calculate spot size focused presence both coefficients, applicable Scanning (Transmission) Microscopes correctors.