| Abstract: | The principle of mirror microscopy has been adapted to provide a relatively low resolution surface microscope (<1000 ×), a large transfer width low energy electron diffractometer and a photoelectron analyser in k|| space. A focused electron beam of ? 10 kV is decelerated through a Johansson lens, reflected in front of the sample and reaccelerated back through the lens to produce an electron image over a field of view of a few microns. The image can be interpreted as a micrograph of work function variations on the surface if other effects (geometry, magnetic field) are uniform. In the LEED mode, diffracted beams virtually retain their positions on the screen over the whole impact energy range used (0.160 V). Secondary electrons are preferentially focused around the lens-gun electro-optic axis, thus effectively filtering them out from the diffraction pattern. The design has an inherently large coherence length, of up to 104 Å. Photoelectrons can similarly be imaged in k|| space on the detector plane. The addition of energy filtering at the screen allows the two-dimensional Fermi surface to be imaged. |
