Abstract
New type of detection system has been designed and tested in the Scanning Electron Microscope. Backscattered electrons (BSE) at low energies of electron impact are collected by an annular detector above the specimen, consisting of eight concentric ring-shaped collectors arranged around the optical axis so that polar angles of the initial velocity vectors of electrons can be distinguished. Backscattering of electrons, in particular around and below 1 keV of impact energy, provides rich information content that even enhances toward higher angles with respect to the surface normal. Slow, high-angle BSE are normally not detected with standard detectors. The cathode lens principle was used to secure high lateral resolution, high collection efficiency and large amplification of the detector at low energies. Prospective applications include the grain orientation contrast, contrast between amorphous and crystallinic phases, etc.
