Backscattered Electron Images Backscattered Electron Images Backscattered electron images can be generated from samples with relatively smooth surfaces, as opposed to secondary electron image that rely on sample roughness to produce an image.
Backscattered electrons are high-energy electrons that rebound from the sample surface.
Hence, a high mean Z material will produce more backscattered electrons than a low mean Z one. In the sample shown below, the brightest areas are magnetite, a high Z Fe oxide. The next brightest areas are pyroxene crystals that contain Fe, but also lower Z elements, such as Si, the medium grey areas are volcanic glass, and the darkest grey areas are feldspar.