Electron Imaging (BSE and SE)

The EPMA is equipped with both backscattered electron (BSE) and secondary electron (SE) detectors allowing for the rapid aquisition of high resolution electron images. The BSE detector collects high-resolution grey-scale images of a sample, in which the brightness scales with the mean atomic number at each point. In this example from a fine-grained sedimentary rock, the black areas are pore spaces, medium gray is quartz, lighter grey is potassium-rich feldspar, and speckled areas are kaolinite. The scale bar is 100 microns long; features a few microns across can readily be distinguished without additional magnification. The SE detector is similar to the BSE detector, but is only sensitive to low energy secondary electrons generated near the sample surface, thus is much more sensitive to small variations in surface topography.