Electron Probe Microanalysis and Microscopy: Focused Electron Beam Techniques and Applications in Characterization of Mineral Inclusions in Diamond

Electromagnetic lens-focused electron beam, commonly called electron probe, is widely used in microanalysis and microscopy For example, electron probe is exclusively used in a scanning electron microscope (SEM) to acquire information of samples on images at micro-to nano-scales (BSE, SE, CL, etc.), chemistry (EDS, WDS, etc.), and crystal structure (EBSD). Electron probe, not parallel electron beam, is also used in STEM mode in a transmission electron microscope (TEM) to acquire similar information of samples (bright field, dark field, HAADF, EFTEM, EDS, EELS, electron diffraction, etc.) at nano-to pico-scales. All these techniques in microanalysis and microscopy use an electron probe as primary input signal to bombard a sample; and the signals detected can come from above the sample surface (SEM) or below the sample if an electron probe penetrates through the sample (STEM). Therefore, the techniques mentioned above all belong to electron probe microanalysis and microscopy or EPMM in short. In EPMM techniques, the electron probe scans across the sample and this dynamic process is different from the static process in the parallel electron beam techniques (TEM mode).