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How does energy-dispersive X-ray analysis add elemental information to scanning electron microscopy?

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Moon rock crystals — surface analysis A scanning-electron-microscope photograph of pyroxene and plagioclase crystals (the long and the short crystals, respectively) that grew in a cavity in a fragment of Moon rock gathered during the Apollo 14 mission.

Scanning electron microscopy (SEM) is primarily a topographic technique that uses a focused electron beam to generate physical images of a surface by analyzing backscattered electrons. While SEM provides high-resolution topographical detail, it does not inherently provide chemical information.12

Energy-dispersive X-ray (EDX) analysis adds elemental information to this process by capturing the X-rays generated when the electron beam interacts with the sample. Because these X-rays are characteristic of the specific elements present in the specimen, an EDX analyzer can measure their energy and intensity to identify the sample's composition. By scanning the electron probe across the surface, this data can be used to create an elemental map, allowing researchers to visualize the distribution of specific elements alongside the topographical image. This combination is widely utilized in fields such as mineralogy, metallurgy, and solid-state science.12