Energiedispersive

Energy-dispersive refers to a class of detection methods that measure the energy of individual photons or particles, enabling identification of their source or element of origin. In X-ray spectroscopy, energy-dispersive techniques are used to determine elemental composition by recording the energies of characteristic X-rays emitted from a sample when it is excited by electrons, photons, or other excitation sources.

The most common implementation is energy-dispersive X-ray spectroscopy (EDS or EDX), typically attached to scanning electron microscopes (SEM-EDS) or transmission electron microscopes (TEM-EDS). A semiconductor detector, such as a silicon drift detector (SDD) or a silicon-lithium (Si(Li)) detector, converts each incoming X-ray into an electrical pulse with a height proportional to the X-ray energy. An energy-dispersive spectrum plots counts against energy, showing peaks at energies corresponding to elements present in the sample.

Applications include qualitative and quantitative elemental analysis, mapping of element distributions, and acquisition of point spectra or line scans. EDS is widely used in materials science, geology, metallurgy, electronics, and forensic science. It provides rapid, broad-range detection (from light elements up to heavier elements) but with limited energy resolution compared with some alternative techniques. Typical limitations include difficulty quantifying light elements, peak overlaps that require deconvolution, and quantitative accuracy that depends on sample thickness, matrix effects, and calibration.

Compared with wavelength-dispersive X-ray spectroscopy (WDS), energy-dispersive systems are faster and better suited for rapid screening and elemental mapping but offer lower energy resolution. Energy-dispersive detectors are also used in other contexts, such as gamma-ray spectroscopy, though the term is most commonly associated with X-ray microanalysis in electron microscopes.