Energy Dispersive Spectroscopy (EDS)
EDS can be used to determine chemical composition and show elemental dispersion.
Chemical Analysis
- The chemical composition of a sample can be determined using x-ray analysis.
- This is done by collecting and analysing the characteristic x-rays that are emitted by the sample during electron bombardment.
- X-rays can be detected using either Energy Dispersive Spectroscopy (EDS) or Wavelength Dispersive Spectroscopy (WDS) techniques.
X-ray Generation
- When an electron from a K-shell is replaced by one from the next closest shell (L), the energy released is designated as a Kα x-ray.
- When an electron from a K-shell is replaced by one from the second closest shell (M), the energy released is designated as a Kβ x-ray.
- Each shell has a different energy level and as an electron drops shells the excess energy is released as a photon (γ) which is the x-ray.
- These events cause a unique energy release and can be detected in the SEM using an energy-dispersive spectroscopy (EDS) detector.
