EDS is also
capable of Quantitative analysis on a wide variety of materials
Principle of
operation
The technique
utilizes x-rays that are emitted from the sample during bombardment by
the electron beam to characterize the elemental composition of the
analyzed volume. When the sample is bombarded by the electron beam of
the SEM, or Electron Microprobe, electrons are ejected from the atoms
comprising the sample's surface. A resulting electron vacancy is filled
by an electron from a higher shell, and an x-ray is emitted to balance
the energy difference between the two electrons. The EDS detector
measures the number of emitted x-rays versus their energy. The energy of
the x-ray is characteristic of the element from which the x-ray was
emitted. A spectrum of the energy versus relative counts of the detected
x-rays is obtained and evaluated for qualitative and quantitative
determinations of the elements present in the sampled volume.
