In
X-ray fluorescence (XRF) a material is exposed to
X-rays with a relatively high
energy. These
photons are capable of exciting (ejecting) the
electrons in the core levels of the material under investigation. The induced excited state relaxes under emission of a X-ray photon with a smaller energy. This emitted
light is analysed in a
spectrometer. Because the core levels have very different energies for different elements the XRF spectrum contains information on the elemental composition of the sample under investigation.
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