X-ray fluorescence

X-ray fluorescence is an analytical technique that identifies and often quantifies elements by measuring characteristic X-rays emitted after a sample is irradiated with X-rays or other energetic radiation.

Characteristic X-rays: X-rays with energies characteristic of transitions between inner electron shells in atoms. Their energies form the element-specific peaks measured in X-ray fluorescence.
X-ray fluorescence spectroscopy: The spectroscopic analysis of materials using their emitted fluorescent X-rays. This broader practice includes the measurement and interpretation methods used in X-ray fluorescence.
Atomic number: The number of protons in an atom's nucleus, which defines its chemical element. Element identity determines the energies of its characteristic X-ray lines.
X-ray diffraction: A method that uses X-ray scattering to determine the ordered structure of crystalline materials. Diffraction identifies crystal structure, whereas fluorescence identifies elemental composition.
Photoelectric effect: The emission of an electron from a material after it absorbs a photon. Absorption of an incident X-ray can eject an inner-shell electron and initiate fluorescence.
Portable X-ray fluorescence: X-ray fluorescence analysis performed with a handheld or field-portable instrument. Portable instruments bring elemental screening to objects and sites without laboratory sampling.
X-ray: Electromagnetic radiation with wavelengths shorter than ultraviolet light and long enough to interact with atoms. Both the excitation beam and measured fluorescence are X-rays.
Inductively coupled plasma mass spectrometry: An analytical method that ionizes a sample in plasma and separates ions by mass-to-charge ratio. It can measure trace elements with high sensitivity but generally requires sample preparation.
Electron shell: A region of an atom associated with electrons having particular allowed energies. Vacancies in inner shells set the energies of the emitted characteristic X-rays.
X-ray fluorescence microscopy: A method that maps elemental composition across a sample at microscopic spatial scales. Focused excitation reveals where elements occur, not only which elements are present.

Linked from 27 pages