Wavelength dispersive X-ray spectroscopy

From Free net encyclopedia

The Wavelength dispersive X-ray spectroscopy is a method used to determine the energy spectrum of an X-ray radiation. It is mainly used in chemical analysis, in an X-ray fluorescence spectrometer, or in an electron microprobe (Castaing probe).

Explanation

The X-rays emitted by the analysed object are collimated by parallel copper blades (called collimator or Soller slits), and irradiate a known single crystal. The single crystal diffracts the photons (Bragg's law) and are collected by a detector, usually a scintillation counter or a proportional counter.

The single crystal and the detector are mounted on a goniometer which is a device is similar to a traditional X-ray diffractometer. It is usually operated under vacuum to reduce the absorption of soft radiation (low-energy photons) by the air and thus increase the sensitivity for the detection and quantitation of light elements (between boron and oxygen).

See also

• Energy dispersive X-ray spectroscopy

External links

• The Science of Spectroscopy - supported by NASA, includes OpenSpectrum, a Wiki-based learning tool for spectroscopy that anyone can edit

• Parallax Research Inc. - Suppliers of High Resolution WDS Systems for Light Element and Transition Element Microanalysis

• WDS microanalysis for low voltage/beam current SEM applications - From Thermo Electron Corporation

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