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

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, the device is similar to a traditional X-ray diffractometer, except it is usually 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