X-Ray Diffraction Process

X-ray waves O and O are parallel. The extra distance traveled by wave O in traveling through the crystal is AB + BC. For diffraction to occur, it is necessary that this distance be a whole number of wavelengths, n that is. 

The equation nk = 2d sin0 is known as the Bragg equation. The important result of this equation is that at any particular angle of incidence 0, only X-rays of a particular wavelength fulfill the requirement of staying in phase and being reinforced and are therefore diffracted by the crystal. Diffraction of X-rays by crystals forms the basis of XRD for crystal structure determination and is also the reason XRF spectrometry is possible, as will be seen. 

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In this chapter we will focus on X-ray diffraction processes for the analysis of materials. XRD is sensitive to crystalline phases down to 0.1-1 wt%. Conventional XRD instruments use monochromatic (that is, with a well defined wavelength) X-ray radiation from Cu, Cr, Mo or Ag sources. Cm, in particular with the K-a line... 

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