Changes

==X-ray diffraction (XRD)==

==X-ray diffraction (XRD)==

The principal advantage of XRD is that a qualitative or semiquantitative evaluation of mineralogy is generated. A fixed wavelength X-ray source such as copper X-ray tubes, which have a 1.54A wavelength, is used to irradiate a powdered sample. The incident angle 9 (theta) of the diffracted beam and the intensity are recorded with a counter or tube ([[:file:sem-xrd-cl-and-xf-methods_fig2.png|Figure 2]]). If parallel planes of atoms of a crystal are struck at the same angle, coherent (additive) intensity is detected and recorded as a peak. Bragg's Law (see <ref name=pt05r43>Cullity, B. D., 1959, Elements of X-ray Diffraction: Reading, MA, Addison-Wesley, 514 p.</ref> is the basis for determining the characteristic peaks (''d'' spacing) for known minerals and compounds (''n''λ = 2''d'' sin θ). Tables of standards established by the JCPDS (Joint Council of Powder Diffraction Standards) can be consulted for mineral identification, where 6 is the incident angle, λ the X-ray wavelength and ''d'' the spacing between planes of atoms in the crystal.

The principal advantage of XRD is that a qualitative or semiquantitative evaluation of mineralogy is generated. A fixed wavelength X-ray source such as copper X-ray tubes, which have a 1.54A wavelength, is used to irradiate a powdered sample. The incident angle 9 (theta) of the diffracted beam and the intensity are recorded with a counter or tube ([[:file:sem-xrd-cl-and-xf-methods_fig2.png|Figure 2]]). If parallel planes of atoms of a crystal are struck at the same angle, coherent (additive) intensity is detected and recorded as a peak. Bragg's Law (see <ref name=pt05r43>Cullity, B. D., 1959, Elements of X-ray Diffraction: Reading, MA, Addison-Wesley, 514 p.</ref>) is the basis for determining the characteristic peaks (''d'' spacing) for known minerals and compounds (''n''λ = 2''d'' sin θ). Tables of standards established by the JCPDS (Joint Council of Powder Diffraction Standards) can be consulted for mineral identification, where 6 is the incident angle, λ the X-ray wavelength and ''d'' the spacing between planes of atoms in the crystal.

[[file:sem-xrd-cl-and-xf-methods_fig3.png|left|thumb|{{figure number|3}}X-ray diffraction patterns.]]

[[file:sem-xrd-cl-and-xf-methods_fig3.png|left|thumb|{{figure number|3}}X-ray diffraction patterns.]]