X-Ray Diffraction
Páginas: 3 (720 palabras)
Publicado: 27 de enero de 2013
1 Rodrigo Suárez
2 X-Ray Diffraction
It all started when German physicist W. C. Röntgen discovered in 1895 a strange unknown radiation was being called radiation X. For his work on thesubject, was awarded the Nobel Prize for Physics in 1901. Max von Laue, in 1912, discovered that crystalline substances act as three-dimensional diffraction gratings for X-ray wavelengths similar tothe spacing of planes in a crystal lattice.¹ X-ray diffraction is now a common technique for the study of crystal structures and atomic spacing.
X-ray diffraction is based on constructive interferenceof monochromatic X-rays and a crystalline sample. These X-rays are generated by a cathode ray tube, filtered to produce monochromatic radiation, collimated to concentrate, and directed toward thesample. The interaction of the incident rays with the sample produces constructive interference when conditions satisfy Bragg's Law.
Bragg's law allows studying the directions in which the X-raydiffraction on
the glass surface of a constructive interference occurs, given that predicts
the angles at which the X rays are diffracted by an atomic structure material
periodic (crystallinematerials).
[pic]
Fig 1. Reflection of X rays from two layers of atoms.²
This law came from a British physicists William Henry Bragg and his son William Lawrence Bragg in 1913. Bragg'slaw confirms the existence of real particles in the scale atomic, providing a very powerful technique for exploring the area. For the X-ray diffraction they were awarded with the Nobel Prize of Physicsin 1915 for his work in determining the crystal structure of NaCl, ZnS and diamond.³
If we have an x-ray beam incident on a crystal form specular occur dispersion of these rays so that thecondition for Bragg's diffraction. As we can see from Figure 1, the difference between the two reflected beams is 2d sin (ø).⁴
If we need to have constructive interference, we must demand that the path...
2 X-Ray Diffraction
It all started when German physicist W. C. Röntgen discovered in 1895 a strange unknown radiation was being called radiation X. For his work on thesubject, was awarded the Nobel Prize for Physics in 1901. Max von Laue, in 1912, discovered that crystalline substances act as three-dimensional diffraction gratings for X-ray wavelengths similar tothe spacing of planes in a crystal lattice.¹ X-ray diffraction is now a common technique for the study of crystal structures and atomic spacing.
X-ray diffraction is based on constructive interferenceof monochromatic X-rays and a crystalline sample. These X-rays are generated by a cathode ray tube, filtered to produce monochromatic radiation, collimated to concentrate, and directed toward thesample. The interaction of the incident rays with the sample produces constructive interference when conditions satisfy Bragg's Law.
Bragg's law allows studying the directions in which the X-raydiffraction on
the glass surface of a constructive interference occurs, given that predicts
the angles at which the X rays are diffracted by an atomic structure material
periodic (crystallinematerials).
[pic]
Fig 1. Reflection of X rays from two layers of atoms.²
This law came from a British physicists William Henry Bragg and his son William Lawrence Bragg in 1913. Bragg'slaw confirms the existence of real particles in the scale atomic, providing a very powerful technique for exploring the area. For the X-ray diffraction they were awarded with the Nobel Prize of Physicsin 1915 for his work in determining the crystal structure of NaCl, ZnS and diamond.³
If we have an x-ray beam incident on a crystal form specular occur dispersion of these rays so that thecondition for Bragg's diffraction. As we can see from Figure 1, the difference between the two reflected beams is 2d sin (ø).⁴
If we need to have constructive interference, we must demand that the path...
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