Bragg s law

The spectrum of the secondary emission, that is, the intensity of X-ray radiation as a function of wavelength is established using a crystal analyzer based on Bragg s law. 

Figure Bl.8.2. Bragg s law. Wlien X = 2d sin 0, there is strong, constructive interference. (B) THE RECIPROCAL LATTICE...

Figure Bl.8.3. Ewald s reciprocal lattice construction for the solution of the Bragg equation. If Sj-s. is a vector of the reciprocal lattice, Bragg s law is satisfied for the corresponding planes. This occurs if a reciprocal lattice point lies on the surface of a sphere with radius 1/X whose centre is at -s..

The amplitude and therefore the intensity, of the scattered radiation is detennined by extending the Fourier transfomi of equation (B 1.8.11 over the entire crystal and Bragg s law expresses die fact that this transfomi has values significantly different from zero only at the nodes of the reciprocal lattice. The amplitude varies, however, from node to node, depending on the transfomi of the contents of the unit cell. This leads to an expression for the structure amplitude, denoted by F(hld), of the fomi... 

Bradyrhizobium Bragg effects Bragg equation Braggite Bragg mirrors Bragg reflector Bragg s law Braids Brain... 

Both ultrasonic and radiographic techniques have shown appHcations which ate useful in determining residual stresses (27,28,33,34). Ultrasonic techniques use the acoustoelastic effect where the ultrasonic wave velocity changes with stress. The x-ray diffraction (xrd) method uses Bragg s law of diffraction of crystallographic planes to experimentally determine the strain in a material. The result is used to calculate the stress. As of this writing, whereas xrd equipment has been developed to where the technique may be conveniently appHed in the field, convenient ultrasonic stress measurement equipment has not. This latter technique has shown an abiHty to differentiate between stress reHeved and nonstress reHeved welds in laboratory experiments. 

X-ray data are recorded either on image plates or by electronic detectors The rules for diffraction are given by Bragg s law Phase determination is the major crystallographic problem Phase information can also be obtained by Multiwavelength Anomalous Diffraction experiments... 

When there is constructive interference from X rays scattered by the atomic planes in a crystal, a diffraction peak is observed. The condition for constructive interference from planes with spacing dhkl is given by Bragg s law. 

Before the development of semiconductor detectors opened the field of energy-dispersive X-ray spectroscopy in the late nineteen-sixties crystal-spectrometer arrangements were widely used to measure the intensity of emitted X-rays as a function of their wavelength. Such wavelength-dispersive X-ray spectrometers (WDXS) use the reflections of X-rays from a known crystal, which can be described by Bragg s law (see also Sect. 4.3.1.3)... 

Bragg s Law (Equation 1-11) is obeyed so well that it is possible to use x-ray diffraction from crystals for highly precise determinations either of d or of A. The former type of determination is basic in establishing crystal structure. 

Satisfactory monochromatization by Bragg reflection from a flat crystal presupposes parallel beams hence the necessity for collimation. This necessity is implicit in Bragg s Law (Equation 1-11), according to which the wavelength singled out for first-order reflection by a crystal of spacing d depends only upon 0, the angle of incidence. One may turn... 

Figure 8. A schematic representation of the elements of the X-ray diffraction pattern from relaxed muscle. These reflections are interpreted to arise from various repeating structures in the muscle. Bragg s law, which states that...

Figure 4.4. X-rays scattered by atoms in an ordered lattice interfere constructively in directions given by Bragg s law. The angles of maximum intensity enable one to calculate the spacings between the lattice planes and allow furthermore for phase identification. Diffractograms are measured as a function of the angle 26. When the sample is a...

This is the Bragg condition, or Bragg s law, the fundamental law of X-ray crystallography. 

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