Bragg scattering angle

BS spectrometers can be described as a particular case of TAS in which Bragg scattering angles on the monochromator and on the analyzers are equal or close to 90°. Differentiation of the Bragg s law gives... 

A, Bragg scattering angles 2d in SAXS reach up to about 5°. The detection of the scattered intensity is usually realized with electronic detectors as, for example, proportional counters, scintillation counters, or semiconductor-based counters. Point detectors and position-sensitive devices are common. 

Figure 23 Bragg relation for crystalline coherent scatter.The atomic distances are comparable to the X-ray wavelength. When the difference in path lengths from reflections off adjacent crystal planes is a multiple of the wavelength, reinforcement occurs. Scatter is significantly favored when the X-ray energy and scatter angle obey the Bragg Law.

Fig. 1.6 (a) Arrangement of X-ray source, sample, and detector, used in X-ray direction from powders, (b) Typical diffraction pattern, showing the X-ray scattering as a function of angle. (The notation 20 is conventionally used for the scattering angle, as this relates to the theoretical interpretation given in Fig. 1.7.) The different peaks in (b) come from crystals oriented at different angles, so as to satisfy Bragg s Law (eqn 1.10) for an appropriate set of atomic planes.

Scattering angles 20 < 5° correspond to dq < 1, where d is the characteristic size of the scattering object. With q = 2n/d, one obtains Bragg s law 2tfein9 = X. The magnitude of the scattering vector is inversely proportional to the size of an object. 

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