If, however, this condition is not satisfied, then destructive interference will occur. Then the scattered radiation will undergo constructive interference and thus the crystal will appear to have reflected the X-radiation. In honor of the discoverers of this equation the peak maximum posi- tion has been named the Bragg angle B and the interference peak measured in the ref lection. In other words, given the fol lowing conditions: If the path difference is equal to an integer multiple of the wavelength, then X-rays A and B (and by extension C) will arrive at atom X in the same phase. Bragg Consider a set of Nf 1 equidistant atomic planes of spacing d, and a monochromatic plane X-wave falling on it at a glancing angle 0 (Fig. From the Law of Sines we can express this distance YX in terms of the lattice distance and the X-ray incident angle: The path difference between the ray reflected at atom X and the ray reflected at atom Y can be seen to be 2YX. Monochromatic X-rays A, B, and C are incident upon the crystal at an angle θ. And, when the path difference, \(d\) is equal to a whole number, \(n\), of wavelength, a constructive interference will occur.Ĭonsider a single crystal with aligned planes of lattice points separated by a distance d. The law states that when the x-ray is incident onto a crystal surface, its angle of incidence, \(\theta\), will reflect back with a same angle of scattering, \(\theta\).
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