Tiêu đề 33. X-RAY DIFFRACTION.pdf ✅

PHARMD GURU Page 4 BRAGG’S LAW: W.L Bragg in 1913 showed that scattered radiation from a crystal behaves as if the diffracted beam were reflected from a plane passing through points of the crystal lattice in a manner that makes these crystal lattice planes analogous to mirrors. The conditions leading to diffraction are given by Bragg's law. Consider the reflection of two parallel rays of the same wavelength by two adjacent planes of a lattice. One ray strikes point D on the upper plane but the other ray must travel an additional distance AB before striking the plane immediately below. Similarly, the reflected rays will differ in path length by a distance BC.