eguruchela

Laue’s experiment


The Laue method is mainly used to determine the orientation of large single crystals. White radiation is reflected from, or transmitted through, a fixed crystal.Max von Laue used continuous radiation to impact on a stationary crystal. With this procedure the crystal generates a set of diffracted beams that show the internal symmetry of the crystal. In these circumstances, and taking into account Bragg's Law, the experimental constants are the interplanar spacings d and the crystal position referred to the incident beam. The variables are the wavelength λ and the integer number n .

nλ = 2 dhkl sin θnh,nk,nl

the diffraction pattern will contain (for the same spacing d) the diffracted beams corresponding to the first order of diffraction (n=1) of a certain wavelength, the second order (n=2) of half the wavelength (λ/2), the third order (n=3) with wavelength λ/3, etc