Guinier-Tennevin method

Fig. 8-29 Guinier-Tennevin method, (a) Perfect crystal. Focused diffracted beam, (b) Bent or polygonized crystal. Enlarged view of nonfocused beam.

A modification of the Guinier-Tennevin method can reveal additional information about a deformed crystal [8.12, 8.13]. If a Seller slit with horizontal plates is placed in the incident beam and the crystal is twisted about a vertical axis, the original vertical-line Laue spot broadens into a striated region composed of fine inclined lines, and the inclination of these lines is a measure of the torsional strain in the crystal (Fig. 8-30(c)). 

Fig. 8-30 Single Laue spots obtained by the Guinier-Tennevin method on a film placed at the focusing position Fof Fig. 8-29(a). Spots (a), (b), and (c) are from the transverse planes of a quartz crystal plate, 37 x 13 x 0.5 mm (a) unstrained, magnification 2X, (b) elastically bent, 2X, (c) elastically twisted, 5X. Spot (d) is from an aluminum crystal after plastic deformation, 4X. Julien et al. [8.12-8.14].

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