International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C, ch. 2.8, p. 124

Section 2.8.3. Application to investigations of heavy crystals

M. Schlenkera and J. Baruchelb

al'Institut National Polytechnique de Grenoble, Laboratoire Louis Néel du CNRS, BP 166, F-38042 Grenoble CEDEX 9, France, and bExperiment Division, ESRF, BP 220, F-38043 Grenoble CEDEX, France

2.8.3. Application to investigations of heavy crystals

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As indicated in (c) in Section 2.8.1[link], the absorption of neutrons by most materials is very small. As a result, it is possible to investigate the defect distribution in samples that are too large and/or contain elements too heavy to be suitable for X-ray topography. Another interesting potentiality is the investigation of crystals where X-rays induce a reaction, for example polymerization (Dudley, Baruchel & Sherwood, 1990[link]). While there is no problem except for the resolution and exposure time with thin crystals of heavy materials (Baruchel, Schlenker, Zarka & Petroff, 1978[link]), the observation of large crystals by the standard, wide-beam technique that corresponds to standard topography implies a superposition of the contributions of sizeable portions of the crystal. It is therefore convenient to restrict the observation to a virtual slice, exactly as in Lang's method of X-ray section topography in low-absorption cases (Schlenker, Baruchel, de la Bathie & Wilson, 1975[link]; Davidson & Case, 1976[link]). This method is useful in particular in the process of preparation of monochromator crystals (Hustache, 1979[link]). It has been applied in metallographic investigations of large crystals of copper-based alloys (Tomimitsu, Doi & Kamada, 1983[link]).

References

Baruchel, J., Schlenker, M., Zarka, A. & Petroff, J. F. (1978). Neutron diffraction topographic investigation of growth defects in natural lead carbonate single crystals. J. Cryst. Growth, 44, 356–362.
Davidson, J. B. & Case, A. L. (1976). Applications of the fly's eye neutron camera: diffraction tomography and phase transition studies. Proc. Conf. on Neutron Scattering, ORNL, USERDA CONF 760601–P2, pp. 1124–1135.
Dudley, M., Baruchel, J. & Sherwood, J. N. (1990). Neutron topography as a tool for studying reactive organic crystals: a feasibility study. J. Appl. Cryst. 23, 186–198.
Hustache, R. (1979). Sélection de blocs monocristallins dans un cristal de beryllium par topographie neutronique. Nucl. Instrum. Methods, 163, 151–156.
Schlenker, M., Baruchel, J., Perrier de la Bathie, R. & Wilson, S. A. (1975). Neutron diffraction section topography: observing crystal slices before cutting them. J. Appl. Phys. 46, 2845–2848.
Tomimitsu, H., Doi, K. & Kamada, K. (1983). Neutron diffraction topographic observations of substructures in Cu-based alloys. Physica (Utrecht), B120, 96–102.








































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