Diffraction topography (short: "topography") is an X-ray imaging technique based on Bragg diffraction. Diffraction topographic images ("topographs") record the intensity profile of a beam of X-rays (or, sometimes, neutrons) diffracted by a crystal. A topograph thus represents a two-dimensional spatial intensity mapping of reflected X-rays, i.e. the spatial fine structure of a Bragg spot. This intensity mapping reflects the distribution of scattering power inside the crystal; topographs therefore reveal the irregularities in a non-ideal crystal lattice. X-ray diffraction topography is one variant of X-ray imaging, making use of diffraction contrast rather than absorption contrast which is usually used in radiography and computed tomography (CT).
Topography is used for monitoring crystal quality and visualizing defects in many different crystalline materials. It has proved helpful e.g. when developing new crystal growth methods, for monitoring growth and the crystal quality achieved, and for iteratively optimizing growth conditions. In many cases, topography can be applied without preparing or otherwise damaging the sample; it is therefore one variant of non-destructive testing.
Read more about Diffraction Topography: History, Basic Principle of Topography, Theory of Diffraction Topography, Experimental Realization - Instrumentation, Experimental Techniques I - Some Classical Topographic Techniques, Literature
Famous quotes containing the word topography:
“That the mere matter of a poem, for instance—its subject, its given incidents or situation; that the mere matter of a picture—the actual circumstances of an event, the actual topography of a landscape—should be nothing without the form, the spirit of the handling, that this form, this mode of handling, should become an end in itself, should penetrate every part of the matter;Mthis is what all art constantly strives after, and achieves in different degrees.”
—Walter Pater (1839–1894)