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A method for the rapid orientation of back‐reflection Laue X‐ray photographs for zinc
Author(s) -
Hitch T. T.,
Nunes J. J.,
Katz J. L.
Publication year - 1974
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889874008818
Subject(s) - zinc , reflection (computer programming) , orientation (vector space) , x ray , optics , x ray crystallography , materials science , crystallography , physics , geometry , chemistry , diffraction , computer science , metallurgy , mathematics , programming language
A particularly fast method of orienting zinc single crystals with a standard back-reflection Laue X-ray camera and relatively short exposures is described• The method, similar to one described by Barrett (1952), depends on the identification by inspection of the location of the (0001) pole and superposition of the other strong poles on a special standard projection (Fig. 1 ). In back-reflection films for zinc crystals, most poles of strongly reflecting planes lie on a number of rather obvious zones which intersect at the (0001) poles• Orientation of the crystal requires that the two or three zones most densely populated with Laue spots ('major zones'), intersections of more than two zones, and all the zone axes be mapped from the Laue film onto a stereographic net with the help of a Greninger chart. The major zones are then extended until they intersect at a point presumed to be the (0001) pole• All poles and fiducial marks are then rotated so that the chosen major-zones intersection is brought to the center• If the poles of the stereographic projection can then be made to superimpose on those of the standard projection (Fig. 1 ), the orientation is uniquely determined• When a few spots on the stereographic projection will not match with the standard projection in the five simplified segments, but coincidence is otherwise good, rotation of the difficult poles to the more nearly complete segment will usually show coincidence• The more nearly complete segment of the standard projection, plotted from computer calculation by Skelton (1967), includes all poles with h and k from 0 through 5 and / f rom 0 through 10, as well as certain others seen sufficiently often to be included by more extensive calculations. The other five segments include only the poles of strongly reflecting planes which were noted again and again in these analyses. The X-rays used were from Cu-target tubes operated at 35 kV. The method has been used on cadmium directly; the maximum angular discrepancy incurred by using Fig. 1 with cadmium is one degree•