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Manuscript Title: Calculation of crystal orientations using Laue patterns.
Authors: E. Preuss
Program title: COL
Catalogue identifier: AAQF_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 18(1979)277
Programming language: Fortran.
Computer: IBM 370/168.
Operating system: MVS.
RAM: 200K words
Word size: 8
Keywords: Crystallography, Crystal structures, Crystal diffraction, X-ray diffraction, Orientation of single Crystals, Single crystal surface Preparation, Flat and cylindrical Laue photographs, Transmission and Back-reflection Laue technique.
Classification: 8.

Subprograms used:
Cat Id Title Reference
AAQE_v1_0 PLOMAC CPC 18(1979)261

Nature of problem:
The program evaluates the orientation of single crystals numerically.

Solution method:
This method uses cylindrical, flat transmission or flat back-reflection laue photographs. The Miller indices and the coordinates of three Laue spots on the film must be known. The indexing of the Laue spots can be performed by using the plot program of the author described in this issue of CPC. The crystal parameters of the unit cell have to be inserted into the program. In the calculations, trigonometric functions, vector algebra, formulas of analytic geometry and transformation equations relating the Miller indices of any crystal type with those of a rectangular Cartesian coordinate system are used. The transformations are performed in both directions. The crystal orientation in components of a vector given in the coordinate system of the crystal axes will be printed out in fixed point numbers. In order to obtain the Miller indices of the required orientation, those numbers can be converted into integers by a common factor. Since the precision wanted for this statement may be varying, this must be performed by the user of the program.

The crystal parameters of the unit cell must be known. The three indexed Laue spots on the photograph are not allowed to be reflections from equivalent lattice planes.

Running time:
Less than 1 s.