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Convenient off‐line error quantification and characterization of concentricity of two circles of rotation for diffractometer alignment
Author(s) -
Cranswick L. M. D.,
Donaberger R.,
Swainson I. P.,
Tun Z.
Publication year - 2008
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/s0021889808004652
Subject(s) - rotation (mathematics) , solver , dial , diffractometer , software , computer science , optics , line (geometry) , least squares function approximation , microsoft excel , algorithm , physics , geometry , acoustics , mathematics , computer vision , programming language , scanning electron microscope , statistics , estimator , operating system
To ensure concentricity of the θ–2θ rotation stages, but with a very limited 2θ range of rotation, an alignment technique using two dial gauges mounted at right angles to each other ( X and Y axes) is described. The deflections of the orthogonal dial gauges are measured as a function of 2θ, with their probes impinging on a cylindrical pin centred on the θ axis. The X and Y corrections required to bring the two rotation stages into concentricity can then be found using a least‐squares fitting via a freestanding program or via the `solver' optimization within the Microsoft Excel spreadsheet software. The same dial gauges provide guidance for applying the required positional corrections. An Excel spreadsheet for determining the X and Y corrections via least squares has been deposited.