Coordinate Systems for Bragg-Brentano Geometry

The coordinate system CSs is associated with the well-aligned sample. The x -axis coincides with the rotation axis of the diffractometer. The y -axis is an intersection of the sample surface with the equatorial plane. The origin of the coordinate system is the center of the sample. 

The coordinate system CSf is associated with the source. Without source misalignment jy Zf -plane lies in the equatorial plane of the diffractometer and the jy-axis has angle n/2—cp with the y -axis of the coordinate system CSg. The origin of the coordinate system CSf lies in the middle of the source. 

The coordinate system CSr is associated with the receiving slit. Without misalignment the y -plane lies in the equatorial plane of the diffractometer 

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