INTRODUCTION
The concept of 2D X-ray diffraction is of both fundamental and technological importance. The proper study begins
with the asymmetrical Bragg reflection geometry. The term, the asymmetrical Bragg reflection geometry, means that
the angles between incident and diffracted (reflected) X-ray beams, which are identical angles to the reflecting
crystal planes, but different to the specimen surface. Besides the Bragg angle θ, the description needs to introduce an
angular variable α, which is designated as the angle between the sample surface and the incident X-ray beam. Both
angles α and θ are two independent angular variables necessary to construct the two-dimensional system in various
applications of diffractometry, especially when flat-layer specimens are used to a far greater extent than the one
angular variable θ.....
