Receiving slit plane intersection

The plane 90 determines, together with the equation of the receiving slit plane, the line of the intersection of these planes. In the coordinate system CSr the line of the intersection can be obtained easily from Equation (20) by setting the component z of the vector X to 0. Substituting coordinates of vector V and vector U in the coordinate system CS we obtain the equation of a straight line in the receiving slit plane ... 

Figure 6.8 Intersections of the degenerated diffraction cone (20 = 90°) and receiving slit plane. Diffraction cones are produced by the incident ray from fixed point Ai = 0, 0) to points on the sample A2 having only an axial compo nent. The black rectangle represents the receiving slit. (Reprinted from Ref. 54. Permission of the International Union of Crystallography.)...

Absorption. An absorption correction is important for thick specimens with small absorption coefficient for X-rays. Consideration of absorption means that point A2 has a non-zero y component. As a consequence of this there is another conic that is important for considering the absorption. This conic is the intersection of the diffraction cone and the surface plane of the sample. Figure 6.16 shows schematically a part of the diffraction cone and a cross-section of the latter with the sample surface plane (plane in coordinate system CSl.). Points Dip (i= 1-4) are point projections of the receiving slit from point A2. Points Pap are projections of the intersection points P of the receiving slit and conic in the receiving slit plane. 

Figure 6.17 Intersection of the diffraction cone with a) the receiving slit plane, and b) the sample plane. Case of absorption (the vertex of the diffraction cone is under the sample plane). D2D2D3D4 receiving slit. DjpD2pD3pD4p projection of the receiving slit from vertex of the diffraction cone into the sample plane.

Intersection of the Diffraction and Reflection Conics in the Receiving Slit Plane... 

Suppose points = xi,yi,0 and Xj = x2,y2,0 represent the intersections of the conic and receiving slit boundary. The registered intensity is proportional to the dihedral angle 4> between two planes containing points Ai, A2, Xi and A, 2, This angle is the angle between the two normals Ni and N2 to the plane in question ... 

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