Diffractometer, 4-circle kappa geometry

Alternatively, four-circle diffractometer can have a k (kappa) geometry, in which the / circle is replaced by two arcs, one of which ( > block ) rotates around the vertical > axis and the other ( k block ) around the k shaft, mounted on the (o block (Figure 12). The k and co axes always form the magic angle a = 54°. Note that in either geometry, every... 

Figure 12 Scheme of a four-circle diffractometer (a) conventional geometry, (b) k (kappa) geometry... 

The x circle is a relatively bulky object whose thickness can stop the measurement of diffracted beams at high 6. Also, collision of the x circle with the collimator or X-ray tube housing has to be avoided. An alternative is the Kappa goniostat geometry. In the Kappa diffractometer (see figure A1.8) the Kappa axis is inclined at 50° to the tu-axis and can be rotated about the tu-axis the K-axis is an alternative to x> therefore. The... 

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