Surface transmitted beam

Several practical issues of the scatterometer must be considered in the case of characterizing nominally smooth surfaces. The incident laser beam may be collimated, but more commonly it is brought to a focus at a distance defined by the arc in which the detector rotates. In addition, a deflection mirror or an optical fiber might be used to direct light to the detector element. These features permit measurements close to the specular and transmitted beams, and this is critical to folly characterize the scattered light. This is especially significant since the scattered light intensity... 

Some polymers, although transparent, may have a cloudy or milky appearance, generally known as haze. It is often measured quantitatively as the amount of light deviating by more than 2.5 degrees from the transmitted beam direction. Haze is often the result of surface imperfections, particularly with thin films of low-density polyethylene. 

This transmission method provides an image of a section through the crystal and as such enables the experimenter to study the three-dimensional distribution of defects. The beam from the spot of a fine-focus or microfocus source is collimated into a ribbon beam of width approximately 10 //m before the singlecrystal specimen. This provides an incident beam of width small compared with that of the base of the Borrmaim fan formed by extremes of the diffracted and transmitted beams with the crystal surface. [In other words, the beam width must... 

Figure 3.29 Diffraction pattern formation from a thin foil specimen in a TEM. The surface of Ewald sphere intersects the elongated diffraction spots. An elongated spot reflects the diffraction intensity distribution along the transmitted beam direction.

By understanding the formation of dislocation line images, the formation of the dislocation pattern in Figure 3.47b can be interpreted by a schematic illustration (Figure 3.49). Figure 3.47b shows a line-up of dislocations. The lined-up dislocations lie in a crystal slip plane that is inclined to the transmitted beam. The slip plane is cut off at the upper and lower surfaces of a... 

The spots lying on any one curve are reflections from planes belonging to one zone. This is due to the fact that the Laue reflections from planes of a zone all lie on the surface of an imaginary cone whose axis is the zone axis. As shown in Fig. 3-7(a), one side of the cone is tangent to the transmitted beam, and the angle of inclination of the zone axis (Z.A.) to the transmitted beam is equal to the semi-apex angle of the cone. A film placed as shown intersects the cone in an... 

A transmission Laue pattern is made of a cubic crystal in the orientation of Prob. 3-1. By means of a stereographic projection similar to Fig. 3-8, show that the beams diffracted by the planes (2T0), (2T3), and (211), all of which belong to the zone [l20], lie on the surface of a cone whose axis is the zone axis. What is the angle between the zone axis and the transmitted beam ... 

The Evanescent wave is the X-ray field that propagates into the solid surface in a reflection geometry near the critical incidence angle. It is the exponentially damped transmitted beam. 

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