Grazing incidence scattering geometry

Figure 1.7 sketches the grazing incidence scattering geometry used for studies of thin films and surfaces. The set of polarization vectors (cr, n), the polar and azimuthal angles (0, ) describing the relative orientation of the v/ave vector ko of the incident photons to the direction of the magnetization vector m of the sample are indicated. 

Grazing incidence scattering geometry the photon beam with a wave vector k is illuminating the sample at an incidence angle (typically below 1 ).The polarization vector basis of the phonon (ejJ = x,y,z) and the projections of and 6y along the direction of the beam propagation are shown, n denotes the surface normal. 

FIGURE 27.7 Grazing incidence X-ray scattering geometry. The X-rays are incident on the sample at an angle (j) and are detected at a combination of two angles 29 and 2c ). ... 

Figure 6.4 Schematics of the relationship between X-ray characterization and the crystal state of the thin films, (a)-(c), and the scattering geometry of the grazing incidence X-ray diffraction in the reciprocal space, (d).

XRD requires a periodic two- or three-dimensional structure at the surface of a specimen. The measurements are performed in a similar electrochemical cell as described for XAS. The removal of the electrolyte due to the pressing of the polymer window on the specimen surface reduces the disturbing X-ray scattering from water. The grazing incidence geometry weakens the contribution of the diffraction of the... 

Grazing incidence Optical microscopy Small-angle scattering Surface scattering Synchrotron radiation Thin film geometry... 

Fig. 1. Grazing incidence X-ray scattering geometry. All notations are defined in the text.

Figure 3.59. Top and side-view of the experimental set-up for grazing incidence X-ray diffraction measurements on Langmuir monolayers. The footprint of the Incident beam is indicated by the darker area. Only the crossed-beam area ABCD contributes to the detected scattering. The Seller eollimator selects a horizontal scattering angle of 20 the position-sensitive detector (PSD) has its axis vertical and measures the Bragg rod profiles. In this geometry one has the ability to determine the lateral (q ) as well as the vertieal (q ) components of the scattering vector. (Redrawn from J. Als-Nielsen and K. KJaer, loc. clt.

Fig. 2 NICISS pattern for He backscattering at NiAl(l 11). He scattering at a) Ni and b) A1 atoms. -scan the intensity of scattered He is plotted as function of the grazing angle of incidence v /j (0° - 120°) with a constant azimuth rotation (cp [112] for V / = 0°). The inset shows a side view and an on top view of the scattering geometry. Open circles Ni, hatched circles A1 atoms. Head-on scattering situation from first layer atoms (A) and second layer atoms (B) is indicated, (from ref [44]).

Figure 38. Scattering geometry in grazing-incidence surface diffraction.

Thus a very significant enhancement can be obtained. In addition and again because of the grazing incidence geometry, the incident beam can have a large footprint so that it samples a large number of scatterers. 

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