Grazing-incidence transmission X-ray scattering: surface scattering in the Born approximation

Lu, X.; Yager, K.G.; Johnston, D.; Black, C.T.; Ocko, B.M.

doi:10.1107/S0021889812047887

Figure 1
(a) A three-dimensional illustration of GTSAXS and GISAXS geometries. The incident beam (red arrow) impinges on the sample at a grazing angle of $[\alpha_{\rm i}]$ and the scattered beam is collected by an area detector. The direct incoming beam (orange dotted line) goes through the origin of the q_r-q_z reciprocal space. In the scattering image, the solid line [ $[q_z = (2\pi/\lambda) \sin \alpha_{\rm i}]$ ] marks the surface horizon, which divides the whole scattering image into the GTSAXS and GISAXS regimes. The dotted line corresponds to the direct beam (q_z = 0). (b) A two-dimensional Ewald sphere illustration of the GTSAXS, GISAXS and TSAXS regimes. The rather large grazing incident angle shown is for illustrative purpose. In GISAXS measurements $[\alpha_{\rm i}]$ is close to grazing incidence and in TSAXS the range is typically $[20 \leq \alpha_{\rm i} \leq 90]$ °.