PRINCIPLES OF TOTAL REFLECTION XRF - Total-Reflection X-Ray Fluorescence Analysis and Related Methods - page 98

Figure2.14. Standing waves in front of and within a thin layer deposited on a thick substrate. Case
A: 70 nm silicon on gold. The normalized intensity is plotted vs. the depth normal to the Si layer at
various glancing angles: (a) α = 0.097 ° dotted, 0.103 ° solid, and 0.111 ° dashed. (b) α = 0.097 ° dotted,
0.106 ° solid, and 0.117 ° dashed. Figure from Ref. [4], reproduced with permission from APS.
Copyright1991, American Physical Society
excessive intensity can be explained by the layer acting as a wave guide [4].
Radiation is swapped back and forth in this waveguide and consequently is
reinforced. The extremely high antinode of Figure 2.14 corresponds to the first
extremely deep break in the reflectivity curve of Figure 2.2. X-ray waveguide
effects are specifically dealt with and described by Zheludeva etal . [13].