Reflection and penetration depth

Fig. 4.31. Variation of the coefficient of reflection and penetration depth for X-rays of 1.5405 A incident on a perfectly flat silicon surface.

In Table 1, critical angles, reflectivity, and penetration depth of some common materials used in total reflection X-ray analysis are summarized for an excitation energy of 17.44keV, corresponding to Mo K excitation. The table shows that the reflectivity for materials composed of light elements is high, but decreases for heavier elements. In the latter case, absorption effects become more prominent and affect the reflectivity negatively. 

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