Abstract
This article is about the lecture given as an introduction to the theme lectures "Probing depth of XAFS" at 63rd SASJ meeting. In the first half, the principle of the basic measurement modes in X-ray absorption fine structure (XAFS) spectroscopy, i.e., transmission, fluorescence yield, and electron yield, are described. Especially, the thickness effect (self-absorption effect) in fluorescence yield mode is explained in detail by use of a simple mathematical model. In the second half, the probing depths of partial fluorescence yield and Auger electron yield are estimated by similar models, and the previously reported values of probing depth of total electron yield were compiled into a graph.