This book (Practical Electron Microscopy and Database) is a reference for TEM and SEM students, operators, engineers, technicians, managers, and researchers.
 

=================================================================================

In TEM analysis, the mean free path of elastic scattering of an electron represents how thin the specimen needs to avoid or minimize plural scattering.

The inelastic scattering of electrons occurs at smaller angles than that for elastic scattering. Figure 2863a shows an example of angular-resolved electron scattering profiles in logarithmic scale. The reference spectrum (vacuum) in blue is dominated by unscattered electrons in the range −4 to 4 mrad. Due to the scattering of the incident electrons with a rhenium (Re) TEM specimen, the modified spectrum in red was formed.

The mean free path of elastic scattering (λ_el) is given by, [1]

For instance, I_Sample is equal to I_Re in Figure 2863a.

Figure 2863b shows the experimental values of λ_el [1] and λ_in(Z) [2] as oscillatory functions of Z for Z > 20. Comparison of λ_el and λ_in values suggests that the elastic component should dominate scattering of incident high-energy electrons for most inorganic solids and of incident electrons penetrating thin TEM specimens.

Figure 2863b. The mean free path of elastic scattering λ_el of 200 keV electrons (solid squares) [1] and that of inelastic values λ_in (open circles) (Adapted from [2]).

[1] Konstantin Iakoubovskii and Kazutaka Mitsuishi, Elastic scattering of 200 keV electrons in elemental solids: experimental observation of atomic-number-dependent oscillatory behavior, J. Phys.: Condens. Matter 21 (2009) 155402.
[2] Iakoubovskii K, Mitsuishi K, Nakayama Y and Furuya K (2008) Phys. Rev. B 77, 104102.