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Energy-filtering transmission electron microscopy (TEM) and bright-field TEM can be used to extract local sample thickness 
$t$ and to generate two-dimensional sample thickness maps. Electron tomography can be used to accurately verify the local 
$t$. The relations of log-ratio of zero-loss filtered energy-filtering TEM beam intensity (
$I_{{\rm ZLP}}$) and unfiltered beam intensity (
$I_{\rm u}$) versus sample thickness 
$t$ were measured for five values of collection angle in a microscope equipped with an energy filter. Furthermore, log-ratio of the incident (primary) beam intensity (
$I_{\rm p}$) and the transmitted beam 
$I_{{\rm tr}}$ versus 
$t$ in bright-field TEM was measured utilizing a camera before the energy filter. The measurements were performed on a multilayer sample containing eight materials and thickness 
$t$ up to 800 nm. Local thickness 
$t$ was verified by electron tomography. The following results are reported:
• The maximum thickness 
$t_{{\rm max}}$ yielding a linear relation of log-ratio, 
$\ln ( {I_{\rm u}}/{I_{{\rm ZLP}}})$ and 
$\ln ( {I_{\rm p}}/{I_{{\rm tr}}} )$, versus 
$t$.
• Inelastic mean free path (
$\lambda _{{\rm in}}$) for five values of collection angle.
• Total mean free path (
$\lambda _{{\rm total}}$) of electrons excluded by an angle-limiting aperture.
• 
$\lambda _{{\rm in}}$ and 
$\lambda _{{\rm total}}$ are evaluated for the eight materials with atomic number from 
$\approx$10 to 79.
The results can be utilized as a guide for upper limit of 
$t$ evaluation in energy-filtering TEM and bright-field TEM and for optimizing electron tomography experiments.
