Electron microscopy
  
Fraction of Transmitted Electrons Depending on Sample Thickness
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As an examlpe of interaction between incident electrons and matters, Figure 1183a shows the fractions of the transmitted (ηT) and backscattered (ηB) electrons from some Al films with an incident electron beam at accelerating energies of 15 keV and 20 keV, respectively. Those fractions are thickness-dependent. The data was obtained with Monte Carlo calculations. [1] It is reasonable that the fraction of transmitted electrons at higher voltages (20 keV) is much larger than that at lower voltages (15 keV).

Fractions of the transmitted and backscattered electrons from some Al films with an incident electron beam at an accelerating energy of 15 keV

Figure 1183a. Fractions of the transmitted and backscattered electrons from some Al (aluminium) films with an incident electron beam at accelerating energies of 15 keV and 20 keV, respectively. The dash curves present the fractions of backscattered electrons, while the solid curves present those of the transmitted electrons. The red curves are obtained at an accelerating voltage of 20 keV, while the green ones are from 15 keV. Adapted from [1]

Figure 1183b shows the fraction of transmitted electrons at different accelerating voltages of incident electron beam obtained by Monte Carlo modeling from some materials.

Fraction of transmitted electrons at different accelerating voltages

Figure 1183b. Fraction of transmitted electrons at different accelerating voltages.

Figure 1183c shows the fraction of transmitted electrons as a function of the thickness, t, for Al and Au films at different energies of the incident electrons.

Backscattering coefficient, η, on the electron incident surface as a function of the thicknesses, t, at different energies of the incident electrons: (a) Al, and (b) Au films secondary electron yields δ and δT generated by the incident and transmitted electrons on the top (entrance) surface and bottom (exit) surfaces
(a)
(b)
Figure 4564b. Fraction of transmitted electrons as a function of the thickness, t, for Al and Au films at different energies of the incident electrons: (a) Al, and (b) Au films. Adapted from [2]

 

 

 

 

 

 

 

 

[1] R Shimizu, Y. Kataoka, T. Ikuta, T. Koshikawa and H. Hashimoto, A Monte Carlo approach to the direct simulation of electron
penetration in solids, J. Phys. D: Appl. Phys., Vol. 9, 1976.
[2] L Reimer and H Drescher, Secondary electron emission of 10-100 keV electrons from transparent fdms of A1 and Au, J. Phys. D: Appl. Phys., Vol. 10, 1977.

 

 

 
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