Practical Electron Microscopy and Database

Constant-loss approximation [1 – 3] suggested that the energy dissipation of primary electrons (PE) within the material is approximately constant, the number of primary electrons would decrease linearly to a depth R. The number of SEs produced per unit path length would be a constant, given by,

            ----------------- [4471]

where ξ -- Energy required to excite one SE inside the solid
R -- Maximum range of the PE.

[1] Joy DC (1987) J Microsc 147(1):51
[2] Dionne GF (1973) J Appl Phys 44(12):5361
[3] Lye RG, Dekker AJ (1957) Phys Rev 107(4):977