An empirical calculation of the energy loss of transmitted electrons at 25-100 keV

With the use of an empirical treatment of fast-electron scattering, the average energy of transmitted electrons is calculated as a function of film thickness for 25, 50 and 100 keV electrons in aluminium, copper, tin and lead. The values for the transmission and energy dissipation are taken from the experimental data and the theoretical results of Spencer (1959), respectively. The calculated results for the average energy fairly closely obey a square law of the Thomson-Whiddington type (1912, 1914) except at large film thicknesses, where the calculated values are larger than those obtained from the square law. An empirical expression with two adjustable parameters is fitted to the calculated results to describe the average energy in the entire range. A comparison is given between the calculated and measured values for the average energy.