Energy losses of 20-40 keV electrons in 150-650 μg cm^-2 metal films

Measurements of the energy loss spectra of transmitted electrons show agreement of the most probable energy loss Delta E_p with the Landau formula and the mean energy loss Delta E_m with the Bethe formula. Deviations from the Bethe law caused by increased path lengths are observed for thick films of high atomic number at low electron energies. The energy distributions are compared with the theories of Landau (1944) and Blunck and Leisegang (1950) and a correction for increased mean path length by Yang.