Transmission of Slow Electrons through Thin Films

The transmission of electrons with energies of 600-6000 ev through films of aluminium and of aluminium oxide of 180-1100 A thickness has been investigated. The transmittance was measured for angles of acceptance between 18 and 36° and the results were compared with Bothe's formula. The range of the electrons as a function of their initial energy was found by extrapolation. Energy distributions for electrons transmitted through the films have been measured and values for the transmitted energies as a function of the primary energy and of the film thickness were compared with the available theoretical results. Some modifications of Bothe's theory of multiple scattering in the region of low electron energies have been suggested and numerical values for the relevant correction factors have been calculated. The results show that the discrepancies between the theory and the experimental results presented in the paper are considerably reduced.