Monte-Carlo Simulation of Low Energy Electron Scattering in Solids

Abstract

A new Monte‐Carlo program for simulation of low energy electron scattering in solids is presented. Applications to electron microscopy and electron microprobe analysis are discussed. Elastic interactions are described by Mott cross sections within the framework of partial wave analysis (PWA) whereas the inelastic collisions are based upon the momentum dependent dynamic form factor S(q, ω). For inelastic interactions with weakly bound valence electrons, S(q, ω) is expressed in terms of the energy loss function Im {—/1ε(q, ω)} of the linear dielectric theory. On the other hand, generalized oscillator strengths (GOS) are chosen in case of excitation of tightly bound core level electrons. The electron energy range extends from several keV down to energies of about 10 eV, i.e. just above the vacuum level. Secondary electron (SE) creation and cascade processes have been included, where the SE transport has been treated in the same way as the scattering of the primary electrons.

Semi-empirical dielectric descriptions of the Bethe surface of the valence bands of condensed water

“…On the other hand, the relatively simple dispersion formulae adopted in the present FED model seem also very effective in reproducing the experimental data while retaining the convenience of working with the Drude function. As noted by Kuhr and Fitting [44] and also confirmed here, the dispersion of the damping-coefficient (Eq. (9d)) provides the expected momentum broadening of the Bethe ridge and results in a notable improvement over earlier extended-Drude models.…”

Alpha particle and proton relative thermoluminescence efficiencies in LiF:Mg,Cu,P:is track structure theory up to the task?

“…In the TRIPOS-E calculations of D(r), the simulation threshold for electron transport was set at 50 eV, which is unjustified since the optical approximation is invalid in this energy range. In fact, an improved version is available (61) in which the dielectric function was made to be momentum dependent. It may be therefore that the results of the TRIPOS-E calculations could be significantly improved over the first 10 nm from the track axis if more accurate models for the transport of low-energy electrons are incorporated.…”

Relative electron inelastic mean free paths for diamond and graphite at 8keV and intrinsic contributions to the energy-loss

“…A major issue is the utilization of the large inelastic mean free path (IMFP) of the photoelectrons, i.e., the distance until the electron undergoes an inelastic scattering event and loses energy. For the classical region of photoelectron spectroscopy up to 2 keV a host of measured and calculated data exists due to its intensive application over many years, of which we give here only a few references [2][3][4][5][6][7][8][9]. However, there are relatively few measurements of IMFPs at higher energies, up to 10 keV and above.…”

“…This allows performing the analysis analytically, without specific Monte Carlo calculations that are often applied at lower energies where large-angle scattering is of importance (see e.g. [6][7][8]). The photoelectrons are released by the hard Xray beam in the carbon samples uniformly over a large depth (>1 m).…”