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Electron inelastic mean free path for LiF, CaF2, Al2O3 and liquid water from 433 keV down to the energy gap



Miguel Flores-Mancera, John S. Villarrubia, G. Massillon


We report new calculations, which include the influence of the band gap and exciton states, of the electron inelastic mean free path (IMFP) for liquid water, LiF, CaF2 and Al2O3 from the band gap to 442 keV. Among compounds, liquid water is the most studied due to its role in radiobiological research, whereas LiF and CaF2 are the most widely used thermoluminescent dosimeters in environmental monitoring, medical and space dosimetry. For these four compounds, IMFP data reported in the literature account for the energy gap in only one paper for Al2O3 and another one for LiF. No published IMFP data are available for CaF2, and available results for liquid water do not include energy gap treatment. Previous treatments have not modified the integration domain to accommodate the exciton states. Our calculation was carried out using an electron beam-solid-state interaction model through the relativistic full Penn algorithm. Integration limits that consider the band gap, the valence band width, and exciton interactions have been used. The results suggest that at electron energies below 100 eV, the different choice of models for integration limits can affect the IMFP by more than 12 % and the exciton interaction by 9 %. At higher energies, the discrepancies associated with the choice of energy loss function and other input parameters are around 6 %.


Electron scattering, dielectric properties, inorganic insulators, dosimetry materials, inelastic mean free paths


Flores-Mancera, M. , Villarrubia, J. and Massillon, G. (2020), Electron inelastic mean free path for LiF, CaF2, Al2O3 and liquid water from 433 keV down to the energy gap, ACS Ω, [online],, (Accessed May 24, 2024)


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Created February 16, 2020, Updated October 12, 2021