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Depth profiles of charge deposition in absorbers irradiated by electrons have been computed by using the ITS Monte Carlo system version 3.0. Plane-parallel electron beams with energies from 0.1 to 100 MeV have been assumed to impinge normally on slab absorbers of effectively semi-infinite thickness. Absorber materials considered are elemental solids of atomic numbers between 4 and 92 (Be, C, Al, Cu, Ag, Au and U). To study the accuracy of the Monte Carlo results, benchmarks at the energies of 5, 10 and 20 MeV have been generated by interpolating published experimental results. Extrapolated ranges rex, most probable depths zm of charge deposition and average depths zav of charge deposition have been determined from both the ITS and interpolated experimental charge-deposition distributions. The depth profiles and derived parameters show good agreement between calculation and experiment, except for small discrepancies for Au absorbers, where the ITS results show a slightly lower penetrability of electrons. The Monte Carlo results of rex have been compared with the semiempirical formula of Tabata et al. [Nucl. Instr. and meth. 103 (1972) 85], and some deficiencies of the latter, due to the lack of data used in determining adjustable coefficients of the formula, have been found. The use of the ratio of the continuous slowing-down approximation range r0 to zav as an estimate of multiple scattering detours is discussed. |
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