Comparison of backscattering computer simulations to experimental measurements

The results of Monte Carlo computer code simulations of backscattering for normally incident, monoenergetic light, keV ions bombarding planar amorphous (or polycrystalline) targets were compared to all pertinent experimental data found by the authors in the literature. These comparisons address a great many combinations of target material, ion species, and incident ion energy. For all combinations of targets and ions studitd, the reflection coefficients R and backscattered energy fractions γ were found to be approximately universal functions of the ion's incident reduced energy ε. Empirical closed form expressions for R and γ were derived and are found to be given by R = R 0 e −αε and γ = γ0 e −βε where R 0 = 11.1 ± 0.8, α= 0.275 ± 0.030, γ0 = 4.1 ± 0.6, and β = 0.295 ± 0.040, valid in the range of 1.5 ≤ ε ≤ 9. The agreement between simulation and experimental data is generally very good, especially at the higher energies.