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. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Med Phys. 2020 Dec 12;48(1):19–56. doi: 10.1002/mp.14226

TABLE IV.

Difference between Geant4 simulation results and NIST XCOM. σref is the 1 σ uncertainty of the reference data. Ray: Rayleigh scattering; Photo: photoelectric effect; Comp: Compton scattering; Conv: pair and triplet production.

Test Difference with respect to the reference data
Opt0 Opt3 Opt4 Livermore Penelope
Total ≤ 1 σref
Ray < 1 σref, in particular: < 10% for E < 10 keV, ≤ 5% for 10 keV < E < 100 keV, < 1% for E > 100 keV < 1 σref in particular: < 10% for E ≤ 3 keV, ≤ 5% for 3 keV < E< 10 keV, < 1% for E > 10 keV
Photo < 1 σref with exceptions at 1 MeV-2 MeV and E ≥ 500 MeV
Comp ≤ 1 σref in particular: > 5% for E < 10 keV, ≤ 5% for 10 keV < E < 20 keV, ≤ 1% for E > 20 keV < 1 σref ≤ 1 σref ≤ 1 σref, in particular: > 5% for E < 6 keV, ≤ 5% for 6 keV < E < 60 keV ≤ 1% for E > 60 keV
Conv ≤ 5% for 2 MeV, ≤ 3% for 3 MeV < E < 10 MeV, ≤ 1% for E > 10 MeV ≤ 1% for E ≥ 2 MeV (< 1 σref) ≤ 5% for 2 MeV, ≤ 3% for 3 MeV < E < 10 MeV ≤ 1% for E > 10 MeV ≤ 1% for E ≥ 2 MeV (≤ 1 σref)