Implementation of EPICS2017 on Geant4 Livermore photon models


Please cite the following paper:
Implementation of the EPICS2017 database for photons in Geant4,
Z. Li, C. Michelet, S. Incerti, I. Ivanchenko, M. Novak, S. Guatelli, H. Seznec,
Phys. Med. 95 (2022) 94-115 (link)
Thank you.

Description of EPICS2017 data

  • Technical note: EPICS2017

  • EPICS2017/EPICS2014/EPDL97 data are available via IAEA website. We wish to deeply thank Dr D. E. Cullen for kindly providing the EPICS data files.


Implementation for gamma conversion process

  • Technical note: gamma conversion

  • Plots

    • Comparison of pair production cross-sections between EPICS2017 and EPDL97

    • Comparison of triplet production cross-sections between EPICS2017 and EPDL97

  • ROOT macros (see list in the technical note above)


Implementation for Compton effect

  • Technical note: Compton effect

  • Plots

    • Comparison of cross-sections between EPICS2017 and EPDL97

    • Comparison of scattering functions between EPICS2017 and EPDL97

    • Relative difference in fitted scattering functions of Compton effect as a function of momentum transfer for Geant4 11.0 (EPICS2017) and 10.6 (EPDL97)

  • ROOT macros (see list in the technical note above)


Implementation for the photoelectric effect

  • Technical note: photoelectric effect

  • Plots

    • Comparison of binding energies between EPICS2017 and EPDL97. This also includes relative difference (RD) compared to tabulated values.

    • Comparison of total cross-sections between EPICS2017 and EPDL97. This also includes relative difference (RD) compared to tabulated values.

    • Fitted subshell cross-sections of for Geant4 11.0: low energy fit (blue filled squares), high energy fit (red open circles), tabulated EPICS2017 (green points). This also includes relative difference (RD) compared to tabulated values.

    • Maximal relative difference in low energy fit and high energy fit of subshell cross-sections of the photoelectric effect, as a function of atomic number (Z: 1-100) for Geant4 11.0 (red open circles) and 10.6 (blue filled squares).

    • Mean absolute relative difference in low energy fit and high energy fit of subshell cross-sections of the photoelectric effect, as a function of atomic number (Z: 1-100), for Geant4 11.0 (red open circles) and 10.6 (blue filled squares).

    • Maximal relative difference in low energy fit and high energy fit of total cross-sections of the photoelectric effect as a function of atomic number (Z: 1-100), for Geant4 11.0 (red open circles) and Geant4 10.6 (blue filled squares).

  • ROOT macros (see list in the technical note above)


Implementation for Rayleigh scattering

  • Technical note: Rayleigh scattering

  • Plots

    • Comparison of cross-sections between EPICS2017 (red open circles) and EPDL97 (blue filled squares)

    • Comparison of form factors between EPICS2017 (red open circles) and EPDL97 (blue filled squares)

    • Relative difference in fitted square of form factors of Rayleigh scattering as a function of momentum transfer, for Geant4 11.0 (red open circles) and 10.6 (blue filled squares).

    • Mean absolute relative difference in fitted square of form factors of Rayleigh scattering compared to tabulated data as a function of atomic number (Z: 1-100), for Geant4 11.0 (red open circles) and Geant4 10.6 (blue filled squares).

    • ROOT macros (see list in the technical note above)


Comparative study of Geant4 photon models with respect to the XCOM data library


  • Plots

    • Mass attenuation coefficient and relative difference (RD) compared to the XCOM database for the selected materials as a function of energy, for Geant4 11.0 (red open circles) and 10.6 (blue open squares) as well as XCOM data (green filled triangles), for:

    • Maximal relative difference in mass attenuation coefficients as a function of atomic number, for Geant4 11.0 (red open circles for the selected chemical elements, cross + for compound materials) and 10.6 (blue filled squares for the selected chemical elements, cross × for compound materials) compared to XCOM, for total and each process. The values for the selected compound materials are represented according to their effective atomic number: 3.3 for water and 4.4 for ICRU compact bone.

    • Mean absolute relative difference in mass attenuation coefficients as a function of atomic number, for Geant4 11.0 (red open circles for the selected chemical elements, cross + for compound materials) and 10.6 (blue filled squares for the selected chemical elements, cross × for compound materials) compared to XCOM, for total and each process. The values for the selected compound materials are represented according to their effective atomic number: 3.3 for water and 4.4 for ICRU compact bone.

  • ROOT macros (see list in the technical note above)


Last updated on 01/03/2022