# 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**: EPICS2017EPICS2017/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 conversionPlots

**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 effectPlots

**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 effectPlots

**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**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 scatteringPlots

**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

**Technical note****:**comparative study

Result

**files**

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