ASSESSING THE CONTRIBUTION OF CROSS-SECTIONS TO THE UNCERTAINTY OF MONTE CARLO CALCULATIONS IN MICRO- AND...

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Computational Science

Background:

• Monte Carlo (MC) simulations are crucial for micro and nanodosimetry.
• Variations in MC codes and their underlying physical models can introduce uncertainties in simulation results.
• EURADOS Working Group 6, Task Group 6.2, organized an international exercise to assess these uncertainties.

Purpose of the Study:

• To quantify the uncertainty in micro and nanodosimetric simulation results due to different electron-impact cross-sections and physical models used in various MC codes.
• To compare simulation outcomes from different MC codes (GEANT4-DNA, PENELOPE, MCNP6, FLUKA, NASIC, PHITS).
• To identify the primary sources of deviation in simulation results.

Main Methods:

• An international Monte Carlo (MC) exercise was conducted involving multiple participants and codes.
• Participants simulated micro and nanodosimetric quantities using their preferred MC codes.
• Results were compared to identify deviations attributable to different cross-sections, tracking methods, and cut-off energies.

Main Results:

• Microdosimetric simulations showed minimal influence from the choice of MC code when the electron source was within the target.
• Nanodosimetric simulations, particularly the mean ionisation cluster size distribution (ICSD), were sensitive to the physical models employed by different MC codes.
• The ICSD was identified as a key metric for studying the impact of cross-section data on simulation uncertainty.

Conclusions:

• The choice of MC code and its associated physical models significantly impacts nanodosimetric results, specifically the ICSD.
• Understanding the uncertainty contribution from different cross-section datasets is crucial for accurate nanodosimetry.
• Further investigation using identical cross-section datasets is planned to isolate the impact of cross-sections on simulation uncertainty.