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Monte Carlo Electron Track Structure Calculations in Liquid Water Using a New Model Dielectric Response Function
Dimitris Emfietzoglou1, George Papamichael1,2, Hooshang Nikjoo3
1a Medical Physics Laboratory, University of Ioannina Medical School, Ioannina 45110, Greece.
Radiation Research
|June 27, 2017
Summary
Accurate cross sections are crucial for Monte Carlo simulations of radiation effects. This study uses the Emfietzoglou-Cucinotta-Nikjoo (ECN) model to improve simulations of low-energy electron transport in liquid water, impacting DNA-level radiation research.
Area of Science:
- Radiation physics and chemistry
- Computational biophysics
- Materials science
Background:
- Monte Carlo track structure codes are vital for understanding radiation effects at the DNA level.
- Code performance relies heavily on accurate interaction cross sections, especially for low-energy electrons in biological media.
- Condensed-phase effects in liquid water are challenging to model but crucial for accurate simulations.
Purpose of the Study:
- To calculate inelastic cross sections for low-energy electrons using the Emfietzoglou-Cucinotta-Nikjoo (ECN) dielectric function model.
- To investigate the impact of condensed-phase effects and advanced scattering physics on electron track structure simulations.
- To compare simulation results using the ECN model with those using the Born approximation and the Oak Ridge National Laboratory (ORNL) dielectric function.
Main Methods:
- Developed and applied the Emfietzoglou-Cucinotta-Nikjoo (ECN) model for liquid water's dielectric function.
- Calculated inelastic cross sections beyond the plane wave Born approximation for electrons (10 eV-10 keV).
- Performed Monte Carlo track structure simulations for microdosimetry of low-energy electrons in liquid water.
Main Results:
- The ECN model provides a practical, self-consistent, and analytic parameterization of the dielectric function for liquid water.
- Inelastic cross sections calculated using the ECN model show significant differences compared to the Born approximation.
- Both the dielectric function and corrections to the Born approximation notably affect electron track structure at the nanometer scale.
Conclusions:
- The choice of dielectric function and inclusion of beyond-Born approximation corrections are critical for accurate nanodosimetry simulations.
- The ECN model offers an improved approach for modeling electron interactions in liquid water for radiation research.
- Accurate simulation of low-energy electron transport is essential for understanding radiation damage at the molecular level.
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