University of Wollongong
Browse

Electron emission from amorphous solid water after proton impact: Benchmarking PTra and Geant4 track structure Monte Carlo simulations

Download (1.08 MB)
journal contribution
posted on 2024-11-15, 05:46 authored by M U Bug, H Rabus, Anatoly RozenfeldAnatoly Rozenfeld
Track structure Monte Carlo simulations of ionising radiation in water are often used to estimate radiation damage to DNA. For this purpose, an accurate simulation of the transport of densely ionising low-energy secondary electrons is particularly important, but is impaired by a high uncertainty of the required physical interaction cross section data of liquid water. A possible tool for the verification of the secondary electron transport in a track structure simulation has been suggested by Toburen et al. (2010), who have measured the angle-dependent energy spectra of electrons, emitted from a thin layer of amorphous solid water (ASW) upon a passage of 6. MeV protons. In this work, simulations were performed for the setup of their experiment, using the PTB Track structure code (PTra) and Geant4-DNA. To enable electron transport below the ionisation threshold, additional excitation and dissociative attachment anion states were included in PTra and activated in Geant4. Additionally, a surface potential was considered in both simulations, such that the escape probability for an electron is dependent on its energy and impact angle at the ASW/vacuum interface. For vanishing surface potential, the simulated spectra are in good agreement with the measured spectra for energies above 50. eV. Below, the simulations overestimate the yield of electrons by a factor up to 4 (PTra) or 7 (Geant4-DNA), which is still a better agreement than obtained in previous simulations of this experimental situation. The agreement of the simulations with experimental data was significantly improved by using a step-like increase of the potential energy at the ASW surface. 2012 Elsevier Ltd.

History

Citation

Bug, M. U., Rabus, H. & Rosenfeld, A. B. (2012). Electron emission from amorphous solid water after proton impact: Benchmarking PTra and Geant4 track structure Monte Carlo simulations. Radiation Physics and Chemistry, 81 (12), 1804-1812.

Journal title

Radiation Physics and Chemistry

Volume

81

Issue

12

Pagination

1804-1812

Language

English

RIS ID

68810

Usage metrics

    Categories

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC