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Title: Low and High Energy Modeling in Geant4

Abstract

Four of the most-used Geant4 hadronic models, the Quark-gluon string, Bertini-style cascade, Binary cascade and Chiral Invariant Phase Space, are discussed. These models cover high, medium and low energies, respectively, and represent a more theoretical approach to simulating hadronic interactions than do the Low Energy and High Energy Parameterized models. The four models together do not yet cover all particles for all energies, so the Low Energy and High Energy Parameterized models, among others, are used to fill the gaps. The validity range in energy and particle type of each model is presented, as is a discussion of the models' distinguishing features. The main modeling stages are also described qualitatively and areas for improvement are pointed out for each model.

Authors:
;  [1]; ; ; ;  [2];  [3];
  1. Stanford Linear Accelerator Center, Menlo Park, California (United States)
  2. CERN, Geneva (Switzerland)
  3. Helsinki Institute of Physics, Helsinki (Finland)
Publication Date:
OSTI Identifier:
21054987
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 896; Journal Issue: 1; Conference: Hadronic shower simulation workshop, Batavia, IL (United States), 6-8 Sep 2006; Other Information: DOI: 10.1063/1.2720453; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHIRALITY; COMPUTERIZED SIMULATION; G CODES; GLUONS; HADRONS; PHASE SPACE; QUARK-GLUON INTERACTIONS; QUARKS; STRING MODELS

Citation Formats

Wright, Dennis H., Koi, Tatsumi, Folger, Gunter, Ivanchenko, Vladimir, Kossov, Mikhail, Starkov, Nikolai, Heikkinen, Aatos, and Wellisch, Hans-Peter. Low and High Energy Modeling in Geant4. United States: N. p., 2007. Web. doi:10.1063/1.2720453.
Wright, Dennis H., Koi, Tatsumi, Folger, Gunter, Ivanchenko, Vladimir, Kossov, Mikhail, Starkov, Nikolai, Heikkinen, Aatos, & Wellisch, Hans-Peter. Low and High Energy Modeling in Geant4. United States. doi:10.1063/1.2720453.
Wright, Dennis H., Koi, Tatsumi, Folger, Gunter, Ivanchenko, Vladimir, Kossov, Mikhail, Starkov, Nikolai, Heikkinen, Aatos, and Wellisch, Hans-Peter. Mon . "Low and High Energy Modeling in Geant4". United States. doi:10.1063/1.2720453.
@article{osti_21054987,
title = {Low and High Energy Modeling in Geant4},
author = {Wright, Dennis H. and Koi, Tatsumi and Folger, Gunter and Ivanchenko, Vladimir and Kossov, Mikhail and Starkov, Nikolai and Heikkinen, Aatos and Wellisch, Hans-Peter},
abstractNote = {Four of the most-used Geant4 hadronic models, the Quark-gluon string, Bertini-style cascade, Binary cascade and Chiral Invariant Phase Space, are discussed. These models cover high, medium and low energies, respectively, and represent a more theoretical approach to simulating hadronic interactions than do the Low Energy and High Energy Parameterized models. The four models together do not yet cover all particles for all energies, so the Low Energy and High Energy Parameterized models, among others, are used to fill the gaps. The validity range in energy and particle type of each model is presented, as is a discussion of the models' distinguishing features. The main modeling stages are also described qualitatively and areas for improvement are pointed out for each model.},
doi = {10.1063/1.2720453},
journal = {AIP Conference Proceedings},
number = 1,
volume = 896,
place = {United States},
year = {Mon Mar 19 00:00:00 EDT 2007},
month = {Mon Mar 19 00:00:00 EDT 2007}
}
  • Four of the most-used Geant4 hadronic models, the Quark-gluon string, Bertini-style cascade, Binary cascade and Chiral Invariant Phase Space, are discussed. These models cover high, medium and low energies, respectively, and represent a more theoretical approach to simulating hadronic interactions than do the Low Energy and High Energy Parameterized models. The four models together do not yet cover all particles for all energies, so the Low Energy and High Energy Parameterized models, among others, are used to fill the gaps. The validity range in energy and particle type of each model is presented, as is a discussion of the models'more » distinguishing features. The main modeling stages are also described qualitatively and areas for improvement are pointed out for each model.« less
  • Purpose: The GEANT4-DNA physics models are upgraded by a more accurate set of electron cross sections for ionization and excitation in liquid water. The impact of the new developments on low-energy electron transport simulations by the GEANT4 Monte Carlo toolkit is examined for improving its performance in dosimetry applications at the subcellular and nanometer level. Methods: The authors provide an algorithm for an improved implementation of the Emfietzoglou model dielectric response function of liquid water used in the GEANT4-DNA existing model. The algorithm redistributes the imaginary part of the dielectric function to ensure a physically motivated behavior at the bindingmore » energies, while retaining all the advantages of the original formulation, e.g., the analytic properties and the fulfillment of the f-sum-rule. In addition, refinements in the exchange and perturbation corrections to the Born approximation used in the GEANT4-DNA existing model are also made. Results: The new ionization and excitation cross sections are significantly different from those of the GEANT4-DNA existing model. In particular, excitations are strongly enhanced relative to ionizations, resulting in higher W-values and less diffusive dose-point-kernels at sub-keV electron energies. Conclusions: An improved energy-loss model for the excitation and ionization of liquid water by low-energy electrons has been implemented in GEANT4-DNA. The suspiciously low W-values and the unphysical long tail in the dose-point-kernel have been corrected owing to a different partitioning of the dielectric function.« less
  • Purpose: The GEANT4 general-purpose Monte Carlo simulation toolkit is able to simulate physical interaction processes of electrons, hydrogen and helium atoms with charge states (H{sup 0}, H{sup +}) and (He{sup 0}, He{sup +}, He{sup 2+}), respectively, in liquid water, the main component of biological systems, down to the electron volt regime and the submicrometer scale, providing GEANT4 users with the so-called ''GEANT4-DNA'' physics models suitable for microdosimetry simulation applications. The corresponding software has been recently re-engineered in order to provide GEANT4 users with a coherent and unique approach to the simulation of electromagnetic interactions within the GEANT4 toolkit framework (sincemore » GEANT4 version 9.3 beta). This work presents a quantitative comparison of these physics models with a collection of experimental data in water collected from the literature. Methods: An evaluation of the closeness between the total and differential cross section models available in the GEANT4 toolkit for microdosimetry and experimental reference data is performed using a dedicated statistical toolkit that includes the Kolmogorov-Smirnov statistical test. The authors used experimental data acquired in water vapor as direct measurements in the liquid phase are not yet available in the literature. Comparisons with several recommendations are also presented. Results: The authors have assessed the compatibility of experimental data with GEANT4 microdosimetry models by means of quantitative methods. The results show that microdosimetric measurements in liquid water are necessary to assess quantitatively the validity of the software implementation for the liquid water phase. Nevertheless, a comparison with existing experimental data in water vapor provides a qualitative appreciation of the plausibility of the simulation models. The existing reference data themselves should undergo a critical interpretation and selection, as some of the series exhibit significant deviations from each other. Conclusions: The GEANT4-DNA physics models available in the GEANT4 toolkit have been compared in this article to available experimental data in the water vapor phase as well as to several published recommendations on the mass stopping power. These models represent a first step in the extension of the GEANT4 Monte Carlo toolkit to the simulation of biological effects of ionizing radiation.« less
  • The crews of present-day jet aircrafts are a significant occupationally exposed group, receiving relatively high effective doses from exposure to cosmic radiation, with the possibility of higher effective doses if the cruising altitudes of future aircrafts increase. To assess effective doses from exposure to cosmic radiation, the MAX (Male Adult voXel) phantom has been coupled with the GEANT4 Monte Carlo code. This radiation transport code has been distributed and upgraded by a group of international scientists at CERN/Switzerland, and, among other types of radiation, allows for the simulation of neutron transport through matter. The high-energy neutrons contribute to about 70%more » of the neutron effective dose, which in turn represents between 35% and 60% of the total effective dose to aircraft crews, according to recent studies. The high-energy neutrons spectrum is obtained at aircraft altitude simulating 106 events, each one representing an extensive air shower produced from experimental distributed cosmic rays interactions with atmospherics atoms. The GEANT4/MAX simulation anthropomorphic model calculates the conversion coefficient from fluence to effective dose of cosmic rays neutrons for the (80-120)MeV energetic interval and of 10x5 monoenergetic 100-MeV neutrons. A comparison of the values from the two methods gives an estimation of aircraft environment condition, which is a very important influencing factor. The main obstacle in this research is the long air showers simulation time required to obtain validatable data. An upgrade of the two methods comparison result is presented but is not conclusive, while the monoenergetic irradiation traditional method is in agreement with the literature.« less