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Overview on Monte Carlo modelling
Published in Gavin Poludniowski, Artur Omar, Pedro Andreo, Calculating X-ray Tube Spectra, 2022
Gavin Poludniowski, Artur Omar, Pedro Andreo
Geant4 provides a large selection of physics models and data for over 100 different particle types. An application can be configured using pre-built physics constructors that initialize a specific physics list. For x-ray simulations there are several electromagnetic (EM) physics constructors available that have been benchmarked for medical physics applications [179]: G4EmLivermorePhysicsImplements the Livermore Evaluated Photon-, Electron-, and Atomic Data libraries (EPDL, EEDL, EADL), for photon interactions, electron ionization (below 100 keV), and atomic relaxation, respectively. These libraries provide a more accurate description of electromagnetic physics in the low-energy range than Geant4's standard sublibraries.G4EmPenelopePhysicsImplements the models and cross sections developed for the PENELOPE Monte Carlo system (described in Section 7.3.5).G4EmStandardPhysics_option4Implements a combination of physics data and models (including Livermore and PENELOPE) that have been selected based on their perceived performance in terms of accuracy over computational efficiency.
Monte Carlo Simulations in Imaging and Therapy
Published in George C. Kagadis, Nancy L. Ford, Dimitrios N. Karnabatidis, George K. Loudos, Handbook of Small Animal Imaging, 2018
Panagiotis Papadimitroulas, George C. Kagadis, George K. Loudos
Since the early 1990s, there are several codes that have been extensively used for the simulation of radiation physics. Electron gamma shower (EGS) (Nelson et al. 1985) and integrated TIGER series (ITS) (Halbleib et al. 1992) were the standard tools for the calculation of the transport of electron and photon beams mainly in the field of radiotherapy (RT) and for dosimetric studies. ITS consists of three independent codes, namely TIGER, CYLTRAN, and ACCEPT, simulating photon and electron interactions down to 1 keV. MCNP (Monte Carlo N-particle transport) (Brown 2003) was also a standard code for radiation physics, which was extensively applied in the field of medicine in the late 1990s. Initially, due to the association of MCNP in simulating neutrons, it was widely used for military purposes. Lately, after the involvement of electron transportation and high-energy photons and low-energy photon simulations, MCNP was established as “gold standard” in the field of diagnostic and nuclear and therapeutic medicine. ETRAN (Seltzer 1991) was also one of the first widely used MC programs using the stopping powers of ICRU 37 (ICRU 1984). Most of the data in ICRU Report 35 were calculated based on ETRAN code, as it provided very accurate electron transport. In 2001, PENELOPE was published, which is a code system for MC simulations of coupled electron and photon transport in arbitrary materials and complex quadric geometries (Sempau et al. 1997, 2003). Two years later, CERN made available in the public domain the Geant4 simulation toolkit, which is a generic MC code, handling the physical processes of particles interacting with matter (http://geant4.cern.ch/). Its areas of application include high energy, nuclear and accelerator physics, as well as studies in medical and space science (Agostinelli et al. 2003). Geant4 managed to be one of the “strongest” reference MC codes in the field of medical physics and for clinical and preclinical simulations. This statement can be understood by the future widely used MC codes that were developed based on the core of Geant4. Geant4 application for tomographic emission (GATE) (Jan et al. 2004), Geant4-based architecture for medicine-oriented simulations (GAMOS) (Arce et al. 2008), TOPAS (Tool for PArticle Simulation) (Perl et al. 2012), and PTSIM (Particle Therapy Simulation) (Akagi et al. 2011) are typical examples of such codes. PTSIM and TOPAS are specified for RT and particle therapy studies. GAMOS is a user-friendly framework to implement GEANT4 simulations for nuclear medicine (NM) applications, which has been recently validated in small animal positron emission tomography (PET) imaging (Canadas et al. 2011). Finally, GATE is an advanced toolkit developed by the international OpenGATE collaboration (http://www.opengatecollaboration.org/home) and dedicated to numerical simulations in medical imaging and RT (PET, singlephoton emission tomography [SPECT], computed tomography [CT], RT, dosimetry).
Geant4 Extension for Neutronic Calculation of Nuclear Reactor Core
Published in Nuclear Technology, 2023
Hossein Hashemi-Jozani, Khalil Moshkbar-Bakhshayesh, Soroush Mohtashami, Behzad Rokhbin
Up until now, some well-known Monte Carlo codes such as MCNP,[1] TRIPOLI-4,[2] KENO,[3] and OpenMC,[4] which have high accuracy in critical calculations, have been accepted as the best available references. One very efficient Monte Carlo code that can be accessed and extended by the user is the Geant4 toolkit. Geant4[5] is widely used for high-energy particle physics, nuclear physics, accelerator design/application such as simulating D-T fusion interaction,[6] aerospace engineering, medical physics such as estimating the range of ions in target,[7] and so on. Recent advances in high-precision hadronic physics models have led to the use of this code in neutron physics.[8] Therefore, the simulation of a nuclear reactor core by the new Geant4 physics models is achievable. Moreover, the capabilities for more efficient simulation of the electron transport, the ability to apply thermodynamic/thermohydraulic effects, and the ability of movement simulation, etc., make the simulation of a reactor core using the Geant4 toolkit very precious.
Bistatic RCS reduction caused by radionuclide layer for spherical object
Published in Waves in Random and Complex Media, 2023
The emitted alpha particles with an energy of about 5.45 MeV from the radioactive nucleus Americium-241, and their deposition energy at a short distance, can ionize the air around and produce a high density of electrons in surface layers. The codes used to calculate the range and deposition energy are Geant4 and SRIM. Geant4 is a toolkit for simulating the passage of particles through matter and is capable of handling all physics processes including electromagnetic, hadronic, and nucleus–nucleus interactions which are indispensable to calculating three-dimensional dose distributions and deposition energies in air and ion therapy [29]. The SRIM Monte Carlo simulation code is widely used to compute several parameters relevant to ion beam implantation and ion beam processing of materials [30].
Elemental characterization of quartzite of Pouma sub-division of Cameroon and radiation attenuation properties based on XCOM and GEANT4 Monte Carlo simulation
Published in Radiation Effects and Defects in Solids, 2022
Patricia-Laurelle Degbe, Cebastien Joel Guembou Shouop, Daniel Bongue, Merylle Glawdys Beyinda, Maurice Ndontchueng Moyo, Moïse Godfroy Kwato Njock
Geant4 (GEometry ANd Tracking) is a toolkit that the user can assemble according to his specific needs. It is a widely distributed Monte Carlo tool used to simulate the passage of particles through matter. Written in C++ and based on Object-Oriented Programming (OOP), it is a library of classes, each of which has a specific role in the simulation steps (37–39, 48–60). The Geant4 code offers the possibility to the user to make a complete description of the geometry, to define its own materials, to select and generate the particles, and to describe the physical processes involved in the simulation. The result obtained from such a Monte Carlo simulation strongly depends on theory developed, materials and elements implemented in the geometry description, experimental data (used as a tabulated library), or parameterizations (48). Several classes have been implemented to generate a large number of particles such as photons, protons, electrons, neutrons, ions, and high energy particles in the energy range from 250 eV to several TeV. The most important classes implemented for this study were the Detector Construction (for the overall geometry of the system), the Physical Processes (to get the processes by which photons interact with matter), the Primary Particle Generator (essential to gun particles of interest in the simulation) and the output data were extracted in Root and text formats.