WorldWideScience

Sample records for des resonances geantes

  1. Magnetic resonance studies of solid polymers; Etude des polymeres solides par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, R. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    This paper is a review of the application of nuclear magnetic resonance (NMR) to solid polymers. In the first, theoretical part, the elements of the theory of NMR, which are necessary for the study of the properties of solid polymers are discussed: the moments method, nuclear relaxation and the distribution of correlation times. In the second part the experimental results are presented. (author) [French] Cette etude est une recherche bibliographique sur l'application de la resonance magnetique nucleaire (RMN) aux polymeres solides. Dans la premiere partie theorique on discute les elements de la theorie de RMN, necessaires pour l'etude des proprietes des polymeres solides: la methode des moments, la relaxation nucleaire et la distribution des temps de correlation. La deuxieme partie presente les resultats des experiences. (auteur)

  2. GEANT4 in ALICE

    CERN Document Server

    Hrivnacova, I

    1999-01-01

    The smooth way of transition from existing GEANT3 based simulation software to GEANT4 adopted by ALICE will be explained. The AliRoot package as a client of the Monte Carlo interface (pure abstract class) is used in GEANT4 based classes for building GEANT4 objects (geometry physics list, primary generator). We shall also summarise our experience with GEANT4 and give an overview of what parts of GEANT4 are used in the current ALICE GEANT4 simulation prototype, what functionality has been added and what problems have been encountered.

  3. Giant resonance and dipolar states of light nuclei; La resonance geante et les etats dipolaires des noyaux legers

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    Cross-section for ({gamma},n) reactions on C{sup 12},, O{sup 10}, Mg{sup 24} and Ca{sup 40} have been measured using 'monochromatic' gamma rays of variable energy obtained from the annihilation in flight of fast positrons. We compare the observed structure with the shell model of nucleus, including residual interaction between nucleons by 'hole particle' techniques. (author) [French] Les photons 'monochromatiques', d'energie variable, produits par l'annihilation en vol de positons, sont utilises pour mesurer la section efficace ({gamma},n) de {sup 12}C, {sup 16}O, {sup 21}Mg et {sup 40}Ca. La structure observee est comparee aux previsions theoriques du modele a particules independantes, tenant compte de l'interaction residuelle entre nucleons par la methode 'trou-particule'. (auteur)

  4. A Geant4-based Simulation to Evaluate the Feasibility of Using Nuclear Resonance Fluorescence (NRF) in Determining Atomic Compositions of Body Tissue in Cancer Diagnostics and Irradiation

    Science.gov (United States)

    Gilbo, Yekaterina; Wijesooriya, Krishni; Liyanage, Nilanga

    2017-01-01

    Customarily applied in homeland security for identifying concealed explosives and chemical weapons, NRF (Nuclear Resonance Fluorescence) may have high potential in determining atomic compositions of body tissue. High energy photons incident on a target excite the target nuclei causing characteristic re-emission of resonance photons. As the nuclei of each isotope have well-defined excitation energies, NRF uniquely indicates the isotopic content of the target. NRF radiation corresponding to nuclear isotopes present in the human body is emitted during radiotherapy based on Bremsstrahlung photons generated in a linear electron accelerator. We have developed a Geant4 simulation in order to help assess NRF capabilities in detecting, mapping, and characterizing tumors. We have imported a digital phantom into the simulation using anatomical data linked to known chemical compositions of various tissues. Work is ongoing to implement the University of Virginia's cancer center treatment setup and patient geometry, and to collect and analyze the simulation's physics quantities to evaluate the potential of NRF for medical imaging applications. Preliminary results will be presented.

  5. Geant-Validation

    CERN Document Server

    De La Cruz Fernandez, Gonzalo

    2017-01-01

    The aim of this document is to demonstrate the work performed in Geant-Validation application by Summer Student Gonzalo de la Cruz Fernández. In the following pages the architecture of Geant-Val and the main improvements and design decisions taken are described, as well as the main security challenges faced and what measures we have adopted against them.

  6. Study of the fluctuations of the partial and total radiative widths by neutron capture resonance method; Etude des fluctuations des largeurs radiatives partielles et totales par la capture des neutrons de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, V.D. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-06-01

    Radiative capture experiments by neutron time-of-flight methods have been made for following studies: distribution of partial radiative widths, effects of correlation between different radiative transitions, fluctuations of total radiative widths {gamma}{sub {gamma}} from resonance to resonance, variation of {gamma}{sub {gamma}} with number of mass and the search for the existence of potential capture. Also, some other experiments with the use of neutron capture gamma-rays spectra have been investigated. (author) [French] Par la capture des neutrons de resonance dont les energies sont selectionnees a l'aide de la technique du temps de vol, differents types d'experiences ont ete realisees concernant les etudes des distributions des largeurs radiatives partielles, des effets de correlation entre differentes voies de desexcitation, de la fluctuation des largeurs radiatives totales {gamma}{sub {gamma}} de resonance a resonance, de la variation de la quantite {gamma}{sub {gamma}} en fonction du nombre de masse et de la mise en evidence de l'existence du processus de capture potentielle. Quelques autres applications de l'emploi du spectre de rayons gamma ont egalement ete presentees. (auteur)

  7. The GEANT4 Visualisation System

    Energy Technology Data Exchange (ETDEWEB)

    Allison, J.; /Manchester U.; Asai, M.; /SLAC; Barrand, G.; /Orsay; Donszelmann, M.; /SLAC; Minamimoto, K.; /Inst. Comput. Fluid Dyn., Tokyo; Tanaka, S.; /Ritsumeikan U.; Tcherniaev, E.; /CERN; Tinslay, J.; /SLAC

    2007-11-02

    The Geant4 Visualization System is a multi-driver graphics system designed to serve the Geant4 Simulation Toolkit. It is aimed at the visualization of Geant4 data, primarily detector descriptions and simulated particle trajectories and hits. It can handle a variety of graphical technologies simultaneously and interchangeably, allowing the user to choose the visual representation most appropriate to requirements. It conforms to the low-level Geant4 abstract graphical user interfaces and introduces new abstract classes from which the various drivers are derived and that can be straightforwardly extended, for example, by the addition of a new driver. It makes use of an extendable class library of models and filters for data representation and selection. The Geant4 Visualization System supports a rich set of interactive commands based on the Geant4 command system. It is included in the Geant4 code distribution and maintained and documented like other components of Geant4.

  8. Geant4 in Scientific Literature

    CERN Document Server

    Pia, M G; Bell, Z W; Dressendorfer, P V

    2009-01-01

    The Geant4 reference paper published in Nuclear Instruments and Methods A in 2003 has become the most cited publication in the whole Nuclear Science and Technology category of Thomson-Reuter's Journal Citation Reports. It is currently the second most cited article among the publications authored by two major research institutes, CERN and INFN. An overview of Geant4 presence (and absence) in scholarly literature is presented; the patterns of Geant4 citations are quantitatively examined and discussed.

  9. Geant4 Applications in Space

    Energy Technology Data Exchange (ETDEWEB)

    Asai, M.; /SLAC

    2007-11-07

    Use of Geant4 is rapidly expanding in space application domain. I try to overview three major application areas of Geant4 in space, which are apparatus simulation for pre-launch design and post-launch analysis, planetary scale simulation for radiation spectra and surface and sub-surface explorations, and micro-dosimetry simulation for single event study and radiation-hardening of semiconductor devices. Recently, not only the mission dependent applications but also various multi-purpose or common tools built on top of Geant4 are also widely available. I overview some of such tools as well. The Geant4 Collaboration identifies that the space applications are now one of the major driving forces of the further developments and refinements of Geant4 toolkit. Highlights of such developments are introduced.

  10. Dental magnetic resonance imaging; MRT der Zaehne und des Zahnhalteapparats

    Energy Technology Data Exchange (ETDEWEB)

    Hilgenfeld, Tim; Bendszus, Martin; Haehnel, Stefan [Universitaetsklinikum Heidelberg (Germany). Abt. fuer Neuroradiologie

    2016-03-15

    Growing distribution and utilization of digital volume tomography (DVT) extend the spectrum of clinical dental imaging. Additional diagnostic value, however, comes along with an increasing amount of radiation. In contrast, magnetic resonance imaging is a radiation free imaging technique. Furthermore, it offers a high soft tissue contrast. Morphological and numerical dental anomalies, differentiation of periapical lesions and exclusion of complications of dental diseases are field of applications for dental MRI. In addition, detection of caries and periodontal lesions and injury of inferior alveolar nerve are promising application areas in the future.

  11. A Customizable GeantV Calorimeter Application

    CERN Document Server

    Schmitz, Ryan; Vallecorsa, Sofia; Novak, Mihaly; CERN. Geneva. EP Department

    2017-01-01

    A customizable calorimeter application was written in GeantV. This application includes a GeantV-native detector construction file as well as GeantV-native physics models and new data collection structures. Including these features makes this one of the first examples of a completely standalone GeantV application. A comparison to Geant4 was made which showed the consistency of the GeantV-native physics models included in this example. Finally, the workflow improvements made by the creation of this application are described.

  12. Functional magnetic resonance imaging in the activation of working memory; Funktionelle Magnetresonanztomographie bei Aktivierung des Arbeitsgedaechtnisses

    Energy Technology Data Exchange (ETDEWEB)

    Spitzer, M. [Sektion Experimentelle Psychopathologie, Psychiatrische Universitaetsklinik, Heidelberg (Germany); Kammer, T. [Sektion Experimentelle Psychopathologie, Psychiatrische Universitaetsklinik, Heidelberg (Germany); Bellemann, M.E. [Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg (Germany); Gueckel, F. [Inst. fuer Klinische Radiologie, Klinische Fakultaet 2, Univ. Heidelberg, Klinikum Mannheim (Germany); Georgi, M. [Inst. fuer Klinische Radiologie, Klinische Fakultaet 2, Univ. Heidelberg, Klinikum Mannheim (Germany); Gass, A. [Neurologische Klinik, Klinische Fakultaet 2, Univ. Heidelberg, Klinikum Mannheim (Germany); Brix, G. [Forschungsschwerpunkt Radiologische Diagnostik und Therapie, Deutsches Krebsforschungszentrum, Heidelberg (Germany)

    1996-07-01

    Functional magnetic resonance imaging was used in conjunction with a letter detection task for the study of working memory in 16 normal subjects. Because of movement artifacts, data from only 9 subjects were analysed. In the activation taks, subjects responded by pressing a button whenever any presented letter was the same as the second last in the sequence. In the control condition, the subjects had to respond to a fixed letter. Hence, the activation condition and the control condition differend only subjectively, i.e., regarding the task demand, whereas the stimuli and the type and frequency of response were identical. The activation condition produced significant activation in the dorsolateral prefrontal cortex (Brodmann`s areas 10, 46, and 9). In contrast to experimental tasks previsouly used rather extensively to study the prefrontal cortex, the present paradigm is characterized by its simplicity, interpretability, and its ties to known neurophysiology of the frontal cortex. (orig.) [Deutsch] Unter Verwendung eines Buchstabenerkennungsparadigmas wurde die Funktion des Arbeitsgedaechtnisses mittels funktioneller Magnetresonanztomographie an 16 gesunden Probanden untersucht, von denen 9 ausgewertet werden konnten. Aktivierungsbedingung (Reaktion auf jeden Buchstaben, der identisch ist mit dem jeweils vorletzten Buchstaben) und Kontrollbedingung (Reaktion auf einen bestimmten vorselektierten Buchstaben) unterschieden sich lediglich durch unterschiedliche Instruktionen. Die beiden Bedingungen waren damit subjektiv verschieden, jedoch durch physikalisch identische Reize sowie eine identische Reaktion (Erkennen des zu diskriminierenden Zielreizes und Knopfdruck) charakterisiert. Unter der das Arbeitsgedaechtnis beanspruchenden Aktivierungsbedingung wurde eine umschriebene signifikante Vermehrung der Aktivtaet im dorsolateralen praefrontalen Kortex (Brodmannsche Areale 10, 46 und 9) beobachtet. Im Gegensatz zu anderen experimentellen Paradigmen, die zu funktionellen

  13. Recent developments in GEANT4

    Science.gov (United States)

    Allison, J.; Amako, K.; Apostolakis, J.; Arce, P.; Asai, M.; Aso, T.; Bagli, E.; Bagulya, A.; Banerjee, S.; Barrand, G.; Beck, B. R.; Bogdanov, A. G.; Brandt, D.; Brown, J. M. C.; Burkhardt, H.; Canal, Ph.; Cano-Ott, D.; Chauvie, S.; Cho, K.; Cirrone, G. A. P.; Cooperman, G.; Cortés-Giraldo, M. A.; Cosmo, G.; Cuttone, G.; Depaola, G.; Desorgher, L.; Dong, X.; Dotti, A.; Elvira, V. D.; Folger, G.; Francis, Z.; Galoyan, A.; Garnier, L.; Gayer, M.; Genser, K. L.; Grichine, V. M.; Guatelli, S.; Guèye, P.; Gumplinger, P.; Howard, A. S.; Hřivnáčová, I.; Hwang, S.; Incerti, S.; Ivanchenko, A.; Ivanchenko, V. N.; Jones, F. W.; Jun, S. Y.; Kaitaniemi, P.; Karakatsanis, N.; Karamitrosi, M.; Kelsey, M.; Kimura, A.; Koi, T.; Kurashige, H.; Lechner, A.; Lee, S. B.; Longo, F.; Maire, M.; Mancusi, D.; Mantero, A.; Mendoza, E.; Morgan, B.; Murakami, K.; Nikitina, T.; Pandola, L.; Paprocki, P.; Perl, J.; Petrović, I.; Pia, M. G.; Pokorski, W.; Quesada, J. M.; Raine, M.; Reis, M. A.; Ribon, A.; Ristić Fira, A.; Romano, F.; Russo, G.; Santin, G.; Sasaki, T.; Sawkey, D.; Shin, J. I.; Strakovsky, I. I.; Taborda, A.; Tanaka, S.; Tomé, B.; Toshito, T.; Tran, H. N.; Truscott, P. R.; Urban, L.; Uzhinsky, V.; Verbeke, J. M.; Verderi, M.; Wendt, B. L.; Wenzel, H.; Wright, D. H.; Wright, D. M.; Yamashita, T.; Yarba, J.; Yoshida, H.

    2016-11-01

    GEANT4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made to the toolkit in order to accommodate the needs of these user communities, and to efficiently exploit the growth of computing power made available by advances in technology. The adaptation of GEANT4 to multithreading, advances in physics, detector modeling and visualization, extensions to the toolkit, including biasing and reverse Monte Carlo, and tools for physics and release validation are discussed here.

  14. Nuclear spectroscopy with Geant4

    Directory of Open Access Journals (Sweden)

    Sarmiento Luis G.

    2016-01-01

    Full Text Available The simulation toolkit Geant4 was originally developed at CERN for high-energy physics. Over the years it has been established as a swiss army knife not only in particle physics but it has seen an accelerated expansion towards nuclear physics and more recently to medical imaging and γ- and ion- therapy to mention but a handful of new applications. The validity of Geant4 is vast and large across many particles, ions, materials, and physical processes with typically various different models to choose from. Unfortunately, atomic nuclei with atomic number Z > 100 are not properly supported. This is likely due to the rather novelty of the field, its comparably small user base, and scarce evaluated experimental data. To circumvent this situation different workarounds have been used over the years. In this work the simulation toolkit Geant4 will be introduced with its different components and the effort to bring the software to the heavy and superheavy region will be described.

  15. Introduction to the Geant4 Simulation toolkit

    Science.gov (United States)

    Guatelli, S.; Cutajar, D.; Oborn, B.; Rosenfeld, A. B.

    2011-05-01

    Geant4 is a Monte Carlo simulation Toolkit, describing the interactions of particles with matter. Geant4 is widely used in radiation physics research, from High Energy Physics, to medical physics and space science, thanks to its sophisticated physics component, coupled with advanced functionality in geometry description. Geant4 is widely used at the Centre for Medical Radiation Physics (CMRP), at the University of Wollongong, to characterise and optimise novel detector concepts, radiotherapy treatments, and imaging solutions. This lecture consists of an introduction to Monte Carlo method, and to Geant4. Particular attention will be devoted to the Geant4 physics component, and to the physics models describing electromagnetic and hadronic physics interactions. The second part of the lecture will be focused on the methodology to adopt to develop a Geant4 simulation application.

  16. Computed tomography and magnetic resonance imaging of congenital abnormalities of the temporal bone; Computertomographie und Magnetresonanztomographie kongenitaler Veraenderungen des aeusseren Ohrs, Mittel- und Innenohrs sowie des inneren Gehoergangs

    Energy Technology Data Exchange (ETDEWEB)

    Czerny, C.; Imhof, H. [Abteilung fuer Osteologie, Univ.-Klinik fuer Radiodiagnostik, Wien (Austria); Gstoettner, W. [Univ.-Klinik fuer Hals-Nasen-Ohren-Heilkunde, Frankfurt/Main (Germany)

    2003-03-01

    Congenital abnormalities of the temporal bone are mostly accompanied by conductive or sensori-neural hearing loss. Before any therapeutic procedures are done high resolution CT (HRCT) and magnetic resonance imaging (MRI) should be performed to establish the correct diagnosis and to plan the potentially surgical intervention. HRCT best depicts osseous changes especially those of the external auditory canal and the middle ear containing the ossicles and the osseous structures of the temporal bone and the petrous bone containing the inner ear. MRI excellently shows soft tissue changes of the inner ear especially on the high resolution 3DT2-weighted sequences which give a superb contrast between the nerves and the cerebro-spinal fluid. Malformations of the external auditory canal consists of aplasia or hypoplasia and those of the middle ear range form extreme hypoplasia or aplasia to very mild deformations of the ossicles. Malformations of the inner ear also range form complete aplasia to very mild hypoplasia of the organs of the inner ear as well as malformations concerning the nerves in the internal auditory canal range from aplasia to hypoplasia. Malformations of the temporal bone can either occur isolated or in combination in which malformations of the external and middle ear may be accompanied by those of the inner ear. Furthermore, malformations of the temporal bone may also occur in otofacial, otocervical or otoskeletal syndromes. These syndromes may be accompanied by certain malformations of the temporal bone. HRCT and MRI are both excellent methods to depict congenital abnormalities of the temporal bone and of the inner ear and should be used as complementary methods because HRCT best depicts osseous changes and MRI superbly depicts soft tissue changes. Both methods are important to establish the correct diagnosis to plan the therapeutic procedures. (orig.) [German] Angeborene Missbildungen des Schlaefenbeins sind oft mit Schwerhoerigkeit bis Taubheit

  17. Diffusion-weighted magnetic resonance imaging of the abdomen; Diffusionsgewichtete Magnetresonanztomographie des Abdomens

    Energy Technology Data Exchange (ETDEWEB)

    Schmid-Tannwald, C.; Reiser, M.F.; Zech, C.J. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany)

    2011-03-15

    Diffusion-weighted magnetic resonance imaging (DW-MRI) provides qualitative and quantitative information of tissue cellularity and the integrity of cellular membranes. Since DW-MRI can be performed without ionizing radiation exposure and contrast media application, DW-MRI is a particularly attractive tool for patients with allergies for gadolinium-based contrast agents or renal failure. Recent technical developments have made DW-MRI a robust and feasible technique for abdominal imaging. DW-MRI provides information on the detection and characterization of focal liver lesions and can also visualize treatment effects and early changes in chronic liver disease. In addition DW-MRI is a promising tool for the detection of inflammatory changes in patients with Crohn's disease. (orig.) [German] Die diffusionsgewichtete (DW-)MRT ermoeglicht die Erfassung qualitativer und quantitativer Informationen bzgl. der Gewebezellularitaet und Membranintegritaet. Die DW-MRT ist insbesondere bei Patienten mit einer Allergie gegen gadoliniumhaltige Kontrastmittel oder eingeschraenkter Nierenfunktion attraktiv, da ihr Einsatz nicht mit Strahlenexposition oder Kontrastmittelgabe verbunden ist. Durch technische Weiterentwicklungen ist die robuste Anwendung der DW-MRI in der Bildgebung des Abdomens seit einiger Zeit moeglich geworden. In der Leberdiagnostik lassen sich Zusatzinformationen zur Detektion und Charakterisierung von Leberlaesionen gewinnen, aber auch Therapieerfolge dokumentieren und fruehe chronische Leberveraenderungen visualisieren. Neben ihrer Rolle bei hepatologischen und onkologischen Fragestellungen erscheint der Einsatz der DW-MRT zudem bei entzuendlichen Fragestellungen wie dem Morbus Crohn sehr viel versprechend. (orig.)

  18. Validity of the electrical model representation of the effects of nuclear magnetic resonance (1961); Validite de la representation par modele electrique des effets de resonance magnetique nucleaire (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1961-07-01

    When studying the behaviour of a magnetic resonance transducer formed by the association of an electrical network and of a set of nuclear spins, it is possible to bring about a representation that is analytically equivalent by means of an entirely electrical model, available for transients as well as steady-state. A detailed study of the validity conditions justifies its use in most cases. Also proposed is a linearity criterion of Bloch's equations in transient state that is simply the prolongation of the well-known condition of non-saturation in the steady-state. (author) [French] L'etude du comportement d'un transducteur a resonance magnetique forme de l'association d'un reseau electrique et d'un ensemble de noyaux dotes de spin, montre qu'il est possible d'en deduire une representation analytiquement equivalente au moyen d'un modele entierement electrique utilisable pour un regime transitoire aussi bien que pour un regime permanent. Une etude detaillee des conditions de validite permet d'en justifier l'emploi dans la majorite des cas. On propose enfin un critere de linearite des equations de Bloch en regime transitoire, qui constitue un prolongement de la condition connue de non-saturation en regime stationnaire. (auteur)

  19. Experiences on Grid Production for GEANT4

    CERN Document Server

    Lamanna, M; Méndez-Lorenzo, P; Moscicki, J; Ribon, A

    2007-01-01

    Geant4 is a worldwide collaboration of scientists and software engineers whose goal is to develop, maintain and provide support for the Geant4 package, representing a general purpose Monte Carlo toolkit for simulating the propagation of particles through matter. Geant4 is currently employed in a row of particle physics experiments (BaBar, HARP, ATLAS, CMS, LHCb), and is also applied in other areas like space science, medical applications, and radiation studies. Due to the complexity of the Geant4 code and to the broad spectrum of possible configurations - involving a variety of physical processes for different source particles, particle energies and target or shielding materials - an intensive testing of new release candidates is mandatory to thoroughly test each of its components, especially before major releases, generally twice a year. Regression tests are required to be performed by the Geant4 team within a short period of time (2 to 3 weeks), basically demanding vast computational resources (equivalent t...

  20. Geant4 for the atlas electromagnetic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Kordas, K.; Parrour, G. [Laboratoire de l' Accelerateur Lineaire, 91 - Orsay (France); Simion, St. [Columbia Univ., New York, NY (United States). Nevis Labs

    2001-04-01

    We have recently employed the Geant4 tool-kit for the simulation of the barrel part of the ATLAS electromagnetic calorimeter. The two approaches used for the description of this geometry are presented and compared. Subsequently, we test the new simulation tool against the predictions of Geant3, the previous generation of the Geant simulation. We do so for muons. With the caveat of some differences in the detector geometry implementations in Geant4 and Geant3, we also show some extremely preliminary results for electrons. A comparison between the two geometry models has shown that there are very small differences, which are under study, but in general the tailored geometry approach is proven sound. We also investigated a way to reduce significantly the memory usage of the straight-forward 'static' geometry description. Comparing Geant4 against Geant3, we find that the mean energy depositions for 50 and 100 GeV muons are in agreement between the two simulations, but the two yield significantly different distributions. Preliminary results on electrons are encouraging and we plan to study these particles next, including comparisons with test beam data. (authors)

  1. Geant4 application in a Web browser

    Science.gov (United States)

    Garnier, Laurent; Geant4 Collaboration

    2014-06-01

    Geant4 is a toolkit for the simulation of the passage of particles through matter. The Geant4 visualization system supports many drivers including OpenGL[1], OpenInventor, HepRep[2], DAWN[3], VRML, RayTracer, gMocren[4] and ASCIITree, with diverse and complementary functionalities. Web applications have an increasing role in our work, and thanks to emerging frameworks such as Wt [5], building a web application on top of a C++ application without rewriting all the code can be done. Because the Geant4 toolkit's visualization and user interface modules are well decoupled from the rest of Geant4, it is straightforward to adapt these modules to render in a web application instead of a computer's native window manager. The API of the Wt framework closely matches that of Qt [6], our experience in building Qt driver will benefit for Wt driver. Porting a Geant4 application to a web application is easy, and with minimal effort, Geant4 users can replicate this process to share their own Geant4 applications in a web browser.

  2. Visualization drivers for Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Beretvas, Andy; /Fermilab

    2005-10-01

    This document is on Geant4 visualization tools (drivers), evaluating pros and cons of each option, including recommendations on which tools to support at Fermilab for different applications. Four visualization drivers are evaluated. They are OpenGL, HepRep, DAWN and VRML. They all have good features, OpenGL provides graphic output without an intermediate file. HepRep provides menus to assist the user. DAWN provides high quality plots and even for large files produces output quickly. VRML uses the smallest disk space for intermediate files. Large experiments at Fermilab will want to write their own display. They should proceed to make this display graphics independent. Medium experiment will probably want to use HepRep because of it's menu support. Smaller scale experiments will want to use OpenGL in the spirit of having immediate response, good quality output and keeping things simple.

  3. Geant4 - A Simulation Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Dennis H

    2002-08-09

    GEANT4 is a toolkit for simulating the passage of particles through matter. it includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. it has been designed and constructed to expose the physics models utilized, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.

  4. GEANT4 A Simulation toolkit

    CERN Document Server

    Agostinelli, S; Amako, K; Apostolakis, John; Araújo, H M; Arce, P; Asai, M; Axen, D A; Banerjee, S; Barrand, G; Behner, F; Bellagamba, L; Boudreau, J; Broglia, L; Brunengo, A; Chauvie, S; Chuma, J; Chytracek, R; Cooperman, G; Cosmo, G; Degtyarenko, P V; Dell'Acqua, A; De Paola, G O; Dietrich, D D; Enami, R; Feliciello, A; Ferguson, C; Fesefeldt, H S; Folger, G; Foppiano, F; Forti, A C; Garelli, S; Giani, S; Giannitrapani, R; Gibin, D; Gómez-Cadenas, J J; González, I; Gracía-Abríl, G; Greeniaus, L G; Greiner, W; Grichine, V M; Grossheim, A; Gumplinger, P; Hamatsu, R; Hashimoto, K; Hasui, H; Heikkinen, A M; Howard, A; Hutton, A M; Ivanchenko, V N; Johnson, A; Jones, F W; Kallenbach, Jeff; Kanaya, N; Kawabata, M; Kawabata, Y; Kawaguti, M; Kelner, S; Kent, P; Kodama, T; Kokoulin, R P; Kossov, M; Kurashige, H; Lamanna, E; Lampen, T; Lara, V; Lefébure, V; Lei, F; Liendl, M; Lockman, W; Longo, F; Magni, S; Maire, M; Mecking, B A; Medernach, E; Minamimoto, K; Mora de Freitas, P; Morita, Y; Murakami, K; Nagamatu, M; Nartallo, R; Nieminen, P; Nishimura, T; Ohtsubo, K; Okamura, M; O'Neale, S W; O'Ohata, Y; Perl, J; Pfeiffer, A; Pia, M G; Ranjard, F; Rybin, A; Sadilov, S; Di Salvo, E; Santin, G; Sasaki, T; Savvas, N; Sawada, Y; Scherer, S; Sei, S; Sirotenko, V I; Smith, D; Starkov, N; Stöcker, H; Sulkimo, J; Takahata, M; Tanaka, S; Chernyaev, E; Safai-Tehrani, F; Tropeano, M; Truscott, P R; Uno, H; Urbàn, L; Urban, P; Verderi, M; Walkden, A; Wander, W; Weber, H; Wellisch, J P; Wenaus, T; Williams, D C; Wright, D; Yamada, T; Yoshida, H; Zschiesche, D

    2003-01-01

    Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.

  5. GEANT4--a simulation toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Agostinelli, S.; Allison, J. E-mail: john.allison@man.ac.uk; Amako, K.; Apostolakis, J.; Araujo, H.; Arce, P.; Asai, M.; Axen, D.; Banerjee, S.; Barrand, G.; Behner, F.; Bellagamba, L.; Boudreau, J.; Broglia, L.; Brunengo, A.; Burkhardt, H.; Chauvie, S.; Chuma, J.; Chytracek, R.; Cooperman, G.; Cosmo, G.; Degtyarenko, P.; Dell' Acqua, A.; Depaola, G.; Dietrich, D.; Enami, R.; Feliciello, A.; Ferguson, C.; Fesefeldt, H.; Folger, G.; Foppiano, F.; Forti, A.; Garelli, S.; Giani, S.; Giannitrapani, R.; Gibin, D.; Gomez Cadenas, J.J.; Gonzalez, I.; Gracia Abril, G.; Greeniaus, G.; Greiner, W.; Grichine, V.; Grossheim, A.; Guatelli, S.; Gumplinger, P.; Hamatsu, R.; Hashimoto, K.; Hasui, H.; Heikkinen, A.; Howard, A.; Ivanchenko, V.; Johnson, A.; Jones, F.W.; Kallenbach, J.; Kanaya, N.; Kawabata, M.; Kawabata, Y.; Kawaguti, M.; Kelner, S.; Kent, P.; Kimura, A.; Kodama, T.; Kokoulin, R.; Kossov, M.; Kurashige, H.; Lamanna, E.; Lampen, T.; Lara, V.; Lefebure, V.; Lei, F.; Liendl, M.; Lockman, W.; Longo, F.; Magni, S.; Maire, M.; Medernach, E.; Minamimoto, K.; Mora de Freitas, P.; Morita, Y.; Murakami, K.; Nagamatu, M.; Nartallo, R.; Nieminen, P.; Nishimura, T.; Ohtsubo, K.; Okamura, M.; O' Neale, S.; Oohata, Y.; Paech, K.; Perl, J.; Pfeiffer, A.; Pia, M.G.; Ranjard, F.; Rybin, A.; Sadilov, S.; Di Salvo, E.; Santin, G.; Sasaki, T.; Savvas, N.; Sawada, Y.; Scherer, S.; Sei, S.; Sirotenko, V.; Smith, D.; Starkov, N.; Stoecker, H.; Sulkimo, J.; Takahata, M.; Tanaka, S.; Tcherniaev, E.; Safai Tehrani, E.; Tropeano, M.; Truscott, P.; Uno, H.; Urban, L.; Urban, P.; Verderi, M.; Walkden, A.; Wander, W.; Weber, H.; Wellisch, J.P.; Wenaus, T.; Williams, D.C.; Wright, D.; Yamada, T.; Yoshida, H.; Zschiesche, D

    2003-07-01

    GEANT4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.

  6. Automation on computer of the partial area method in the analysis of resonances induced by 'S' neutrons 2. with an interference term and extension of the method to the treatment of multi resonances (1963); Automatisation sur ordinateur de la methode des aires partielles dans l'analyse des resonances induites par les neutrons ''S''. 2, avec terme d'interference et extension de la methode au traitement des multiresonances (1963)

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, G.; Corge, C.R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    This report deals with the numerical analysis on an I.B.M. 7090 computer of transmission resonances induced by 's' wave neutrons in time of flight experiments. The analysis method used is the partial area one. In this second part the interference term is taken into account. Modifications have been made in the programs and subroutines described in the first part, to determine the resonant transmissions from experimental raw data, and the relating partial areas. Also programs and subroutines are thoroughly described, which estimate the resonance parameters. The field of the partial area method has been extended to cover the case where several resonances have to be treated simultaneously, provided they do not interfere. (authors) [French] Le pretent rapport a pour objet l'analyse numerique sur ordinateur I.B.M. 7090 des resonances dues aux neutrons ''s'' dans les experiences de transmission par temps de vol, la methode d'analyse utilisee etant la methode dea aires partielles. Dans cette deuxieme partie il a ete tenu compte du terme d'interference. On y trouvera une description des amenagements apportes aux programmes et sous-programmes decrits dans la premiere partie pour determiner les transmissions interfero-resonnantes a partir des donnees experimentales brutes et les aires partielles afferentes. Sont egalement decrits les programmes et sous-programmes necessaires au calcul des parametres caracteristiques des resonances. Le domaine d'application de la methode a ete etendu au traitement simultane de plusieurs resonances groupees n'interferant pas entre elles. (auteurs)

  7. Validation of Hadronic Models in GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Koi, Tatsumi; Wright, Dennis H.; /SLAC; Folger, Gunter; Ivanchenko, Vladimir; Kossov, Mikhail; Starkov, Nikolai; /CERN; Heikkinen, Aatos; /Helsinki Inst. of Phys.; Truscott,; Lei, Fan; /QinetiQ; Wellisch, Hans-Peter

    2007-09-26

    Geant4 is a software toolkit for the simulation of the passage of particles through matter. It has abundant hadronic models from thermal neutron interactions to ultra relativistic hadrons. An overview of validations in Geant4 hadronic physics is presented based on thin target measurements. In most cases, good agreement is available between Monte Carlo prediction and experimental data; however, several problems have been detected which require some improvement in the models.

  8. Validation of hadronic models in GEANT4

    CERN Document Server

    Koi, Tatsumi; Folger, Günter; Ivanchenko, Vladimir; Kossov, Mikhail; Starkov, Nikolai; Heikkinen, Aatos; Truscott, Pete; Lei, Fan; Wellisch, Hans-Peter

    2007-01-01

    Geant4 is a software toolkit for the simulation of the passage of particles through matter. It has abundant hadronic models from thermal neutron interactions to ultra relativistic hadrons. An overview of validations in Geant4 hadronic physics is presented based on thin-target measurements. In most cases, good agreement is available between Monte Carlo prediction and experimental data; however, several problems have been detected which require some improvement in the models.

  9. GEANT4-MT : bringing multi-threading into GEANT4 production

    Science.gov (United States)

    Ahn, Sunil; Apostolakis, John; Asai, Makoto; Brandt, Daniel; Cooperman, Gene; Cosmo, Gabriele; Dotti, Andrea; Dong, Xin; Jun, Soon Yung; Nowak, Andrzej

    2014-06-01

    GEANT4-MT is the multi-threaded version of the GEANT4 particle transport code.(1, 2) The key goals for the design of GEANT4-MT have been a) the need to reduce the memory footprint of the multi-threaded application compared to the use of separate jobs and processes; b) to create an easy migration of the existing applications; and c) to use efficiently many threads or cores, by scaling up to tens and potentially hundreds of workers. The first public release of a GEANT4-MT prototype was made in 2011. We report on the revision of GEANT4-MT for inclusion in the production-level release scheduled for end of 2013. This has involved significant re-engineering of the prototype in order to incorporate it into the main GEANT4 development line, and the porting of GEANT4-MT threading code to additional platforms. In order to make the porting of applications as simple as possible, refinements addressed the needs of standalone applications. Further adaptations were created to improve the fit with the frameworks of High Energy Physics (HEP) experiments. We report on performances measurements on Intel Xeon™, AMD Opteron™ the first trials of GEANT4-MT on the Intel Many Integrated Cores (MIC) architecture, in the form of the Xeon Phi™ co-processor.(3) These indicate near-linear scaling through about 200 threads on 60 cores, when holding fixed the number of events per thread.

  10. GeantV: from CPU to accelerators

    Science.gov (United States)

    Amadio, G.; Ananya, A.; Apostolakis, J.; Arora, A.; Bandieramonte, M.; Bhattacharyya, A.; Bianchini, C.; Brun, R.; Canal, P.; Carminati, F.; Duhem, L.; Elvira, D.; Gheata, A.; Gheata, M.; Goulas, I.; Iope, R.; Jun, S.; Lima, G.; Mohanty, A.; Nikitina, T.; Novak, M.; Pokorski, W.; Ribon, A.; Sehgal, R.; Shadura, O.; Vallecorsa, S.; Wenzel, S.; Zhang, Y.

    2016-10-01

    The GeantV project aims to research and develop the next-generation simulation software describing the passage of particles through matter. While the modern CPU architectures are being targeted first, resources such as GPGPU, Intel© Xeon Phi, Atom or ARM cannot be ignored anymore by HEP CPU-bound applications. The proof of concept GeantV prototype has been mainly engineered for CPU's having vector units but we have foreseen from early stages a bridge to arbitrary accelerators. A software layer consisting of architecture/technology specific backends supports currently this concept. This approach allows to abstract out the basic types such as scalar/vector but also to formalize generic computation kernels using transparently library or device specific constructs based on Vc, CUDA, Cilk+ or Intel intrinsics. While the main goal of this approach is portable performance, as a bonus, it comes with the insulation of the core application and algorithms from the technology layer. This allows our application to be long term maintainable and versatile to changes at the backend side. The paper presents the first results of basket-based GeantV geometry navigation on the Intel© Xeon Phi KNC architecture. We present the scalability and vectorization study, conducted using Intel performance tools, as well as our preliminary conclusions on the use of accelerators for GeantV transport. We also describe the current work and preliminary results for using the GeantV transport kernel on GPUs.

  11. Magnetic resonance imaging in the diagnosis of benign and malignant pelvic tumors; Magnetresonanztomographie benigner und maligner Tumoren des weiblichen Beckens

    Energy Technology Data Exchange (ETDEWEB)

    Hauth, E.A.M.; Stattaus, J.; Debatin, J.F.; Ruehm, S.G. [Universitaetsklinikum Essen (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie

    2004-06-01

    Magnetic resonance imaging (MRI) is an accepted imaging method for diagnosing diseases of the female pelvis. This review article describes the role of MR imaging for the diagnosis of benign and malignant pelvic tumors. Sagittal T2-weighted fast spin echo sequences can be effectively applied to diagnose leiomyomas of the uterus and provide exact pretreatment measurements of size and localization. In the diagnostic work-up endometrial carcinoma, fat-saturated, T1-weighted gradient echo sequences make it possible to determine precisely how deep myometrial infiltration extends and what tissue should be included in preoperative treatment planning. In cervical cancer staging, MRI permits both assessment of local tumor extent and determination of tumor volume for planning and monitoring radiotherapy. The usefulness of MRI in cervical cancer staging is, however, limited since not all early-stage cancer (FIGO stage I A and small stage I B tumors) can be detected. Hence, it appears that the use of MRI as a screening method for cervical cancer cannot be recommended. MRI can distinguish between benign and malignant ovarian tumors with high sensitivity and specificity. Standard and fat-saturated T1-weighted sequences usually can diagnose teratomas with a specificity of 100%. Axial fat-saturated, contrast enhanced T1-weighted spin echo sequences are useful in the staging of malignant ovarian tumors since they facilitate evaluation of their internal structure and will disclose peritoneal metastases. Besides staging of ovarian cancer, MRI can be applied for localization and for monitoring treatment response. (orig.) [German] Die Magnetresonanztomographie (MRT) gilt als etabliertes Verfahren in der bildgebenden Diagnostik von Pathologien des weiblichen Beckens. Die vorliegende Uebersichtsarbeit beschreibt die Rolle der MRT in der Diagnostik benigner und maligner Tumoren unter Verwendung geeigneter Untersuchungstechniken. Sagittale T2-gewichtete FSE-Sequenzen sind zur Diagnostik von

  12. Contribution to the study of molecular movements in cyclohexane by electron spin resonance and electron-nuclear double resonance using a radical probe; Contribution a l'etude des mouvements moleculaires dans le cyclohexane par resonance paramagnetique electronique et double resonance electronique-nucleaire a l'aide d'une sonde radicalaire

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    Solutions of stable free radicals of the nitroxide type have been studied as a function of temperature. In the plastic or globular state, the cyclohexane molecules have rapid rotational and diffusional movements. They transmit this movement to dissolved free radicals. Conversely, measurements by electron spin resonance of the absolute movement of the radicals, and by electron nuclear double resonance of their movement relative to the cyclohexane molecules give very precise methods for local analyses of the movement present in the cyclohexane matrix. The principle of these techniques makes up the 'radical probe method'. (author) [French] Des solutions de radicaux libres stables, du type nitroxyde dans le cyclohexane ont ete etudiees, en fonction de la temperature. Les molecules de cyclohexane, dans l'etat plastique ou globulaire, sont animees de mouvements rapides de rotation sur elles-memes et de diffusion. Elles transmettent leur mobilite aux radicaux libres dissous. Reciproquement, la mesure du mouvement absolu des radicaux, a l'aide de la resonance paramagnetique electronique, et celle du mouvement relatif des radicaux et des molecules de cyclohexane par double resonance electronique-nucleaire, constituent des methodes tres precises pour analyser localement les mouvements presents dans la matrice de cyclohexane. Ce principe et ces techniques constituent la 'methode de la sonde radicalaire'. (auteur)

  13. Experiences on Grid production for Geant4

    CERN Document Server

    Ribon, Alberto

    2006-01-01

    Geant4 is a general purpose toolkit for simulating the tracking and interaction of particles through matter. It is currently used in production in several particle physics experiments (BaBar, HARP, ATLAS, CMS, LHCb), and it has also applications in other areas, as space science, medical applications, and radiation studies. The complexity of the Geant4 code requires careful testing of all of its components, especially before major releases (which happens twice a year, in June and December). In this talk, I will describe the recent development of an automatic suite for testing hadronic physics in high energy calorimetry applications. The idea is to use a simplified set of hadronic calorimeters, with different beam particle types, and various beam energies, and comparing relevant observables between a given reference version of Geant4 and the new candidate one. Only those distributions that are statistically incompatible are then printed out and finally inspected by a person to look for possible bugs. The suite ...

  14. A CAD Interface for GEANT4

    CERN Document Server

    Poole, Christopher M; Trapp, Jamie V; Langton, Christian M

    2011-01-01

    Typically used as a tool for Monte Carlo simulation of high energy physics experiments, GEANT4 is increasingly being employed for the simulation of complex radiotherapy treatments. Often the specification of components within a clinical linear accelerator treatment head is provided in a CAD file format. Direct import of these CAD files into GEANT4 may not be possible, and complex components such as individual leaves within a multi-leaf collimator may be difficult to define via other means. Solutions that allow for users to work around the limited support in the GEANT4 toolkit for loading predefined CAD geometries has been presented by others, however these solutions require intermediate file format conversion using commercial software. Here within we describe a technique that allows for CAD models to be directly loaded as geometry without the need for commercial software and intermediate file format conversion. Robustness of the interface was tested using a set of CAD models of various complexity; for the mod...

  15. Geant4 VMC 3.0

    Science.gov (United States)

    Hřivnáčová, I.; Gheata, A.

    2015-12-01

    Virtual Monte Carlo (VMC) [1] provides an abstract interface into Monte Carlo transport codes. A user VMC based application, independent from the specific Monte Carlo codes, can be then run with any of the supported simulation programs. Developed by the ALICE Offline Project and further included in ROOT [2], the interface and implementations have reached stability during the last decade and have become a foundation for other detector simulation frameworks, the FAIR facility experiments framework being among the first and largest. Geant4 VMC [3], which provides the implementation of the VMC interface for Geant4 [4], is in continuous maintenance and development, driven by the evolution of Geant4 on one side and requirements from users on the other side. Besides the implementation of the VMC interface, Geant4 VMC also provides a set of examples that demonstrate the use of VMC to new users and also serve for testing purposes. Since major release 2.0, it includes the G4Root navigator package, which implements an interface that allows one to run a Geant4 simulation using a ROOT geometry. The release of Geant4 version 10.00 with the integration of multithreading processing has triggered the development of the next major version of Geant4 VMC (version 3.0), which was released in November 2014. A beta version, available for user testing since March, has helped its consolidation and improvement. We will review the new capabilities introduced in this major version, in particular the integration of multithreading into the VMC design, its impact on the Geant4 VMC and G4Root packages, and the introduction of a new package, MTRoot, providing utility functions for ROOT parallel output in independent files with necessary additions for thread-safety. Migration of user applications to multithreading that preserves the ease of use of VMC will be also discussed. We will also report on the introduction of a new CMake [5] based build system, the migration to ROOT major release 6 and the

  16. Foil Diffuser Investigation with GEANT4

    CERN Document Server

    Fabritius, Joseph M; Walstrom, Peter

    2013-01-01

    An investigation into the appropriate materials for use as a diffuser foil in electron radiography was undertaken in GEANT4. Simulations were run using various refractory materials to determine a material of appropriate Z number such that energy loss is minimal. The plotted results of angular spread and energy spread are shown. It is concluded that higher Z number materials such as tungsten, tantalum, platinum or uranium could be used as diffuser materials. Also, an investigation into the handling of bremsstrahlung, multiple coulomb scattering, and ionization in GEANT4 was performed.

  17. Magnetic resonance imaging of brain involvement in aids. Imagerie par resonance magnetique des atteintes encephaliques du SIDA

    Energy Technology Data Exchange (ETDEWEB)

    Cordoliani, Y.S.; Pharaboz, C.; Jeanbourquin, D.; Le Gall, R.; Derosier, C.; Cosnard, G. (Hopital des Armees du Val-de-Grace, 75 - Paris (FR))

    1991-01-01

    Magnetic resonance imaging is the most sensitive and the most specific technique for the study of the neurological complications of AIDS. The analysis of the images must be aimed at recognizing the specific lesions produced by the human immunodeficiency virus (HIV), in order to identify the opportunistic lesions, which are often multiple. For each major opportunistic disease, a number of arguments likely to guide the treatment can be pointed out.

  18. Comparison of GEANT4 Simulations with Testbeam Data and GEANT3 for the ATLAS Liquid Argon Calorimeter

    Institute of Scientific and Technical Information of China (English)

    D.Benchekroun; G.Karapetian; 等

    2001-01-01

    We present several comparisons of GEANT4 simulations with test beam data and GEANT3 simulations for different liquid argon(LAr) calorimeters of the ATLAS detector,All relevant parts of the test beam setup(scintilators,multi wire proportional chambers,cryostat etc.)are described in GEANT4 as well as in GEANT3.Muon and electron data at different energies have been compared with Monte Carlo prediction.

  19. A method for detector description exchange among ROOT GEANT4 and GEANT3

    Institute of Scientific and Technical Information of China (English)

    YOU Zheng-Yun; LIANG Yu-Tie; MAO Ya-Jun

    2008-01-01

    GEANT3 and GEANT4 are the detector simulation software programs that are widely used in most nuclear and particle physics experiments. ROOT is a program for framework, data analysis, online and offline software. Detector description is an important function in all these programs. Due to different detector construction methods and respective detector data representative, it is difficult to exchange the detector data among them. A new method based on GDML is developed to automatically convert the detector data among ROOT, GEANT4 and GEANT3. Any existing detector geometry in one program can be mapped to the geometry in the other two programs. In the software development of an experiment, different applications can share and reuse the same detector description. The application of this method in the PHENIX experiment upgrade and PHENIX Forward Vertex Silicon detector design is introduced.

  20. Beam Tools for Geant4 (User's Guide)

    CERN Document Server

    Daniel, E

    2002-01-01

    Geant4 is a tool kit developed by a collaboration of physicists and computer professionals in the high energy physics field for simulation of the passage of particles through matter. The motivation for the development of the Beam Tools is to extend the Geant4 applications to accelerator physics. The Beam Tools are a set of C++ classes designed to facilitate the simulation of accelerator elements: r.f. cavities, magnets, absorbers, etc. These elements are constructed from Geant4 solid volumes like boxes, tubes, trapezoids, or spheres. There are many computer programs for beam physics simulations, but Geant4 is ideal to model a beam through a material or to integrate a beam line with a complex detector. There are many such examples in the current international High Energy Physics programs. For instance, an essential part of the R and D associated with the Neutrino Source/Muon Collider accelerator is the ionization cooling channel, which is a section of the system aimed to reduce the size of the muon beam in pha...

  1. New networking solutions support GEANT2

    CERN Multimedia

    2006-01-01

    "Researchers across the globe are benefiting from new advanced networking solutions, deployed as part of the GEANT2. For the first time, scientists collaborating on the world's largest particle physics experiment, the Large Hadron Collider (LHC), now have access to point-to-point network connections between distributed research centres." (1 page)

  2. Geant4 VMC 3.0

    CERN Document Server

    Hřivnáčová, I

    2015-01-01

    Virtual Monte Carlo (VMC) [1] provides an abstract interface into Monte Carlo transport codes. A user VMC based application, independent from the specific Monte Carlo codes, can be then run with any of the supported simulation programs. Developed by the ALICE Offline Project and further included in ROOT [2], the interface and implementations have reached stability during the last decade and have become a foundation for other detector simulation frameworks, the FAIR facility experiments framework being among the first and largest.Geant4 VMC [3], which provides the implementation of the VMC interface for Geant4 [4], is in continuous maintenance and development, driven by the evolution of Geant4 on one side and requirements from users on the other side. Besides the implementation of the VMC interface, Geant4 VMC also provides a set of examples that demonstrate the use of VMC to new users and also serve for testing purposes. Since major release 2.0, it includes the G4Root navigator package, which implements an in...

  3. GEANT4, the physicists simulation toolkit

    CERN Multimedia

    Perricone, Mike

    2005-01-01

    One of the biggest projects ever mounted in science: the development of the proposed International Linear Collider; serving as combination instruction manual/toolkit/support network is GEANT4, a freely-available software ackage that simulates the passage of particles through scientific instruments (2 pages)

  4. Validation Test of Geant4 Simulation of Electron Backscattering

    CERN Document Server

    Kim, Sung Hun; Basaglia, Tullio; Han, Min Cheol; Hoff, Gabriela; Kim, Chan Hyeong; Saracco, Paolo

    2015-01-01

    Backscattering is a sensitive probe of the accuracy of electron scattering algorithms implemented in Monte Carlo codes. The capability of the Geant4 toolkit to describe realistically the fraction of electrons backscattered from a target volume is extensively and quantitatively evaluated in comparison with experimental data retrieved from the literature. The validation test covers the energy range between approximately 100 eV and 20 MeV, and concerns a wide set of target elements. Multiple and single electron scattering models implemented in Geant4, as well as preassembled selections of physics models distributed within Geant4, are analyzed with statistical methods. The evaluations concern Geant4 versions from 9.1 to 10.1. Significant evolutions are observed over the range of Geant4 versions, not always in the direction of better compatibility with experiment. Goodness-of-fit tests complemented by categorical analysis tests identify a configuration based on Geant4 Urban multiple scattering model in Geant4 vers...

  5. Magnetic resonance neurography. Imaging of peripheral nerves; MR-Neurografie. Bildgebung des peripheren Nervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Eppenberger, Patrick [Zurich Univ. (Switzerland). Inst. fuer Rechtsmedizin; Universitaetsspital Zuerich, Zurich (Switzerland). Inst. fuer Diagnostische und Interventionelle Radiologie; Chhabra, Avneesh [Johns Hopkins Univ., Baltimore, MD (United States). Diagnostische Radiologie, MSK Radiologie und Orthopedic Surgery; Johns Hopkins Univ., Baltimore, MD (United States). Russell H. Morgan Dept. of Radiology and Radiological Science; Andreisek, Gustav [Universitaetsspital Zuerich, Zurich (Switzerland). Inst. fuer Diagnostische und Interventionelle Radiologie

    2012-12-15

    Magnetic resonance neurography (MRN) is a non-invasive technique using magnetic resonance imaging (MRI) in order to diagnose peripheral nerve pathologies and their underlying etiologies. MRN is already in clinical use and is now mostly used to delineate the anatomy of nerves and to establish the continuity or discontinuity of nerves in patients with traumatic nerve injuries, as well as to monitor processes of peripheral nerve degeneration and regeneration. This article reviews established and evolving novel MRN technologies with regard to their potential to meet the requirements for non-invasive imaging of peripheral nerves in clinical settings. (orig.)

  6. Magnetic resonance imaging of the bowel. Today and tomorrow; Magnetresonanztomografie des Darms. Altbewaehrtes und Innovatives

    Energy Technology Data Exchange (ETDEWEB)

    Kinner, S.; Hahnemann, M.L.; Forsting, M.; Lauenstein, T.C. [Univ. Hospital Essen (Germany). Dept. of Diagnostic and Interventional Radiology and Neuroradiology

    2015-03-15

    Magnetic resonance imaging of the small bowel has been feasible for more than 15 years. This review is meant to give an overview of typical techniques, sequences and indications. Furthermore, newly evaluated promising techniques are presented, which have an impact on the advance of MR imaging of the small and large bowel.

  7. Magnetic resonance imaging and magnetic resonance arthography of the acetabular labrum: Comparison with surgical findings; Magnetresonanztomographie und Magnetresonanzarthrographie des Labrum acetabulare: Vergleich mit operativen Ergebnissen

    Energy Technology Data Exchange (ETDEWEB)

    Czerny, C. [Universitaetsklinik fuer Radiodiagnostik, Vienna (Austria). Abt. fuer Osteologie; Kramer, J. [Universitaetsklinik fuer Radiodiagnostik, Vienna (Austria). Abt. fuer Osteologie; Institut fuer bildgebende Diagnostik am Schillerpark, Linz (Austria); Neuhold, A. [Krankenhaus Rudolfinerhaus, Vienna (Austria). Inst. fuer bildgebende Diagnostik; Urban, M. [Krankenhaus Sozialmedizinisches Zentrum Ost, Vienna (Austria). Abt. fuer Radiodiagnostik; Tschauner, C. [Orthopaedisches Landeskrankenhaus Stolzalpe (Austria); Hofmann, S. [Krankenhaus Sozialmedizinisches Zentrum Ost, Vienna (Austria). Abt. fuer Radiodiagnostik; Orthopaedisches Landeskrankenhaus Stolzalpe (Austria)

    2001-08-01

    Aim of the study: To evaluate the accuracy of magnetic resonance imaging (MRI) and magnetic resonance (MR) arthrography in detecting acetabular labral lesions in correlation to surgical findings. Patients and methods: Forty patients (40 hips) with chronic hip pain and a strong clinical suspicion of labral lesions were examined with MRI in the coronal and axial plane by obtaining T{sub 1} weighted and proton density-weighted spin echo sequences. Additionally, MR arthrography of the high joint in the coronal oblique and sagittal oblique plane was performed by obtaining T{sub 1}-weighted three-dimensional gradient echo sequences after the intraarticular injection of gadopentate dimeglumine. The labra were prospectively evaluated on the basis of morphology, signal intensity, the presence or absence of a tear, and their attachment to the acetabulum. All patients underwent surgery, and the MRI findings and MR arthrography findings were compared with the surgical results. Results: Surgically, 34 labral lesions, and 6 normal labra were detected. MRI correctly depicted labral lesions in 24 patients and two normal labra, and MR arthrography correctly depicted labral lesions in 30 patients and 5 normal labra compared with the surgical results. The sensitivity of MRI was 80%, the accuracy of MRI was 65%, the sensitivity of MR arthrography was 95%, and the accuracy of MR arthgrography was 88%. Conclusions: MR arthrography enables considerably more accurate detection of acetabular labral lesions than MRI. MR arthrography should be the method of choice for the diagnosis of the presence or absence of acetabular labral lesions in patients with chronic hip pain and a strong clinical suspicion of labral lesions. (orig.) [German] Ziel: Die Bestimmung der Wertigkeit der konventionellen Magnetresonanztomographie (MRT) und der Magnetresonanzarthrographie (MR-Arthrographie) in der Abklaerung von Laesionen des Labrum acetabulare im Vergleich mit Operationsbefunden (Goldstandard). Methode

  8. GEANT4 Physics Lists for HEP

    CERN Document Server

    Apostolakis, J; Grichine, V; Howard, A; Ivanchenko, V; Kosov, M; Ribon, A; Uzhinsky, V; Wright, D H

    2009-01-01

    In GEANT4, a Physics List is a consistent set of. physics models that is able to cover all combinations of incident particle type, energy, and target material. Various Physics Lists are possible and useful, according to the specific application domains (e.g. high-energy physics, shielding, space-application, medical physics, etc.), and the best compromise between accuracy and CPU time that the user can accept. Users are allowed to write their own preferred Physics List, but several pre-defined ones are available in GEANT4 for convenience, and indeed they are used by the large majority of users. We present here the Physics Lists that are of interest for high-energy physics applications.

  9. GEANT simulation of the $\\gamma$ nuclear gauge

    CERN Document Server

    Ouardi, A; Benchekroun, D; Hoummada, A

    2003-01-01

    The gamma nuclear gauging technique used for monitoring the sediment load suspended in water, is based on the detection of gamma rays emitted by a radioactive source. The GEANT321 Monte Carlo simulation tool, originally developed at CERN for high energy physics experiments, is used for the evaluation and calibration of gamma nuclear gauges. A set of parameters, principally the source energy, the source-detector separation, the lead block thickness and the energy threshold below which the sediments elemental composition affects the measurement or the energy corresponding to the Compton and photoelectric windows separation, are discussed and evaluated in the case of the gamma scattering gauge. For the gamma transmission gauge, the GEANT321 code has been used to define the optimal source detector distance interval, particularly for the Moroccan sediment samplers, and to check the influence of the radionuclide existing in the suspension, on the gauge response accuracy. Experimental calibration was also carried ou...

  10. Detector Geometry Simulation Using GEANT4

    Directory of Open Access Journals (Sweden)

    Daisy Kalra

    2015-08-01

    Full Text Available Neutrino oscillation is an important phenomenon to explain the massive nature of neutrinos. This quantum mechanical phenomenon can be understood as mixing in quark sector just like the one we have in lepton sector. Observed deficit of solar neutrino flux is explained through neutrino oscillations and this study is the only way to investigate for small difference of neutrino masses thus gives signatures for the physics beyond Standard Model. Experimental results by Superkamiokande put a huge interest of experimentalists in neutrino field. In the present article after discussing the theoretical background of neutrinos and their status in standard model, latest important long baseline neutrino oscillations experiments as NOvA and LBNE has been discussed. Straw Tube Detector, an important part of LBNE-near detector, has been reviewed the geometry of which is studied through a software Geometry and Tracking (Geant4. Using Geant4, an important aspect of detector geometry and simulation has been studied.

  11. Polarised Geant4 - Applications at the ILC

    Energy Technology Data Exchange (ETDEWEB)

    Schaelicke, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Laihem, K. [RWTH Aachen (Germany). III. Physikalisches Inst. B; Starovoitov, P. [NCPHEP BSU, Minsk (Belarus)

    2007-11-15

    Geant4 is a Monte Carlo simulation framework for the description of interactions of particles and matter. Starting with version 8.2 a new package of QED physics processes is available, allowing for the studies of interactions of polarised particles with polarised media dedicated to beam applications. In this contribution some details about the implementation are presented and applications to the linear collider are discussed. (orig.)

  12. Polarised Geant4 - Applications at the ILC

    OpenAIRE

    Schälicke, Andreas; Laihem, Karim; Starovoitov, Pavel

    2007-01-01

    Geant4 is a Monte Carlo simulation framework for the description of interactions of particles and matter. Starting with version 8.2 a new package of QED physics processes is available, allowing for the studies of interactions of polarised particles with polarised media dedicated to beam applications. In this contribution some details about the implementation are presented and applications to the linear collider are discussed.

  13. Clinical applications of proton magnetic resonance spectroscopy of the brain; Klinische Anwendungen der Protonen-Magnetresonanzspektroskopie des Gehirns

    Energy Technology Data Exchange (ETDEWEB)

    Laubenberger, J.; Bayer, S.; Thiel, T.; Hennig, J.; Langer, M. [Radiologische Universitaetsklinik Freiburg (Germany). Abt. Roentgendiagnostik

    1998-06-01

    In spite of all the scientific advances of the past few years, proton magnetic resonance spectroscopy of the brain has not attained the status of a routine examination technique with clinically accepted indications. The method should be considered as an additional option to MR imaging for inherited and acquired encephalopathic changes as well as, in future, for localization diagnosis of epilepsies. A proton magnetic resonance spectroscopic investigation without a prior intensive clinical and imaging investigation is not useful. Above all, factors influencing metabolite distribution such as for example, serum osmolability must be known. Methodological prerequisites for the clinical application of proton resonance spectroscopy are, first of all, a high stability of the chosen technique as well as a sufficiently certain quantification of metabolites and the availability of a reference group. The use of short echo times is necessary for the quantification of glutamine and the osmolyte myo-inositol. Indications for individual cases in which clinical investigations and MR topography cannot provide sufficient certainty and spectroscopy can furnish additional information are, in addition to uses in neuropediatrics, the suspicion of Alzheimer`s dementia, HIV encephalopathy in early manifestations, and unclarified depressions of consciousness accompanying liver cirrhosis. (orig.) [Deutsch] Die Protonen-Magnetresonanzspektroskopie des Gehirns ist trotz aller wissenschaftlicher Fortschritte der letzten Jahre noch nicht zu einer Routineuntersuchung mit anerkannter klinischer Indikationsstellung geworden. Die Untersuchung muss bei angeborenen und erworbenen enzephalopathischen Veraenderungen sowie in Zukunft in der Lokalisationsdiagnostik von Epilepsien als Zusatzoption zur MR-Bildgebung erachtet werden. Eine protonenspektroskopische Untersuchung ohne ausgiebige klinische und bildgebende Basisuntersuchung ist nicht sinnvoll. Insbesondere muessen Einflussfaktoren, wie z

  14. Geant4 models for space radiation environment.

    Science.gov (United States)

    Ivantchenko, Anton; Nieminen, Petteri; Incerti, Sebastien; Santin, Giovanni; Ivantchenko, Vladimir; Grichine, Vladimir; Allison, John

    The space radiation environment includes wide varieties of particles from electrons to heavy ions. In order to correctly predict the dose received by astronauts and devices the simulation models must have good applicability and produce accurate results from 10 MeV/u up to 10 GeV/u, where the most radioactive hazardous particles are present in the spectra. Appropriate models should also provide a good description of electromagnetic interactions down to very low energies (10 eV/u - 10 MeV/u) for understanding the damage mechanisms due to long-term low doses. Predictions of biological dose during long interplanetary journeys also need models for hadronic interactions of energetic heavy ions extending higher energies (10 GeV/u - 100 GeV/u, but possibly up to 1 TeV/u). Geant4 is a powerful toolkit, which in some areas well surpasses the needs from space radiation studies, while in other areas is being developed and/or validated to properly cover the modelling requirements outlined above. Our activities in ESA projects deal with the research and development of both Geant4 hadronic and electromagnetic physics. Recently the scope of verification tests and benchmarks has been extended. Hadronic tests and benchmarks run proton, pion, and ion interactions with matter at various energies. In the Geant4 hadronic sub-libraries, the most accurate cross sections have been identified and selected as a default for all particle types relevant to space applications. Significant developments were carried out for ion/ion interaction models. These now allow one to perform Geant4 simulations for all particle types and energies relevant to space applications. For the validation of ion models the hadronic testing suite for ion interactions was significantly extended. In this work the results of benchmarking versus data in a wide energy range for projectile protons and ions will be shown and discussed. Here we show results of the tests runs and their precision. Recommendations for Geant4

  15. Geant4 - Current and Future : A Snowmass 2013 White Paper

    CERN Document Server

    Asai, Makoto

    2013-01-01

    The US involvement in Geant4 started with its adoption by the BaBar experiment at SLAC in 1997 and the subsequent creation of a group at SLAC supporting BaBar and contributing to Geant4 development. SLAC has provided the leadership of the international Geant4 Collaboration for the recent years and carries major responsibilities for evolutionary development of the existing code with work to implement multithreading and explore new application domains as well as new technologies such as GPUs. This paper presents the current and the future developments being carried by the SLAC Geant4 team.

  16. Allowing for crystalline structure effects in Geant4

    Science.gov (United States)

    Bagli, Enrico; Asai, Makoto; Dotti, Andrea; Pandola, Luciano; Verderi, Marc

    2017-07-01

    In recent years, the Geant4 toolkit for the Monte Carlo simulation of radiation with matter has seen large growth in its divers user community. A fundamental aspect of a successful physics experiment is the availability of a reliable and precise simulation code. Geant4 currently does not allow for the simulation of particle interactions with anything other than amorphous matter. To overcome this limitation, the GECO (GEant4 Crystal Objects) project developed a general framework for managing solid-state structures in the Geant4 kernel and validate it against experimental data. Accounting for detailed geometrical structures allows, for example, simulation of diffraction from crystal planes or the channeling of charged particle.

  17. Geant4 2005 10. user conference and collaboration workshop. Slides

    Energy Technology Data Exchange (ETDEWEB)

    Maire, M.; Amako, K.; Agapov, I.; Allison, J.; Amako, K.; Anah, J.; Apostolakis, J.; Asai, M.; Aso, T.; Barrand, G.; Becheva, E.; Berthoumieux, E.; Bongrand, M.; Boudard, A.; Canchel, G.; Capra, R.; Carlier, Th.; Chambon, P.; Chipaux, R.; Cognet, M.A.; Cornelius, I.; Cosmo, G.; Beenhouwer, J. de; Derreumaux, S.; Desbree, A.; Descourt, P.; Dridi, W.; Ersmark, T.; Faddegon, B.; Ferrer, L.; Flacco, A.; Folger, G.; Francis, S.; Giovinazzo, J.; Glinec, Y.; Godart, J.; Goncalves, P.; Gottschlag, H.; Grichine, V.; Guatelli, S.; Gudowska, I.; Guemnie Tafo, A.; Gueye, P.; Gumplinger, P.; Gurriaran, R.; Hannachi, F.; Heikkinen, A.; Hill, D.; Honore, P.F.; Howard, A.; Hrivnacova, I.; Hubert, X.; Incerti, S.; Ivanchenko, V.; Jacquemier, J.; Jones, F.; Kerhoas-Cavata, S.; Klem, J.; Koi, T.; Kosov, M.; Labalme, M.; Lang, N.; Lemercier, M.; Lemiere, Y.; Leroy, P.; Link, O.; Liu, B.; Lydon, J.; Maire, M.; Marchand, D.; Marquet, Ch.; Mascialino, B.; Matea, I.; Mccormick, J.; Mclaren, I.; Merchant, M.; Miceli, A.; Mine, Ph.; Moretto, Ph.; Mount, R.; Murakami, K.; Nachab, H.; Nehmeh, S.; Nieminen, P.; Paganetti, H.; Pallon, J.; Pandola, L.; Perl, J.; Perrot, F.; Pia Maria, G.; Piqueras, I.; Pouthier, Th.; Pshenichnov, I.; Raaijmakers, A.; Raaymakers, B.; Reuillon, R.; Ribon, A.; Rodrigues, P.; Rogel, G.; Salehzahi, F.; Santin, G.; Sasaki, T.; Schubert, M.; Seznec, H.; Shipley, D.; Skaza, F.; Thiam Cheick, O.; Tome, B.; Traneus, E.; Trindade, A.; Truscott, P.; Vacanti, G.; Verderi, M.; Watase, Y.; Wright, D.; Yarba, J.; Yoshida, H.; Zacharatou-Jarlskog, Ch.; Zhang, Q

    2005-07-01

    Originally developed for the simulation of large scale particle physics experiments, the field of applications of the conferences Geant4 is growing fast worldwide especially at the physics medicine biology frontier. In this framework the 2005 Geant4 conference was dedicated to simulations with a strong interest at the physics medicine biology frontier. In particular the following topics were discussed: review of simulation applications for medicine, validation of Geant4 models for medical physics, simulation of radiotherapy and irradiation setups, treatment planning in radiotherapy, dosimetry, parallelization, imaging techniques, data handling, related GRID developments and applications and the Geant4 DNA project with related Monte Carlo tools. Slides are provided. (A.L.B.)

  18. Multiparametric magnetic resonance imaging in the detection of prostate cancer; Multiparametrische Magnetresonanztomografie zur Detektion des Prostatakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Durmus, T.; Baur, A.; Hamm, B. [Charite Universitaetsmedizin Berlin (Germany). Dept. of Radiology

    2014-03-15

    Prostate cancer is the most common malignancy in men, but only about 10 % of patients die from that cancer. Recent studies suggest that not all patients benefit from a radical therapeutic approach. When prostate cancer is suspected, magnetic resonance imaging (MRI) can make an important contribution to cancer localization within the prostate. Many studies show that T2-weighted morphologic imaging should be supplemented by multiparametric MRI techniques including diffusion-weighted imaging, contrast-enhanced sequences, and MR spectroscopy. This approach detects aggressive prostate cancer with high sensitivity and specificity. The findings of multiparametric MRI additionally contribute information to the assessment of cancer aggressiveness. The use of these multiparametric MRI techniques will gain an increasing role in the clinical management of prostate cancer patients. They can help in establishing a definitive diagnosis with a minimum of invasiveness and may also contribute to optimal individualized treatment. This review article presents the different techniques of multiparametric MRI and discusses their contribution to the detection of prostate cancer. Moreover, this review outlines an objective approach to image interpretation and structured reporting of MRI findings using the PI-RADS criteria. The review concludes with an outline of approaches to prostate biopsy on the basis of MRI (transrectal ultrasound, direct MRI guidance of tissue sampling, and MRI-ultrasound fusion biopsy) and emerging future uses of MRI in the planning of focal treatment options and in the active surveillance of patients diagnosed with prostate cancer. (orig.)

  19. Capture reactions at astrophysically relevant energies: extended gas target experiments and GEANT simulations

    CERN Document Server

    Kölle, V; Braitmayer, S E; Mohr, P J; Wilmes, S; Staudt, G; Hammer, J W; Jäger, M; Knee, H; Kunz, R; Mayer, A

    1999-01-01

    Several resonances of the capture reaction sup 2 sup 0 Ne(alpha, gamma) sup 2 sup 4 Mg were measured using an extended windowless gas target system. Detailed GEANT simulations were performed to derive the strength and the total width of the resonances from the measured yield curve. The crucial experimental parameters, which are mainly the density profile in the gas target and the efficiency of the gamma-ray detector, were analyzed by a comparison between the measured data and the corresponding simulation calculations. The excellent agreement between the experimental data and the simulations gives detailed insight into these parameters. (author)

  20. Study by electron spin resonance of the free radicals created under irradiation in glycine; Etude par la technique de resonance paramagnetique electronique des radicaux crees sous irradiation dans la glycine

    Energy Technology Data Exchange (ETDEWEB)

    Thomet, P.; Rassat, A.; Servoz-Gavin, P.; Choudens, H. de [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-07-01

    The free radicals created by different radiations in glycine are measured by electron spin resonance and their number is evaluated in function of the absorbed dose. This number decreases when the LET of the radiations increases ; in other words,high LET radiations gives less radiochemical effects; in contrary with the fact that high LET radiations creates more damage in biological materials. The decreasing with time of the number of free radicals and the speed of this decrease is a function of temperature; by the study of the kinetics of this decrease, an attempt has been made to prove the presence of three radicals. (authors) [French] Les radicaux crees par divers rayonnements dans la glycine sont detectes par resonance paramagnetique electronique et leur nombre est evalue en fonction de la dose. Ce nombre varie dans le sens inverse du T.E.L moyen, c'est-a-dire que les rayonnements de T.E.L eleves donnent des effets radiochimiques plus petits alors que les effets radiobiologiques sont importants avec des T.E.L eleves. La decroissance dans le temps du nombre de radicaux est observee et la vitesse de diminution des radicaux est liee a la temperature. Etudiant la cinetique de recombinaison, on peut faire l'hypothese de l'existence de 3 radicaux. (auteurs)

  1. Low energy neutron propagation in MCNPX and GEANT4

    CERN Document Server

    Lemrani, R; Gerbier, G; Kudryavtsev, V A; Robinson, M; Spooner, N J C

    2006-01-01

    Simulations of neutron background from rock for underground experiments are presented. Neutron propagation through two types of rock, lead and hydrocarbon material is discussed. The results show a reasonably good agreement between GEANT4, MCNPX and GEANT3 in transporting low-energy neutrons.

  2. An interface for GEANT4 simulation using ROOT geometry navigation

    CERN Document Server

    Gheata, A

    2008-01-01

    The ROOT geometry modeller (TGeo) offers powerful tools for detector geometry description. The package provides several functionalities like: navigation, geometry checking, enhanced visualization, geometry editing GUI and many others, using ROOT I/O. A new interface module g4root was recently developed to take advantage of ROOT geometry navigation optimizations in the context of GEANT4 simulation. The interface can be used either by native GEANT4-based simulation applications or in the more general context of the Virtual Monte Carlo (VMC) framework developed by ALICE offline and ROOT teams. The latter allows running GEANT3, GEANT4 and FLUKA simulations without changing either the geometry description or the user code. The interface was tested and stressed in the context of ALICE simulation framework. A description of the interface, its usage as well as recent results in terms of reliability and performance will be presented. Some benchmarks will be compared for ROOT-TGeo or GEANT4 based navigation.

  3. GEANT4 Simulation of the NPDGamma Experiment

    Science.gov (United States)

    Frlez, Emil

    2014-03-01

    The n-> + p --> d + γ experiment, currently taking data at the Oak Ridge SNS facility, is a high-precision measurement of weak nuclear forces at low energies. Detecting the correlation between the cold neutron spin and photon direction in the capture of neutrons on Liquid Hydrogen (LH) target, the experiment is sensitive to the properties of neutral weak current. We have written a GEANT4 Monte Carlo simulation of the NPDGamma detector that, in addition to the active CsI detectors, also includes different targets and passive materials as well as the beam line elements. The neutron beam energy spectrum, its profiles, divergencies, and time-of-flight are simulated in detail. We have used the code to cross-calibrate the positions of (i) polarized LH target, (ii) Aluminum target, and (iii) CCl4 target. The responses of the 48 CsI detectors in the simulation were fixed using data taken on the LH target. Both neutron absorption as well as scattering and thermal processes were turned on in the GEANT4 physics lists. We use the results to simulate in detail the data obtained with different targets used in the experiment within a comprehensive analysis. This work is supported by NSF grant PHY-1307328.

  4. Geant4 - Towards major release 10

    Science.gov (United States)

    Cosmo, G.; Geant4 Collaboration

    2014-06-01

    The Geant4 simulation toolkit has reached maturity in the middle of the previous decade, providing a wide variety of established features coherently aggregated in a software product, which has become the standard for detector simulation in HEP and is used in a variety of other application domains. We review the most recent capabilities introduced in the kernel, highlighting those, which are being prepared for the next major release (version 10.0) that is scheduled for the end of 2013. A significant new feature contained in this release will be the integration of multi-threading processing, aiming at targeting efficient use of modern many-cores system architectures and minimization of the memory footprint for exploiting event-level parallelism. We discuss its design features and impact on the existing API and user-interface of Geant4. Revisions are made to balance the need for preserving backwards compatibility and to consolidate and improve the interfaces; taking into account requirements from the multithreaded extensions and from the evolution of the data processing models of the LHC experiments.

  5. Study of the nature and of the properties of paramagnetic centers observed by electron spin resonance in conjugated polymers; Etude de la nature des propriete des centres paramagnetiques observes par resonance paramagnetique electronique dans les polymeres conjugues

    Energy Technology Data Exchange (ETDEWEB)

    Nechtschein, M. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-06-15

    Conjugated polymers contain paramagnetic centers. It is established that these centers are free radicals and a model which defines their electronic structure is proposed. The interactions between these centers are studied, notably by dynamic polarisation experiments. Finally it is shown that the centers have catalytic properties. (author) [French] Les polymeres conjugues contiennent des centres paramagnetiques. L'origine radicalaire de ces centres est etablie et un modele precisant leur structure electronique est propose. Les interactions entre ces centres sont etudiees, notamment a l'aide d'experiences de polarisation dynamique. Des proprietes catalytiques sont mises en evidence. (auteur)

  6. Geant4 Low Energy Electromagnetic Physics

    Institute of Scientific and Technical Information of China (English)

    S.Chauvie; G.Depaola; 等

    2001-01-01

    Geant4 Low Energy Electromagnetic package Provides a precise treatment of electromagnetic interations of particles with matter down to very low energies (250 oV for electrons and photons,<1 keV for hadrons and ions),It includes a veriety of models for the electromagnetic processes of electrons,photons,hadrons and ions,taking into account advance features,such as shell effects and effects due to charge dependence.The comprehensive set of particle types it can handle,the variety of modeling approaches and the extended coverage of energy range make this package a unique tool among Monte Carlo codes on the market,and of relevance to serveral experimental domains in HIEP,astroparticle physics,space science and biomedical studies.

  7. An Overview of the Geant4 Toolkit

    CERN Document Server

    Apostolakis, John

    2007-01-01

    Geant4 is a toolkit for the simulation of the transport of radiation trough matter. With a flexible kernel and choices between different physics modeling choices, it has been tailored to the requirements of a wide range of applications. With the toolkit a user can describe a setup's or detector's geometry and materials, navigate inside it, simulate the physical interactions using a choice of physics engines, underlying physics cross-sections and models, visualise and store results. Physics models describing electromagnetic and hadronic interactions are provided, as are decays and processes for optical photons. Several models, with different precision and performance are available for many processes. The toolkit includes coherent physics model configurations, which are called physics lists. Users can choose an existing physics list or create their own, depending on their requirements and the application area. A clear structure and readable code, enable the user to investigate the origin of physics results. App...

  8. GEANT4 and CREME96 compare using only protons fluxes

    CERN Document Server

    Falzetta, Giuseppe; Zanini, Alba

    2007-01-01

    CREME96 and GEANT4 are two well known particles transport codes through matter. In this work, we present a comparison between the protons fluxes outgoing from an aluminium target, obtained by using both tools. The primary proton flux is obtained by CREME96 only and it is the same for both cases. We study different thickness targets and two different GEANT4 physics lists in order to show how the spectra of the outgoing proton fluxes are modified. Our results show good agreement of simulation data for both tools, for both GEANT4 physics lists and for every thickness target analysed.

  9. Methode impulsionnelle numerisee (MIN) pour l'isolement et l'identification des resonances de tubes immerges

    Science.gov (United States)

    Pareige, P.; Rembert, P.; Izbicki, J. L.; Maze, G.; Ripoche, J.

    1989-02-01

    The method of isolation and identification of resonances (MIIR) allows a direct verification of “resonance scattering theory” (RST). Indeed it provides the resonance spectra of aluminum elastic cylindrical shells, insonified by plane acoustic waves and it also allows the experimental determination of the mode number of each resonance of the target. At this day, when the shells are insonified by a short pulse it is only possible to obtain the resonance spectrum with a fast Fourier transform of the backscattered response. This paper presents an impulse method which allows the isolation of resonances and besides the identification of each eigenmode of the target.

  10. Benchmarking Geant4 for spallation neutron source calculations

    Science.gov (United States)

    DiJulio, Douglas D.; Batkov, Konstantin; Stenander, John; Cherkashyna, Nataliia; Bentley, Phillip M.

    2016-09-01

    Geant4 is becoming increasingly used for radiation transport simulations of spallation neutron sources and related components. Historically, the code has seen little usage in this field and it is of general interest to investigate the suitability of Geant4 for such applications. For this purpose, we carried out Geant4 calculations based on simple spallation source geometries and also with the the European Spallation Source Technical Design Report target and moderator configuration. The results are compared to calculations performed with the Monte Carlo N- Particle extended code. The comparisons are carried out over the full spallation neutron source energy spectrum, from sub-eV energies up to thousands of MeV. Our preliminary results reveal that there is generally good agreement between the simulations using both codes. Additionally, we have also implemented a general weight-window generator for Geant4 based applications and present some results of the method applied to the ESS target model.

  11. Geant4 hadronic and electromagnetic validation tests in LHCb

    CERN Multimedia

    Griffith, Peter Noel

    2016-01-01

    LHCb uses Geant4 to simulate the interactions of particles with the detector material and components. The simulation response can vary significantly due to modification of material description, of detector geometry, or of the Geant4 toolkit itself. Therefore, an extensive variety of tools have been developed to study the effects of Geant4 modification on the LHCb simulation framework and on stand-alone environments within the LHCb software infrastructure. These tools have proven to be very effective for investigating new and alternative models provided by Geant4, and also in identifying and fixing anomalous behaviours that arise from changes. The next goal is to have these validation tests run autonomously and periodically, alerting the relevant users when problems are detected. Quick and easy comparison of the results from different software versions and simulation models will be made possible through the web interface of the LHCb Performance and Regression testing system, LHCbPR.

  12. GPU in Physics Computation: Case Geant4 Navigation

    CERN Document Server

    Seiskari, Otto; Niemi, Tapio

    2012-01-01

    General purpose computing on graphic processing units (GPU) is a potential method of speeding up scientific computation with low cost and high energy efficiency. We experimented with the particle physics simulation toolkit Geant4 used at CERN to benchmark its geometry navigation functionality on a GPU. The goal was to find out whether Geant4 physics simulations could benefit from GPU acceleration and how difficult it is to modify Geant4 code to run in a GPU. We ported selected parts of Geant4 code to C99 & CUDA and implemented a simple gamma physics simulation utilizing this code to measure efficiency. The performance of the program was tested by running it on two different platforms: NVIDIA GeForce 470 GTX GPU and a 12-core AMD CPU system. Our conclusion was that GPUs can be a competitive alternate for multi-core computers but porting existing software in an efficient way is challenging.

  13. Set up of a method for the adjustment of resonance parameters on integral experiments; Mise au point d`une methode d`ajustement des parametres de resonance sur des experiences integrales

    Energy Technology Data Exchange (ETDEWEB)

    Blaise, P.

    1996-12-18

    Resonance parameters for actinides play a significant role in the neutronic characteristics of all reactor types. All the major integral parameters strongly depend on the nuclear data of the isotopes in the resonance-energy regions.The author sets up a method for the adjustment of resonance parameters taking into account the self-shielding effects and restricting the cross section deconvolution problem to a limited energy region. (N.T.).

  14. SEU rate calculation with GEANT4 (comparison with CREME 86)

    CERN Document Server

    Inguimbert, C

    2004-01-01

    This paper reports on single-event upset (SEU) rate calculations using the GEANT4 code. Single event effect rate modeling can be performed using various approaches. In this paper, we propose to compare the standard rectangular parallepiped (RPP) cosmic ray effects in microelectronic code (CREME86) model with our direct Monte Carlo simulation using the GEANT 4 (radiation transport code developed by CERN) software. The results obtained on two device types are in good agreement with CREME86. (14 refs).

  15. Determination of neutron resonance parameters of Neptunium 237 between 0 and 500 eV. The covariance matrices of statistical and of systematic origin, relating the resonance parameters, are also given; Determination des parametres des resonances neutroniques du neptunium 237, en dessous de 500eV, et obtention des matrices de covariances statistiques et systematiques entre les parametres de ces resonances

    Energy Technology Data Exchange (ETDEWEB)

    Lepretre, A.; Herault, N. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Brusegan, A.; Noguere, G.; Siegler, P. [Institut des Materiaux et des Metrologies - IRMM, Joint Research Centre, Gell (Belgium)

    2002-12-01

    This report is a follow up of the report CEA DAPNIA/SPHN-99-04T of Vincent Gressier. In the frame of a collaboration between the 'Commissariat a l'Energie Atomique (CEA)' and the Institute for Reference Materials and Measurement (IRMM, Geel, Belgique), the resonance parameters of neptunium 237 have been determined in the energy interval between 0 and 500 eV. These parameters have been obtained by using the Refit code in analysing simultaneously three transmission experiments. The covariance matrix of statistical origin is provided. A new method, based on various sensitivity studies is proposed for determining also the covariance matrix of systematic origin, relating the resonance parameters. From an experimental viewpoint, the study indicated that, with a large probability, the background spectrum has structure. A two dimensional profiler for the neutron density has been proved feasible. Such a profiler could, among others, demonstrate the existence of the structured background. (authors)

  16. Geant4 electromagnetic physics updates for space radiation effects simulation

    Science.gov (United States)

    Ivantchenko, Anton; Nieminen, Petteri; Incerti, Sebastien; Santin, Giovanni; Ivantchenko, Vladimir; Grichine, Vladimir; Allison, John; Karamitos, Mathiew

    The Geant4 toolkit is used in many applications including space science studies. The new Geant4 version 10.0 released in December 2013 includes a major revision of the toolkit and offers multi-threaded mode for event level parallelism. At the same time, Geant4 electromagnetic and hadronic physics sub-libraries have been significantly updated. In order to validate the new and updated models Geant4 verification tests and benchmarks were extended. Part of these developments was sponsored by the European Space Agency in the context of research aimed at modelling radiation biological end effects. In this work, we present an overview of results of several benchmarks for electromagnetic physics models relevant to space science. For electromagnetic physics, recently Compton scattering, photoelectric effect, and Rayleigh scattering models have been improved and extended down to lower energies. Models of ionization and fluctuations have also been improved; special micro-dosimetry models for Silicon and liquid water were introduced; the main multiple scattering model was consolidated; and the atomic de-excitation module has been made available to all models. As a result, Geant4 predictions for space radiation effects obtained with different Physics Lists are in better agreement with the benchmark data than previous Geant4 versions. Here we present results of electromagnetic tests and models comparison in the energy interval 10 eV - 10 MeV.

  17. Recent Developments in the Geant4 Hadronic Framework

    Science.gov (United States)

    Pokorski, Witold; Ribon, Alberto

    2014-06-01

    In this paper we present the recent developments in the Geant4 hadronic framework. Geant4 is the main simulation toolkit used by the LHC experiments and therefore a lot of effort is put into improving the physics models in order for them to have more predictive power. As a consequence, the code complexity increases, which requires constant improvement and optimization on the programming side. At the same time, we would like to review and eventually reduce the complexity of the hadronic software framework. As an example, a factory design pattern has been applied in Geant4 to avoid duplications of objects, like cross sections, which can be used by several processes or physics models. This approach has been applied also for physics lists, to provide a flexible configuration mechanism at run-time, based on macro files. Moreover, these developments open the future possibility to build Geant4 with only a specified sub-set of physics models. Another technical development focused on the reproducibility of the simulation, i.e. the possibility to repeat an event once the random generator status at the beginning of the event is known. This is crucial for debugging rare situations that may occur after long simulations. Moreover, reproducibility in normal, sequential Geant4 simulation is an important prerequisite to verify the equivalence with multithreaded Geant4 simulations.

  18. Implementation of the LPM effect in the discrete-bremsstrahlung simulation of GEANT 3 and GEANT 4

    Energy Technology Data Exchange (ETDEWEB)

    Mangiarotti, A. [Laboratorio de Instrumentacao e Fisica Experimental de Parti' culas, Coimbra (Portugal); Ballestrero, S. [School of Physics, University of the Witwatersrand, Johannesburg (South Africa); Sona, P. [Dipartimento di Fisica, Universita degli Studi di Firenze, Polo Scientifico, Sesto F.no, Via G. Sansone 1, Sesto Fiorentino 50019 , Firenze (Italy)], E-mail: pietro.sona@fi.infn.it; Uggerhoj, U.I. [Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark)

    2008-12-15

    Experimental data, recently measured at CERN, on the LPM effect have been used to benchmark the description of the discrete bremsstrahlung incorporated into the GEANT 3 and GEANT 4 codes. The limited accuracy of the native versions required a major revision in the framework of the original Migdal theory. The results obtained with the new implementation agree quite satisfactorily with measurements. The stability of the calculations when several parameters are varied has been thoroughly investigated.

  19. An Overview of the Geant4 Toolkit

    Science.gov (United States)

    Apostolakis, John; Wright, Dennis H.

    2007-03-01

    Geant4 is a toolkit for the simulation of the transport of radiation through matter. With a flexible kernel and choices between different physics modeling choices, it has been tailored to the requirements of a wide range of applications. With the toolkit a user can describe a setup's or detector's geometry and materials, navigate inside it, simulate the physical interactions using a choice of physics engines, underlying physics cross-sections and models, visualise and store results. Physics models describing electromagnetic and hadronic interactions are provided, as are decays and processes for optical photons. Several models, with different precision and performance are available for many processes. The toolkit includes coherent physics model configurations, which are called physics lists. Users can choose an existing physics list or create their own, depending on their requirements and the application area. A clear structure and readable code, enable the user to investigate the origin of physics results. Application areas include detector simulation and background simulation in High Energy Physics experiments, simulation of accelerator setups, studies in medical imaging and treatment, and the study of the effects of solar radiation on spacecraft instruments.

  20. GEANT4 simulations of the DANCE array

    Energy Technology Data Exchange (ETDEWEB)

    Jandel, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)]. E-mail: mjandel@lanl.gov; Bredeweg, T.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Couture, A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Fowler, M.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Bond, E.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Chadwick, M.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clement, R.R.C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Esch, E.-I. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); O' Donnell, J.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Reifarth, R. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Rundberg, R.S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ullmann, J.L. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Vieira, D.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wilhelmy, J.B. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wouters, J.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Macri, R.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Wu, C.Y. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Becker, J.A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

    2007-08-15

    The detector for advanced neutron capture experiments (DANCE) at Los Alamos National Laboratory (LANL) is used for neutron capture cross sections measurements. Its high granularity of 160 BaF{sub 2} detectors in a 4{pi} geometry allows for highly efficient detection of prompt {gamma}-rays following a neutron capture. The performance of the detector was simulated using the GEANT4 Monte Carlo code. The model includes all 160 BaF{sub 2} crystals with realistic dimensions and geometry. The {sup 6}LiH shell, beam pipe, crystal wrapping material, aluminum holders, photomultiplier material and materials of the calibration sources were included in the simulation. Simulated {gamma}-ray energy and total {gamma}-ray energy spectra gated on cluster and crystal multiplicities were compared to measured data using {sup 88}Y, {sup 60}Co, {sup 22}Na calibration sources. Good agreement was achieved. A total efficiency and peak-to-total ratio as a function of {gamma}-ray energy was established for mono-energetic {gamma}-rays.

  1. GEANT4 simulations of the DANCE array

    Science.gov (United States)

    Jandel, M.; Bredeweg, T. A.; Couture, A.; Fowler, M. M.; Bond, E. M.; Chadwick, M. B.; Clement, R. R. C.; Esch, E.-I.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.; Wouters, J. M.; Macri, R. A.; Wu, C. Y.; Becker, J. A.

    2007-08-01

    The detector for advanced neutron capture experiments (DANCE) at Los Alamos National Laboratory (LANL) is used for neutron capture cross sections measurements. Its high granularity of 160 BaF2 detectors in a 4π geometry allows for highly efficient detection of prompt γ-rays following a neutron capture. The performance of the detector was simulated using the GEANT4 Monte Carlo code. The model includes all 160 BaF2 crystals with realistic dimensions and geometry. The 6LiH shell, beam pipe, crystal wrapping material, aluminum holders, photomultiplier material and materials of the calibration sources were included in the simulation. Simulated γ-ray energy and total γ-ray energy spectra gated on cluster and crystal multiplicities were compared to measured data using 88Y, 60Co, 22Na calibration sources. Good agreement was achieved. A total efficiency and peak-to-total ratio as a function of γ-ray energy was established for mono-energetic γ-rays.

  2. Geant4-DNA simulation of electron slowing-down spectra in liquid water

    Science.gov (United States)

    Incerti, S.; Kyriakou, I.; Tran, H. N.

    2017-04-01

    This work presents the simulation of monoenergetic electron slowing-down spectra in liquid water by the Geant4-DNA extension of the Geant4 Monte Carlo toolkit (release 10.2p01). These spectra are simulated for several incident energies using the most recent Geant4-DNA physics models, and they are compared to literature data. The influence of Auger electron production is discussed. For the first time, a dedicated Geant4-DNA example allowing such simulations is described and is provided to Geant4 users, allowing further verification of Geant4-DNA track structure simulation capabilities.

  3. Geant4-DNA simulation of electron slowing-down spectra in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Incerti, S., E-mail: sebastien.incerti@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Univ. Bordeaux, CENBG, UMR 5797, F-33170, Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Kyriakou, I. [Medical Physics Laboratory, University of Ioannina Medical School, 45110 Ioannina (Greece); Tran, H.N. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam)

    2017-04-15

    This work presents the simulation of monoenergetic electron slowing-down spectra in liquid water by the Geant4-DNA extension of the Geant4 Monte Carlo toolkit (release 10.2p01). These spectra are simulated for several incident energies using the most recent Geant4-DNA physics models, and they are compared to literature data. The influence of Auger electron production is discussed. For the first time, a dedicated Geant4-DNA example allowing such simulations is described and is provided to Geant4 users, allowing further verification of Geant4-DNA track structure simulation capabilities.

  4. Study of the influence of chemical binding on resonant absorption and scattering of neutrons; Etude de l'influence des liaisons chimiques sur l'absorption et la diffusion des neutrons aux energies de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Naberejnev, D.G. [Aix-Marseille-1 Univ., 13 - Marseille (France)

    1999-02-01

    At present time the problem of taking into account of the crystalline binding in the heavy nuclei resonance range is not correctly treated in nuclear data processing codes. The present work deals separately with resonant absorption and scattering of neutrons. The influence of crystalline binding is considered for both types of reactions in the harmonic crystal frame work. The harmonic crystal model is applied to the study of resonant absorption cross sections to show the inconsistency of the free gas model widely in use in reactor neutronics. The errors due to the use of the latter were found to be non negligible. These errors should be corrected by introducing a more elaborated harmonic crystal model in codes for resonances analysis and on the nuclear data processing stage. Currently the influence of crystalline binding on transfer cross section in the resonance domain is taken into account in a naive manner using the model of the free nucleus at rest in the laboratory system. In this work I present a formalism (Uncoupled Phonon Approximation) which permits to consider in more detail the crystalline structure of the nuclear fuel. This formalism shows new features in comparison with the static model. (author)

  5. New experimental determination of the neutron resonance parameters of {sup 99}Tc; Nouvelle determination experimentale des parametres de resonances neutroniques de {sup 99}Tc

    Energy Technology Data Exchange (ETDEWEB)

    Brienne-Raepsaet, C. [CEA Bruyeres-le-Chatel, 91 (France). Dept. de Physique Theorique et Appliquee]|[Aix-Marseille-1 Univ., 13 - Marseille (France)

    1999-04-01

    In order to improve nuclear data for nuclear waste transmutation cross-sections of Tc{sup 99} in the resonance energy region have been performed using the time-of-flight method at the pulsed white neutron source GELINA of the Institute for Reference Materials and Measurements, Geel, Belgium. The energy range studied spreads from 3 eV to 100 KeV. 2 kinds of measurements have been performed: capture and transmission measurements. In the energy range between 0 and 2 KeV, more than 220 resonances have been analyzed. About 130 resonances which had stayed previously undiscovered, have been detected and analyzed. Because of instability problems concerning the process of measuring itself, the systematic error is not yet determined. The accuracy which takes into account statistical and systematic errors is expected to be between 4 and 5%.

  6. Progress in Geant4 Electromagnetic Physics Modelling and Validation

    Science.gov (United States)

    Apostolakis, J.; Asai, M.; Bagulya, A.; Brown, J. M. C.; Burkhardt, H.; Chikuma, N.; Cortes-Giraldo, M. A.; Elles, S.; Grichine, V.; Guatelli, S.; Incerti, S.; Ivanchenko, V. N.; Jacquemier, J.; Kadri, O.; Maire, M.; Pandola, L.; Sawkey, D.; Toshito, T.; Urban, L.; Yamashita, T.

    2015-12-01

    In this work we report on recent improvements in the electromagnetic (EM) physics models of Geant4 and new validations of EM physics. Improvements have been made in models of the photoelectric effect, Compton scattering, gamma conversion to electron and muon pairs, fluctuations of energy loss, multiple scattering, synchrotron radiation, and high energy positron annihilation. The results of these developments are included in the new Geant4 version 10.1 and in patches to previous versions 9.6 and 10.0 that are planned to be used for production for run-2 at LHC. The Geant4 validation suite for EM physics has been extended and new validation results are shown in this work. In particular, the effect of gamma-nuclear interactions on EM shower shape at LHC energies is discussed.

  7. Nuclear spectroscopy with Geant4. The superheavy challenge

    Science.gov (United States)

    Sarmiento, Luis G.

    2016-12-01

    The simulation toolkit Geant4 was originally developed at CERN for high-energy physics. Over the years it has been established as a swiss army knife not only in particle physics but it has seen an accelerated expansion towards nuclear physics and more recently to medical imaging and γ- and ion- therapy to mention but a handful of new applications. The validity of Geant4 is vast and large across many particles, ions, materials, and physical processes with typically various different models to choose from. Unfortunately, atomic nuclei with atomic number Z > 100 are not properly supported. This is likely due to the rather novelty of the field, its comparably small user base, and scarce evaluated experimental data. To circumvent this situation different workarounds have been used over the years. In this work the simulation toolkit Geant4 will be introduced with its different components and the effort to bring the software to the heavy and superheavy region will be described.

  8. Progress in Geant4 Electromagnetic Physics Modelling and Validation

    CERN Document Server

    Apostolakis, J; Bagulya, A; Brown, J M C; Burkhardt, H; Chikuma, N; Cortes-Giraldo, M A; Elles, S; Grichine, V; Guatelli, S; Incerti, S; Ivanchenko, V N; Jacquemier, J; Kadri, O; Maire, M; Pandola, L; Sawkey, D; Toshito, T; Urban, L; Yamashita, T

    2015-01-01

    In this work we report on recent improvements in the electromagnetic (EM) physics models of Geant4 and new validations of EM physics. Improvements have been made in models of the photoelectric effect, Compton scattering, gamma conversion to electron and muon pairs, fluctuations of energy loss, multiple scattering, synchrotron radiation, and high energy positron annihilation. The results of these developments are included in the new Geant4 version 10.1 and in patches to previous versions 9.6 and 10.0 that are planned to be used for production for run-2 at LHC. The Geant4 validation suite for EM physics has been extended and new validation results are shown in this work. In particular, the effect of gamma-nuclear interactions on EM shower shape at LHC energies is discussed.

  9. Progress in Geant4 Electromagnetic Physics Modelling and Validation

    CERN Document Server

    Apostolakis, J; Bagulya, A; Brown, J M C; Burkhardt, H; Chikuma, N; Cortes-Giraldo, M A; Elles, S; Grichine, V; Guatelli, S; Incerti, S; Ivanchenko, V N; Jacquemier, J; Kadri, O; Maire, M; Pandola, L; Sawkey, D; Toshito, T; Urban, L; Yamashita, T

    2015-01-01

    In this work we report on recent improvements in the electromagnetic (EM) physics models of Geant4 and new validations of EM physics. Improvements have been made in models of the photoelectric effect, Compton scattering, gamma conversion to electron and muon pairs, fluctuations of energy loss, multiple scattering, synchrotron radiation, and high energy positron annihilation. The results of these developments are included in the new Geant4 version 10.1 and in patches to previous versions 9.6 and 10.0 that are planned to be used for production for run-2 at LHC. The Geant4 validation suite for EM physics has been extended and new validation results are shown in this work. In particular, the effect of gamma-nuclear interactions on EM shower shape at LHC energies is discussed.

  10. Magnetic resonance tomography-guided interventional procedure for diagnosis of prostate cancer; MRT-gezielte interventionelle Verfahren zur Abklaerung des Prostatakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, M.; Helbich, T.H.; Fueger, B.J.; Memarsadeghi, M.; Stiglbauer, A.; Linhart, H.G.; Doan, A.; Pinker, K.; Brader, P. [Medizinische Universitaet Wien, Univ.-Klinik fuer Radiodiagnostik, Division fuer Molekulare und Gender-Bildgebung, Wien (Austria); Margreiter, M. [Medizinische Universitaet Wien, Univ.-Klinik fuer Urologie, Wien (Austria)

    2011-11-15

    In recent years magnetic resonance imaging (MRI) has been increasingly established in the diagnosis of prostate cancer in addition to transrectal ultrasonography (TRUS). The use of T2-weighted imaging allows an exact delineation of the zonal anatomy of the prostate and its surrounding structures. Other MR imaging tools, such as dynamic contrast-enhanced T1-weighted imaging or diffusion-weighted imaging allow an inference of the biochemical characteristics (multiparametric MRI). Prostate cancer, which could only be diagnosed using MR imaging or lesions suspected as being prostate cancer, which are localized in the anterior aspect of the prostate and were missed with repetitive TRUS biopsy, need to undergo MR guided biopsy. Recent studies have shown a good correlation between MR imaging and histopathology of specimens collected by MR-guided biopsy. Improved lesion targeting is therefore possible with MR-guided biopsy. So far data suggest that MR-guided biopsy of the prostate is a promising alternative diagnostic tool to TRUS-guided biopsy. (orig.) [German] Neben dem transrektalen Ultraschall (TRUS) hat sich in den letzten Jahren die MRT als nichtinvasive Methode zur Bildgebung von Prostatatumoren etabliert. Mittels T2-gewichteter Sequenzen ist eine exakte anatomische Darstellung der Prostata und ihrer umliegenden Strukturen moeglich. Andere MRT-Techniken ermoeglichen Rueckschluesse auf das biologische Verhalten des Tumors: dynamische kontrastmittelverstaerkte T1-gewichtete Sequenzen zur Darstellung der Angiogenese, diffusionsgewichtete Aufnahmen zur Beurteilung der Zelldichte und die Spektroskopie zur Bestimmung von Gewebemetaboliten wie Cholin und Kreatin (multiparametrische Bildgebung). Prostatatumoren, die nur mittels MRT nachweisbar sind oder verdaechtige Tumoren, die hauptsaechlich anterior in der Prostata lokalisiert sind und in wiederholten TRUS-gezielten Biopsien verfehlt wurden, benoetigen eine MRT-gezielte Biopsie zur Diagnosesicherung. Die bisherigen

  11. Software Aspects of the Geant4 Validation Repository

    CERN Document Server

    Dotti, Andrea; Elvira, Daniel; Genser, Krzysztof; Yarba, Julia; Carminati, Federico; Folger, Gunter; Konstantinov, Dmitri; Pokorski, Witold; Ribon, Alberto

    2016-01-01

    The Geant4, GeantV and GENIE collaborations regularly perform validation and regression tests for simulation results. DoSSiER (Database of Scientic Simulation and Experimental Results) is being developed as a central repository to store the simulation results as well as the experimental data used for validation. DoSSiER is easily accessible via a web application. In addition, a web service allows for programmatic access to the repository to extract records in JSON or XML exchange formats. In this article, we describe the functionality and the current status of various components of DoSSiER as well as the technology choices we made.

  12. Diffusion weighted magnetic resonance imaging: ischemic and traumatic injury of the central nervous system; Diffusionsgewichtete MRI: ischaemische und traumatische Verletzungen des Zentralnervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Huisman, T.A.G.M.; Sorensen, A.G. [Massachusetts General Hospital and Harvard Medical School, Boston (United States). MGH-NMR Center; Hawighorst, H.; Benoit, C.H. [Swiss Paraplegic Center Nottwil (Switzerland). Inst. of Radiology

    2001-12-01

    Diffusion weighted magnetic resonance imaging (DWI) represents a recent development that extends imaging from the depiction of the neuroanatomy into the field of functional and physiologic processes. DWI measures a fundamentally different physiologic parameter than conventional MRI. Image contrast is related to differences in the microscopic motion (diffusion) of water molecules within brain tissue rather than a change in total tissue water. Consequently, DWI can reveal pathology where conventional T1- and T2-weighted MR images are negative. DWI has clinically proven its value in the assessment of acute cerebral stroke and trauma by showing cerebral injury early due to its ability to discriminate between lesions with cytotoxic edema (decreased diffusion) from lesions with vasogenic edema (increased diffusion). Full tensor DWI allows to calculate a variety of functional maps, the most widely used maps include maps of apparent diffusion coefficients and isotropic diffusion. In addition maps of anisotropic diffusion can be calculated which are believed to give information about the integrity and location of fiber tracts. This functional-anatomical information will most probably play an increasingly important role in the early detection of primary and secondary tissue injury from various reasons and could guide and validate current and future neuroprotective treatments. (orig.) [German] Die diffusionsgewichtete Magnetresonanz Tomografie (DWI) stellt ein neues Verfahren dar, welches die Bildgebung von der einfachen Darstellung der Neuroanatomie um das Feld der funktionalen und physiologischen Prozesse erweitert. Im Gegensatz zur konventionellen MRT misst die DWI einen vollkommen anderen physiologischen Parameter. Der Bildkontrast haengt von Unterschieden in der Mikrobewegung (Diffusion) der Wassermolekuele im Hirngewebe ab. Daher kann die DWI pathologische Prozesse aufzeichnen, wo konventionelle T1- und T2-gewichtete MR Bilder unauffaellig bleiben. In der klinischen

  13. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...

  14. Magnetic resonance imaging of lumbar spine disc diseases. Frequency of false negatives; Imagerie par resonance magnetique pour pathologie discale lombaire. Frequence des faux-negatifs

    Energy Technology Data Exchange (ETDEWEB)

    Berthelot, J.M.; Maugars, Y.; Delecrin, Y.; Caillon, F.; Prost, A. [Hopital Hotel-Dieu de Nantes, 44 (France)

    1995-10-01

    Magnetic resonance imaging (MRI) has had an impressive impact on evaluation of degenerative diseases of the spine. Nevertheless, false negatives can occur on images involving lumbar discs. Degenerative disc diseases documented on discography and/or pathology examination of the discs can go unrecognized. Likewise sensitivity for the detection of protruding disc hernias is not totally satisfactory (20% false negatives). Finally, a magnetic resonance image visualizing displacement of the disc is not specific (10 to 15% false positives); images showing protrusion or hernia can be seen in 30% of asymptomatic patients. Although MRI gives slightly more information than other imaging techniques, false images do exist. Moreover, the usefulness of MRI to demonstrate disc disease in case of a negative CT-scan remains to be demonstrated. (authors). 26 refs.

  15. Validation of Geant4 on Proton Transportation for Thick Absorbers: Study Based on Tschalär Experimental Data

    Science.gov (United States)

    Hoff, Gabriela; Denyak, Valeriy; Schelin, Hugo R.; Paschuk, Sergei

    2017-02-01

    Imaging techniques using protons as incident particles are currently being developed to substitute X-ray computer tomography and nuclear magnetic resonance methods in proton therapy. They deal with relatively thick targets, like the human head or trunk, where protons lose a significant part of their energy, however, they have enough energy to exit the target. The physical quantities important in proton imaging are kinetic energy, angle and coordinates of emerging proton from an absorber material. In recent times, many research groups use the Geant4 toolkit to simulate proton imaging devices. Most of the available publications about validation of Geant4 models are for thin or thick absorbers (Bragg Peak studies), that are not consistent with the contour conditions applied to proton imaging. The main objective of this work is to evaluate the kinetic energy spectrum for protons emerging from homogeneous absorbers slabs comparing it to the experimental results published by Tschalär and Maccabee, in 1970. Different models (standard and detailed) available on Geant4 (version 9.6.p03) are explored taking into account its accuracy and computational performance. This paper presents a validation for protons with incident kinetic energies of 19.68 MeV and 49.10 MeV. The validation results from the emerging protons kinetic energy spectra show that: (i) there are differences between the reference data and the data produced by different processes evoked for transportation and (ii) the validation energies are sensitive to sub-shell processes.

  16. Applications of ion cyclotron-resonance to stable isotope separation; Les applications de la resonance cyclotron ionique a la separation des isotopes stables

    Energy Technology Data Exchange (ETDEWEB)

    Louvet, P.; Metayer, L. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement

    1994-12-31

    The principles and the technological basic concepts of the ion cyclotron-resonance process applied to the separation of metallic isotopes which mass ranges from 40 to 200 for medical and nuclear applications, are reviewed. The CEA (France) has developed a prototype plant, ERIC; first results showing high separation factors allow to consider higher production in the future. A modular code has been developed (RICAN) in order to assess the technic-economical feasibility of the process for various isotopes; examples of calculated results (costs and production) for calcium 48 and gadolinium 157 production are presented. 4 figs., 1 tab., 4 refs.

  17. Geant4 electromagnetic physics: improving simulation performance and accuracy

    Science.gov (United States)

    Ivanchenko, V. N.; Incerti, S.; Allison, J.; Bagulya, A.; Brown, J. M. C.; Champion, C.; Elles, S.; Francis, Z.; Grichine, V.; Ivantchenko, A.; Jacquemier, J.; Karamitros, M.; Maire, M.; Mantero, A.; Pandola, L.; Raine, M.; Reis, M. A.; Santin, G.; Sawkey, D.; Schaelicke, A.; Schenk, M.; Taborda, A.; Urban, L.; Yamashita, T.

    2014-06-01

    The most recent upgrades of the electromagnetic (EM) physics "standard" and "low energy" sub-libraries of the general purpose Geant4 Monte Carlo simulation toolkit are described. These upgrades are relevant to different application domains including high energy physics, medical physics and space science. Validation results are presented and discussed.

  18. Simulation of UHE muons propagation for GEANT3

    OpenAIRE

    S. BottaiU.and INFN - Firenze; Perrone, L.

    2015-01-01

    A simulation package for the transport of high energy muons has been developed. It has been conceived to replace the muon propagation software modules implemented in the detector simulation program GEANT3. Here we discuss the results achieved with our package and we check the agreement with numerical calculations up to 10**8 GeV.

  19. Geant4 simulations for the TOTEM upgrade program

    CERN Document Server

    Nemes, F

    2013-01-01

    The TOTEM physics goals require the installation of new cylindrical shaped Roman Pots, which are radiofrequency optimized and are able to house timing detectors. The topic of this analysis note is to study the secondary production of the standard box and the new cylindrical shaped Roman Pots. The studies and the results are based on Geant4 simulations.

  20. Geant4 models for simulation of multiple scattering

    CERN Document Server

    Ivanchenko, V N; Maire, M; Urban, L

    2010-01-01

    Recent progress in development of single and multiple scattering models within the Geant4 toolkit is presented. Different options available to users are discussed. The comparisons with the data are shown. The trade of precision versus CPU performance is discussed with the focus on LHC detectors simulation

  1. A model for multiple scattering in GEANT4

    CERN Document Server

    Urbán, László

    2006-01-01

    We present a model to simulate the multiple scattering of charged particles in matter. The model is based on Lewis theory; it does not use the Moliere formalism. It simulates the scattering of a charged particle after a given step, computes the path length correction and the lateral displacement as well. This model is used in GEANT4.

  2. Reanimation of the RICH Test Beam Simulation in GEANT4

    CERN Document Server

    Arzymatov, Kenenbek

    2017-01-01

    This test was originally developed by Sajan Easo (LHCb) ten years ago mostly for the purpose of testing the behavior of photomultipliers, but it wasn’t used in regression testing in Gauss/Geant4 famework. The goal of project is to revive simulation of cherenkov radiaton test by completing.

  3. Resolution Improvement in Multidimensional Nuclear Magnetic Resonance Spectroscopy of Proteins; Amelioration de la resolution dans la resonance magnetique nucleaire multidimensionnelle des proteines

    Energy Technology Data Exchange (ETDEWEB)

    Duma, L

    2004-07-01

    The work presented in this thesis is concerned with both liquid-state and solid-state nuclear magnetic resonance (NMR) spectroscopy. Most of this work is devoted to the investigation by solid-state NMR of C{sup 13}-enriched compounds with the principal aim of presenting techniques devised for further improving the spectral resolution in multidimensional NMR of microcrystalline proteins. In fully C{sup 13}-labelled compounds, the J-coupling induces a broadening of the carbon lineshapes. We show that spin-state-selective technique called IPAP can be successfully combined with standard polarisation transfer schemes in order to remove the J-broadening in multidimensional solid-state NMR correlation experiments of fully C{sup 13}-enriched proteins. We present subsequently two techniques tailored for liquid-state NMR spectroscopy. The carbon directly detected techniques provide chemical shift information for all backbone hetero-nuclei. They are very attracting for the study of large bio-molecular systems or for the investigation of paramagnetic proteins. In the last part of this thesis, we study the spin-echo J-modulation for homonuclear two-spin 1/2 systems. Under magic-angle spinning, the theory of J-induced spin-echo modulation allows to derive a set of modulation regimes which give a spin-echo modulation exactly equal to the J-coupling. We show that the chemical-shift anisotropy and the dipolar interaction tend to stabilize the spin-echo J-modulation. The theoretical conclusions are supported by numerical simulations and experimental results obtained for three representative samples containing C{sup 13} spin pairs. (author)

  4. Software Quality Metrics for Geant4: An Initial Assessment

    CERN Document Server

    Ronchieri, Elisabetta; Giacomini, Francesco

    2016-01-01

    In the context of critical applications, such as shielding and radiation protection, ensuring the quality of simulation software they depend on is of utmost importance. The assessment of simulation software quality is important not only to determine its adoption in experimental applications, but also to guarantee reproducibility of outcome over time. In this study, we present initial results from an ongoing analysis of Geant4 code based on established software metrics. The analysis evaluates the current status of the code to quantify its characteristics with respect to documented quality standards; further assessments concern evolutions over a series of release distributions. We describe the selected metrics that quantify software attributes ranging from code complexity to maintainability, and highlight what metrics are most effective at evaluating radiation transport software quality. The quantitative assessment of the software is initially focused on a set of Geant4 packages, which play a key role in a wide...

  5. Geant4 used in medical physics and hadrontherapy technique

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article mainly presents the application of Geant4 package (Geant4.7.0, 2005), developed by CERN (the Center of European Research of Nucleus), in medical physics and a novel technique, namely, hadrontherapy. The distribution of energy deposition in a water model by different radiation beams was also given. The results show that the distributions for proton beams are completely different from those for other radiation beams. Charged particles like protons exhibit little scattering when they penetrate the matter and give the highest energy deposition near the end of their range just before they reach the resting state. These characteristics permit very precise control of the shape of the energy distribution inside the patient's body.

  6. Geant4 simulations of the lead fluoride calorimeter

    CERN Document Server

    Savchenko, A A; Dabagov, S B; Anastasi, A; Venanzoni, G; Strikhanov, M N

    2016-01-01

    In this paper we simulate the emission by charged particles in complex structures with help of Geant4. We take into account Cherenkov radiation, transition radiation, bremsstrahlung, pair production and other accompanying processes. As an application we investigate the full size electromagnetic calorimeter for the muon g-2 experiment at Fermilab. A calorimeter module (24 are expected in the experiment) consists of a Delrin front panel for installation of the laser calibration system, 54 PbF2 Cherenkov crystals wrapped by the black Millipore paper, and silicon photo-multiplier sensors. We report here on a simulation of radiation from positrons passing through the calorimeter system. We carry out the simulation using Geant4 toolkit, which provides a complete set of tools for all areas of detector simulation: geometry, tracking, detector response, run, event and track management, and visualization. We consider Cherenkov photons expansion when a positron moves down through the calorimeter at the arbitrary angle o...

  7. Simulations of an X-Ray Detector Using Geant4

    Science.gov (United States)

    Ertley, Camden; McConnell, Mark; Bloser, Peter; Legere, Jason; Connor, Taylor; Ryan, James

    2009-10-01

    NASA's Black Hole Finder Probe mission has two proposed concepts. CASTER, one of the proposed concepts, is a scintillator based Coded Aperture Survey Telescope for Energetic Radiation. This paper focuses on the development of a simulation that accurately models the proposed CASTER detector. The current detector design consists of a Lanthanum Bromide (LaBr3) scintillator directly coupled to a multianode photomultiplier tube (MAPMT). This detector should be optimized to give the best energy and position resolution. The simulation is based on the Geant4 toolkit, a set of detector simulation tools developed at CERN. Geant4 was chosen because it accurately models radiation devices and detectors, while allowing the simulation of transport and boundary conditions of optical photons. The results of the simulation were compared with data taken in the lab with a ^57Co and an ^241Am source. Once validated, the simulations will be used to optimize the final detector design.

  8. Performance of GeantV EM Physics Models

    Energy Technology Data Exchange (ETDEWEB)

    Amadio, G.; et al.

    2016-10-14

    The recent progress in parallel hardware architectures with deeper vector pipelines or many-cores technologies brings opportunities for HEP experiments to take advantage of SIMD and SIMT computing models. Launched in 2013, the GeantV project studies performance gains in propagating multiple particles in parallel, improving instruction throughput and data locality in HEP event simulation on modern parallel hardware architecture. Due to the complexity of geometry description and physics algorithms of a typical HEP application, performance analysis is indispensable in identifying factors limiting parallel execution. In this report, we will present design considerations and preliminary computing performance of GeantV physics models on coprocessors (Intel Xeon Phi and NVidia GPUs) as well as on mainstream CPUs.

  9. Edge localized modes control by resonant magnetic perturbations; Controle des instabilites de bord par perturbations magnetiques resonantes

    Energy Technology Data Exchange (ETDEWEB)

    Nardon, E

    2007-10-15

    The present work is dedicated to one of the most promising methods of control of the ELMs (Edge Localized Modes), based on a system of coils producing Resonant Magnetic Perturbations (RMPs). Our main objectives are, on the one hand, to improve the physical understanding of the mechanisms at play, and on the other hand to propose a concrete design of ELMs control coils for ITER. In order to calculate and analyze the magnetic perturbations produced by a given set of coils, we have developed the ERGOS code. The first ERGOS calculation was for the DIII-D ELMs control coils, the I-coils. It showed that they produce magnetic islands chains which overlap at the edge of the plasma, resulting in the ergodization of the magnetic field. We have then used ERGOS for the modelling of the experiments on ELMs control using the error field correction coils at JET and MAST. In the case of JET, we have shown the existence of a correlation between the mitigation of the ELMs and the ergodization of the magnetic field at the edge, in agreement with the DIII-D result. In order to design the ELMs control coils for ITER we have used ERGOS intensively, taking the case of the DIII-D I-coils as a reference. Three candidate designs came out, which we presented at the ITER Design Review, in 2007. Recently, the ITER management decided to provide a budget for building ELMs control coils, the design of which remains to be chosen between two of the three options that we proposed. Finally, in order to understand better the non-linear magnetohydrodynamics phenomena taking place in ELMs control by RMPs, we performed numerical simulations, in particular with the JOREK code for a DIII-D case. The simulations reveal the existence of convection cells induced at the edge by the magnetic perturbations, and the possible screening of the RMPs in presence of rotation.

  10. Peripartum changes of the pelvic ring: usefulness of magnetic resonance imaging; Peripartale Veraenderungen des Beckenringes: Wie sinnvoll ist die Magnetresonanztomografie?

    Energy Technology Data Exchange (ETDEWEB)

    Hermann, K.G.A.; Muehler, M.R.; Lembcke, A.; Hamm, B. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Radiologie; Halle, H. [Charite - Universitaetsmedizin Berlin (Germany). Klinik fuer Geburtshilfe und Perinatalmedizin; Reisshauer, A. [Charite - Universitaetsmedizin Berlin (Germany). Medizinische Klinik mit Schwerpunkt Rheumatologie und Klinische Immunologie; Schink, T. [Charite - Universitaetsmedizin Berlin (Germany). Inst. fuer Biometrie und Klinische Epidemiologie; Vsianska, L.; Bollow, M. [Augusta-Kranken-Anstalt, Bochum (Germany). Inst. fuer Radiologie

    2007-12-15

    Purpose: Postpartum pelvic pain beyond the normal level poses a problem to obstetricians. Beyond normal physiologic loosening of the pubic symphysis and sacroiliac joints (SIJs) during pregnancy, symphyseal separation and rupture must be excluded. The aim of this prospective study was to determine whether magnetic resonance imaging (MRI) allows for reliable differentiation of normal postpartum findings and pathologic lesions. Material and Methods: The study included a total of 77 women (mean age 30), among them 21 healthy subjects (group A), 21 asymptomatic postpartum women (group B), and 35 patients with postpartum pelvic pain (group C). The analyzed parameters comprised symphyseal and iliosacral tenderness, subjective pain assessed on a visual analog scale, and data pertaining to obstetric history. All 77 women underwent 1.5T MRI of the pelvic ring using oblique angulated coronal T 1-weighted and STIR sequences for imaging of the symphysis and SIJs in one slice package. Analysis of the MR images comprised signal intensities of pelvic bone marrow, width of the symphyseal cleft, and the symphyseal capsule. Results: Subjects in group A in general had a normal bone marrow signal. The STIR sequence showed increased signal intensity of the pubic bone near the symphysis in 16 women (76%) of group B and 31 patients of group C (86%) (not significant). An increased periarticular bone marrow signal of the SIJs on the STIR images was seen in 13 women (62%) of group B and 23 patients (63%) of group C. The mean width of the symphyseal cleft differed significantly among the three groups (3.4 mm vs. 5.4 mm vs. 6.7 mm). A width > 10 mm was observed in only 4 cases (11%). Moreover, associated findings such as interpubic hematoma (n = 23) or tears of the symphyseal capsule (n = 7) were detected in patients of group C. (orig.)

  11. GEANT4 tuning for pCT development

    Energy Technology Data Exchange (ETDEWEB)

    Yevseyeva, Olga; Assis, Joaquim T. de [Universidade do Estado do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico; Evseev, Ivan; Schelin, Hugo R.; Paschuk, Sergei A.; Milhoretto, Edney; Setti, Joao A.P. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Diaz, Katherin S. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Havana (Cuba); Hormaza, Joel M. [Universidade Estadual Paulista Julio de Mesquisa Filho (DFB/IB/UNESP), Botucatu, SP (Brazil). Inst. de Biociencias. Dept. de Fisica e Biofisica; Lopes, Ricardo T. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2010-07-01

    Full text. Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Thus, the fidelity of proton computed tomography (pCT) simulations as a tool for proton therapy planning depends in the general case on the accuracy of results obtained for the proton interaction with thick absorbers.GEANT4 simulations of proton energy spectra after passing thick absorbers do not agree well with existing experimental data, as showed previously. Moreover, the spectra simulated for the Bethe-Bloch domain showed an unexpected sensitivity to the choice of low-energy electromagnetic models during the code execution. These observations were done with the GEANT4 version 8.2 during our simulations for pCT. This work describes in more details the simulations of the proton passage through aluminum absorbers with varied thickness. The simulations were done by modifying only the geometry in the Hadron therapy Example, and for all available choices of the Electromagnetic Physics Models. As the most probable reasons for these effects is some specific feature in the code, or some specific implicit parameters in the GEANT4 manual, we continued our study with version 9.2 of the code. Some improvements in comparison with our previous results were obtained. The simulations were performed considering further applications for pCT development. (author)

  12. Validation of Geant4 hadronic physics models at intermediate energies

    Science.gov (United States)

    Banerjee, Sunanda; Geant4 Hadronic Group

    2010-04-01

    GEANT4 provides a number of physics models at intermediate energies (corresponding to incident momenta in the range 1-20 GeV/c). Recently, these models have been validated with existing data from a number of experiments: (a) inclusive proton and neutron production with a variety of beams (π-, π+, p) at different energies between 1 and 9 GeV/c on a number of nuclear targets (from beryllium to uranium); (2) inclusive pion/kaon/proton production from 14.6 GeV/c proton beams on nuclear targets (from beryllium to gold); (3) inclusive pion production from pion beams between 3-13 GeV/c on a number of nuclear targets (from beryllium to lead). The results of simulation/data comparison for different GEANT4 models are discussed in the context of validating the models and determining their usage in physics lists for high energy application. Due to the increasing number of validations becoming available, and the requirement that they be done at regular intervals corresponding to the GEANT4 release schedule, automated methods of validation are being developed.

  13. GEANT4 simulation of slow positron beam implantation profiles

    Science.gov (United States)

    Dryzek, Jerzy; Horodek, Paweł

    2008-09-01

    The paper presents the positron implantation profiles, which are important for proper interpretation of data produced in slow-positron depth defect spectroscopy (VEPAS). In the paper, we compared the profiles reported in other publications and those obtained using the GEANT4 codes, which are used for the simulation of interaction of energetic particles with matter. The comparison shows that the GEANT4 codes produce profiles which match fairly well with those generated by other codes, which take into account more accurately processes at low energies when positrons interact with core electrons, valence electrons, plasmons etc. The profiles in different materials simulated for different implant energies were parameterized using two analytical formulas: the Makhovian profile and the profile proposed by Ghosh et al. [V.J. Ghosh, D.O. Welch, K.G. Lynn, in: E. Ottewite, A.H. WeissSlow (Eds.), Positron Beam Techniques for Solids and Surfaces, Jackson Hole, Wyoming, AIP Conference Proceedings, Vol. 303, New York, 1994, p. 37]. The adjustable parameters obtained are presented in Tables 1 and 2. The total backscattering probability obtained from the GEANT4 simulations is in agreement with experimental data reported.

  14. GEANT4 Tuning For pCT Development

    Science.gov (United States)

    Yevseyeva, Olga; de Assis, Joaquim T.; Evseev, Ivan; Schelin, Hugo R.; Paschuk, Sergei A.; Milhoretto, Edney; Setti, João A. P.; Díaz, Katherin S.; Hormaza, Joel M.; Lopes, Ricardo T.

    2011-08-01

    Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Thus, the fidelity of proton computed tomography (pCT) simulations as a tool for proton therapy planning depends in the general case on the accuracy of results obtained for the proton interaction with thick absorbers. GEANT4 simulations of proton energy spectra after passing thick absorbers do not agree well with existing experimental data, as showed previously. Moreover, the spectra simulated for the Bethe-Bloch domain showed an unexpected sensitivity to the choice of low-energy electromagnetic models during the code execution. These observations were done with the GEANT4 version 8.2 during our simulations for pCT. This work describes in more details the simulations of the proton passage through aluminum absorbers with varied thickness. The simulations were done by modifying only the geometry in the Hadrontherapy Example, and for all available choices of the Electromagnetic Physics Models. As the most probable reasons for these effects is some specific feature in the code, or some specific implicit parameters in the GEANT4 manual, we continued our study with version 9.2 of the code. Some improvements in comparison with our previous results were obtained. The simulations were performed considering further applications for pCT development.

  15. Quantitative Test of the Evolution of Geant4 Electron Backscattering Simulation

    CERN Document Server

    Basaglia, Tullio; Hoff, Gabriela; Kim, Chan Hyeong; Kim, Sung Hun; Pia, Maria Grazia; Saracco, Paolo

    2016-01-01

    Evolutions of Geant4 code have affected the simulation of electron backscattering with respect to previously published results. Their effects are quantified by analyzing the compatibility of the simulated electron backscattering fraction with a large collection of experimental data for a wide set of physics configuration options available in Geant4. Special emphasis is placed on two electron scattering implementations first released in Geant4 version 10.2: the Goudsmit-Saunderson multiple scattering model and a single Coulomb scattering model based on Mott cross section calculation. The new Goudsmit-Saunderson multiple scattering model appears to perform equally or less accurately than the model implemented in previous Geant4 versions, depending on the electron energy. The new Coulomb scattering model was flawed from a physics point of view, but computationally fast in Geant4 version 10.2; the physics correction released in Geant4 version 10.2p01 severely degrades its computational performance. Evolutions in ...

  16. Performance Evaluation of Multithreaded Geant4 Simulations Using an Intel Xeon Phi Cluster

    OpenAIRE

    2015-01-01

    International audience; The objective of this study is to evaluate the performances of Intel Xeon Phi hardware accelerators for Geant4 simulations, especially for multithreaded applications. We present the complete methodology to guide users for the compilation of their Geant4 applications on Phi processors. Then, we propose series of benchmarks to compare the performance of Xeon CPUs and Phi processors for a Geant4 example dedicated to the simulation of electron dose point kernels, the TestE...

  17. Coleman et la construction des institutions : peut-on négliger la rationalité sociale?

    NARCIS (Netherlands)

    Lindenberg, Siegwart

    2003-01-01

    Cet article se donne pour objectif de comprendre comment un geant de la sociologie comme James S. Coleman a pu &tre si peu fecond sur un point qu'il considerait comme majeur pour le sociologue : la construction des institutions. L'article defend I'idee selon laquelle la theorie de I'action hautement

  18. GEANT4 simulation of gamma ray in a double-gap resistive plate chamber

    Institute of Scientific and Technical Information of China (English)

    J. T. Rhee; M. Jamil; Steve Hall; Y. J. Jeon

    2006-01-01

    For more than 20 years nuclear physicists have used the GEANT code to simulate particle-matter interaction. In most recent version, GEANT4 is a toolkit for simulating the passage of particles though matter, which contains a complete range of functionality including tracking, geometry, physics models, and hits. In this article, an attempt to use GEANT4 to model a double-gap resistive plate chamber (RFC) with its improved efficiency is presented. The efficiencies of the double-gap RFC have been evaluated as a function of gamma energy range 0.005-1OOOMeV. A comparison to available previous simulation package GEANT3 data is also performed.

  19. Influence of Geant4 parameters on proton dose distribution

    Directory of Open Access Journals (Sweden)

    Asad Merouani

    2015-09-01

    Full Text Available Purpose: The proton therapy presents a great precision during the radiation dose delivery. It is useful when the tumor is located in a sensitive area like brain or eyes. The Monte Carlo (MC simulations are usually used in treatment planning system (TPS to estimate the radiation dose. In this paper we are interested in estimating the proton dose statistical uncertainty generated by the MC simulations. Methods: Geant4 was used in the simulation of the eye’s treatment room for 62 MeV protons therapy, installed in the Istituto Nazionale Fisica Nucleare Laboratori Nazionali del Sud (LNS-INFN facility in Catania. This code is a Monte Carlo based on software dedicated to simulate the passage of particles through the matter. In this work, we are interested in optimizing the Geant4 parameters on energy deposit distribution by proton to achieve the spatial resolution of dose distribution required for cancer therapy. We propose various simulations and compare the corresponding dose distribution inside water to evaluate the statistical uncertainties. Results: The simulated Bragg peak, based on facility model is in agreement with the experimental data, The calculations show that the mean statistical uncertainty is less than 1% for a simulation set with 5 × 104 events, 10-3 mm production threshold and a 10-2 mm step limit. Conclusion: The set of Geant4 cut and step limit values can be chosen in combination with the number of events to reach precision recommended from International Commission on Radiation Units and measurements (ICRU in Monte Carlo codes for proton therapy treatment.

  20. Calibration of the radiation monitor onboard Akebono using Geant4

    Science.gov (United States)

    Asai, Keiko; Takashima, Takeshi; Koi, Tatsumi; Nagai, Tsugunobu

    Natural high-energy electrons and protons (keV-MeV) in the space contaminate the data re-ciprocally. In order to calibrate the energy ranges and to remove data contamination on the radiation monitor (RDM) onboard the Japanese satellite, Akebono (EXOS-D), the detector is investigated using the Geant4 simulation toolkit of computational particle tracing. The semi-polar orbiting Akebono, launched in February 1989, is active now. This satellite has been observed the space environment at altitudes of several thousands km. The RDM instrument onboard Akebono monitors energetic particles in the Earth's radiation belt and gives important data accumulated for about two solar cycles. The data from RDM are for electrons in three energy channels of 0.3 MeV, protons in three energy channels of ¿ 30 MeV, and alpha particles in one energy channels of 15-45 MeV. The energy ranges are however based on information of about 20 years ago so that the data seem to include some errors actuary. In addition, these data include contamination of electrons and protons reciprocally. Actuary it is noticed that the electron data are contaminated by the solar protons but unknown quantitative amount of the contamination. Therefore we need data calibration in order to correct the energy ranges and to remove data contamination. The Geant4 simulation gives information of trajectories of incident and secondary particles whose are interacted with materials. We examine the RDM monitor using the Geant4 simulation. We find from the results that relativistic electrons of MeV behave quite complicatedly because of particle-material interaction in the instrument. The results indicate that efficiencies of detection and contamination are dependent on energy. This study compares the electron data from Akebono RDM with the simultaneous observation of CRRES and tries to lead the values of correction for each of the energy channels.

  1. GEANT4 for breast dosimetry: parameters optimization study.

    Science.gov (United States)

    Fedon, C; Longo, F; Mettivier, G; Longo, R

    2015-08-21

    Mean glandular dose (MGD) is the main dosimetric quantity in mammography. MGD evaluation is obtained by multiplying the entrance skin air kerma (ESAK) by normalized glandular dose (DgN) coefficients. While ESAK is an empirical quantity, DgN coefficients can only be estimated with Monte Carlo (MC) methods. Thus, a MC parameters benchmark is needed for effectively evaluating DgN coefficients. GEANT4 is a MC toolkit suitable for medical purposes that offers to the users several computational choices. In this work we investigate the GEANT4 performances testing the main PhysicsLists for medical applications. Four electromagnetic PhysicsLists were implemented: the linear attenuation coefficients were calculated for breast glandularity 0%, 50%, 100% in the energetic range 8-50 keV and DgN coefficients were evaluated. The results were compared with published data. Fit equations for the estimation of the G-factor parameter, introduced by the literature for converting the dose delivered in the heterogeneous medium to that in the glandular tissue, are proposed and the application of this parameter interaction-by-interaction or retrospectively is discussed. G4EmLivermorePhysicsList shows the best agreement for the linear attenuation coefficients both with theoretical values and published data. Moreover, excellent correlation factor (r2>0.99) is found for the DgN coefficients with the literature. The final goal of this study is to identify, for the first time, a benchmark of parameters that could be useful for future breast dosimetry studies with GEANT4.

  2. MCNPX and GEANT4 simulation of γ -ray polymeric shields

    Indian Academy of Sciences (India)

    Tabbakh F

    2016-04-01

    In this work, the shielding ability of a polymeric compound with gadolinium for gamma radiation has been investigated. The conceptual calculation of radiation attenuation and energy absorption as a function of different Gd percentages and the calculation of total compound density are performed using MCNP and GEANT4. It is found that, 2 mm of the compound can reduce up to 5% and 50% of 1 MeV and 50 keV $\\gamma$-rays respectively. Both Monte Carlo tools are in a good agreement.

  3. Progress in Hadronic Physics Modelling in Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Apostolakis, John; /CERN; Folger, Gunter; /CERN; Grichine, Vladimir; /CERN; Heikkinen, Aatos; /Helsinki Inst. of Phys.; Howard, Alexander; /CERN; Ivanchenko, Vladimir; /CERN; Kaitaniemi, Pekka; /Helsinki Inst. of Phys.; Koi, Tatsumi; /SLAC; Kosov, Mikhail; /CERN /Moscow, ITEP; Quesada, Jose Manuel; /Seville U.; Ribon, Alberto; /CERN; Uzhinsky, Vladimir; /CERN; Wright, Dennis; /SLAC

    2011-11-28

    Geant4 offers a set of models to simulate hadronic showers in calorimeters. Recent improvements to several models relevant to the modelling of hadronic showers are discussed. These include improved cross sections, a revision of the FTF model, the addition of quasi-elastic scattering to the QGS model, and enhancements in the nuclear precompound and de-excitation models. The validation of physics models against thin target experiments has been extended especially in the energy region 10 GeV and below. Examples of new validation results are shown.

  4. The application of Geant4 simulation code for brachytherapy treatment

    CERN Document Server

    Agostinelli, S; Garelli, S; Paoli, G; Nieminen, P; Pia, M G

    2000-01-01

    Brachytherapy is a radiotherapeutic modality that makes use of radionuclides to deliver a high radiation dose to a well-defined volume while sparing surrounding healthy structures. At the National Institute for Cancer Research of Genova a High Dose Rate remote afterloading system provides Ir(192) endocavitary brachytherapy treatments. We studied the possibility to use the Geant4 Monte Carlo simulation toolkit in brachytherapy for calculation of complex physical parameters, not directly available by experiment al measurements, used in treatment planning dose deposition models.

  5. Geant4 and Fano cavity test: where are we?

    CERN Document Server

    Elles, S; Maire, M; Urbàn, L

    2008-01-01

    The electron transport algorithm implemented in Geant4 has been recently revised. The modifications concern several physics aspects of the simulation model: the step limitation, the energy loss along a step and the multiple scattering. The Fano cavity setup was used to test these developments. The upgrades increase significantly the accuracy of the electron transport simulation. The ratio of simulated to theoretical dose deposition in the cavity is stable to ~1% while varying several parameters and within ~1.5% of the expected value for water and graphite. Work is underway to identify and resolve the remaining shift.

  6. Geant4 and beyond: recent progress in precision physics modeling

    CERN Document Server

    Batic, Matej; Han, Min Cheol; Hauf, Steffen; Hoff, Gabriela; Kim, Chan Hyeong; Kim, Han Sung; Kim, Sung Hun; Kuster, Markus; Pia, Maria Grazia; Saracco, Paolo; Weidenspointner, Georg

    2014-01-01

    This extended abstract briefly summarizes ongoing research activity on the evaluation and experimental validation of physics methods for photon and electron transport. The analysis includes physics models currently implemented in Geant4 as well as modeling methods used in other Monte Carlo codes, or not yet considered in general purpose Monte Carlo simulation systems. The validation of simulation models is performed with the support of rigorous statistical methods, which involve goodness-of-fit tests followed by categorical analysis. All results are quantitative, and are fully documented.

  7. GEANT4 simulation of electron energy deposition in extended media

    CERN Document Server

    Kadri, O; Gharbi, F; Trabelsi, A

    2007-01-01

    The present work demonstrates that GEANT4 yields a consistent description of electron transport processes in semi-infinite homogeneous and heterogeneous extended media. This comparison covers the e− energy deposition profiles in a range of elements from aluminum to tantalum through molybdenum at source energies from 0.3 to 1.0 MeV and at incident angles from 0° to 60°. The good agreement between simulation results and data confirms that the Monte Carlo used code is capable of accurate electron beam energy deposition calculation even under such conditions.

  8. Geant4 Simulation of Annihilation and excitation of Positronium

    CERN Document Server

    Gad, Andreas

    2016-01-01

    The purpose of this report is to document the work done during the summer of 2016 (18/6- 26/8) as a part of the CERN Summer Student Programme. The work has been done at the AEgIS (Antihydrogen Experiment: Gravity, Interferometry, Spectroscopy) collaboration under the supervision of Lillian Smestad and Michael Doser. The goal of the project was to create a Monte Carlo simulation in Geant4, of Positronium annihilation and excitation in the positron test chamber of the AEgIs experiment.

  9. Simulation of the GEM silicon central tracker using GEANT

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, M.L.; Kinnison, W.W.

    1994-01-01

    The silicon central tracker of the GEM detector has been simulated using the high energy physics simulations code GEANT. This paper will describe the level of detail of the geometry of the tracker that is in the code, including the silicon detectors themselves as well as all non-sensitive volumes such as support structures; the digitization, or detector response to particles, of the silicon detectors; the coordinate reconstruction from the digitizations, and some of the results of the simulations regarding the detector performance.

  10. SU-E-T-347: Validation of the Condensed History Algorithm of Geant4 Using the Fano Test

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H; Mathis, M; Sawakuchi, G [The Univerity of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2014-06-01

    Purpose: To validate the condensed history algorithm and physics of the Geant4 Monte Carlo toolkit for simulations of ionization chambers (ICs). This study is the first step to validate Geant4 for calculations of photon beam quality correction factors under the presence of a strong magnetic field for magnetic resonance guided linac system applications. Methods: The electron transport and boundary crossing algorithms of Geant4 version 9.6.p02 were tested under Fano conditions using the Geant4 example/application FanoCavity. User-defined parameters of the condensed history and multiple scattering algorithms were investigated under Fano test conditions for three scattering models (physics lists): G4UrbanMscModel95 (PhysListEmStandard-option3), G4GoudsmitSaundersonMsc (PhysListEmStandard-GS), and G4WentzelVIModel/G4CoulombScattering (PhysListEmStandard-WVI). Simulations were conducted using monoenergetic photon beams, ranging from 0.5 to 7 MeV and emphasizing energies from 0.8 to 3 MeV. Results: The GS and WVI physics lists provided consistent Fano test results (within ±0.5%) for maximum step sizes under 0.01 mm at 1.25 MeV, with improved performance at 3 MeV (within ±0.25%). The option3 physics list provided consistent Fano test results (within ±0.5%) for maximum step sizes above 1 mm. Optimal parameters for the option3 physics list were 10 km maximum step size with default values for other user-defined parameters: 0.2 dRoverRange, 0.01 mm final range, 0.04 range factor, 2.5 geometrical factor, and 1 skin. Simulations using the option3 physics list were ∼70 – 100 times faster compared to GS and WVI under optimal parameters. Conclusion: This work indicated that the option3 physics list passes the Fano test within ±0.5% when using a maximum step size of 10 km for energies suitable for IC calculations in a 6 MV spectrum without extensive computational times. Optimal user-defined parameters using the option3 physics list will be used in future IC simulations to

  11. Etude de la Production des Mesons d* Sur le PIC de Resonance du Boson Z Observes AU Lep avec le Detecteur Opal

    Science.gov (United States)

    Przysiezniak, Helenka

    L'etude de la production des mesons D* est effectuee a partir d'evenements multihadroniques rm Z^0to q| q, avec des donnees prises en 1990, 1991 et 1992 avec le detecteur OPAL au LEP. La notation q definit les quarks des cinq saveurs pouvant etre observees au LEP: up (u), down (d), strange (s), charme (c), beaute (b). Les D* et les correlations D*-leptons sont identifiees et ces dernieres servent a effecteur une separation claire entre les evenements rm Z^0to b| b et Z^0to c| c. On mesure la distribution de la variable de fragmentation x_{rm D^ *}=E_{rm D^*}/E _{rm faisceau} pour les D* produits dans les evenements rm Z^0 to c| c. Elle est notee f _{rm cto D^*}. Ce resultat est a la base d'une publication OPAL (1), avec trois autres methodes de separation etudiees en parallele, donnat la premiere mesure OPAL de f _{rm cto D^*} qui soit independante de toute modelisation de la fragmentation des quarks lourds, ainsi qu'une mesure de Gamma_{rm c| c} parmi les plus precises effectuees a ce jour, ou Gamma_{rm c| c} est la largeur partielle de la desintegration du Z^0 en une paire cc. En ce qui concerne les resultats obtenus dans le cadre de cette these, la valeur moyenne de la distribution f_ {rm cto D^*}, notee cto D^*}>, est donnee par:cto D^*}>=0.530+/-0.027 +/-0.022ou la premiere erreur est statistique, et la seconde est systematique. On mesure aussi le taux de production des mesons D*, donnee par: {Gamma({rm Z^0to D^ *}X)overGamma_{rm hadrons}}=0.207+/-0.007+/-0.017 ou Gamma_{rm hadrons } est la largeur totale de la desintegration du Z^0 en paires de qq des cinq saveurs. La separation entre evenements rm Z^0to b| b et Z^0 to c| c, dans lesquels sont produits des D* se desintegrant selon rm D^ *to D^0pito (Kpi)pi, nous donne:(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)La variable de fragmentation x_ {rm cto D^*} est utilisee pour tester les modeles des processes perturbatifs et non-perturbatifs qui entrent en jeu lors de la fragmentation des quarks b et c

  12. Validation of Geant4 Hadronic Generators versus Thin Target Data

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, S.; /Fermilab; Folger, G.; /CERN; Ivanchenko, A.; /CERN /CENBG, Gradignan; Ivanchenko, V.N.; /CERN /NeurOK, Moscow /Metz U.; Kossov, M.; /CERN; Quesada, J.M.; /Seville U.; Schalicke, A.; /DESY, Zeuthen; Uzhinsky, V.; /CERN; Wenzel, H.; /Fermilab; Wright, D.H.; /SLAC; Yarba, J.; /Fermilab

    2012-04-19

    The GEANT4 toolkit is widely used for simulation of high energy physics (HEP) experiments, in particular, those at the Large Hadron Collider (LHC). The requirements of robustness, stability and quality of simulation for the LHC are demanding. This requires an accurate description of hadronic interactions for a wide range of targets over a large energy range, from stopped particle reactions to low energy nuclear interactions to interactions at the TeV energy scale. This is achieved within the Geant4 toolkit by combining a number of models, each of which are valid within a certain energy domain. Comparison of these models to thin target data over a large energy range indicates the strengths and weaknesses of the model descriptions and the energy range over which each model is valid. Software has been developed to handle the large number of validation tests required to provide the feedback needed to improve the models. An automated process for carrying out the validation and storing/displaying the results is being developed and will be discussed.

  13. Geant4 supplied parameters for gamma reaction history at NIF

    Science.gov (United States)

    Rubery, Michael; Horsfield, Colin; Herrmann, Hans; Kim, Yongho; Mack, Joe; Young, Carl; Evans, Scott; Sedillo, Tom; Miller, Kirk; Stoeffl, Wolfgang; Grafil, Elliot

    2011-10-01

    The GRH diagnostics at NIF and Omega report ICF burn parameters through detection of multi-MeV γ emissions. Of particular interest is ` γ bang-time' (GBT), defined as the temporal separation between light impacting the capsule and peak in the nuclear reaction history; GBT can constrain shock and compression parameters, and indicate fuel/ablator mix. Early NIF commissioning experiments have identified contributions to GRH signals from n,n' γ reactions with remaining capsule ablator, hohlraum and thermo-mechanical package, outside the fuel hotspot region. Such contributions are mitigated by increasing the Cherenkov threshold above the energy of these emissions. The pressure adjustment modifies parameters important to GBT, such as cell time-of-flight and detector FWHM; corrections simulated using Geant4 are presented using models experimentally validated at Duke University. Beyond GBT, studies suggest GRH may be capable of recording ablator ρR, unfolding the DT γ spectrum, and inferring the DTγ /DTn branching ratio. All calculations rely on the energy-resolved intensity response as a function of gas pressure. Geant4 response simulations, together with calculations by LANL using the experimentally validated ACCEPT code, are also presented.

  14. The Inner Detector software moves to Geant4

    CERN Multimedia

    Elsing, M

    2004-01-01

    2004 is a year of change and of several major milestones for the Inner Detector software. The first of these milestones was met in March when a set of test events was successfully processed through Geant4 and afterwards through the full Inner Detector offline software chain. In the picture, a reconstructed single muon event from this test sample is displayed in different projections. Even though this looks almost trivial, it required the successful integration of several new software components besides Geant4 into the Inner Detector code. A new ATLAS wide Detector Description software package called GeoModel has been fully deployed in the Inner Detector as the single source of geometry information for both the simulation and the reconstruction. New code to emulate the digitization for all detectors and a new data model have been put in place to cope with the new simulation input. And finally the two major offline reconstruction packages, namely xKalman and iPatRec, were migrated to use the new Inner Detector ...

  15. Les effets des interfaces sur les proprietes magnetiques et de transport des multicouches nickel/iron et cobalt/silver

    Science.gov (United States)

    Veres, Teodor

    Cette these est consacree a l'etude de l'evolution structurale des proprietes magnetiques et de transport des multicouches Ni/Fe et nanostructures a base de Co et de l'Ag. Dans une premiere partie, essentiellement bibliographique, nous introduisons quelques concepts de base relies aux proprietes magnetiques et de transport des multicouches metalliques. Ensuite, nous presentons une breve description des methodes d'analyse des resultats. La deuxieme partie est consacree a l'etude des proprietes magnetiques et de transport des multicouches ferromagnetiques/ferromagnetiques Ni/Fe. Nous montrerons qu'une interpretation coherente de ces proprietes necessite la prise en consideration des effets des interfaces. Nous nous attacherons a mettre en evidence, a evaluer et a etudier les effets de ces interfaces ainsi que leur evolution, et ce, suite a des traitements thermiques tel que le depot a temperature elevee et l'irradiation ionique. Les analyses correlees de la structure et de la magnetoresistance nous permettront d'emettre des conclusions sur l'influence des couches tampons entre l'interface et le substrat ainsi qu'entre les couches elles-memes sur le comportement magnetique des couches F/F. La troisieme partie est consacree aux systemes a Magneto-Resistance Geante (MRG) a base de Co et Ag. Nous allons etudier l'evolution de la microstructure suite a l'irradiation avec des ions Si+ ayant une energie de 1 MeV, ainsi que les effets de ces changements sur le comportement magnetique. Cette partie debutera par l'analyse des proprietes d'une multicouche hybride, intermediaire entre les multicouches et les materiaux granulaires. Nous analyserons a l'aide des mesures de diffraction, de relaxation superparamagnetique et de magnetoresistance, les evolutions structurales produites par l'irradiation ionique. Nous etablirons des modeles qui nous aideront a interpreter les resultats pour une serie des multicouches qui couvrent un large eventail de differents comportements magnetiques

  16. Combination of electromagnetic physics processes for microdosimetry in liquid water with the Geant4 Monte Carlo simulation toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Ivanchenko, V.N. [Ecoanalytica, 119899 Moscow (Russian Federation); Geant4 Associates International Ltd. (United Kingdom); Incerti, S., E-mail: incerti@cenbg.in2p3.fr [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, BP120, 33175 Gradignan (France); Francis, Z. [Universite Saint Joseph, Science Faculty, Department of Physics, Beirut (Lebanon); Tran, H.N.; Karamitros, M. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, BP120, 33175 Gradignan (France); Bernal, M.A. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas - UNICAMP, Campinas 13083-859 SP (Brazil); Champion, C. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, BP120, 33175 Gradignan (France); Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, 1 Boulevard Arago, Technopole 2000, 57078 Metz (France); Gueye, P. [Hampton University, Physics Department, Hampton, VA 23668 (United States); Collaboration: Geant4-DNA Collaboration

    2012-02-15

    The Geant4 Monte Carlo simulation toolkit provides a set of electromagnetic physics processes adapted to the detailed simulation of particle interactions in liquid water for microdosimetry applications, such as single-cell irradiation with light ion beams. These processes, developed within the framework of the Geant4-DNA project, adopt a software design allowing their combination with other electromagnetic physics processes available in the Geant4 toolkit. This work describes the combination of Geant4-DNA electron processes with Geant4 photon processes.

  17. Consistency evaluation between EGSnrc and Geant4 charged particle transport in an equilibrium magnetic field

    Science.gov (United States)

    Yang, Y. M.; Bednarz, B.

    2013-02-01

    Following the proposal by several groups to integrate magnetic resonance imaging (MRI) with radiation therapy, much attention has been afforded to examining the impact of strong (on the order of a Tesla) transverse magnetic fields on photon dose distributions. The effect of the magnetic field on dose distributions must be considered in order to take full advantage of the benefits of real-time intra-fraction imaging. In this investigation, we compared the handling of particle transport in magnetic fields between two Monte Carlo codes, EGSnrc and Geant4, to analyze various aspects of their electromagnetic transport algorithms; both codes are well-benchmarked for medical physics applications in the absence of magnetic fields. A water-air-water slab phantom and a water-lung-water slab phantom were used to highlight dose perturbations near high- and low-density interfaces. We have implemented a method of calculating the Lorentz force in EGSnrc based on theoretical models in literature, and show very good consistency between the two Monte Carlo codes. This investigation further demonstrates the importance of accurate dosimetry for MRI-guided radiation therapy (MRIgRT), and facilitates the integration of a ViewRay MRIgRT system in the University of Wisconsin-Madison's Radiation Oncology Department.

  18. Simulation of a Helical Channel using GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Elvira, V. D. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lebrun, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Spentzouris, P. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2001-02-01

    We present a simulation of a 72 m long cooling channel proposed by V. Balbekov based on the helical cooling concept developed by Ya. Derbenev. LiH wedge absorbers provide the energy loss mechanism and 201 MHz cavities are used for re-acceleration. They are placed inside a main solenoidal field to focus the beam. A helical field with an amplitude of 0.3 T and a period of 1.8 m provides momentum dispersion for emittance exchange.The simulation is performed using GEANT4. The total fractional transmission is 0.85, and the transverse, longitudinal, and 3-D cooling factors are 3.75, 2.27, and 14.61, respectively. Some version of this helical channel could eventually be used to replace the first section of the double flip channel to keep the longitudinal emittance under control and increase transmission. Although this is an interesting option, the technical challenges are still significant.

  19. Photon elastic scattering simulation: validation and improvements to Geant4

    CERN Document Server

    Batic, Matej; Pia, Maria Grazia; Saracco, Paolo

    2012-01-01

    Several models for the simulation of photon elastic scattering are quantitatively evaluated with respect to a large collection of experimental data retrieved from the literature. They include models based on the form factor approximation, on S-matrix calculations and on analytical parameterizations; they exploit publicly available data libraries and tabulations of theoretical calculations. Some of these models are currently implemented in general purpose Monte Carlo systems; some have been implemented and evaluated for the first time in this paper for possible use in Monte Carlo particle transport. The analysis mainly concerns the energy range between 5 keV and a few MeV. The validation process identifies the newly implemented model based on second order S-matrix calculations as the one best reproducing experimental measurements. The validation results show that, along with Rayleigh scattering, additional processes, not yet implemented in Geant4 nor in other major Monte Carlo systems, should be taken into acc...

  20. Low and High Energy Modeling in Geant4

    CERN Document Server

    Wright, Dennis H; Folger, Günter; Ivanchenko, Vladimir; Kossov, Mikhail; Starkov, Nikolai; Heikkinen, Aatos; Wellisch, Hans-Peter

    2007-01-01

    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.

  1. Low And High Energy Modeling in GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Dennis H.; Koi, Tatsumi; /SLAC; Folger, Gunter; Ivanchenko, Vladimir; Kossov, Mikhail; Starkov, Nikolai; /CERN; Heikkinen, Aatos; /Helsinki Inst. of Phys.; Wellisch,

    2007-10-05

    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.

  2. Recent Developments And Validations in Geant4 Hadronic Physics

    Energy Technology Data Exchange (ETDEWEB)

    Wright, D.H.; Koi, T.; Folger, G.; Ivanchenko, V.; Kossov, M.; Starkov, N.; Heikkinen, A.; Wellisch, H.P.; /SLAC /CERN /Helsinki Inst. of Phys.

    2007-02-12

    The Geant4 hadronic models cover the entire range of energies required by calorimeters in new and planned experiments. The extension and improvement of the elastic, cascade, parameterized and quark-gluon string models will be discussed. Such improvements include the extension to more particle types, a review and correction of cross sections, and a better treatment of energy and momentum conservation. Concurrent with this development has been a validation program which includes comparisons with double differential cross sections. An ongoing hadronic shower validation will also be discussed which includes the examination of longitudinal shower shapes and the performance of the above models as well as their interaction with electromagnetic processes such as multiple scattering.

  3. A GEANT4 simulation study of BESⅢ endcap TOF upgrade

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; SHAO Ming; LI Cheng; CHEN Hong-Fang; HENG Yue-Kun; SUN Yong-Jie; TANG Ze-Bo

    2013-01-01

    A GEANT4-based Monte-Carlo (MC) model is developed to study the performance of endcap timeof-flight (ETOF) at BESⅢ.It's found that the multiple scattering effects,mainly from the materials at the MDC endcap,can cause multi-hit on the ETOF's readout cell and significantly influence the timing property of ETOF.A multi-gap resistive plate chamber (MRPC) with a smaller readout cell structure is more suitable for the ETOF detector due to significantly reduced multi-hit rate (per channel),from 71.5% for currently-used scintillator-based ETOF to 21.8% or 16.7% for MRPC-based ETOF,depending on the readout pad size used.The timing performance of an MRPC ETOF is also improved.These simulation results suggest and guide an ETOF upgrade effort at BESⅢ.

  4. Integration of Geant4 with the Gaudi Framework

    Institute of Scientific and Technical Information of China (English)

    I.Belyaev; M.Frank; 等

    2001-01-01

    The GAUDI software framework is to be used for all event-processing applications in the LHCb experiment.The GEANT4 toolkit has been integrated into GAUDI to form the basis of the LHCb simulation program GAUSS.The benefits of this approach are that it permits re-use of basic services,such as persistency,interactivity and data visualization,as well as physics algorithms that were originally developed in the context of the reconstruction and analysis programs.Following the GAUDI philosophy,the integration has been achieved by developing a number of services with abstract interfaces that can be plugged in at run-time.We describe the overall design and details of the components for interfacing the detector geometry,the primary interaction and the output from tracking particles through the detector.

  5. Recent improvements on the description of hadronic interactions in Geant4

    Science.gov (United States)

    Dotti, A.; Apostolakis, J.; Folger, G.; Grichine, V.; Ivanchenko, V.; Kosov, M.; Ribon, A.; Uzhinsky, V.; Wright, D. H.

    2011-04-01

    We present an overview of recent improvements of hadronic models in Geant4 for the physics configurations (Physics Lists) relevant to applications in high energy experiments. During last year the improvements have concentrated on the study of unphysical discontinuities in calorimeter observables in the transition regions between the models used in Physics Lists. The microscopic origin of these have been investigated, and possible improvements of Geant4 code are currently under validation. In this paper we discuss the status of the latest version of Geant4 with emphasis on the most promising new developments, namely the Fritiof based and CHIPS Physics Lists.

  6. Geant4-related R&D for new particle transport methods

    CERN Document Server

    Augelli, M; Evans, T; Gargioni, E; Hauf, S; Kim, C H; Kuster, M; Pia, M G; Filho, P Queiroz; Quintieri, L; Saracco, P; Santos, D Souza; Weidenspointner, G; Zoglauer, A

    2009-01-01

    A R&D project has been launched in 2009 to address fundamental methods in radiation transport simulation and revisit Geant4 kernel design to cope with new experimental requirements. The project focuses on simulation at different scales in the same experimental environment: this set of problems requires new methods across the current boundaries of condensed-random-walk and discrete transport schemes. An exploration is also foreseen about exploiting and extending already existing Geant4 features to apply Monte Carlo and deterministic transport methods in the same simulation environment. An overview of this new R&D associated with Geant4 is presented, together with the first developments in progress.

  7. Simultaneous excitement of electron and ion resonances in a magnetoplasma by a high frequency electromagnetic field low frequency modulated; Excitation simultanee des resonances electronique et ionique dans un plasma dans un champ magnetique statique, produite par un champ electromagnetique HF module a une basse frequence

    Energy Technology Data Exchange (ETDEWEB)

    Zilli, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-07-01

    A single-particle, collisionless, non-relativistic theory is exposed, in which the possibility is shown of exciting electron and ion resonances in a magnetoplasma, by means of a high frequency electromagnetic field, whose amplitude is low frequency modulated. Two solutions of this problem are given in this report. The first one rests on the possibility of exciting the ion cyclotron resonance taking into account the low frequency electromagnetic field low frequency modulated. In the second solution the possibility of exciting the electron and ion resonances is considered in an electromagnetic field, whose magnetic component parallel to vector B{sub 0} is low frequency modulated. The results are discussed in the field of a cylindrical wave guide driven in the TE{sub 01}-mode, vector B{sub 0} being parallel to the axis. (Author) [French] On montre dans l'etude du mouvement d'une particule, lorsqu'on neglige les effets relativistes et les collisions, qu'il est possible d'exciter la resonance des electrons et des ions dans un plasma place dans un champ magnetique statique et dans un champ electromagnetique HF module en amplitude a une basse frequence. Dans cette note on presente deux solutions de ce probleme. La premiere repose sur la possibilite d'exciter la resonance cyclotron des ions en prenant en consideration le champ electromagnetique BF produit par les electrons qui tournent transversalement au champ magnetique statique B{sub 0}, sous l'influence d'un champ electromagnetique HF module a basse frequence. La deuxieme est celle ou le champ BF est une modulation, appliquee de l'exterieur, de l'amplitude de la composante magnetique du champ HF. On considere le cas ou cette composante magnetique oscillante est parallele a celle du champ magnetique statique. On discute les resultats dans le cas d'un mode TE{sub 01} se propageant dans un guide circulaire en presence d'un champ magnetique statique axial. (auteur)

  8. Research in Geant4 electromagnetic physics design, and its effects on computational performance and quality assurance

    CERN Document Server

    Augelli, M; Hauf, S; Kim, C H; Kuster, M; Pia, M G; Filho, P Queiroz; Quintieri, L; Saracco, P; Santos, D Souza; Weidenspointner, G; Zoglauer, A

    2009-01-01

    The Geant4 toolkit offers a rich variety of electromagnetic physics models; so far the evaluation of this Geant4 domain has been mostly focused on its physics functionality, while the features of its design and their impact on simulation accuracy, computational performance and facilities for verification and validation have not been the object of comparable attention yet, despite the critical role they play in many experimental applications. A new project is in progress to study the application of new design concepts and software techniques in Geant4 electromagnetic physics, and to evaluate how they can improve on the current simulation capabilities. The application of a policy-based class design is investigated as a means to achieve the objective of granular decomposition of processes; this design technique offers various advantages in terms of flexibility of configuration and computational performance. The current Geant4 physics models have been re-implemented according to the new design as a pilot project....

  9. GEANT 4: an Object-Oriented toolkit for simulation in HEP

    CERN Multimedia

    Kent, P; Sirotenko, V; Komogorov, M; Pavliouk, A; Greeniaus, G L; Kayal, P I; Routenburg, P; Tanaka, S; Duellmann, D; Innocente, V; Paoli, S; Ranjard, F; Riccardi, F; Ruggier, M; Shiers, J; Egli, S; Kimura, A; Urban, P; Prior, S; Walkden, A; Forti, A; Magni, S; Strahl, K; Kokoulin, R; Braune, K; Volcker, C; Ullrich, T; Takahata, M; Nieminen, P; Ballocchi, G; Mora De Freitas, P; Verderi, M; Rybine, A; Langeveld, W; Nagamatsu, M; Hamatsu, R; Katayama, N; Chuma, J; Felawka, L; Gumplinger, P; Axen, D

    2002-01-01

    %RD44 %title\\\\ \\\\The GEANT4 software has been developed by a world-wide collaboration of about 100 scientists from over 40 institutions and laboratories participating in more than 10 experiments in Europe, Russia, Japan, Canada, and the United States. The GEANT4 detector simulation toolkit has been designed for the next generation of High Energy Physics (HEP) experiments, with primary requirements from the LHC, the CP violation, and the heavy ions experiments. In addition, GEANT4 also meets the requirements from the space and medical communities, thanks to very low energy extensions developed in a joint project with the European Space Agency (ESA). GEANT4 has exploited advanced software engineering techniques (for example PSS-05) and Object-Oriented technology to improve the validation process of the physics results, and in the same time to make possible the distributed software design and development in the world-wide collaboration. Fifteen specialised working groups have been responsible for fields as diver...

  10. Experiences in the Gridification of the Geant4 Toolkit in the WLCG/EGEE Environment

    CERN Document Server

    Mendez-Lorenzo, R; Ribon, A

    2007-01-01

    The general patterns observed in supporting the Geant4 application in the EGEE infrastructure are discussed. Regression testing of Geant4 public releases is in the focus of this paper. Geant4 is a toolkit for the Monte Carlo simulation of the interaction of particle with matter, used by a wide field of research, including high energy and nuclear physics and also medical, accelerator and space physics studies. The support required for the release regression testing of Geant4 toolkit, including setting up of the new, official Virtual Organization in the EGEE, is explained. Recent developments of automatic regression testing suites and the benefits of the optimization layer above the standard Grid infrastructure are presented.

  11. Dental magnetic resonance tomography (dental-MRT) as a method for imaging of the maxillo-mandibular bone; Dentale Magnetresonanztomographie (Dental-MRT) als Verfahren zur Darstellung des maxillomandibulaeren Zahnhalteapparates

    Energy Technology Data Exchange (ETDEWEB)

    Gahleitner, A.; Nasel, C.; Schick, S.; Dorffner, S.; Imhof, H.; Trattnig, S. [Wien Univ. (Austria). Abt. fuer Osteologie; Bernhart, T.; Mailath, G.; Watzek, G. [Wien Univ. (Austria). Abt. fuer Orale Chirurgie

    1998-10-01

    Purpose: To establish a new method for dental imaging using magnetic resonance tomography named Dental-MRT and to demonstrate its usefulness in diagnosing dentogen pathologies of the mandible and maxilla. Methods: Seven healthy volunteers, three patients with pulpitis, two patients with dentigerous cysts, two patients after tooth transplantation, and three patients with atrophic mandibles have been evaluated. Optimized axial T{sub 1}- and T{sub 2}-weighted gradient echo and spin echo sequences in 2D and 3D technique have been established to perform studies of the jaws. The acquired images were reconstructed with a standard dental software package on a workstation as panorama and cross-sectional views of the mandible or maxilla. Results: The entire maxillo-mandibular bone, teeth, dental pulp, and the content of the mandibular canal were well depicted. Patients with pulpitis demonstrate bone marrow edema in the periapical region. Dentigerous cysts and their relation to the surrounding structures are clearly shown. After contrast media administration marked enhancement of the dental pulp can be demonstrated. Conclusion: Dental-MRT promises to provide a new tool for visualization and detection of dental diseases. (orig.) [Deutsch] Ziel: Das Vorstellen der Dental-MRT als neue Methode zur Darstellung des Ober- und Unterkiefers und ihre Anwendung bei der Diagnose zahnmedizinischer Erkankungen. Methoden: 7 gesunde Probanden, drei Patienten mit Pulpitis, zwei Patienten mit odontogenen Zysten, zwei Patienten nach Zahntransplantationen und drei Patienten mit atrophem Unterkiefer wurden untersucht. Optimierte axiale T{sub 1}- und T{sub 2}-gewichtete Gradienten-Echo- und Spin-Echo-Sequenzen in 2D und 3D-Technik wurden angewandt. Nach der Untersuchung wurden Panoramaschnitte und dentale Rekonstruktionen des Ober- und Unterkiefers, unter Verwendung einer gebraeuchlichen Dental-Software, angefertigt. Ergebnisse: Der gesamte Kieferbereich, Zaehne, Pulpa und der Inhalt des

  12. Monte Carlo simulation of the electron transport through thin slabs: A comparative study of PENELOPE, GEANT3, GEANT4, EGSnrc and MCNPX

    Energy Technology Data Exchange (ETDEWEB)

    Vilches, M. [Servicio de Fisica y Proteccion Radiologica, Hospital Regional Universitario ' Virgen de las Nieves' , Avda. de las Fuerzas Armadas, 2, E-18014 Granada (Spain)]. E-mail: mvilches@ugr.es; Garcia-Pareja, S. [Servicio de Radiofisica Hospitalaria, Hospital Regional Universitario ' Carlos Haya' , Avda. Carlos Haya, s/n, E-29010 Malaga (Spain)]. E-mail: garciapareja@gmail.com; Guerrero, R. [Servicio de Radiofisica, Hospital Universitario ' San Cecilio' , Avda. Dr. Oloriz, 16, E-18012 Granada (Spain)]. E-mail: rafael.guerrero.alcalde.sspa@juntadeandalucia.es; Anguiano, M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)]. E-mail: mangui@ugr.es; Lallena, A.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Granada, E-18071 Granada (Spain)]. E-mail: lallena@ugr.es

    2007-01-15

    The Monte Carlo simulation of the electron transport through thin slabs is studied with five general purpose codes: PENELOPE, GEANT3, GEANT4, EGSnrc and MCNPX. The different material foils analyzed in the old experiments of Kulchitsky and Latyshev [L.A. Kulchitsky, G.D. Latyshev, Phys. Rev. 61 (1942) 254] and Hanson et al. [A.O. Hanson, L.H. Lanzl, E.M. Lyman, M.B. Scott, Phys. Rev. 84 (1951) 634] are used to perform the comparison between the Monte Carlo codes. Non-negligible differences are observed in the angular distributions of the transmitted electrons obtained with the some of the codes. The experimental data are reasonably well described by EGSnrc, PENELOPE (v.2005) and GEANT4. A general good agreement is found for EGSnrc and PENELOPE (v.2005) in all the cases analyzed.

  13. Implementation of mathematical phantom of hand and forearm in GEANT4 Monte Carlo code; Implementacao de fantoma matematico de mao e antebraco em codigo Monte Carlo GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Pessanha, Paula Rocha; Queiroz Filho, Pedro Pacheco de; Santos, Denison de Souza, E-mail: pessanha.paular@gmail.com, E-mail: queiroz@ird.gov.br, E-mail: santosd@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ),Rio de Janeiro, RJ (Brazil)

    2014-07-01

    In this work, the implementation of a hand and forearm Geant4 phantom code, for further evaluation of occupational exposure of ends of the radionuclides decay manipulated during procedures involving the use of injection syringe. The simulation model offered by Geant4 includes a full set of features, with the reconstruction of trajectories, geometries and physical models. For this work, the values calculated in the simulation are compared with the measurements rates by thermoluminescent dosimeters (TLDs) in physical phantom REMAB®. From the analysis of the data obtained through simulation and experimentation, of the 14 points studied, there was a discrepancy of only 8.2% of kerma values found, and these figures are considered compatible. The geometric phantom implemented in Geant4 Monte Carlo code was validated and can be used later for the evaluation of doses at ends.

  14. Comparison of GEANT4 very low energy cross section models with experimental data in water

    Energy Technology Data Exchange (ETDEWEB)

    Incerti, S.; Ivanchenko, A.; Karamitros, M.; Mantero, A.; Moretto, P.; Tran, H. N.; Mascialino, B.; Champion, C.; Ivanchenko, V. N.; Bernal, M. A.; Francis, Z.; Villagrasa, C.; Baldacchino, G.; Gueye, P.; Capra, R.; Nieminen, P.; Zacharatou, C. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, BP 120, 33175 Gradignan (France); Karolinska Institutet, P.O. Box 260, S-171-76 Stockholm (Sweden); Laboratoire de Physique Moleculaire et des Collisions, Universite Paul Verlaine-Metz, 1 Boulevard Arago, Technopo circumflex le 2000, 57078 Metz (France); Departamento de Fisica, Universidad Simon Bolivar, P.O. Box 89000, Caracas 1080-A (Venezuela, Bolivarian Republic of); IRSN, Institut de Radioprotection et de Surete Nucleaire, BP17, 92262 Fontenay-aux-Roses (France); CEA Saclay, IRAMIS, UMR 3299 CEA-CNRS SIS2M, Laboratoire de Radiolyse, F-91191 Gif-sur-Yvette Cedex (France); Department of Physics, Hampton University, Hampton, Virginia 23668 (United States); Via Niella 12, 17100 Savona (Italy); ESA-ESTEC, 2200 AG Noordwijk (Netherlands); Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen (Denmark)

    2010-09-15

    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 (since 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

  15. Geant4 hadronic physics validation with ATLAS Tile Calorimeter test-beam data

    Science.gov (United States)

    Alexa, C.; Constantinescu, S.; DiÅ£ǎ, S.

    2006-10-01

    We present comparison studies between Geant4 shower packages and ATLAS Tile Calorimeter test-beam data collected at CERN in H8 beam line at the SPS. Emphasis is put on hadronic physics lists and data concerning differences between Tilecal response to pions and protons of same energy. The ratio between the pure hadronic fraction of pion and the pure hadronic fraction of proton Fhπ/Fhp was estimated with Tilecal test-beam data and compared with Geant4 simulations.

  16. The performance of the geant4 standard EM package for LHC and other applications

    CERN Document Server

    Apostolakis, J; Elles, S; Ivanchenko, V N; Kadri, O; Maire, M; Urbàn, L

    2008-01-01

    Current status of the Standard electro-magnetic (EM) package of the Geant4 toolkit is described. We report on the stability of results with respect to variation of production threshold and Physics List. This illustrates the trade between CPU time and precision of simulation predictions. New comparisons of the Geant4 simulation with the experimental data are shown. The CPU benchmark results are discussed.

  17. GEANT4 physics evaluation with testbeam data of the ATLAS hadronic end-cap calorimeter

    Science.gov (United States)

    Kiryunin, A. E.; Oberlack, H.; Salihagić, D.; Schacht, P.; Strizenec, P.

    2009-04-01

    The validation of GEANT4 physics models is done by comparing experimental data from beam tests of modules of the ATLAS hadronic end-cap calorimeter with GEANT4 based simulations. Various physics lists for the simulation of hadronic showers are evaluated. We present results of studies of the calorimeter performance parameters (like energy resolution and shower shapes) as well as results of investigations of the influence of the Birks' law and of cuts on the time of development of hadronic showers.

  18. Comparisons of Electron and Muon Signals in the Atlas Liquid Argon Calorimeters with GEANT4 Simulations

    Science.gov (United States)

    Benchekroun, D.; Karpetian, G.; Mazini, R.; Kiryunin, A.; Salihagic, D.; Strizenec, P.; Kish, J.; Kordas, K.; Parrour, G.; Leltchouk, M.; Negroni, S.; Seligman, W.; Loch, P.; Soukharev, A.

    2002-01-01

    Signals from electrons and muons taken at testbeams with different modules of the ATLAS Liquid Argon Calorimeter have been compared to corresponding simulations using the GEANT4 toolkit. These simulations have also been compared in some detail with GEANT3 based predictions. Results for signal linearity, energy resolution, and shower shapes all generally indicate a good agreement between experiment and the two simulation packages, typically at the level of a few percent.

  19. Inter-Comparison and Validation of Geant4 Photon Interaction Models

    CERN Document Server

    Augelli, M; Pia, M G; Queiroz, P P; Quintieri, L; Souza-Santos, D; Sudhakar, M; Saracco, P; Weidenspointner, G; Zoglauer, A

    2009-01-01

    A R&D project, named Nano5, has been recently launched to study an architectural design in view of addressing new experimental issues related to particle transport in high energy physics and other related physics disciplines with Geant4. In this frame, the first step has involved the redesign of the photon interaction models currently available in Geant4; this task has motivated a thorough investigation of the physics and computational features of these models, whose first results are presented here.

  20. Electron paramagnetic resonance study of radicals formed by radiolysis at 77 K of nitroalkanes and of their solutions in organic glasses. Chromatography analysis of radiolysis products of nitromethane in ethanol solution in a vitreous medium; Etude par resonance paramagnetique electronique des radicaux formes par radiolyse a 77 K des nitroalcanes et de leurs solutions dans les verres organiques analyse par chromatographie des produits de la radiolyse du nitromethane en solution dans l'ethanol en milieux vitreux

    Energy Technology Data Exchange (ETDEWEB)

    Rosilio, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-05-01

    With a view to explaining the formation of the final products resulting from the photolysis and the radiolysis of nitro-alkanes, we have attempted to identify the paramagnetic species formed as intermediates during the radiolysis. Our work has covered the structure and the reactivity of the radicals formed by 7 irradiation of the nitrogen containing derivatives at 77 K, and on the mechanism of formation and of disappearance of these radicals in the various matrices used. The radicals resulting from the removal of a hydrogen atom in the {alpha} position of the NO{sub 2} group, and the radicals resulting from addition reactions on the nitrogen group characterized by an unpaired electron on the nitrogen have been identified, either during the radiolysis of pure nitroalkanes, or during the radiolysis of nitro-alkanes in solution in organic glasses at 77 K. A study has been made of the conformation and the movements of radicals in the matrices, and the mechanism of formation of the observed radicals produced generally by the capture by the nitro-alkanes of primary radiolysis species. The nitro-alkanes in ethanol solution can behave as traps both for electrons and for free radicals. The study of the radiolysis of nitro-alkanes in solution in a polar ethanol glass has been completed with chemical analyses on the final radiolysis products; it has been possible to deduce the capture efficiency of trapped electrons and of free radicals by nitro-alkanes in ethanol. For this we have determined the radio-chemical yields of hydrogen, acetaldehyde and glycol as a function of the capture agent concentration, for the nitro-methane-ethanol system. A mechanism for the disappearance of the observed radicals is proposed. (author) [French] Dans le but d'expliquer la formation des produits finals formes au cours de la photolyse et la radiolyse des nitroalcanes, nous nous sommes proposes d'identifier les especes paramagnetiques se formant intermediairement au cours de la

  1. Geant4 simulations of the lead fluoride calorimeter

    Science.gov (United States)

    Savchenko, A. A.; Tishchenko, A. A.; Dabagov, S. B.; Anastasi, A.; Venanzoni, G.; Strikhanov, M. N.; Basti, A.; Bedeschi, F.; Bartolini, M.; Cantatore, G.; Cauz, D.; Corradi, G.; Di Sciascio, G.; Di Stefano, R.; Driutti, A.; Escalante, O.; Ferrari, C.; Fioretti, A.; Gabbanini, C.; Gioiosa, A.; Hampai, D.; Iacovacci, M.; Karuza, M.; Liedl, A.; Lusiani, A.; Marignetti, F.; Mastroianni, S.; Moricciani, D.; Pauletta, G.; Piacentino, G. M.; Raha, N.; Santi, L.

    2017-07-01

    In this paper we simulate the charged particle interaction with complex structures, including the emission, with help of Geant4. We take into account Cherenkov radiation, transition radiation, bremsstrahlung, pair production and other accompanying processes. As an application we investigate the full size electromagnetic calorimeter for the muon g-2 experiment at Fermilab. A calorimeter module consists of a Delrin front panel for installation of the laser calibration system, 54 PbF2 Cherenkov crystals wrapped by black Tedlar paper, and silicon photo-multiplier sensors. We report here on results of a simulation of the radiation from positrons striking the calorimeter system. The Cherenkov radiation expansion when a positron moves down through the calorimeter at the arbitrary angle of incidence has been considered. Both spectral and angular distributions of Cherenkov optical photons in different parts of the calorimeter system was evaluated as well as the transition radiation and pre-shower distributions from both the Delrin panel and the Al vacuum chamber of the g-2 storage ring.

  2. Design and performance evaluations of generic programming techniques in a R&D prototype of Geant4 physics

    CERN Document Server

    Pia, M G; Sudhakar, M; Zoglauer, A; Augelli, M; Gargioni, E; Kim, C H; Quintieri, L; Filho, P P de Queiroz; Santos, D de Souza; Weidenspointner, G; Begalli, M

    2010-01-01

    A R&D project has been recently launched to investigate Geant4 architectural design in view of addressing new experimental issues in HEP and other related physics disciplines. In the context of this project the use of generic programming techniques besides the conventional object oriented is investigated. Software design features and preliminary results from a new prototype implementation of Geant4 electromagnetic physics are illustrated. Performance evaluations are presented. Issues related to quality assurance in Geant4 physics modelling are discussed.

  3. Study of some properties of 's' neutron resonance parameters for target nuclei I = 1/2 and I = 3/2 in function of spin value J = I + 1/2 in the energy range 1 {yields} 5000 eV; Etude de quelques proprietes des parametres de resonances des neutrons ''s'' pour des noyaux cibles I = 1/2 et I = 3/2 en fonction de la valeur du spin J = I + 1/2 dans le domaine d'energie 1 eV {yields} 5000 eV

    Energy Technology Data Exchange (ETDEWEB)

    Julien, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-05-15

    Different kinds of experiments and analysis methods allowing to achieve neutron resonances parameters in the low energy range (1 eV {yields} 5000 eV) are described. A great deal of effort to improve experimental conditions and data processing in order to know the spin value J = I {+-} 1/2 has been spent. The time of flight method was used. A few target nuclei I = 3/2 and 1 = 1/2 have been studied. For I = 3/2 (Ga, As, 3r, Au) we find S{sub o} J = 2 {approx_equal} 2 S{sub o} J = 1 and S{sub o} J = 1 {approx_equal} S{sub o} J = 0 for I = 1/2 (Tm, Pt) but {sup 77}Se. Fluctuations of the total radiative width {gamma}{sub {gamma}} depend on the spin value I = I {+-} 1/2 when E1 transition, are enhanced for one of the both spin states. The magnitude of these fluctuations can be explained of the strength of E1 transitions (E{sub {gamma}} {approx} 7 MeV) is supposed to be proportional to E{sup 5}{sub {gamma}} instead of E{sup 3}{sub {gamma}}. The distribution of levels spacings against spin value J are considered and are compared to theoretical predictions. (author) [French] On decrit les differentes methodes d'analyse permettant d'obtenir les parametres des resonances de neutron dans le domaine d'energie 1 eV {yields} 5000 eV. Un effort particulier a ete fait pour connaitre la valeur du spin J = I {+-} 1/2. Les types d'experience et les analyses des donnees, developpes et ameliores pour determiner J sont decrits. Les resultats obtenus ont permis l'etude de differentes proprietes en fonction du spin J. On trouve: S{sub o} J 2 {approx_equal} 2 S{sub o} J = 1 pour les noyaux I = 3/2 etudies (Ga, As, Br, Au) et S{sub o} J = 1 {approx_equal} S{sub o} J = 0 Pour le Tm et {sup 195}Pt de spin I = 1/2. On constate que les largeurs radiatives totales {gamma}{sub {gamma}} fluctuent si des transitions E1 aux premiers etats excites sont favorisees. Ces fluctuations peuvent etre expliquees si on suppose que les intensites de ces transitions sont

  4. New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction; Nouvelles etudes structurales de cristaux liquides par reflectivite et diffraction resonante des rayons X

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, P

    2007-04-15

    This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B{sub 2} liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B{sub 2} phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation.

  5. Comparisons of the Electron and Muon Testbeam Response of the ATLAS Liquid Argon Calorimeters with GEANT4 Simulations

    CERN Document Server

    Benchekroun, D; Karapetian, G V; Kiryunin, A E; Kish, J; Kordas, K; Leltchouk, M; Loch, P; Mazini, R; Negroni, S; Parrour, G; Salihagic, D; Seligman, W; Soukharev, A M; Strízenec, P; Unal, G

    2004-01-01

    GEANT4, a new simulation toolkit, is now in use by the different sub-detectors which are currently being built and tested for the ATLAS experiment. The validation of the GEANT4 electromagnetic physics is done by comparing the response of the various modules of the ATLAS liquid argon calorimeters to electron and muon test beams to the results of GEANT4 simulations. Comparisons to the corresponding GEANT3 predictions has been done as well. This note presents the status of the work on this validation.

  6. Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm

    Science.gov (United States)

    Famulari, Gabriel; Pater, Piotr; Enger, Shirin A.

    2017-07-01

    The aim of this study was to calculate microdosimetric distributions for low energy electrons simulated using the Monte Carlo track structure code Geant4-DNA. Tracks for monoenergetic electrons with kinetic energies ranging from 100 eV to 1 MeV were simulated in an infinite spherical water phantom using the Geant4-DNA extension included in Geant4 toolkit version 10.2 (patch 02). The microdosimetric distributions were obtained through random sampling of transfer points and overlaying scoring volumes within the associated volume of the tracks. Relative frequency distributions of energy deposition f(>E)/f(>0) and dose mean lineal energy (\\bar{y}D ) values were calculated in nanometer-sized spherical and cylindrical targets. The effects of scoring volume and scoring techniques were examined. The results were compared with published data generated using MOCA8B and KURBUC. Geant4-DNA produces a lower frequency of higher energy deposits than MOCA8B. The \\bar{y}D values calculated with Geant4-DNA are smaller than those calculated using MOCA8B and KURBUC. The differences are mainly due to the lower ionization and excitation cross sections of Geant4-DNA for low energy electrons. To a lesser extent, discrepancies can also be attributed to the implementation in this study of a new and fast scoring technique that differs from that used in previous studies. For the same mean chord length (\\bar{l} ), the \\bar{y}D calculated in cylindrical volumes are larger than those calculated in spherical volumes. The discrepancies due to cross sections and scoring geometries increase with decreasing scoring site dimensions. A new set of \\bar{y}D values has been presented for monoenergetic electrons using a fast track sampling algorithm and the most recent physics models implemented in Geant4-DNA. This dataset can be combined with primary electron spectra to predict the radiation quality of photon and electron beams.

  7. Study of neutrons resonances as a function of spin for the nuclei I = 1/2 (silver, thulium, platinum) between 1 and 800 eV; Etude des resonnances de neutrons en foncton de leur spin pour les noyaux I = 1/2 (argent, thulium et platine) entre 1 et 800 eV

    Energy Technology Data Exchange (ETDEWEB)

    De Barros, S.M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1966-04-01

    The assignment of spins has been made for 120 levels of 239 detected. From these data we have deduced that: - The ratio of average spacing of each state of spin obeys the law of 2 J + 1. - The values of the strength function of {sup 195}Pt and {sup 169}Tm are in agreement with the model of Chase et Al and has the same values for the two states of spin. - The fluctuations of total radiation widths of resonances are observed in the case of {sup 195}Pt for the two spin-states. - The neutron widths are governed by the distributions of Porter and Thomas with one degree of freedom; the observed spacings are consistent with the Wigner distribution for two populations. (author) [French] L'attribution de spin a ete faite pour 120 niveaux sur 239 detectes. On en deduit: - Le rapport des espacements moyens pour chaque etat de spin qui obeit a la loi en (2j + 1). - Les valeurs des fonctions densites de {sup 195}Pt et {sup 169}Tm sont en accord avec le modele du noyau deforme de Chase et al. et ont la meme valeur pour les deux etats de spin. - Des fluctuations, dans les largeurs radiatives totales des resonances sont observees dans le cas de {sup 195}Pt pour les deux etats de spin. - Les largeurs de diffusion suivent les distributions de Porter et Thomas a un degre de liberte; les espacements celles de Wigner a deux populations. (auteur)

  8. Extending Geant4 Parallelism with External Libraries (MPI, TBB) and Its Use on HPC Resources

    CERN Document Server

    Dotti, Andrea; Barrand, Guy; Hrivnacova, Ivana; Murakami, Koichi

    2016-01-01

    With Geant4 Version 10.0, released in December 2013, one of the most widely used Monte-Carlo codes has been ported to take full advantage of multi- and many-core CPUs thanks to the introduction of event-level parallelism via multithreading. In this paper we review recent developments to allow for a better integration of parallel Geant4 jobs with external libraries. We have chosen to develop examples using the popular Intel Threading Building Block (for short TBB) as an alternative parallelization approach to the native Geant4 POSIX. To simplify the scaling of a Geant4 application across nodes on a cluster we are improving the support of MPI in Geant4. In particular it is now possible to run an hybrid MPI/MT application that uses MPI to scale across nodes and MT to scale across cores. %The recent developments allow users to easily implement parallel application resources that scale on a very large number of nodes and cores typical of HPC resources.

  9. Review of Geant4-DNA applications for micro and nanoscale simulations.

    Science.gov (United States)

    Incerti, S; Douglass, M; Penfold, S; Guatelli, S; Bezak, E

    2016-10-01

    Emerging radiotherapy treatments including targeted particle therapy, hadron therapy or radiosensitisation of cells by high-Z nanoparticles demand the theoretical determination of radiation track structure at the nanoscale. This is essential in order to evaluate radiation damage at the cellular and DNA level. Since 2007, Geant4 offers physics models to describe particle interactions in liquid water at the nanometre level through the Geant4-DNA Package. This package currently provides a complete set of models describing the event-by-event electromagnetic interactions of particles with liquid water, as well as developments for the modelling of water radiolysis. Since its release, Geant4-DNA has been adopted as an investigational tool in kV and MV external beam radiotherapy, hadron therapies using protons and heavy ions, targeted therapies and radiobiology studies. It has been benchmarked with respect to other track structure Monte Carlo codes and, where available, against reference experimental measurements. While Geant4-DNA physics models and radiolysis modelling functionalities have already been described in detail in the literature, this review paper summarises and discusses a selection of representative papers with the aim of providing an overview of a) geometrical descriptions of biological targets down to the DNA size, and b) the full spectrum of current micro- and nano-scale applications of Geant4-DNA.

  10. Use of GEANT4 vs. MCNPX for the characterization of a boron-lined neutron detector

    Science.gov (United States)

    van der Ende, B. M.; Atanackovic, J.; Erlandson, A.; Bentoumi, G.

    2016-06-01

    This work compares GEANT4 with MCNPX in the characterization of a boron-lined neutron detector. The neutron energy ranges simulated in this work (0.025 eV to 20 MeV) are the traditional domain of MCNP simulations. This paper addresses the question, how well can GEANT4 and MCNPX be employed for detailed thermal neutron detector characterization? To answer this, GEANT4 and MCNPX have been employed to simulate detector response to a 252Cf energy spectrum point source, as well as to simulate mono-energetic parallel beam source geometries. The 252Cf energy spectrum simulation results demonstrate agreement in detector count rate within 3% between the two packages, with the MCNPX results being generally closer to experiment than are those from GEANT4. The mono-energetic source simulations demonstrate agreement in detector response within 5% between the two packages for all neutron energies, and within 1% for neutron energies between 100 eV and 5 MeV. Cross-checks between the two types of simulations using ISO-8529 252Cf energy bins demonstrates that MCNPX results are more self-consistent than are GEANT4 results, by 3-4%.

  11. Validation of Geant4 fragmentation for Heavy Ion Therapy

    Science.gov (United States)

    Bolst, David; Cirrone, Giuseppe A. P.; Cuttone, Giacomo; Folger, Gunter; Incerti, Sebastien; Ivanchenko, Vladimir; Koi, Tatsumi; Mancusi, Davide; Pandola, Luciano; Romano, Francesco; Rosenfeld, Anatoly B.; Guatelli, Susanna

    2017-10-01

    12C ion therapy has had growing interest in recent years for its excellent dose conformity. However at therapeutic energies, which can be as high as 400 MeV/u, carbon ions produce secondary fragments. For an incident 400 MeV/u 12C ion beam, ∼ 70 % of the beam will undergo fragmentation before the Bragg Peak. The dosimetric and radiobiological impact of these fragments must be accurately characterised, as it can result in increasing the risk of secondary cancer for the patient as well as altering the relative biological effectiveness. This work investigates the accuracy of three different nuclear fragmentation models available in the Monte Carlo Toolkit Geant4, the Binary Intranuclear Cascade (BIC), the Quantum Molecular Dynamics (QMD) and the Liege Intranuclear Cascade (INCL++). The models were benchmarked against experimental data for a pristine 400 MeV/u 12C beam incident upon a water phantom, including fragment yield, angular and energy distribution. For fragment yields the three alternative models agreed between ∼ 5 and ∼ 35 % with experimental measurements, the QMD using the ;Frag; option gave the best agreement for lighter fragments but had reduced agreement for larger fragments. For angular distributions INCL++ was seen to provide the best agreement among the models for all elements with the exception of Hydrogen, while BIC and QMD was seen to produce broader distributions compared to experiment. BIC and QMD performed similar to one another for kinetic energy distributions while INCL++ suffered from producing lower energy distributions compared to the other models and experiment.

  12. Low-energy electron dose-point kernel simulations using new physics models implemented in Geant4-DNA

    Energy Technology Data Exchange (ETDEWEB)

    Bordes, Julien, E-mail: julien.bordes@inserm.fr [CRCT, UMR 1037 INSERM, Université Paul Sabatier, F-31037 Toulouse (France); UMR 1037, CRCT, Université Toulouse III-Paul Sabatier, F-31037 (France); Incerti, Sébastien, E-mail: incerti@cenbg.in2p3.fr [Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Lampe, Nathanael, E-mail: nathanael.lampe@gmail.com [Université de Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Bardiès, Manuel, E-mail: manuel.bardies@inserm.fr [CRCT, UMR 1037 INSERM, Université Paul Sabatier, F-31037 Toulouse (France); UMR 1037, CRCT, Université Toulouse III-Paul Sabatier, F-31037 (France); Bordage, Marie-Claude, E-mail: marie-claude.bordage@inserm.fr [CRCT, UMR 1037 INSERM, Université Paul Sabatier, F-31037 Toulouse (France); UMR 1037, CRCT, Université Toulouse III-Paul Sabatier, F-31037 (France)

    2017-05-01

    When low-energy electrons, such as Auger electrons, interact with liquid water, they induce highly localized ionizing energy depositions over ranges comparable to cell diameters. Monte Carlo track structure (MCTS) codes are suitable tools for performing dosimetry at this level. One of the main MCTS codes, Geant4-DNA, is equipped with only two sets of cross section models for low-energy electron interactions in liquid water (“option 2” and its improved version, “option 4”). To provide Geant4-DNA users with new alternative physics models, a set of cross sections, extracted from CPA100 MCTS code, have been added to Geant4-DNA. This new version is hereafter referred to as “Geant4-DNA-CPA100”. In this study, “Geant4-DNA-CPA100” was used to calculate low-energy electron dose-point kernels (DPKs) between 1 keV and 200 keV. Such kernels represent the radial energy deposited by an isotropic point source, a parameter that is useful for dosimetry calculations in nuclear medicine. In order to assess the influence of different physics models on DPK calculations, DPKs were calculated using the existing Geant4-DNA models (“option 2” and “option 4”), newly integrated CPA100 models, and the PENELOPE Monte Carlo code used in step-by-step mode for monoenergetic electrons. Additionally, a comparison was performed of two sets of DPKs that were simulated with “Geant4-DNA-CPA100” – the first set using Geant4′s default settings, and the second using CPA100′s original code default settings. A maximum difference of 9.4% was found between the Geant4-DNA-CPA100 and PENELOPE DPKs. Between the two Geant4-DNA existing models, slight differences, between 1 keV and 10 keV were observed. It was highlighted that the DPKs simulated with the two Geant4-DNA’s existing models were always broader than those generated with “Geant4-DNA-CPA100”. The discrepancies observed between the DPKs generated using Geant4-DNA’s existing models and “Geant4-DNA-CPA100” were

  13. Des tuiles, des toits et des couleurs

    OpenAIRE

    Bonnot, Thierry

    2007-01-01

    La Bourgogne est une des régions françaises dont l’image de marque est le plus imprégnée par la notion de tradition. Elle est présentée comme un terroir où il fait bon vivre, où la gastronomie demeure à travers les siècles une valeur de base, où les paysages sont majestueux et où la gloire passée est sans cesse rappelée par de somptueux monuments. Parmi quelques emblèmes, l’hôtel-Dieu de Beaune et ses toitures de tuiles colorées sont très souvent mobilisés pour représenter ces valeurs « tradi...

  14. Application of GEANT4 radiation transport toolkit to dose calculations in anthropomorphic phantoms

    CERN Document Server

    Rodrigues, P; Peralta, L; Alves, C; Chaves, A; Lopes, M C

    2003-01-01

    In this paper we present the implementation of a dose calculation application, based on the GEANT4 Monte Carlo toolkit. Validation studies were performed with an homogeneous water phantom and an Alderson--Rando anthropomorphic phantom both irradiated with high--energy photon beams produced by a clinical linear accelerator. As input, this tool requires computer tomography images for automatic codification of voxel based geometries and phase space distributions to characterize the incident radiation field. Simulation results were compared with ionization chamber, thermoluminescent dosimetry data and commercial treatment planning system calculations. In homogeneous water phantom, overall agreement with measurements were within 1--2%. For anthropomorphic simulated setups (thorax and head irradiation) mean differences between GEANT4 and TLD measurements were less than 2%. Significant differences between GEANT4 and a semi--analytical algorithm implemented in the treatment planning system, were found in low density ...

  15. MeV Neutron Production from Thermal Neutron Capture in {6}^Li Simulated with Geant4

    CERN Document Server

    Santoro, Valentina; Bentley, Phillip M

    2015-01-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to $\\gamma$-ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for $^6$Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  16. Validation of Geant4 physics models for {sup 56}Fe ion beam in various media

    Energy Technology Data Exchange (ETDEWEB)

    Jalota, Summit, E-mail: summit.jalota@gmail.com [Department of Physics, National Institute of Technology, Kurukshetra 136 119 (India); Kumar, Ashavani, E-mail: ashavani@yahoo.com [Department of Physics, National Institute of Technology, Kurukshetra 136 119 (India)

    2012-11-15

    The depth-dose distribution of a {sup 56}Fe ion beam has been studied in water, polyethylene, nextel, kevlar and aluminum media. The dose reduction versus areal depth is also calculated for {sup 56}Fe ions in carbon, polyethylene and aluminum using the Monte Carlo simulation toolkit Geant4. This study presents the validation of physics models available in Geant4 by comparing the simulated results with the experimental data available in the literature. Simulations are performed using binary cascade (BIC), abrasion-ablation (AA) and quantum molecular dynamics (QMD) models; integrated into Geant4. Deviations from experimental results may be due to the selection of simple geometry. This paper also addresses the differences in the simulated results from various models.

  17. MeV Neutron Production from Thermal Neutron Capture in 6Li Simulated With Geant4

    Science.gov (United States)

    Santoro, Valentina; DiJulio, Douglas D.; Bentley, Phillip M.

    2016-09-01

    Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to y- ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for 6 Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.

  18. Validation of recent Geant4 physics models for application in carbon ion therapy

    CERN Document Server

    Lechner, A; Ivanchenko, V N

    2010-01-01

    Cancer treatment with energetic carbon ions has distinct advantages over proton or photon irradiation. In this paper we present a simulation model integrated into the Geant4 Monte Carlo toolkit (version 9.3) which enables the use of ICRU 73 stopping powers for ion transport calculations. For a few materials, revised ICRU 73 stopping power tables recently published by ICRU (P. Sigmund, A. Schinner, H. Paul, Errata and Addenda: ICRU Report 73 (Stopping of Ions Heavier than Helium), International Commission on Radiation Units and Measurements, 2009) were incorporated into Geant4, also covering media like water which are of importance in radiotherapeutical applications. We examine, with particular attention paid to the recent developments, the accuracy of current Geant4 models for simulating Bragg peak profiles of C-12 ions incident on water and polyethylene targets. Simulated dose distributions are validated against experimental data available in the literature, where the focus is on beam energies relevant to io...

  19. Modeling the relativistic runaway electron avalanche and the feedback mechanism with GEANT4

    Science.gov (United States)

    Skeltved, Alexander Broberg; Østgaard, Nikolai; Carlson, Brant; Gjesteland, Thomas; Celestin, Sebastien

    2014-01-01

    This paper presents the first study that uses the GEometry ANd Tracking 4 (GEANT4) toolkit to do quantitative comparisons with other modeling results related to the production of terrestrial gamma ray flashes and high-energy particle emission from thunderstorms. We will study the relativistic runaway electron avalanche (RREA) and the relativistic feedback process, as well as the production of bremsstrahlung photons from runaway electrons. The Monte Carlo simulations take into account the effects of electron ionization, electron by electron (Møller), and electron by positron (Bhabha) scattering as well as the bremsstrahlung process and pair production, in the 250 eV to 100 GeV energy range. Our results indicate that the multiplication of electrons during the development of RREAs and under the influence of feedback are consistent with previous estimates. This is important to validate GEANT4 as a tool to model RREAs and feedback in homogeneous electric fields. We also determine the ratio of bremsstrahlung photons to energetic electrons Nγ/Ne. We then show that the ratio has a dependence on the electric field, which can be expressed by the avalanche time τ(E) and the bremsstrahlung coefficient α(ε). In addition, we present comparisons of GEANT4 simulations performed with a “standard” and a “low-energy” physics list both validated in the 1 keV to 100 GeV energy range. This comparison shows that the choice of physics list used in GEANT4 simulations has a significant effect on the results. Key Points Testing the feedback mechanism with GEANT4 Validating the GEANT4 programming toolkit Study the ratio of bremsstrahlung photons to electrons at TGF source altitude PMID:26167437

  20. New experimental determination of the neutronic resonance parameters of {sup 237}Np below 500 eV; Nouvelle determination experimentale des parametres de resonances neutroniques de {sup 237}Np en dessous de 500 eV

    Energy Technology Data Exchange (ETDEWEB)

    Gressier, V

    1999-10-01

    For studies of future nuclear reactors dedicated to nuclear waste transmutation, an improvement of the accuracy of the neutron radiative capture cross section of {sup 237}Np appears necessary. In the framework of a collaboration between the Commissariat a l'Energie atomique (CEA) and Institute for Reference Materials and Measurement (IRMM, Geel, Bergium), a new determination of the resonance parameters of {sup 237}Np has been performed. Two types of experiments are carried out at GELINA, the IRMM pulsed neutron source, using the time of flight method: a transmission experiment which is related to the neutron total cross section and a capture experiment which gives the neutron radiative capture cross section. The resonance parameters presented in this work are extracted from the transmission data between 0 and 500 eV with the least square code REFIT, using the Reich-Moore formalism. In parallel, the Doppler effect is investigated. The commonly used free gas model appears inadequate below 20 eV for neptunium dioxide at room temperature. By the use of the program DOPUSH, which calculates the Doppler broadening with a harmonic crystal model according to Lamb's theory, we are able to produce abetter fit of the experimental data for the resonances of {sup 237}Np in NpO{sub 2} at low energy or temperatures. In addition to the resonance parameters, a study of their mean value and distribution is included in this work. (authors)

  1. SU-E-T-565: RAdiation Resistance of Cancer CElls Using GEANT4 DNA: RACE

    Energy Technology Data Exchange (ETDEWEB)

    Perrot, Y; Payno, H; Delage, E; Maigne, L [Clermont Universite, CNRS/IN2P3, Laboratoire de Physique Corpusculaire de Clermont-Ferrand, Aubiere (France); Incerti, S [Universite Bordeaux 1, CNRS/IN2P3, Centres d' Etudes Nucleaires de Bordeaux-Gradignan, Gradignan (France); Debiton, E; Peyrode, C; Chezal, J; Miot-Noirault, E; Degoul, F [Clermont Universite, Universite d' Auvergne, Imagerie Moleculaire et Therapie Vectorisee, INSERM U990, Centre Jean Perrin, Clermont-Ferrand (France)

    2014-06-01

    Purpose: The objective of the RACE project is to develop a comparison between Monte Carlo simulation using the Geant4-DNA toolkit and measurements of radiation damage on 3D melanoma and chondrosarcoma culture cells coupled with gadolinium nanoparticles. We currently expose the status of the developments regarding simulations. Methods: Monte Carlo studies are driven using the Geant4 toolkit and the Geant4-DNA extension. In order to model the geometry of a cell population, the opensource CPOP++ program is being developed for the geometrical representation of 3D cell populations including a specific cell mesh coupled with a multi-agent system. Each cell includes cytoplasm and nucleus. The correct modeling of the cell population has been validated with confocal microscopy images of spheroids. The Geant4 Livermore physics models are used to simulate the interactions of a 250 keV X-ray beam and the production of secondaries from gadolinium nanoparticles supposed to be fixed on the cell membranes. Geant4-DNA processes are used to simulate the interactions of charged particles with the cells. An atomistic description of the DNA molecule, from PDB (Protein Data Bank) files, is provided by the so-called PDB4DNA Geant4 user application we developed to score energy depositions in DNA base pairs and sugar-phosphate groups. Results: At the microscopic level, our simulations enable assessing microscopic energy distribution in each cell compartment of a realistic 3D cell population. Dose enhancement factors due to the presence of gadolinium nanoparticles can be estimated. At the nanometer scale, direct damages on nuclear DNA are also estimated. Conclusion: We successfully simulated the impact of direct radiations on a realistic 3D cell population model compatible with microdosimetry calculations using the Geant4-DNA toolkit. Upcoming validation and the future integration of the radiochemistry module of Geant4-DNA will propose to correlate clusters of ionizations with in vitro

  2. Experimental spectra analysis in THM with the help of simulation based on Geant4 framework

    CERN Document Server

    Li, Chengbo; Zhou, Shuhua; Fu, Yuanyong; Zhou, Jing; Meng, Qiuying; Jiang, Zongjun; Wang, Xiaolian

    2014-01-01

    The Coulomb barrier and electron screening cause difficulties in directly measuring nuclear reaction cross sections of charged particles in astrophysical energies. The Trojan-horse method has been introduced to solve the difficulties as a powerful indirect tool. In order to understand experimental spectra better, Geant4 is employed to simulate the method for the first time. Validity and reliability of the simulation are examined by comparing the experimental data with simulated results. The Geant4 simulation can give useful information to understand the experimental spectra better in data analysis and is beneficial to the design for future related experiments.

  3. Semiconductor phonon and charge transport Monte Carlo simulation using Geant4

    CERN Document Server

    Brandt, D; Redl, P; Schneck, K; Asai, M; Kelsey, M; Faiez, D; Bagli, E; Cabrera, B; Partridge, R; Saab, T; Sadoulet, B

    2014-01-01

    A phonon and charge transport simulation based on the Geant4 Monte Carlo toolkit is presented. The transport code is capable of propagating acoustic phonons, electrons and holes in cryogenic crystals. Anisotropic phonon propagation, oblique carrier propagation and phonon emission by accelerated carriers are all taken into account. The simulation successfully reproduces theoretical predictions and experimental observations such as phonon caustics, heat pulse propagation times and mean carrier drift velocities. Implementation of the transport code using the Geant4 toolkit ensures availability to the wider scientific community.

  4. Calculation of neutron fluence to dose equivalent conversion coefficients using GEANT4; Calculo de coeficientes de fluencia de neutrons para equivalente de dose individual utilizando o GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rosane M.; Santos, Denison de S.; Queiroz Filho, Pedro P. de; Mauricio, CLaudia L.P.; Silva, Livia K. da; Pessanha, Paula R., E-mail: rosanemribeiro@oi.com.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    Fluence to dose equivalent conversion coefficients provide the basis for the calculation of area and personal monitors. Recently, the ICRP has started a revision of these coefficients, including new Monte Carlo codes for benchmarking. So far, little information is available about neutron transport below 10 MeV in tissue-equivalent (TE) material performed with Monte Carlo GEANT4 code. The objective of this work is to calculate neutron fluence to personal dose equivalent conversion coefficients, H{sub p} (10)/Φ, with GEANT4 code. The incidence of monoenergetic neutrons was simulated as an expanded and aligned field, with energies ranging between thermal neutrons to 10 MeV on the ICRU slab of dimension 30 x 30 x 15 cm{sup 3}, composed of 76.2% of oxygen, 10.1% of hydrogen, 11.1% of carbon and 2.6% of nitrogen. For all incident energy, a cylindrical sensitive volume is placed at a depth of 10 mm, in the largest surface of the slab (30 x 30 cm{sup 2}). Physic process are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles which reach the sensitive volume. Results obtained are thus compared with values published in ICRP 74. Neutron fluence in the sensitive volume was calculated for benchmarking. The Monte Carlo GEANT4 code was found to be appropriate to calculate neutron doses at energies below 10 MeV correctly. (author)

  5. Inflammatory lesions of the spinal cord and the nerve roots in magnetic resonance imaging; Entzuendliche Erkrankungen des Rueckenmarks und der Nervenwurzeln in der MRT

    Energy Technology Data Exchange (ETDEWEB)

    Sartoretti-Schefer, S. [Inst. fuer Neuroradiologie, Universitaetsspital Zuerich (Switzerland); Wichmann, W. [Inst. fuer Neuroradiologie, Universitaetsspital Zuerich (Switzerland); Valavanis, A. [Inst. fuer Neuroradiologie, Universitaetsspital Zuerich (Switzerland)

    1996-11-01

    The MRI examinations of 52 patients with proven inflammatory lesions (39 patients) or tumorous/postactinic lesions of the spinal cord (6 patients) and vasuclar malformations of the spinal cord (7 patients) were retrospectively analyzed. All examinations were performed on a 1.5 T MR unit, using bi- or triplanar T1-w pre- and postcontrast as well as T2-w SE sequences. Clinical and radiological examinations allow a subdivision of inflammations of the spinal cord and the nerve roots into (mening-oradiculo) myelitis and meningoradiculo (myelitis). The MRI patterns of these two inflammatory subtypes vary: Meningoradiculitis presents with an enhancement of the nerve roots and the leptomeninges; myelitis itself is characterized by single or multiple, diffuse or multifocal, with or without nodular, patchy or diffusely enhancing intramedullary lessions, with or without thickening of the cord and leptomeningeal inflammation. The immunologically suppressed patient suffers from viral infections (especially herpes simplex, varicella-zoster virus, cytomegalovirus), bacterial infections (tuberculosis), but rarely viral infections, sarcoidosis and demyelinating diseases. Idiopathic myelitis is also common. Secondary ischemic and demyelinating processes result in a complex morphology of inflammatory lesions on MRI, and therefore the whole spectrum of demyelinating, ischemic and inflammatory lesions has to be included in the differential diagnosis. Even tumors may imitate inflammatory myelitis and radiculitis. Most commonly, meningoradiculitis can be separated from myelitis. A reliable diagnosis of a specific inflammatory lesion is difficult and is mostly achieved in patients with multiple sclerosis and in patients with HIV-associated cytomegalovirus infection. (orig.) [Deutsch] Entzuendliche Erkrankungen des Rueckenmarks und der Nervenwurzeln werden aus klinischer und radiologischer Sicht in eine (Meningo)-Myeloradikulitis und eine Meningoradikulo-(Myelitis) beim immunsupprimierten

  6. Clinical relevance and indications for cardiac magnetic resonance imaging 2013. An interdisciplinary expert statement; Klinischer Stellenwert und Indikationen zur Magnetresonanztomografie des Herzens 2013. Ein interdisziplinaeres Expertenstatement

    Energy Technology Data Exchange (ETDEWEB)

    Hergan, Klaus [Universitaetsklinikum Salzburg (Austria). Universitaetsinst. fuer Radiologie; Globits, S. [Herz-Kreislauf-Zentrum Gross Gerungs (Austria); Schuchlenz, H. [Landeskrankenhaus Graz-West (Austria). Dept. fuer Kardiologie/Intensivmedizin] [and others

    2013-03-15

    During the last years the indications of Cardiac Magnetic Resonance Imaging (CMRI) have been continuously expanded. However, the acceptance of the method by cardiologists and radiologists does not correlate with respect to the diagnostic potential. Several factors, such as expensive equipment, relatively long examination times, high technical know how and lack of remuneration, limit the application of CMRI in everyday clinical practice. Furthermore, doctors tend to apply more conventional, well established diagnostic procedures, the access to the method is still limited and there exist difficulties in the interdisciplinary collaboration. The interdisciplinary Austrian approach to Cardiac Imaging is aimed to improve the aforementioned problems and to support the implementation of CMRI in the diagnostic tree of cardiac diseases thus enabling a cost efficient management of patients in cardiology. (orig.)

  7. GEANT4 and PHITS simulations of the shielding of neutrons from $^{252}$Cf source

    CERN Document Server

    Shin, Jae Won

    2014-01-01

    Neutron shielding simulations by using GEANT4 and PHITS code are performed. As a neutron source, $^{252}$Cf is considered and the energy distribution of the neutrons emitted from $^{252}$Cf is assumed the Watt fission spectrum. The neutron dose equivalent rates with and without the shield are estimated for shielding materials such as graphite, iron, polyethylene, NS-4-FR and KRAFTON-HB. For the neutron shielding simulations by using GEANT4, high precision (G4HP) model with G4NDL 4.2 based on ENDF-VII data are used. And for PHITS simulations, JENDL-4.0 library are used for the same purpose. It is found that differences between the shielding calculations by using GEANT4 with G4NDL 4.2 and PHITS with JENDL-4.0 library are not significant for all cases considered in this work. We investigate the accuracy of the neutron dose equivalent rates obtained from GEANT4 and PHITS by comparing our simulation results with experimental data and other values calculated earlier. Calculated neutron dose equivalent rates agree w...

  8. GEANT4 Hadronic Physics Validation with Lhc Test-Beam Data

    Science.gov (United States)

    Alexa, Călin

    2005-02-01

    In the framework of the LHC Computing Grid (LCG) Simulation Physics Validation Project, we present first conclusions about the validation of the Geant4 hadronic physics lists based on comparisons with test-beam data collected with three LHC calorimeters: the ATLAS Tilecal, the ATLAS HEC and the CMS HCAL.

  9. CMS validation Experience: Test-beam 2004 data vs Geant4

    Science.gov (United States)

    Piperov, Stefan

    2007-03-01

    A comparison between the Geant4 Monte-Carlo simulation of CMS Detector's Calorimetric System and data from the 2004 Test-Beam at CERN's SPS H2 beam-line is presented. The overall simulated response agrees quite well with the measured response. Slight differences in the longitudinal shower profiles between the MC predictions made with different Physics Lists are observed.

  10. Modeling interactions of intermediate-energy neutrons in a plastic scintillator array with GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Kohley, Z., E-mail: zkohley@gmail.com [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Lunderberg, E.; DeYoung, P.A. [Department of Physics, Hope College, Holland, MI 49423 (United States); Roeder, B.T. [LPC-Caen, ENSICAEN, IN2P3/CNRS et Universite de Caen, 14050 Caen cedex (France); Baumann, T. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Christian, G.; Mosby, S.; Smith, J.K.; Snyder, J.; Spyrou, A.; Thoennessen, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-08-01

    A Monte Carlo simulation of a large-area neutron time-of-flight detector, built on the GEANT4 framework, has been compared with an experimental measurement of the {sup 16}B{yields}{sup 15}B+n decay produced from a 55 MeV/u{sup 17}C beam. The ability of the Monte Carlo simulation to reproduce the intermediate-energy neutron interactions within the detector has been explored using both the stock GEANT4 physics processes and a custom neutron interaction model, MENATE{sub R}. The stock GEANT4 physics processes were unable to reproduce the experimental observables, while excellent agreement was obtained through the inclusion of the MENATE{sub R} model within GEANT4. The differences between the two approaches are shown to be related to the modeling of the neutron-carbon inelastic reactions. Additionally, the use of MENATE{sub R} provided accurate reproduction of experimental signals associated with neutron scattering within the detector. These results provide validation of the Monte Carlo simulation for modeling measurements of multiple neutrons where the identification and removal of false neutron signals, due to multiple neutron scattering, are required.

  11. Geant4-based Monte Carlo simulations on GPU for medical applications.

    Science.gov (United States)

    Bert, Julien; Perez-Ponce, Hector; El Bitar, Ziad; Jan, Sébastien; Boursier, Yannick; Vintache, Damien; Bonissent, Alain; Morel, Christian; Brasse, David; Visvikis, Dimitris

    2013-08-21

    Monte Carlo simulation (MCS) plays a key role in medical applications, especially for emission tomography and radiotherapy. However MCS is also associated with long calculation times that prevent its use in routine clinical practice. Recently, graphics processing units (GPU) became in many domains a low cost alternative for the acquisition of high computational power. The objective of this work was to develop an efficient framework for the implementation of MCS on GPU architectures. Geant4 was chosen as the MCS engine given the large variety of physics processes available for targeting different medical imaging and radiotherapy applications. In addition, Geant4 is the MCS engine behind GATE which is actually the most popular medical applications' simulation platform. We propose the definition of a global strategy and associated structures for such a GPU based simulation implementation. Different photon and electron physics effects are resolved on the fly directly on GPU without any approximations with respect to Geant4. Validations have shown equivalence in the underlying photon and electron physics processes between the Geant4 and the GPU codes with a speedup factor of 80-90. More clinically realistic simulations in emission and transmission imaging led to acceleration factors of 400-800 respectively compared to corresponding GATE simulations.

  12. Comparison of GEANT4 very low energy cross section models with experimental data in water

    DEFF Research Database (Denmark)

    Incerti, S; Ivanchenko, A; Karamitros, M

    2010-01-01

    The GEANT4 general-purpose Monte Carlo simulation toolkit is able to simulate physical interaction processes of electrons, hydrogen and helium atoms with charge states (H0, H+) and (He0, He+, He2+), respectively, in liquid water, the main component of biological systems, down to the electron volt...

  13. CLIC Detector Concepts as described in the CDR: Differences between the GEANT4 and Engineering Models

    CERN Document Server

    Elsener, K; Schlatter, D; Siegrist, N

    2011-01-01

    The CLIC_ILD and CLIC_SiD detector concepts as used for the CDR Vol. 2 in 2011 exist both in GEANT4 simulation models and in engineering layout drawings. At this early stage of a conceptual design, there are inevitably differences between these models, which are described in this note.

  14. Optimization of GEANT4 settings for Proton Pencil Beam Scanning simulations using GATE

    Energy Technology Data Exchange (ETDEWEB)

    Grevillot, Loic, E-mail: loic.grevillot@gmail.co [Universite de Lyon, F-69622 Lyon (France); Creatis, CNRS UMR 5220, F-69622 Villeurbanne (France); Centre de Lutte Contre le Cancer Leon Berard, F-69373 Lyon (France); IBA, B-1348 Louvain-la-Neuve (Belgium); Frisson, Thibault [Universite de Lyon, F-69622 Lyon (France); Creatis, CNRS UMR 5220, F-69622 Villeurbanne (France); Centre de Lutte Contre le Cancer Leon Berard, F-69373 Lyon (France); Zahra, Nabil [Universite de Lyon, F-69622 Lyon (France); IPNL, CNRS UMR 5822, F-69622 Villeurbanne (France); Centre de Lutte Contre le Cancer Leon Berard, F-69373 Lyon (France); Bertrand, Damien; Stichelbaut, Frederic [IBA, B-1348 Louvain-la-Neuve (Belgium); Freud, Nicolas [Universite de Lyon, F-69622 Lyon (France); CNDRI, INSA-Lyon, F-69621 Villeurbanne Cedex (France); Sarrut, David [Universite de Lyon, F-69622 Lyon (France); Creatis, CNRS UMR 5220, F-69622 Villeurbanne (France); Centre de Lutte Contre le Cancer Leon Berard, F-69373 Lyon (France)

    2010-10-15

    This study reports the investigation of different GEANT4 settings for proton therapy applications in the context of Treatment Planning System comparisons. The GEANT4.9.2 release was used through the GATE platform. We focused on the Pencil Beam Scanning delivery technique, which allows for intensity modulated proton therapy applications. The most relevant options and parameters (range cut, step size, database binning) for the simulation that influence the dose deposition were investigated, in order to determine a robust, accurate and efficient simulation environment. In this perspective, simulations of depth-dose profiles and transverse profiles at different depths and energies between 100 and 230 MeV have been assessed against reference measurements in water and PMMA. These measurements were performed in Essen, Germany, with the IBA dedicated Pencil Beam Scanning system, using Bragg-peak chambers and radiochromic films. GEANT4 simulations were also compared to the PHITS.2.14 and MCNPX.2.5.0 Monte Carlo codes. Depth-dose simulations reached 0.3 mm range accuracy compared to NIST CSDA ranges, with a dose agreement of about 1% over a set of five different energies. The transverse profiles simulated using the different Monte Carlo codes showed discrepancies, with up to 15% difference in beam widening between GEANT4 and MCNPX in water. A 8% difference between the GEANT4 multiple scattering and single scattering algorithms was observed. The simulations showed the inability of reproducing the measured transverse dose spreading with depth in PMMA, corroborating the fact that GEANT4 underestimates the lateral dose spreading. GATE was found to be a very convenient simulation environment to perform this study. A reference physics-list and an optimized parameters-list have been proposed. Satisfactory agreement against depth-dose profiles measurements was obtained. The simulation of transverse profiles using different Monte Carlo codes showed significant deviations. This point

  15. SU-E-J-72: Geant4 Simulations of Spot-Scanned Proton Beam Treatment Plans

    Energy Technology Data Exchange (ETDEWEB)

    Kanehira, T; Sutherland, K; Matsuura, T; Umegaki, K; Shirato, H [Hokkaido University, Sapporo, Hokkaido (Japan)

    2014-06-01

    Purpose: To evaluate density inhomogeneities which can effect dose distributions for real-time image gated spot-scanning proton therapy (RGPT), a dose calculation system, using treatment planning system VQA (Hitachi Ltd., Tokyo) spot position data, was developed based on Geant4. Methods: A Geant4 application was developed to simulate spot-scanned proton beams at Hokkaido University Hospital. A CT scan (0.98 × 0.98 × 1.25 mm) was performed for prostate cancer treatment with three or four inserted gold markers (diameter 1.5 mm, volume 1.77 mm3) in or near the target tumor. The CT data was read into VQA. A spot scanning plan was generated and exported to text files, specifying the beam energy and position of each spot. The text files were converted and read into our Geant4-based software. The spot position was converted into steering magnet field strength (in Tesla) for our beam nozzle. Individual protons were tracked from the vacuum chamber, through the helium chamber, steering magnets, dose monitors, etc., in a straight, horizontal line. The patient CT data was converted into materials with variable density and placed in a parametrized volume at the isocenter. Gold fiducial markers were represented in the CT data by two adjacent voxels (volume 2.38 mm3). 600,000 proton histories were tracked for each target spot. As one beam contained about 1,000 spots, approximately 600 million histories were recorded for each beam on a blade server. Two plans were considered: two beam horizontal opposed (90 and 270 degree) and three beam (0, 90 and 270 degree). Results: We are able to convert spot scanning plans from VQA and simulate them with our Geant4-based code. Our system can be used to evaluate the effect of dose reduction caused by gold markers used for RGPT. Conclusion: Our Geant4 application is able to calculate dose distributions for spot scanned proton therapy.

  16. Functional magnetic resonance imaging of the truncus pulmonalis. Principles of magnetic resonance flux measurements for pulmonal hypertension diagnostics; Funktionelle Magnetresonanztomographie des Truncus pulmonalis. Grundlagen der magnetresonanztomographischen Flussmessung zur Diagnostik der pulmonalen Hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Abolmaali, N.

    2006-07-01

    This book gives a detailed introduction into the use of magnetic resonance flux measurements for the examination of pulmonal circulation. It presents the results of phantom experiments and evaluates and verifies sequence techniques optimised for the examination of the pulmonary circulation. This is followed by a description of an elegant experimental design for the quantification of pulmonal hypertension which is unique in its kind. The model can predict the consequences of acute, resistance-related pulmonal hypertension in a reproducible and reversible manner. It thus provides a means of evaluating pulmonal applications of magnetic resonance imaging. The idea for these studies and its implementation are an outstanding example of teamwork and interdisciplinary cooperation. Applying the results to the patient after the statistical analysis is only a small step. The book presents the results of extensive normal value studies which will make it possible to use the measurement technology in paediatric cardiology. Its range of application also includes congenital heart defects, especially ventricular septal defects and primary as well as secondary forms of pulmonal hypertension. It is not only suitable for primary diagnostics but also for post-treatment follow-up and assessment of patients' progress.

  17. Comparison of Geant4 with EGSnrc for Simulation of Gamma-Radiation Detectors Based on Semi-Insulating Materials

    CERN Document Server

    Skrypnyk, A I; Khazhmuradov, M A

    2011-01-01

    We considered GEANT4 version 4.9.4 with different Electromagnetic Physics Package for calculation of response functions of detectors based on semi-insulating materials. Computer simulations with GEANT4 packages were run in order to determine the energy deposition of gamma-quanta in detectors of specified composition (Mercuric (II) Iodide and Thallium Bromide) at various energies from 0.026 to 3 MeV. The uncertainty in these predictions is estimated by comparison of their results with EGSnrc simulations. A general good agreement is found for EGSnrc and GEANT4 with Penelope 2008 model of LowEnergy Electromagnetic package.

  18. MCNP5 and GEANT4 comparisons for preliminary Fast Neutron Pencil Beam design at the University of Utah TRIGA system

    Science.gov (United States)

    Adjei, Christian Amevi

    The main objective of this thesis is twofold. The starting objective was to develop a model for meaningful benchmarking of different versions of GEANT4 against an experimental set-up and MCNP5 pertaining to photon transport and interactions. The following objective was to develop a preliminary design of a Fast Neutron Pencil Beam (FNPB) Facility to be applicable for the University of Utah research reactor (UUTR) using MCNP5 and GEANT4. The three various GEANT4 code versions, GEANT4.9.4, GEANT4.9.3, and GEANT4.9.2, were compared to MCNP5 and the experimental measurements of gamma attenuation in air. The average gamma dose rate was measured in the laboratory experiment at various distances from a shielded cesium source using a Ludlum model 19 portable NaI detector. As it was expected, the gamma dose rate decreased with distance. All three GEANT4 code versions agreed well with both the experimental data and the MCNP5 simulation. Additionally, a simple GEANT4 and MCNP5 model was developed to compare the code agreements for neutron interactions in various materials. Preliminary FNPB design was developed using MCNP5; a semi-accurate model was developed using GEANT4 (because GEANT4 does not support the reactor physics modeling, the reactor was represented as a surface neutron source, thus a semi-accurate model). Based on the MCNP5 model, the fast neutron flux in a sample holder of the FNPB is obtained to be 6.52×107 n/cm2s, which is one order of magnitude lower than gigantic fast neutron pencil beam facilities existing elsewhere. The MCNP5 model-based neutron spectrum indicates that the maximum expected fast neutron flux is at a neutron energy of ~1 MeV. In addition, the MCNP5 model provided information on gamma flux to be expected in this preliminary FNPB design; specifically, in the sample holder, the gamma flux is to be expected to be around 108 γ/cm 2s, delivering a gamma dose of 4.54×103 rem/hr. This value is one to two orders of magnitudes below the gamma

  19. V.U.V. plasma spectroscopy diagnostic of electron cyclotron resonance multicharged ion sources; Diagnostic de plasmas crees dans des sources d'ions multicharges a resonance cyclotronique electronique par spectroscopie V.U.V

    Energy Technology Data Exchange (ETDEWEB)

    Berreby, R

    1997-12-15

    To characterize the multicharged ions within the plasma of an E.C.R. ion source, the V.U.V. spectroscopy is used as a non invasive diagnostic of excited matter. In E.C.R.I. S. (electron cyclotron resonance ion source) electrons are heated and magnetically confined within the mirror machine to overcome the successive ionization potentials of the desired elements. As the electrons bounce inside the magnetic configuration in their gyration movement, they interact with the microwaves injected into the source at the resonance frequency. To enhance the performances in high charge states and extracted currents delivered by E.C.R.I.S., the fundamental parameters of the plasma created in these machines must be known. The goal of spectroscopic diagnostics in the V.U.V. range installed on the sources is to determine electron density and temperature on one hand, and the ionic densities and confinement time on the other hand. We used microchannel plates as detector on a 3 meter grazing incidence spectrometer equipped with a 600 lines/mm holographic grating. The calibration of the whole grating with detector was performed by two different methods. These are the branching ratio and charge exchange methods. Identification of lines emitted by a plasma, which gather the whole charge states of ions is necessary to make an exhaustive study of the plasma state. And finally, the determination of plasma parameters like electron density and temperature and ion densities and confinement times that uses theoretical models were the aim of this work. (author)

  20. Magnetic resonance analysis of the subscapularis muscle after open anterior shoulder stabilization; Magnetresonanztomographische Untersuchung des Musculus subscapularis nach offener vorderer Schulterstabilisierung

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, R.J.; Tsynman, A. [Klinik fuer Strahlenheilkunde, Charite, Berlin (Germany); Scheibel, M. [Zentrum fuer Muskuloskeletale Chirurgie, Charite, Berlin (Germany); Magosch, P.; Habermeyer, P. [Zentrum fuer Schulter- und Ellenbogenchirurgie, ATOS-Praxisklinik Heidelberg (Germany)

    2006-07-15

    Purpose: analysis of the magnetic resonance imaging of the subscapularis musculotendinous unit (SSC) after primary and revision open shoulder stabilization and their correlation with the clinical function. Materials and methods: in a retrospective cohort study, 13 patients (mean age of group A: 36.5 years) after primary and 12 (mean age of group B: 34.2 years) after revision open stabilization underwent postoperative MRI of the shoulder. The digital data was analyzed with respect to the vertical und transverse diameters (V diameter, T diameter) in a defined image slice. A signal intensity analysis was performed (infraspinatus/subscapularis signal-to-noise ratio = ISP/SSC SNR). The clinical examination included the SSC tests and signs and the constant and rowe score. Twelve healthy volunteers (group C) served as the control. Results: from group C to group B, the mean V diameter of the SSC decreased significantly (p < 0.05) as did the mean T diameter of the cranial part of the SSC muscle (= crSSC) (p < 0.05). The mean T diameter of the caudal part of the SSC muscle (= caSSC) did not differ significantly between all groups (p > 0.05). The ISP-SSC SNR was significantly lower (p < 0.05) in the crSSC of groups A und B than in group C. In the caSSC, the SNR increased in groups A and B. In 53.8% of group A and 92.3% of group B, clinical signs of SSC insufficiency were found. There was no significant difference between the constant and the rowe score in both groups (p > 0.05). Complete tendon ruptures were not observed in any case. Conclusions: MRI enables semi-quantitative analysis of the postoperative changes of the subscapularis muscle. The decrease of the ISP/SSC SNR points to a fatty degeneration in the crSSC. The results provide indications of the causes of the clinical dysfunction of the subscapularis musculotendinous unit after open shoulder stabilization. (orig.)

  1. Analysis of the dead layer of a detector of germanium with code ultrapure Monte Carlo SWORD-GEANT; Analisis del dead layer de un detector de germanio ultrapuro con el codigo de Monte Carlo SWORDS-GEANT

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, S.; Querol, A.; Ortiz, J.; Rodenas, J.; Verdu, G.

    2014-07-01

    In this paper the use of Monte Carlo code SWORD-GEANT is proposed to simulate an ultra pure germanium detector High Purity Germanium detector (HPGe) detector ORTEC specifically GMX40P4, coaxial geometry. (Author)

  2. Loin des sciences sociales.

    Directory of Open Access Journals (Sweden)

    René-Éric Dagorn

    2002-05-01

    Full Text Available Plusieurs numéros de Livres Hebdo et du Monde des Livres des mois de janvier-février 2002 permettent de proposer un rapide survol des grandes ventes de l’année 2001 et de quelques tendances éditoriales de l’année 2002. Quelques points ressortent particulièrement de la lecture des articles de ces deux sources : l’intérêt de la nouvelle méthode d’estimation des ventes proposée par l’institut Ipsos et Livres Hebdo , le tableau des grandes ventes en 2001 (et ...

  3. La metamorphose des cypris femelles des Rhizocephales

    NARCIS (Netherlands)

    Veillet, A.

    1964-01-01

    Depuis la découverte de la métamorphose des cypris de Sacculina carcini Thompson par Delage, peu de biologistes se sont intéressés au développement des Rhizocéphales. On admet aujourd'hui que tous les Cirripèdes parasites ont, comme Sacculina carcini, une forme kentrogone qui inocule le parasite au

  4. Structure and aqueous reactivity of silicate glasses high-resolution nuclear magnetic resonance contribution; Structure et reactivite aqueuse des verres silicates apport de la resonance magnetique nucleaire haute-resolution

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, F

    2000-10-25

    This research aims at getting a better understanding of the relations which may exist between the chemical composition of the oxide silicate glasses, the structure and the aqueous reactivity. We study the cations present in most glasses, more particularly the radioactive waste glasses, and those which are more liable to bring information both about structure and reactivity. Among the experimental methods used, the nuclear magnetic resonance of multi-quantum magic-angle spinning (NMR MQ-MAS) has been carried out for the structural characterization of the pristine and altered glasses. In the first part, we discuss the possibility of deducting a type of information from a quantitative approach of the {sup 23}Na, {sup 27}Al and {sup 17}O NMR MQ-MAS. In the second part, we apply this method to glasses containing between two and six oxides. The vitreous compositions studied permit to focus our attention on the influence of sodium, aluminum and calcium on their local structural environment. We point out an evolution of the distributions of bond distances and angles in relation to the glass chemical composition. We show the strong potentiality of the {sup 17}O used to probe the pristine and altered glasses. The influence of the different cations studied on the rate of glass dissolution is debated from the alterations made on short periods. On the basis of all these data, we discuss the importance of the structural effect which may influence the kinetic phenomena of alteration. (author)

  5. Response of a proportional counter to $^{37}$Ar and $^{71}$Ge: real spectra versus GEANT4 simulation

    CERN Document Server

    Abdurashitov, D; Matushko, V; Suerfu, B

    2015-01-01

    The energy deposition spectra of $^{37}$Ar and $^{71}$Ge in a miniature proportional counter are measured and compared in detail to the model response simulated with Geant4. The spectrum of $^{71}$Ge is measured with total statistics of 1.7$\\cdot$10$^8$ events and is presented for the first time. A certain modification of the Geant4 code, making it possible to trace the deexcitation of atomic shells properly, is suggested. After the modification Geant4 is able to reproduce a response of particle detectors in detail in a keV energy range. This feature is very important in the laboratory experiments that search for massive sterile neutrinos as well as for dark matter directly by detection of recoil nuclei. We expect this work to convince physicists to trust Geant4 simulations at low energies.

  6. A Software Toolkit to Study Systematic Uncertainties of the Physics Models of the Geant4 Simulation Package

    Energy Technology Data Exchange (ETDEWEB)

    Genser, Krzysztof [Fermilab; Hatcher, Robert [Fermilab; Perdue, Gabriel [Fermilab; Wenzel, Hans [Fermilab; Yarba, Julia [Fermilab; Kelsey, Michael [SLAC; Wright, Dennis H. [SLAC

    2016-11-10

    The Geant4 toolkit is used to model interactions between particles and matter. Geant4 employs a set of validated physics models that span a wide range of interaction energies. These models are tuned to cover a large variety of possible applications. This raises the critical question of what uncertainties are associated with the Geant4 physics model, or group of models, involved in a simulation project. To address the challenge, we have designed and implemented a comprehen- sive, modular, user-friendly software toolkit that allows the variation of one or more parameters of one or more Geant4 physics models involved in simulation studies. It also enables analysis of multiple variants of the resulting physics observables of interest in order to estimate the uncertain- ties associated with the simulation model choices. Key functionalities of the toolkit are presented in this paper and are illustrated with selected results.

  7. A Software Toolkit to Study Systematic Uncertainties of the Physics Models of the Geant4 Simulation Package

    CERN Document Server

    Genser, Krzysztof; Perdue, Gabriel; Wenzel, Hans; Yarba, Julia; Kelsey, Michael; Wright, Dennis H

    2016-01-01

    The Geant4 toolkit is used to model interactions between particles and matter. Geant4 employs a set of validated physics models that span a wide range of interaction energies. These models are tuned to cover a large variety of possible applications. This raises the critical question of what uncertainties are associated with the Geant4 physics model, or group of models, involved in a simulation project. To address the challenge, we have designed and implemented a comprehen- sive, modular, user-friendly software toolkit that allows the variation of one or more parameters of one or more Geant4 physics models involved in simulation studies. It also enables analysis of multiple variants of the resulting physics observables of interest in order to estimate the uncertain- ties associated with the simulation model choices. Key functionalities of the toolkit are presented in this paper and are illustrated with selected results.

  8. Principle and Potential of Nuclear Magnetic Resonance Applied to the Study of Fluids in Porous Media Principe et potentialité de la résonance magnétique nucléaire appliquée à l'étude des fluides en milieux poreux

    Directory of Open Access Journals (Sweden)

    Chardaire-Riviere C.

    2006-11-01

    Full Text Available Nuclear magnetic resonance (NMR and magnetic resonance imaging (MRI have been used in recent years in many fields, including the chemical and petroleum industries, and medicine. Following a review of the basic principles of these two techniques, their applications concerning the study of fluids in porous media are presented. The use of NMR in petrophysics is limited to the study of porosity, permeability, wettability, and the determination of the pore size distribution and saturation in a sample. MRI is an extremely useful technique, not only as a tomographic approach but, above all, because, it helps today to identify certain properties, such as velocity images. This article also presents the results obtained at Institut Français du Pétrole (IFP concerning the study of wettability by NMR and the use of a high magnetic field to visualize fluids in porous media. In the future, a major potential use of NMR for the study of fluids in porous media resides in the extrapolation of the results obtained by spectroscopy to wireline logs, and to imaging. L'évaluation du taux de récupération optimale d'un gisement d'hydrocarbures repose sur l'utilisation des lois d'écoulements polyphasiques en milieu poreux : les lois de Darcy généralisées. Celles-ci permettent d'interpréter des mesures de laboratoire sur des échantillons de gisement, afin de les introduire dans les modèles numériques de simulation à l'échelle du réservoir. Pour envisager une étude approfondie de ce qui se passe en matière d'écoulement à l'intérieur des milieux poreux, il faut évaluer de manière très précise la distribution des fluides. Pour cette raison, les études tomographiques apportent une contribution importante à la connaissance des écoulements en milieu poreux. Dans cet article la méthode tomographique envisagée est l'imagerie par résonance magnétique (IRM qui est une extension de la résonance magnétique nucléaire (RMN. Les principes de ces deux m

  9. Etude des parametres physiques en vue d'applications medicales de l'actionnement magnetique de dispositifs medicaux par un systeme d'imagerie par resonance magnetique

    Science.gov (United States)

    Mathieu, Jean-Baptiste

    An actuation and control method for medical devices based on the magnetic gradient coils of a Magnetic Resonance Imaging (MRI) was proposed for the first time in 2002 by NanoRobotics Laboratory [1]. The work undertaken in the present thesis began in the context of demonstrating the concept of automatic navigation of a magnetic bead in vivo. From the point of view of actuation, models and experimental data correlate. A maximum velocity of 13cm/s was measured for a 1.5mm diameter chrome steel bead in the carotid artery of a living swine. The bead was under the influence of magnetic gradients applied by a clinical MRI system without any hardware modification. In light of these results, the aim of this thesis is the study of the physical parameters involved in the development of a first medical application: the steering of magnetic particles in MRI in the context of drug targeting. It was demonstrated that an MRI system equipped with a set of magnetic gradient coils with enhanced amplitude was able to apply a high enough actuation force to act upon magnetic microparticles suspended in a liquid. General rules for MRI actuation were identified. First of all, increasing the amplitude of the main magnetic field of the MRI leads to the increase of the actuation force amplitude only until the ferromagnetic body reaches its saturation magnetization. Moreover, soft ferromagnetic bodies appear to be better candidates for MRI based magnetic actuation because they can reach high saturation magnetizations. Magnetic gradient amplitude appears as a foremost factor to increase the amplitude of the magnetic force. Clinical MRI systems do not provide gradients with high enough amplitude for the applications studied here. Theoretical models developed in this thesis predict that a one order of magnitude increase in gradient amplitude would be required. Implementing actuation dedicated gradient coils is therefore suggested. Finally, a larger ferromagnetic body will lead to higher

  10. Geant4 Applications for Modeling Molecular Transport in Complex Vacuum Geometries

    CERN Document Server

    Singal, J; Schindler, R

    2013-01-01

    This letter discusses a novel use of the Geant4 simulation toolkit to model molecular transport in a vacuum environment, in the molecular flow regime. The Geant4 toolkit was originally developed by the high energy physics community to simulate the interactions of elementary particles within complex detector systems. Here its capabilities are utilized to model molecular vacuum transport in geometries where other techniques are impractical. The techniques are verified with an application representing a simple vacuum geometry that has been studied previously both analytically and by basic Monte Carlo simulation. We discuss the use of an application with a very complicated geometry, that of the Large Synoptic Survey Telescope camera cryostat, to determine probabilities of transport of contaminant molecules to optical surfaces where control of contamination is crucial.

  11. Comparison of Geant4-DNA simulation of S-values with other Monte Carlo codes

    Energy Technology Data Exchange (ETDEWEB)

    André, T. [Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Morini, F. [Research Group of Theoretical Chemistry and Molecular Modelling, Hasselt University, Agoralaan Gebouw D, B-3590 Diepenbeek (Belgium); Karamitros, M. [Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, INCIA, UMR 5287, F-33400 Talence (France); Delorme, R. [LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Grenoble INP, 38026 Grenoble (France); CEA, LIST, F-91191 Gif-sur-Yvette (France); Le Loirec, C. [CEA, LIST, F-91191 Gif-sur-Yvette (France); Campos, L. [Departamento de Física, Universidade Federal de Sergipe, São Cristóvão (Brazil); Champion, C. [Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Groetz, J.-E.; Fromm, M. [Université de Franche-Comté, Laboratoire Chrono-Environnement, UMR CNRS 6249, Besançon (France); Bordage, M.-C. [Laboratoire Plasmas et Conversion d’Énergie, UMR 5213 CNRS-INPT-UPS, Université Paul Sabatier, Toulouse (France); Perrot, Y. [Laboratoire de Physique Corpusculaire, UMR 6533, Aubière (France); Barberet, Ph. [Université Bordeaux 1, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); and others

    2014-01-15

    Monte Carlo simulations of S-values have been carried out with the Geant4-DNA extension of the Geant4 toolkit. The S-values have been simulated for monoenergetic electrons with energies ranging from 0.1 keV up to 20 keV, in liquid water spheres (for four radii, chosen between 10 nm and 1 μm), and for electrons emitted by five isotopes of iodine (131, 132, 133, 134 and 135), in liquid water spheres of varying radius (from 15 μm up to 250 μm). The results have been compared to those obtained from other Monte Carlo codes and from other published data. The use of the Kolmogorov–Smirnov test has allowed confirming the statistical compatibility of all simulation results.

  12. Therapeutic dose simulation of a 6 MV Varian Linac photon beam using GEANT4

    Science.gov (United States)

    Salama, E.; Ali, A. S.; Khaled, N. E.; Radi, A.

    2015-10-01

    A developed program in C++ language using GEANT4 libraries was used to simulate the gantry of a 6 MV high energy photon linear accelerator (Linac). The head of a clinical linear accelerator based on the manufacturer's detailed information is simulated. More than 2× 109 primary electrons are used to create the phase space file. Evaluation of the percentage depth dose (PDD) and flatness symmetry (lateral dose profiles) in water phantom were performed. Comparisons between experimental and simulated data were carried out for three field sizes; 5 × 5, 10 × 10 and 15 × 15 cm2. A relatively good agreement appeared between computed and measured PDD. Electron contamination and spatial distribution for both photons and electrons in the simulated beam are evaluated. Moreover, the obtained lateral dose profiles at 15, 50, and 100 mm depth are compatible with the measured values. The obtained results concluded that, GEANT4 code is a promising applicable Monte Carlo program in radiotherapy applications.

  13. Hadronic Shower Models in GEANT4: Validation Strategy and Results.

    Institute of Scientific and Technical Information of China (English)

    JohannesPeterWellisch

    2001-01-01

    Optimal exploitation of hadronic final states played a key role in successes of all recent hadron collider experiment in HEP,and the ability to use hadronic final states will continue to be one of the decisive issues during the analysis phase of the LHC experinents Monte Carlo implementations of hadronic shower models provided with GEANT4 facilitate the use of hadronic final states,and have been developed for many years.We will give an overview on the physics underlying hadronic shower simulation,discussing the three basic types of modelling;data driven,parametrisation driven,and theory driven modelling,and their respective implementation status in GEANT4.We will confront the different types of modelling with a validation suite for hadronic generators based on cross-sections measurements from thin target experiments,and expose the strength and weaknesses of the individual approaches.

  14. Geant4 simulations of the neutron production and transport in the n_TOF spallation target

    Science.gov (United States)

    Lerendegui-Marco, J.; Cortés-Giraldo, M. A.; Guerrero, C.; Quesada, J. M.

    2016-11-01

    The neutron production and transport in the spallation target of the n_TOF facility at CERN has been simulated with Geant4. The results obtained with the different hadronic Physics Lists provided by Geant4 have been compared with the experimental neutron flux in n_TOF-EAR1. The best overall agreement in both the absolute value and the energy dependence of the flux from thermal to 1GeV, is obtained with the INCL++ model coupled with the Fritiof Model(FTFP). This Physics List has been thus used to simulate and study the main features of the new n_TOF-EAR2 beam line, currently in its commissioning phase.

  15. Simulation of positron backscattering and implantation profiles using Geant4 code

    Institute of Scientific and Technical Information of China (English)

    黄世娟; 潘子文; 刘建党; 韩荣典; 叶邦角

    2015-01-01

    For the proper interpretation of the experimental data produced in slow positron beam technique, the positron im-plantation properties are studied carefully using the latest Geant4 code. The simulated backscattering coefficients, the implantation profiles, and the median implantation depths for mono-energetic positrons with energy range from 1 keV to 50 keV normally incident on different crystals are reported. Compared with the previous experimental results, our simula-tion backscattering coefficients are in reasonable agreement, and we think that the accuracy may be related to the structures of the host materials in the Geant4 code. Based on the reasonable simulated backscattering coefficients, the adjustable parameters of the implantation profiles which are dependent on materials and implantation energies are obtained. The most important point is that we calculate the positron backscattering coefficients and median implantation depths in amorphous polymers for the first time and our simulations are in fairly good agreement with the previous experimental results.

  16. MedLinac2: a GEANT4 based software package for radiotherapy

    Directory of Open Access Journals (Sweden)

    Barbara Caccia

    2010-06-01

    Full Text Available Dose distribution evaluation in oncological radiotherapy treatments is an outstanding problem that requires sophisticated computing technologies to optimize the clinical results (i.e. increase the dose to the tumour and reduce the dose to the healthy tissues. Nowdays, dose calculation algorithms based on the Monte Carlo method are generally regarded as the most accurate tools for radiotherapy. The flexibility of the GEANT4 (GEometry ANd Tracking Monte Carlo particle transport simulation code allows a wide range of applications, from high-energy to medical physics. In order to disseminate and encourage the use of Monte Carlo method in oncological radiotherapy, a software package based on the GEANT4 Monte Carlo toolkit has been developed. The developed package (MedLinac2 allows to simulate in an adequate flexible way a linear accelerator for radiotherapy and to evaluate the dose distributions.

  17. Optimization of Voxelization Parameters in Geant4 Tracking and Improvement of the Shooter Benchmarking Program

    CERN Document Server

    Siegel, Zachary

    2013-01-01

    The geometry-based tracking of the ubiquitous particle physics simulation toolkit Geant4 utilizes the idea of voxels, which effectively partition regions into multi-dimensional slices that can decrease simulation time. The extent of voxelization and the size of the voxels is determined by a set of parameters, which until now, defaulted to arbitrary numbers. In this report I document how I tested different values for these parameters and determined which values should be the default. I modified the existing G01 Geant4 example program to get an initial look at how the performance depended on the parameters. Then I modified the Shooter benchmark program, which lacks extraneous physics processes, to collect more refined data and to provide a tool for future testers to perform comprehensive benchmarks. To this end, I created a new geometry, added features to aid in testing over ranges of parameters, and setup the default tests to provide a good sampling of different simulation scenarios.

  18. Comparison of Geant4 hadron generators with data: a critical appraisal

    CERN Document Server

    Boyko, I

    2008-01-01

    Hadron generation models are indispensable for the simulation and calibration of particle physics detectors. The models used by the Geant4 simulation tool kit are compared with inclusive spectra of secondary protons and pions from the interactions with beryllium nuclei of +8.9 GeV/c protons and pions, and of -8.0 GeV/c pions. We report on significant disagreements between data and model predictions especially in the polar-angle distributions of secondary protons and pions.

  19. Shielding studies for 2.5 MeV neutrons using GEANT4

    Science.gov (United States)

    Tovar, Felipe; Castro-Colin, Miguel; Sajo-Bohus, Laszlo

    2008-10-01

    By means of the software GEANT4, a toolkit based on the Monte Carlo method, we seek to study the dispersive effects that 2.5 MeV neutrons have, as well the gamma-yield, after interacting with various attenuating materials with simple geometrical configurations. A simulated mass of Uranium-238 is considered in the study with the purpose of observing the behavior of its characteristic yield after fast neutron irradiation.

  20. artG4: A Generic Framework for Geant4 Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Arvanitis, Tasha [Harvey Mudd Coll.; Lyon, Adam [Fermilab

    2014-01-01

    A small experiment must devote its limited computing expertise to writing physics code directly applicable to the experiment. A software 'framework' is essential for providing an infrastructure that makes writing the physics-relevant code easy. In this paper, we describe a highly modular and easy to use framework for writing Geant4 based simulations called 'artg4'. This framework is a layer on top of the art framework.

  1. Geant4 simulation of a filtered X-ray source for radiation damage studies

    Science.gov (United States)

    Guthoff, M.; Brovchenko, O.; de Boer, W.; Dierlamm, A.; Müller, T.; Ritter, A.; Schmanau, M.; Simonis, H.-J.

    2012-05-01

    Geant4 low energy extensions have been used to simulate the X-ray spectra of industrial X-ray tubes with filters for removing the uncertain low energy part of the spectrum in a controlled way. The results are compared with precisely measured X-ray spectra using a silicon drift detector. Furthermore, this paper shows how the different dose rates in silicon and silicon dioxide layers of an electronic device can be deduced from the simulations.

  2. Geant4 Simulation of a filtered X-ray Source for Radiation Damage Studies

    CERN Document Server

    Guthoff, M; de Boer, W; Dierlamm, A; Müller, T; Ritter, A; Schmanau, M; Simonis, H -J

    2012-01-01

    Geant4 low energy extensions have been used to simulate the X-ray spectra of industrial X-ray tubes with filters for removing the uncertain low energy part of the spectrum in a controlled way. The results are compared with precisely measured X-ray spectra using a silicon drift detector. Furthermore, this paper shows how the different dose rates in silicon and silicon dioxide layers of an electronic device can be deduced from the simulations.

  3. R and D on co-working transport schemes in Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Pia, M G; Saracco, P; Sudhakar, M [INFN Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Zoglauer, A [University of California at Berkeley, Berkeley, CA 94720-7450 (United States); Augelli, M [CNES, 18 Av. Edouard Belin, 31401 Toulouse (France); Gargioni, E [University Medical Center Hamburg-Eppendorf, D-20246 Hamburg (Germany); Kim, C H [Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul, 133-791 (Korea, Republic of); Quintieri, L [INFN Laboratori Nazionali di Frascati, Via Enrico Fermi 40, I-00044 Frascati (Italy); Filho, P P de Queiroz; Santos, D de Souza [IRD, Av. Salvador Allende, s/n. 22780-160, Rio de Janeiro, RJ (Brazil); Weidenspointner, G [MPI Halbleiterlabor, Otto-Hahn-Ring 6, D-81739 Muenchen (Germany); Begalli, M, E-mail: mariagrazia.pia@ge.infn.i [UERJ, R. Sao Francisco Xavier, 524. 20550-013, Rio de Janeiro, RJ (Brazil)

    2010-04-01

    A research and development (R and D) project related to the extension of the Geant4 toolkit has been recently launched to address fundamental methods in radiation transport simulation. The project focuses on simulation at different scales in the same experimental environment; this problem requires new methods across the current boundaries of condensed-random-walk and discrete transport schemes. The new developments have been motivated by experimental requirements in various domains, including nanodosimetry, astronomy and detector developments for high energy physics applications.

  4. Use of GEANT4 programme package for radiation technological modeling problems

    CERN Document Server

    Bratchenko, M I

    2001-01-01

    The results of pilot computer experiments directed toward the application of Geant4 package for modeling of gamma radiation dose distributions in homogeneous phantoms are presented. we demonstrate the potential of the package it self and of the developed add-on software modules for the calculations of three-dimensional absorbed dose distributions taking into account the design and geometry of model irradiators and phantoms.

  5. R&D on co-working transport schemes in Geant4

    CERN Document Server

    Pia, M G; Sudhakar, M; Zoglauer, A; Augelli, M; Gargioni, E; Kim, C H; Quintieri, L; Filho, P P de Queiroz; Santos, D de Souza; Weidenspointner, G; Begalli, M

    2010-01-01

    A research and development (R&D) project related to the extension of the Geant4 toolkit has been recently launched to address fundamental methods in radiation transport simulation. The project focuses on simulation at different scales in the same experimental environment; this problem requires new methods across the current boundaries of condensed-random-walk and discrete transport schemes. The new developments have been motivated by experimental requirements in various domains, including nanodosimetry, astronomy and detector developments for high energy physics applications.

  6. ANALYSE DES MODES DE GESTION DES ENTREPRISES ...

    African Journals Online (AJOL)

    Administrateur

    L'étude de l'art et des biens culturels en général est longtemps restée en ... en économie et management), Université d'Angers / Chef de projet chez Arterial Network. ... culturelles publiques sont apparues à partir de la fin des années 1990.

  7. Des racines et des ailes

    Directory of Open Access Journals (Sweden)

    Stéphanie Vincent-Geslin

    2012-05-01

    Full Text Available Les mobilités pendulaires semblent être en augmentation en Europe depuis une dizaine d’années. Cette croissance du temps passé à se déplacer amène à remettre en question la conjecture de Zahavi et apparaît relativement inexplicable en regard du paradigme classique de l’acteur rationnel traditionnellement utilisé dans le champ des transports. Si, dans la littérature, les temps de déplacements sont principalement expliqués par le contexte résidentiel, la forme urbaine et le travail, ce cadre explicatif ne dit rien des processus de décision eux-mêmes qui amènent aux pendularités intensives.À partir d’une enquête qualitative menée auprès de pendulaires français, suisses et belges, cette contribution propose d’analyser les arbitrages et les éléments déterminants des processus de la grande pendularité. Les mobilités quotidiennes pendulaires apparaissent comme le résultat de compromis entre activité professionnelle, attachement résidentiel et choix de vie et prennent ainsi la forme de stratégies de conciliation entre vie privée et vie professionnelle. Ces mobilités spatiales permettent alors paradoxalement la préservation des ancrages résidentiels, sociaux et familiaux.Roots and wings. Long-distance commuting patterns, or how to conciliate professional and personal lifeLong-distance commuting patterns appear to be increasing in Europe over the last ten years. These raising mobility patterns lead to reappraise the Zahavi conjecture and appear largely inexplicable by the classical rational actor paradigm traditionally used in transportation research. In literature, commuting is mainly explained by residential contexts, urban forms and job. Nevertheless this theoretical frame says little about the decision-making processes themselves. Based on a qualitative survey conducted in three European countries - France, Belgium and Switzerland – among a population of high commuters, this paper proposes an analysis of

  8. GEANT4 simulations of the n{sub T}OF spallation source and their benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Lo Meo, S. [Research Centre ' ' Ezio Clementel' ' , ENEA, Bologna (Italy); Section of Bologna, INFN, Bologna (Italy); Cortes-Giraldo, M.A.; Lerendegui-Marco, J.; Guerrero, C.; Quesada, J.M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); Massimi, C.; Vannini, G. [Section of Bologna, INFN, Bologna (Italy); University of Bologna, Physics and Astronomy Dept. ' ' Alma Mater Studiorum' ' , Bologna (Italy); Barbagallo, M.; Colonna, N. [INFN, Section of Bari, Bari (Italy); Mancusi, D. [CEA-Saclay, DEN, DM2S, SERMA, LTSD, Gif-sur-Yvette CEDEX (France); Mingrone, F. [Section of Bologna, INFN, Bologna (Italy); Sabate-Gilarte, M. [Universidad de Sevilla, Facultad de Fisica, Sevilla (Spain); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Vlachoudis, V. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Collaboration: The n_TOF Collaboration

    2015-12-15

    Neutron production and transport in the spallation target of the n{sub T}OF facility at CERN has been simulated with GEANT4. The results obtained with different models of high-energy nucleon-nucleus interaction have been compared with the measured characteristics of the neutron beam, in particular the flux and its dependence on neutron energy, measured in the first experimental area. The best agreement at present, within 20% for the absolute value of the flux, and within few percent for the energy dependence in the whole energy range from thermal to 1 GeV, is obtained with the INCL++ model coupled with the GEANT4 native de-excitation model. All other available models overestimate by a larger factor, of up to 70%, the n{sub T}OF neutron flux. The simulations are also able to accurately reproduce the neutron beam energy resolution function, which is essentially determined by the moderation time inside the target/moderator assembly. The results here reported provide confidence on the use of GEANT4 for simulations of spallation neutron sources. (orig.)

  9. A study of the runaway relativistic electron avalanche and the feedback theory using GEANT4

    Science.gov (United States)

    Broberg Skeltved, Alexander; Østgaard, Nikolai; Carlson, Brant; Gjesteland, Thomas

    2014-05-01

    This study investigate the Runaway Relativistic Electron Avalanche (RREA) and the feedback process as well as the production of Bremsstrahlung photons from Runaway Electrons (REs). These processes are important to understand the production of the intense bursts of gamma-rays known as Terrestrial Gamma-Ray Flashes (TGFs). Results are obtained from Monte Carlo (MC) simulations using the GEometry ANd Tracking 4 (GEANT4) programming toolkit. The simulations takes into account the effects of electron ionisation, electron by electron scattering (Møller scattering) as well as positron and photon interactions, in the 250 eV-100 GeV energy range. Several physics libraries or 'physics lists' are provided with GEANT4 to implement these physics processes in the simulations. We give a detailed analysis of the electron and the feedback multiplication, in particular the avalanche lengths, Λ, the energy distribution and the feedback factor, γ. We also find that our results vary significantly depending on which physics list we implement. In order to verify our results and the GEANT4 programming toolkit, we compare them to previous results from existing models. In addition we present the ratio of the production of bremsstrahlung photons to runaway electrons. From this ratio we obtain the parameter, α, which describe the electron to photon relation.

  10. Validation of the Geant4 simulation of bremsstrahlung from thick targets below 3 MeV

    CERN Document Server

    Pandola, Luciano; Caccia, Barbara

    2014-01-01

    The bremsstrahlung spectra produced by electrons impinging on thick targets are simulated using the Geant4 Monte Carlo toolkit. Simulations are validated against experimental data available in literature for a range of energy between 0.5 and 2.8 MeV for Al and Fe targets and for a value of energy of 70 keV for Al, Ag, W and Pb targets. All three independent sets of electromagnetic models available in Geant4 to simulate bremsstrahlung are tested. A quantitative analysis is performed reproducing with each model the energy spectrum for the different configurations of emission angles, energies and targets. At higher energies (0.5-2.8 MeV) of the impinging electrons on Al and Fe targets, Geant4 is able to reproduce the spectral shapes and the integral photon emission in the forward direction (at better than 10%). The physics model based on the Penelope Monte Carlo code seems slightly preferable over the other two. However, all models over-estimate the photon emission in the backward hemisphere. For the lower energ...

  11. Modeling proton and alpha elastic scattering in liquid water in Geant4-DNA

    Energy Technology Data Exchange (ETDEWEB)

    Tran, H.N., E-mail: tranngochoang@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); El Bitar, Z. [Institut Pluridisciplinaire Hubert Curien/IN2P3/CNRS, Strasbourg (France); Champion, C. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Karamitros, M. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, INCIA, UMR 5287, F-33400 Talence (France); Bernal, M.A. [Instituto de FísicaGleb Wataghin, Universida de Estadual de Campinas, SP (Brazil); Francis, Z. [Université Saint Joseph, Faculty of Science, Department of Physics, Beirut (Lebanon); The Open University, Faculty of Science, Department of Physical Sciences, Walton Hall, MK7 6AA Milton Keynes (United Kingdom); Ivantchenko, V. [Ecoanalytica, 119899 Moscow (Russian Federation); Lee, S.B.; Shin, J.I. [Proton Therapy Center, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do 410-769 (Korea, Republic of); Incerti, S. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France)

    2015-01-15

    Elastic scattering of protons and alpha (α) particles by water molecules cannot be neglected at low incident energies. However, this physical process is currently not available in the “Geant4-DNA” extension of the Geant4 Monte Carlo simulation toolkit. In this work, we report on theoretical differential and integral cross sections of the elastic scattering process for 100 eV–1 MeV incident protons and for 100 eV–10 MeV incident α particles in liquid water. The calculations are performed within the classical framework described by Everhart et al., Ziegler et al. and by the ICRU 49 Report. Then, we propose an implementation of the corresponding classes into the Geant4-DNA toolkit for modeling the elastic scattering of protons and α particles. Stopping powers as well as ranges are also reported. Then, it clearly appears that the account of the elastic scattering process in the slowing-down of the charged particle improves the agreement with the existing data in particular with the ICRU recommendations.

  12. The Geant4 Visualisation System - a multi-driver graphics system

    CERN Document Server

    Allison, John; Kimura, Akinori; Perl, Joseph

    2013-01-01

    From the beginning the Geant4 Visualisation System was designed to support several simultaneous graphics systems written to common abstract interfaces. Today it has matured into a powerful diagnostic and presentational tool. It comes with a library of models that may be added to the current scene and which include the representation of the Geant4 geometry hierarchy, simulated trajectories and user-written hits and digitisations. The workhorse is the OpenGL suite of drivers for X, Xm, Qt and Win32. There is an Open Inventor driver. Scenes can be exported in special graphics formats for offline viewing in the DAWN, VRML, HepRApp and gMocren browsers. PostScript can be generated through OpenGL, Open Inventor, DAWN and HepRApp. Geant4's own tracking algorithms are used by the Ray Tracer. Not all drivers support all features but all drivers bring added functionality of some sort. This paper describes the interfaces and details the individual drivers.

  13. Assessment of Geant4 prompt gamma emission yields in the context of proton therapy monitoring

    Directory of Open Access Journals (Sweden)

    Marco ePinto

    2016-01-01

    Full Text Available Monte Carlo tools have been long used to assist the research and development of solutions for proton therapy monitoring. The present work focuses on the prompt-gamma emission yields by comparing experimental data with the outcomes of the current version of Geant4 using all applicable proton inelastic models. For the case in study and using the binary cascade model, it was found that Geant4 overestimates the prompt-gamma emission yields by 40.2+/-0.3%, even though it predicts the prompt-gamma profile length of the experimental profile accurately. In addition, the default implementations of all proton inelastic models show an overestimation in the number of prompt gammas emitted. Finally, a set of built-in options and physically-sound Geant4 source code changes have been tested in order to try to improve the discrepancy observed. A satisfactory agreement was found when using the QMD model with a wave packet width equal to 1.3 fm2.

  14. Geant4 Model Validation of Compton Suppressed System for Process monitoring of Spent Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Sarah; Unlu, Kenan; Orton, Christopher R.; Schwantes, Jon M.

    2013-05-01

    Nuclear material accountancy is of continuous concern for the regulatory, safeguards, and verification communities. In particular, spent nuclear fuel reprocessing facilities pose one of the most difficult accountancy challenges: monitoring highly radioactive, fluid sample streams in near real-time. The Multi-Isotope Process monitor will allow for near-real-time indication of process alterations using passive gamma-ray detection coupled with multivariate analysis techniques to guard against potential material diversion or to enhance domestic process monitoring. The Compton continuum from the dominant 661.7 keV 137Cs fission product peak obscures lower energy lines which could be used for spectral and multivariate analysis. Compton suppression may be able to mitigate the challenges posed by the high continuum caused by scattering. A Monte Carlo simulation using the Geant4 toolkit is being developed to predict the expected suppressed spectrum from spent fuel samples to estimate the reduction in the Compton continuum. Despite the lack of timing information between decay events in the particle management of Geant4, encouraging results were recorded utilizing only the information within individual decays without accounting for accidental coincidences. The model has been validated with single and cascade decay emitters in two steps: as an unsuppressed system and with suppression activated. Results of the Geant4 model validation will be presented.

  15. Geant4 models for simulation of hadron/ion nuclear interactions at moderate and low energies.

    Science.gov (United States)

    Ivantchenko, Anton; Ivanchenko, Vladimir; Quesada, Jose-Manuel; Wright, Dennis

    The Geant4 toolkit is intended for Monte Carlo simulation of particle transport in media. It was initially designed for High Energy Physics purposes such as experiments at the Large Hadron Collider (LHC) at CERN. The toolkit offers a set of models allowing effective simulation of cosmic ray interactions with different materials. For moderate and low energy hadron/ion interactions with nuclei there are a number of competitive models: Binary and Bertini intra-nuclear cascade models, quantum molecular dynamic model (QMD), INCL/ABLA cascade model, and Chiral Invariant Phase Space Decay model (CHIPS). We report the status of these models for the recent version of Geant4 (release 9.3, December 2009). The Bertini cascade in-ternal cross sections were upgraded. The native Geant4 precompound and deexcitation models were used in the Binary cascade and QMD. They were significantly improved including emis-sion of light fragments, the Fermi break-up model, the General Evaporation Model (GEM), the multi-fragmentation model, and the fission model. Comparisons between model predictions and data for thin target experiments for neutron, proton, light ions, and isotope production are presented and discussed. The focus of these validations is concentrated on target materials important for space missions.

  16. Parametric-Resonance Ionization Cooling in Twin-Helix.

    Energy Technology Data Exchange (ETDEWEB)

    V.S. Morozov, Ya.S. Derbenev, A. Afanasev, R.P. Johnson, Erdelyi. B., J.A. Maloney

    2011-09-01

    Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a highluminosity muon collider. For the implementation of PIC, we developed an epicyclic twin-helix channel with correlated optics. Wedge-shaped absorbers immediately followed by short rf cavities are placed into the twin-helix channel. Parametric resonances are induced in both planes using helical quadrupole harmonics. We demonstrate resonant dynamics and cooling with stochastic effects off using GEANT4/G4beamline. We illustrate compensation of spherical aberrations and benchmark COSY Infinity, a powerful tool for aberration analysis and compensation.

  17. Multimodal imaging analysis of single-photon emission computed tomography and magnetic resonance tomography for improving diagnosis of Parkinson's disease; Multimodale SPECT- und MRT-Bilddatenanalyse zur Verbesserung der Diagnostik des idiopathischen Parkinson-Syndroms

    Energy Technology Data Exchange (ETDEWEB)

    Barthel, H.; Georgi, P. [Leipzig Univ. (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Mueller, U.; Waechter, T.; Murai, T. [Max-Planck-Inst. fuer Neuropsychologische Forschung, Leipzig (Germany); Slomka, P. [Universitaet West-Ontario, London (Canada). Abt. fuer Nuklearmedizin; Dannenberg, C.; Kahn, T. [Leipzig Univ. (Germany). Klinik und Poliklinik fuer Diagnostische Radiologie

    2000-10-01

    Parkinson's disease (PD) is characterized by a degeneration of nigrostriated dopaminergic neurons, which can be imaged with {sup 123}I-labeled 2{beta}-carbomethoxy-3{beta}-(4-iodophenyl) tropane ([{sup 123}I]{beta}-CIT) and single-photon emission computed tomography (SPECT). However, the quality of the region of interest (ROI) technique used for quantitative analysis of SPECT data is compromised by limited anatomical information in the images. We investigated whether the diagnosis of PD can be improved by combining the use of SPECT images with morphological image data from magnetic resonance imaging (MRI)/computed tomography (CT). We examined 27 patients (8 men, 19 women; aged 55{+-}13 years) with PD (Hoehn and Yahr stage 2.1{+-}0.8) by high-resolution [{sup 123}I]{beta}-CIT SPECT (185-200 MBq, Ceraspect camera). SPECT images were analyzed both by a unimodal technique (ROIs defined directly within the SPECT studies) and a multimodal technique (ROIs defined within individual MRI/CT studies and transferred to the corresponding interactively coregistered SPECT studies). [{sup 123}I]{beta}-CIT binding ratios (cerebellum as reference), which were obtained for heads of caudate nuclei (CA), putamina (PU), and global striatal structures were compared with clinical parameters. Differences between contra- and ipsilateral (related to symptom dominance) striatal [{sup 123}I]{beta}-CIT binding ratios proved to be larger in the multimodal ROI technique than in the unimodal approach (e.g., for PU: 1.2*** vs. 0.7**). Binding ratios obtained by the unimodal ROI technique were significantly correlated with those of the multimodal technique (e.g., for CA: y=0.97x+2.8; r=0.70; P<0.001). Concerning the correlations between SPECT data and clinical parameters, the significance levels in the multimodal ROI technique exceeded those of the unimodal technique, for example, for the correlation between CA and the UPDRS{sub com} subscore (r=-0.49* vs. -0.32). These results show that the

  18. Progressive and resonant wave helices application to electron paramagnetic resonance; Helices a ondes progressives et resonnantes application a la resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Volino, F. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    We show that helices can be used as resonant systems. Their properties are theoretically and experimentally studied. We describe resonant helices for electron paramagnetic resonance in X-band and develop a comparison between their sensitivity and the sensitivity of a normal resonant cavity. For cylindrical samples less than 3 mm diameter, the helix is more sensitive and can produce more intense microwave magnetic fields. (author) [French] Il est montre que les helices peuvent etre utilisees comme systeme resonnant. Leurs proprietes sont discutees theoriquement et experimentalement. Des helices resonnantes en bande X pour la resonance paramagnetique electronique sont decrites et leur sensibilite est comparee a celle des cavites resonnantes. Pour des echantillons cylindriques de moins de 3 mm de diametre, l'helice est plus sensible et peut produire des champs magnetiques hyper fins plus intenses. (auteur)

  19. Extension of PENELOPE to protons: Simulation of nuclear reactions and benchmark with Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Sterpin, E. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels (Belgium); Sorriaux, J. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and ICTEAM Institute, Université catholique de Louvain, Louvain-la-Neuve (Belgium); Vynckier, S. [Center of Molecular Imaging, Radiotherapy and Oncology, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Avenue Hippocrate 54, 1200 Brussels, Belgium and Département de radiothérapie, Cliniques Universitaires Saint-Luc, Avenue Hippocrate 10, 1200 Brussels (Belgium)

    2013-11-15

    Purpose: Describing the implementation of nuclear reactions in the extension of the Monte Carlo code (MC) PENELOPE to protons (PENH) and benchmarking with Geant4.Methods: PENH is based on mixed-simulation mechanics for both elastic and inelastic electromagnetic collisions (EM). The adopted differential cross sections for EM elastic collisions are calculated using the eikonal approximation with the Dirac–Hartree–Fock–Slater atomic potential. Cross sections for EM inelastic collisions are computed within the relativistic Born approximation, using the Sternheimer–Liljequist model of the generalized oscillator strength. Nuclear elastic and inelastic collisions were simulated using explicitly the scattering analysis interactive dialin database for {sup 1}H and ICRU 63 data for {sup 12}C, {sup 14}N, {sup 16}O, {sup 31}P, and {sup 40}Ca. Secondary protons, alphas, and deuterons were all simulated as protons, with the energy adapted to ensure consistent range. Prompt gamma emission can also be simulated upon user request. Simulations were performed in a water phantom with nuclear interactions switched off or on and integral depth–dose distributions were compared. Binary-cascade and precompound models were used for Geant4. Initial energies of 100 and 250 MeV were considered. For cases with no nuclear interactions simulated, additional simulations in a water phantom with tight resolution (1 mm in all directions) were performed with FLUKA. Finally, integral depth–dose distributions for a 250 MeV energy were computed with Geant4 and PENH in a homogeneous phantom with, first, ICRU striated muscle and, second, ICRU compact bone.Results: For simulations with EM collisions only, integral depth–dose distributions were within 1%/1 mm for doses higher than 10% of the Bragg-peak dose. For central-axis depth–dose and lateral profiles in a phantom with tight resolution, there are significant deviations between Geant4 and PENH (up to 60%/1 cm for depth

  20. Validation of the GEANT4 simulation of bremsstrahlung from thick targets below 3 MeV

    Science.gov (United States)

    Pandola, L.; Andenna, C.; Caccia, B.

    2015-05-01

    The bremsstrahlung spectra produced by electrons impinging on thick targets are simulated using the GEANT4 Monte Carlo toolkit. Simulations are validated against experimental data available in literature for a range of energy between 0.5 and 2.8 MeV for Al and Fe targets and for a value of energy of 70 keV for Al, Ag, W and Pb targets. The energy spectra for the different configurations of emission angles, energies and targets are considered. Simulations are performed by using the three alternative sets of electromagnetic models that are available in GEANT4 to describe bremsstrahlung. At higher energies (0.5-2.8 MeV) of the impinging electrons on Al and Fe targets, GEANT4 is able to reproduce the spectral shapes and the integral photon emission in the forward direction. The agreement is within 10-30%, depending on energy, emission angle and target material. The physics model based on the Penelope Monte Carlo code is in slightly better agreement with the measured data than the other two. However, all models over-estimate the photon emission in the backward hemisphere. For the lower energy study (70 keV), which includes higher-Z targets, all models systematically under-estimate the total photon yield, providing agreement between 10% and 50%. The results of this work are of potential interest for medical physics applications, where knowledge of the energy spectra and angular distributions of photons is needed for accurate dose calculations with Monte Carlo and other fluence-based methods.

  1. Comparison of electromagnetic and hadronic models generated using Geant 4 with antiproton dose measured in CERN

    Directory of Open Access Journals (Sweden)

    Mohammad Bagher Tavakoli

    2015-01-01

    Full Text Available After proposing the idea of antiproton cancer treatment in 1984 many experiments were launched to investigate different aspects of physical and radiobiological properties of antiproton, which came from its annihilation reactions. One of these experiments has been done at the European Organization for Nuclear Research known as CERN using the antiproton decelerator. The ultimate goal of this experiment was to assess the dosimetric and radiobiological properties of beams of antiprotons in order to estimate the suitability of antiprotons for radiotherapy. One difficulty on this way was the unavailability of antiproton beam in CERN for a long time, so the verification of Monte Carlo codes to simulate antiproton depth dose could be useful. Among available simulation codes, Geant4 provides acceptable flexibility and extensibility, which progressively lead to the development of novel Geant4 applications in research domains, especially modeling the biological effects of ionizing radiation at the sub-cellular scale. In this study, the depth dose corresponding to CERN antiproton beam energy by Geant4 recruiting all the standard physics lists currently available and benchmarked for other use cases were calculated. Overall, none of the standard physics lists was able to draw the antiproton percentage depth dose. Although, with some models our results were promising, the Bragg peak level remained as the point of concern for our study. It is concluded that the Bertini model with high precision neutron tracking (QGSP_BERT_HP is the best to match the experimental data though it is also the slowest model to simulate events among the physics lists.

  2. Comparison of electromagnetic and hadronic models generated using Geant 4 with antiproton dose measured in CERN.

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Reiazi, Reza; Mohammadi, Mohammad Mehdi; Jabbari, Keyvan

    2015-01-01

    After proposing the idea of antiproton cancer treatment in 1984 many experiments were launched to investigate different aspects of physical and radiobiological properties of antiproton, which came from its annihilation reactions. One of these experiments has been done at the European Organization for Nuclear Research known as CERN using the antiproton decelerator. The ultimate goal of this experiment was to assess the dosimetric and radiobiological properties of beams of antiprotons in order to estimate the suitability of antiprotons for radiotherapy. One difficulty on this way was the unavailability of antiproton beam in CERN for a long time, so the verification of Monte Carlo codes to simulate antiproton depth dose could be useful. Among available simulation codes, Geant4 provides acceptable flexibility and extensibility, which progressively lead to the development of novel Geant4 applications in research domains, especially modeling the biological effects of ionizing radiation at the sub-cellular scale. In this study, the depth dose corresponding to CERN antiproton beam energy by Geant4 recruiting all the standard physics lists currently available and benchmarked for other use cases were calculated. Overall, none of the standard physics lists was able to draw the antiproton percentage depth dose. Although, with some models our results were promising, the Bragg peak level remained as the point of concern for our study. It is concluded that the Bertini model with high precision neutron tracking (QGSP_BERT_HP) is the best to match the experimental data though it is also the slowest model to simulate events among the physics lists.

  3. Liste des intrants 2015

    OpenAIRE

    Speiser, Bernhard; Tamm, Lucius; Maurer, Veronika; Berner, Alfred; Schneider, Claudia; Chevillat, Véronique

    2015-01-01

    La liste des intrants contient tous les produits phytosanitaires, les engrais, les substrats du commerce, les produits de lutte contre les mouches des étables, les agents d'ensilage, les aliments minéraux et complémentaires, les produits pour la désinfection des stabulations et les produits contre les maladies des abeilles autorisés pour l'agriculture biologique. Cette liste est contraignante pour les producteurs de Bio Suisse. Sur les fermes Bio Suisse, seuls les produits mentionnés sont aut...

  4. Preliminary assessment of Geant4 HP models and cross section libraries by reactor criticality benchmark calculations

    DEFF Research Database (Denmark)

    Cai, Xiao-Xiao; Llamas-Jansa, Isabel; Mullet, Steven

    2013-01-01

    to reactor modelling. Before version 9.5, Geant4 HP thermal scattering model (i.e. the S(α; β) model ) supports only three bounded isotopes, namely, H in water and polyethylene, and C in graphite. Newly supported materials include D in heavy water, O and Be in beryllium oxide, H and Zr in zirconium hydride......, U and O in uranium dioxide, Al metal, Be metal, and Fe metal. The native HP cross section library G4NDL does not include data for elements with atomic number larger than 92. Therefore, transuranic elements, which have impacts for a realistic reactor, can not be simulated by the combination of the HP...

  5. Geant4 simulation of optical photon transport in scintillator tile with direct readout by silicon photomultiplier

    Science.gov (United States)

    Korpachev, S.; Chadeeva, M.

    2017-01-01

    The direct coupling of silicon photomultiplier to the scintillator tile is considered to be the main option for active elements of the highly granular hadron calorimeter developed for future linear collider experiments. In this study, the response of the scintillator-SiPM system to minimum ionising particles was simulated using the optical photon transport functionality available in the Geant4 package. The uniformity of response for both flat tile and tile with dimple was estimated from the simulations and compared to the experimental results obtained in the previous studies.

  6. Geant4 simulations on Compton scattering of laser photons on relativistic electrons

    Energy Technology Data Exchange (ETDEWEB)

    Filipescu, D. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6, Romania and National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Utsunomiya, H. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Gheorghe, I.; Glodariu, T. [National Institute for Physics and Nuclear Engineering Horia Hulubei, str. Atomistilor nr. 407 (Romania); Tesileanu, O. [Extreme Light Infrastructure - Nuclear Physics, str. Atomistilor nr. 407, Bucharest-Magurele, P.O.BOX MG6 (Romania); Shima, T.; Takahisa, K. [Research Center for Nuclear Physics, Osaka University, Suita, Osaka 567-0047 (Japan); Miyamoto, S. [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, 3-1-2 Kouto, Kamigori, Hyogo 678-1205 (Japan)

    2015-02-24

    Using Geant4, a complex simulation code of the interaction between laser photons and relativistic electrons was developed. We implemented physically constrained electron beam emittance and spacial distribution parameters and we also considered a Gaussian laser beam. The code was tested against experimental data produced at the γ-ray beam line GACKO (Gamma Collaboration Hutch of Konan University) of the synchrotron radiation facility NewSUBARU. Here we will discuss the implications of transverse missallignments of the collimation system relative to the electron beam axis.

  7. Study of silicon+6LiF thermal neutron detectors: GEANT4 simulations versus real data

    Science.gov (United States)

    Meo, S. Lo; Cosentino, L.; Mazzone, A.; Bartolomei, P.; Finocchiaro, P.

    2017-09-01

    Research and development on alternative thermal neutron detection technologies and methods are nowadays needed as a possible replacement of 3He-based ones. Commercial solid state silicon detectors, coupled with neutron converter layers containing 6Li, have been proved to represent a viable solution for several applications as present in the literature. In order to better understand the detailed operation and the response and efficiency of such detectors, a series of dedicated GEANT4 simulations were performed and compared with real data collected in a few different configurations. The results show an excellent agreement between data and simulations, indicating that the behavior of the detector is fully understood.

  8. Simulation and modeling for the stand-off radiation detection system (SORDS) using GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Andrew S [Los Alamos National Laboratory; Wallace, Mark [Los Alamos National Laboratory; Galassi, Mark [Los Alamos National Laboratory; Mocko, Michal [Los Alamos National Laboratory; Palmer, David [Los Alamos National Laboratory; Schultz, Larry [Los Alamos National Laboratory; Tornga, Shawn [Los Alamos National Laboratory

    2009-01-01

    A Stand-Off Radiation Detection System (SORDS) is being developed through a joint effort by Raytheon, Los Alamos National Laboratory, Bubble Technology Industries, Radiation Monitoring Devices, and the Massachusetts Institute of Technology, for the Domestic Nuclear Detection Office (DNDO). The system is a mobile truck-based platform performing detection, imaging, and spectroscopic identification of gamma-ray sources. A Tri-Modal Imaging (TMI) approach combines active-mask coded aperture imaging, Compton imaging, and shadow imaging techniques. Monte Carlo simulation and modeling using the GEANT4 toolkit was used to generate realistic data for the development of imaging algorithms and associated software code.

  9. GEANT4 simulation of cyclotron radioisotope production in a solid target.

    Science.gov (United States)

    Poignant, F; Penfold, S; Asp, J; Takhar, P; Jackson, P

    2016-05-01

    The use of radioisotopes in nuclear medicine is essential for diagnosing and treating cancer. The optimization of their production is a key factor in maximizing the production yield and minimizing the associated costs. An efficient approach to this problem is the use of Monte Carlo simulations prior to experimentation. By predicting isotopes yields, one can study the isotope of interest expected activity for different energy ranges. One can also study the target contamination with other radioisotopes, especially undesired radioisotopes of the wanted chemical element which are difficult to separate from the irradiated target and might result in increasing the dose when delivering the radiopharmaceutical product to the patient. The aim of this work is to build and validate a Monte Carlo simulation platform using the GEANT4 toolkit to model the solid target system of the South Australian Health and Medical Research Institute (SAHMRI) GE Healthcare PETtrace cyclotron. It includes a GEANT4 Graphical User Interface (GUI) where the user can modify simulation parameters such as the energy, shape and current of the proton beam, the target geometry and material, the foil geometry and material and the time of irradiation. The paper describes the simulation and presents a comparison of simulated and experimental/theoretical yields for various nuclear reactions on an enriched nickel 64 target using the GEANT4 physics model QGSP_BIC_AllHP, a model recently developed to evaluate with high precision the interaction of protons with energies below 200MeV available in Geant4 version 10.1. The simulation yield of the (64)Ni(p,n)(64)Cu reaction was found to be 7.67±0.074 mCi·μA(-1) for a target energy range of 9-12MeV. Szelecsenyi et al. (1993) gives a theoretical yield of 6.71mCi·μA(-1) and an experimental yield of 6.38mCi·μA(-1). The (64)Ni(p,n)(64)Cu cross section obtained with the simulation was also verified against the yield predicted from the nuclear database TENDL and

  10. Absorbed dose estimations of 131I for critical organs using the GEANT4 Monte Carlo simulation code

    Institute of Scientific and Technical Information of China (English)

    Ziaur Rahman; Shakeel ur Rehman; Waheed Arshed; Nasir M Mirza; Abdul Rashid; Jahan Zeb

    2012-01-01

    The aim of this study is to compare the absorbed doses of critical organs of 131I using the MIRD (Medical Internal Radiation Dose) with the corresponding predictions made by GEANT4 simulations.S-values (mean absorbed dose rate per unit activity) and energy deposition per decay for critical organs of 131I for various ages,using standard cylindrical phantom comprising water and ICRP soft-tissue material,have also been estimated.In this study the effect of volume reduction of thyroid,during radiation therapy,on the calculation of absorbed dose is also being estimated using GEANT4.Photon specific energy deposition in the other organs of the neck,due to 131I decay in the thyroid organ,has also been estimated.The maximum relative difference of MIRD with the GEANT4 simulated results is 5.64% for an adult's critical organs of 131I.Excellent agreement was found between the results of water and ICRP soft tissue using the cylindrical model.S-values are tabulated for critical organs of 131I,using 1,5,10,15 and 18 years (adults) individuals.S-values for a cylindrical thyroid of different sizes,having 3.07% relative differences of GEANT4 with Siegel & Stabin results.Comparison of the experimentally measured values at 0.5 and 1 m away from neck of the ionization chamber with GEANT4 based Monte Carlo simulations results show good agreement.This study shows that GEANT4 code is an important tool for the internal dosimetry calculations.

  11. Geant4 Parametrization And Modeling Of Pion Production In Proton-nucleus Interactions Based On Harp Experimental Data: Incident Proton Momenta Are From 3 Gev/c To 12.9 Gev/c

    CERN Document Server

    Giani, S; Panman, J; Grichine, V

    2008-01-01

    Expeimental data of HARP (the hadron production experiment at CERN-PS, PS214) describing inclusive spectra of pions produced in proton-nucleus interactions in the momentum range 3-12.9 GeV/c were compared versus Geant4 model predictions. No special tuning of Geant4 models was done. In addition the data were parameterized in the form suitable for Geant4 and their parameterization is proposed to be used in Geant4 hadron generators.

  12. Simulation of Auger electron emission from nanometer-size gold targets using the Geant4 Monte Carlo simulation toolkit

    Science.gov (United States)

    Incerti, S.; Suerfu, B.; Xu, J.; Ivantchenko, V.; Mantero, A.; Brown, J. M. C.; Bernal, M. A.; Francis, Z.; Karamitros, M.; Tran, H. N.

    2016-04-01

    A revised atomic deexcitation framework for the Geant4 general purpose Monte Carlo toolkit capable of simulating full Auger deexcitation cascades was implemented in June 2015 release (version 10.2 Beta). An overview of this refined framework and testing of its capabilities is presented for the irradiation of gold nanoparticles (NP) with keV photon and MeV proton beams. The resultant energy spectra of secondary particles created within and that escape the NP are analyzed and discussed. It is anticipated that this new functionality will improve and increase the use of Geant4 in the medical physics, radiobiology, nanomedicine research and other low energy physics fields.

  13. Performance of Geant4 in simulating semiconductor particle detector response in the energy range below 1 MeV

    CERN Document Server

    Soti, G.; Breitenfeldt, M.; Finlay, P.; Kraev, I.S.; Knecht, A.; Porobic, T.; Zákoucký, D.; Severijns, N.

    2013-01-01

    Geant4 simulations play a crucial role in the analysis and interpretation of experiments providing low energy precision tests of the Standard Model. This paper focuses on the accuracy of the description of the electron processes in the energy range between 100 and 1000 keV. The effect of the different simulation parameters and multiple scattering models on the backscattering coefficients is investigated. Simulations of the response of HPGe and passivated implanted planar Si detectors to \\beta{} particles are compared to experimental results. An overall good agreement is found between Geant4 simulations and experimental data.

  14. Molecular scale track structure simulations in liquid water using the Geant4-DNA Monte-Carlo processes

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Z., E-mail: ziad.francis@gmail.co [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Dosimetrie des Rayonnements Ionisants, BP 17, 92262 Fontenay-aux-Roses Cedex (France); Incerti, S. [Universite Bordeaux 1, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, Chemin du Solarium, BP120, 33175 Gradignan (France); Capra, R. [Via Niella 12, 17100 Savona (Italy); Mascialino, B. [Department of Medical Radiation Physics, Stockholm University, Box 260, 17176 Stockholm (Sweden); Montarou, G. [Laboratoire de Physique Corpusculaire, 24 avenue des Landais, 63177 Aubiere (France); Stepan, V. [Nuclear Physics Institute ASCR, Na Truhlarce 39/64, Praha 8 (Czech Republic); Villagrasa, C. [Institut de Radioprotection et de Surete Nucleaire, Laboratoire de Dosimetrie des Rayonnements Ionisants, BP 17, 92262 Fontenay-aux-Roses Cedex (France)

    2011-01-15

    This paper presents a study of energy deposits induced by ionising particles in liquid water at the molecular scale. Particles track structures were generated using the Geant4-DNA processes of the Geant4 Monte-Carlo toolkit. These processes cover electrons (0.025 eV-1 MeV), protons (1 keV-100 MeV), hydrogen atoms (1 keV-100 MeV) and alpha particles (10 keV-40 MeV) including their different charge states. Electron ranges and lineal energies for protons were calculated in nanometric and micrometric volumes.

  15. Simulation of Auger electron emission from nanometer-size gold targets using the Geant4 Monte Carlo simulation toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Incerti, S., E-mail: sebastien.incerti@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Suerfu, B.; Xu, J. [Department of Physics, Princeton University, Princeton, NJ (United States); Ivantchenko, V. [Ecoanalytica, Moscow (Russian Federation); Geant4 Associates International Ltd, Hebden Bridge (United Kingdom); Mantero, A. [SWHARD srl, via Greto di Cornigliano 6r, 16152 Genova (Italy); Brown, J.M.C. [School of Mathematics and Physics, Queen’s University Belfast, Belfast, Northern Ireland (United Kingdom); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, SP (Brazil); Francis, Z. [Université Saint Joseph, Faculty of Sciences, Department of Physics, Beirut (Lebanon); Karamitros, M. [Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, IN (United States); Tran, H.N. [Division of Nuclear Physics, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam)

    2016-04-01

    A revised atomic deexcitation framework for the Geant4 general purpose Monte Carlo toolkit capable of simulating full Auger deexcitation cascades was implemented in June 2015 release (version 10.2 Beta). An overview of this refined framework and testing of its capabilities is presented for the irradiation of gold nanoparticles (NP) with keV photon and MeV proton beams. The resultant energy spectra of secondary particles created within and that escape the NP are analyzed and discussed. It is anticipated that this new functionality will improve and increase the use of Geant4 in the medical physics, radiobiology, nanomedicine research and other low energy physics fields.

  16. Magnetic resonance imaging (MRI) of the TMJ: Influence on therapy and inter-observer agreement of two radiologists; Magnetresonanztomographie (MRT) des Kiefergelenkes: Einfluss auf Therapieentscheidung und Uebereinstimmung zweier Auswerter

    Energy Technology Data Exchange (ETDEWEB)

    Vahlensieck, M.; Okweschokwu, S. [Radiologie Haydnhaus, Bonn (Germany); Greven, M. [Medeco Zahnklinik, Bonn (Germany)

    2002-11-01

    Aim: To evaluate the influence of MRI of the temporomandibular joint on the therapeutic strategy in patients with craniomandibular disorders (internal derangement) and, furthermore, to analyze interobserver agreement for defined MRI criteria. Materials and Methods: Fifty-one unilateral and bilateral MRI examinations of 32 patients were enrolled. Therapeutic strategies before and after performance of the MRI were compared. Retrospectively, two radiologists independently analyzed the MR images for position of the disk, position of the condyle, signal intensity of the disk and bilaminar zone, osseous changes and several additional findings, using a check list. Agreement was tested by kappa statistics. Results: In 56% of the cases, changes of the therapeutic regimen were registered after MRI. Statistically significant agreement of the two observers was found for anterior position of the disk (kappa=0.44), transverse position of the disk (kappa=0.46) and position of the condyle (kappa=0.45). No significant agreement was found for signal intensity of the disk (kappa=0.14) or bilaminar zone (kappa=0.24), osseous changes (kappa=0.13) and the additional findings (kappa=0.29). Discussion: MRI has a measurable impact on the therapeutic approach to the internal derangement of the TMJ. The position of the disk and condyle can be reproducibly judged, while the signal intensity of the disk and bilaminar zone and the osseous changes are subject to wide observer variations. (orig.) [German] Zielsetzung: Es sollte der Einfluss der MRT des Kiefergelenkes auf die Therapieentscheidung untersucht werden. Des Weiteren sollten Uebereinstimmungen zweier unabhaengiger Radiologen in der Beurteilung von Kiefergelenk MRT anhand definierter Kriterien bestimmt werden. Material und Methoden: 51 MR-Untersuchungen des Kiefergelenkes wurden ausgewertet. Bei diesen Patienten wurde das urspruengliche mit dem Behandlungskonzept nach MRT verglichen. Alle MRT wurden von zwei Radiologen ausgewertet. Die

  17. Gestion des risques

    CERN Document Server

    Louisot, Jean-Paul

    2009-01-01

    Depuis le début du lie siècle, la gestion des risques connaît une véritable révolution culturelle. Jusqu'alors fonction technique, centrée autour de l'achat de couverture d'assurances, elle est devenue une discipline managériale et transversale : une valise d'instruments que chaque manager doit connaître et appliquer quels que soient son domaine de compétence et ses missions au sein de l'organisation. En effet, la gestion des risques est une culture qui doit être assimilée par chacun des acteurs. C'est précisément l'ambition des 101 questions rassemblées dans cet ouvrage : apporter à chaque manager d'entreprise, de collectivité, d'établissement de santé..., des réponses claires au " pourquoi " et au " comment " : Comment identifier les risques ? Comment analyser les risques ? Quels sont les objectifs de la gestion des risques ? Une carte des risques pour quoi faire ? Pourquoi faut-il financer les risques ? Les entreprises ont-elles des responsabilités pénales ? En quoi consiste la gestion...

  18. Benchmarking nuclear models of FLUKA and GEANT4 for carbon ion therapy

    Energy Technology Data Exchange (ETDEWEB)

    Boehlen, T T; Cerutti, F; Dosanjh, M; Ferrari, A [European Organization for Nuclear Research CERN, CH-1211, Geneva 23 (Switzerland); Gudowska, I [Medical Radiation Physics, Karolinska Institutet and Stockholm University, Box 260 S-171 76 Stockholm (Sweden); Mairani, A [INFN Milan, Via Celoria 16, 20133 Milan (Italy); Quesada, J M, E-mail: Till.Tobias.Boehlen@cern.c [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla (Spain)

    2010-10-07

    As carbon ions, at therapeutic energies, penetrate tissue, they undergo inelastic nuclear reactions and give rise to significant yields of secondary fragment fluences. Therefore, an accurate prediction of these fluences resulting from the primary carbon interactions is necessary in the patient's body in order to precisely simulate the spatial dose distribution and the resulting biological effect. In this paper, the performance of nuclear fragmentation models of the Monte Carlo transport codes, FLUKA and GEANT4, in tissue-like media and for an energy regime relevant for therapeutic carbon ions is investigated. The ability of these Monte Carlo codes to reproduce experimental data of charge-changing cross sections and integral and differential yields of secondary charged fragments is evaluated. For the fragment yields, the main focus is on the consideration of experimental approximations and uncertainties such as the energy measurement by time-of-flight. For GEANT4, the hadronic models G4BinaryLightIonReaction and G4QMD are benchmarked together with some recently enhanced de-excitation models. For non-differential quantities, discrepancies of some tens of percent are found for both codes. For differential quantities, even larger deviations are found. Implications of these findings for the therapeutic use of carbon ions are discussed.

  19. Analysis of GEANT4 Physics List Properties in the 12 GeV MOLLER Simulation Framework

    Science.gov (United States)

    Haufe, Christopher; Moller Collaboration

    2013-10-01

    To determine the validity of new physics beyond the scope of the electroweak theory, nuclear physicists across the globe have been collaborating on future endeavors that will provide the precision needed to confirm these speculations. One of these is the MOLLER experiment - a low-energy particle experiment that will utilize the 12 GeV upgrade of Jefferson Lab's CEBAF accelerator. The motivation of this experiment is to measure the parity-violating asymmetry of scattered polarized electrons off unpolarized electrons in a liquid hydrogen target. This measurement would allow for a more precise determination of the electron's weak charge and weak mixing angle. While still in its planning stages, the MOLLER experiment requires a detailed simulation framework in order to determine how the project should be run in the future. The simulation framework for MOLLER, called ``remoll'', is written in GEANT4 code. As a result, the simulation can utilize a number of GEANT4 coded physics lists that provide the simulation with a number of particle interaction constraints based off of different particle physics models. By comparing these lists with one another using the data-analysis application ROOT, the most optimal physics list for the MOLLER simulation can be determined and implemented. This material is based upon work supported by the National Science Foundation under Grant No. 714001.

  20. Modeling the relativistic runaway electron avalanche and the feedback mechanism with GEANT4

    CERN Document Server

    Skeltved, Alexander Broberg; Carlson, Brant; Gjesteland, Thomas; Celestin, Sebastien

    2016-01-01

    This paper presents the first study that uses the GEometry ANd Tracking 4 (GEANT4) toolkit to do quantitative comparisons with other modelling results related to the production of Terrestrial Gamma-ray Flashes (TGFs) and high-energy particle emission from thunderstorms. We will study the Relativistic Runaway Electron Avalanche (RREA) and the relativistic feedback process, as well as the production of bremsstrahlung photons from Runaway Electrons (REs). The Monte Carlo (MC) simulations take into account the effects of electron ionisation, electron by electron (M{\\o}ller) and electron by positron (Bhabha) scattering as well as the bremsstrahlung process and pair-production, in the $250$ eV$-100$ GeV energy range. Our results indicate that the multiplication of electrons during the development of RREAs and under the influence of feedback, are consistent with previous estimates. This is important to validate GEANT4 as a tool to model RREAs and feedback in homogeneous electric fields. We also determine the ratio o...

  1. Comparisons of hadrontherapy-relevant data to nuclear interaction codes in the Geant4 toolkit

    Science.gov (United States)

    Braunn, B.; Boudard, A.; Colin, J.; Cugnon, J.; Cussol, D.; David, J. C.; Kaitaniemi, P.; Labalme, M.; Leray, S.; Mancusi, D.

    2013-03-01

    Comparisons between experimental data, INCL and other nuclear models available in the Geant4 toolkit are presented. The data used for the comparisons come from a fragmentation experiment realised at GANIL facility. The main purpose of this experiment was to measure production rates and angular distributions of emitted particles from the collision of a 95.A MeV 12C beam and thick PMMA (plastic) targets. The latest version of the Intra Nuclear Cascade of Liege code extended to nucleus-nucleus collisions for ion beam therapy application will be described. This code as well as JQMD and the Geant4 binary cascade has been compared with these hadrontherapy-oriented experimental data. The results from the comparisons exhibit an overall qualitative agreement between the models and the experimental data. However, at a quantitative level, it has been shown that none of this three models manage to reproduce precisely all the data. The nucleus-nucleus extension of INCL, which is not predictive enough for ion beam therapy application yet, has nevertheless proven to be competitive with other nuclear collisions codes.

  2. Geant4 studies of the CNAO facility system for hadrontherapy treatment of uveal melanomas

    Science.gov (United States)

    Rimoldi, A.; Piersimoni, P.; Pirola, M.; Riccardi, C.

    2014-06-01

    The Italian National Centre of Hadrontherapy for Cancer Treatment (CNAO -Centro Nazionale di Adroterapia Oncologica) in Pavia, Italy, has started the treatment of selected cancers with the first patients in late 2011. In the coming months at CNAO plans are to activate a new dedicated treatment line for irradiation of uveal melanomas using the available active beam scan. The beam characteristics and the experimental setup should be tuned in order to reach the necessary precision required for such treatments. Collaboration between CNAO foundation, University of Pavia and INFN has started in 2011 to study the feasibility of these specialised treatments by implementing a MC simulation of the transport beam line and comparing the obtained simulation results with measurements at CNAO. The goal is to optimise an eye-dedicated transport beam line and to find the best conditions for ocular melanoma irradiations. This paper describes the Geant4 toolkit simulation of the CNAO setup as well as a modelised human eye with a tumour inside. The Geant4 application could be also used to test possible treatment planning systems. Simulation results illustrate the possibility to adapt the CNAO standard transport beam line by optimising the position of the isocentre and the addition of some passive elements to better shape the beam for this dedicated study.

  3. Carbon fragmentation measurements and validation of the Geant4 nuclear reaction models for hadrontherapy

    Science.gov (United States)

    De Napoli, M.; Agodi, C.; Battistoni, G.; Blancato, A. A.; Cirrone, G. A. P.; Cuttone, G.; Giacoppo, F.; Morone, M. C.; Nicolosi, D.; Pandola, L.; Patera, V.; Raciti, G.; Rapisarda, E.; Romano, F.; Sardina, D.; Sarti, A.; Sciubba, A.; Scuderi, V.; Sfienti, C.; Tropea, S.

    2012-11-01

    Nuclear fragmentation measurements are necessary when using heavy-ion beams in hadrontherapy to predict the effects of the ion nuclear interactions within the human body. Moreover, they are also fundamental to validate and improve the Monte Carlo codes for their use in planning tumor treatments. Nowadays, a very limited set of carbon fragmentation cross sections are being measured, and in particular, to our knowledge, no double-differential fragmentation cross sections at intermediate energies are available in the literature. In this work, we have measured the double-differential cross sections and the angular distributions of the secondary fragments produced in the 12C fragmentation at 62 A MeV on a thin carbon target. The experimental data have been used to benchmark the prediction capability of the Geant4 Monte Carlo code at intermediate energies, where it was never tested before. In particular, we have compared the experimental data with the predictions of two Geant4 nuclear reaction models: the Binary Light Ions Cascade and the Quantum Molecular Dynamic. From the comparison, it has been observed that the Binary Light Ions Cascade approximates the angular distributions of the fragment production cross sections better than the Quantum Molecular Dynamic model. However, the discrepancies observed between the experimental data and the Monte Carlo simulations lead to the conclusion that the prediction capability of both models needs to be improved at intermediate energies.

  4. Proton and electron deep dose profiles for retinoblastoma based on GEANT 4 code

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Flavia V., E-mail: flaviafisica@gmail.co [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares; Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Campos, Tarcisio P.R. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares; Ribeiro, Kilder L., E-mail: kilderlr@gmail.co [Universidade Estadual de Feira de Santana (UEFS), BA (Brazil). Dept. de Fisica

    2009-07-01

    Herein, the dosimetry responses to a retinoblastoma proton and electron radiation therapy were investigated. The computational tool applied to this simulation was the Geant4 code, version 4.9.1. The code allows simulating the charge particle interaction with eyeball tissue. In the present simulation, a box of 4 cm side water filled had represented the human eye. The simulation was performed considering mono energetic beams of protons and electrons with spectra of 57 to 70 MeV for protons and 2 to 8 MeV for electrons. The simulation was guide by the advanced hadron therapy example distributed with the Geant4 code. The phantom was divided in voxels with 0.2 mm side. The energy deposited in each voxel was evaluated taken the direct beam at one face. The simulation results show the delivery energy and therefore the dose deposited in each voxel. The deep dose profiles to proton and electron were plotted. The well known Bragg peak was reproduced for protons. The maximum delivered dose defined the position at the proton stopped. However, to electrons, the absorbed energies were delivered along its path producing a more continuous distribution following the water depth, but also being stopped in the end of its path. (author)

  5. GMC: a GPU implementation of a Monte Carlo dose calculation based on Geant4.

    Science.gov (United States)

    Jahnke, Lennart; Fleckenstein, Jens; Wenz, Frederik; Hesser, Jürgen

    2012-03-07

    We present a GPU implementation called GMC (GPU Monte Carlo) of the low energy (CUDA programming interface. The classes for electron and photon interactions as well as a new parallel particle transport engine were implemented. The way a particle is processed is not in a history by history manner but rather by an interaction by interaction method. Every history is divided into steps that are then calculated in parallel by different kernels. The geometry package is currently limited to voxelized geometries. A modified parallel Mersenne twister was used to generate random numbers and a random number repetition method on the GPU was introduced. All phantom results showed a very good agreement between GPU and CPU simulation with gamma indices of >97.5% for a 2%/2 mm gamma criteria. The mean acceleration on one GTX 580 for all cases compared to Geant4 on one CPU core was 4860. The mean number of histories per millisecond on the GPU for all cases was 658 leading to a total simulation time for one intensity-modulated radiation therapy dose distribution of 349 s. In conclusion, Geant4-based Monte Carlo dose calculations were significantly accelerated on the GPU.

  6. Modelling PET radionuclide production in tissue and external targets using Geant4

    Science.gov (United States)

    Amin, T.; Infantino, A.; Lindsay, C.; Barlow, R.; Hoehr, C.

    2017-07-01

    The Proton Therapy Facility in TRIUMF provides 74 MeV protons extracted from a 500 MeV H- cyclotron for ocular melanoma treatments. During treatment, positron emitting radionuclides such as 1C, 15O and 13N are produced in patient tissue. Using PET scanners, the isotopic activity distribution can be measured for in-vivo range verification. A second cyclotron, the TR13, provides 13 MeV protons onto liquid targets for the production of PET radionuclides such as 18F, 13N or 68Ga, for medical applications. The aim of this work was to validate Geant4 against FLUKA and experimental measurements for production of the above-mentioned isotopes using the two cyclotrons. The results show variable degrees of agreement. For proton therapy, the proton-range agreement was within 2 mm for 11C activity, whereas 13N disagreed. For liquid targets at the TR13 the average absolute deviation ratio between FLUKA and experiment was 1.9±2.7, whereas the average absolute deviation ratio between Geant4 and experiment was 0. 6±0.4. This is due to the uncertainties present in experimentally determined reaction cross sections.

  7. A Compton camera application for the GAMOS GEANT4-based framework

    Energy Technology Data Exchange (ETDEWEB)

    Harkness, L.J., E-mail: ljh@ns.ph.liv.ac.uk [Oliver Lodge Laboratory, The University of Liverpool, Liverpool L69 7ZE (United Kingdom); Arce, P. [Department of Basic Research, CIEMAT, Madrid (Spain); Judson, D.S.; Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Dormand, J.; Jones, M.; Nolan, P.J.; Sampson, J.A.; Scraggs, D.P.; Sweeney, A. [Oliver Lodge Laboratory, The University of Liverpool, Liverpool L69 7ZE (United Kingdom); Lazarus, I.; Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom)

    2012-04-11

    Compton camera systems can be used to image sources of gamma radiation in a variety of applications such as nuclear medicine, homeland security and nuclear decommissioning. To locate gamma-ray sources, a Compton camera employs electronic collimation, utilising Compton kinematics to reconstruct the paths of gamma rays which interact within the detectors. The main benefit of this technique is the ability to accurately identify and locate sources of gamma radiation within a wide field of view, vastly improving the efficiency and specificity over existing devices. Potential advantages of this imaging technique, along with advances in detector technology, have brought about a rapidly expanding area of research into the optimisation of Compton camera systems, which relies on significant input from Monte-Carlo simulations. In this paper, the functionality of a Compton camera application that has been integrated into GAMOS, the GEANT4-based Architecture for Medicine-Oriented Simulations, is described. The application simplifies the use of GEANT4 for Monte-Carlo investigations by employing a script based language and plug-in technology. To demonstrate the use of the Compton camera application, simulated data have been generated using the GAMOS application and acquired through experiment for a preliminary validation, using a Compton camera configured with double sided high purity germanium strip detectors. Energy spectra and reconstructed images for the data sets are presented.

  8. The study of response of wide band gap semiconductor detectors using the Geant4

    Directory of Open Access Journals (Sweden)

    Hussain Riaz

    2014-01-01

    Full Text Available The energy dependence on the intrinsic efficiency, absolute efficiency, full energy peak absolute efficiency and peak-to-total ratio have been studied for various wide band gap semiconductor detectors using the Geant4 based Monte Carlo simulations. The detector thickness of 1-4 mm and the area in 16-100 mm2 range were considered in this work. In excellent agreement with earlier work (Rybka et al., [20], the Geant4 simulated values of detector efficiencies have been found to decrease with incident g-ray energy. Both for the detector thickness and the detector area, the increasing trends have been observed for total efficiency as well as for full-energy peak efficiency in 0.1 MeV-50 MeV range. For Cd1-xZnxTe, the detector response remained insensitive to changes in relative proportions of Zn. For various wide band gap detectors studied in this work, the detection efficiency of TlBr was found highest over the entire range of energy, followed by the HgI2, CdTe, and then by CZT.

  9. Le dialogisme intertextuel des contes des Grimm

    OpenAIRE

    2012-01-01

    « Le caractère le plus important de l’énoncé, ou en tous cas le plus ignoré, est son dialogisme, c’est-à-dire sa dimension intertextuelle », constate Todorov en référence à la conception dialogique du langage proposée par Bakthine. Cet article introductif postule que ce constat s’applique aussi aux contes des Grimm. En partant des recherches déjà menées sur Apulée, Straporola, Basile, Perrault, La Fontaine et Lhéritier, il présente des concepts (réponse intertextuelle, reconfiguration génériq...

  10. Characterization with GEANT4 of 16OMLCTM Siemens multi leaf collimator in a linear accelerator Siemens OncortM; Caracterizacion con GEANT4 colimador multilaminas siemenes 160-MLC{sup T}M en un acelerador lineal Siemens Oncor

    Energy Technology Data Exchange (ETDEWEB)

    Cortes Giraldo, M. A.; Miras, H.; Arrans, R.; Gallardo, M. I.; Quesada, J. M.

    2011-07-01

    The interest and motivation of this work lies in the ability to present GEANT4 to simulate neutron transport through the material, making it possible to make estimates of pollution existing neutron radiotherapy treatments to energies at which the neutron production is significant.

  11. Study of te evolution of the GEANT4 electrons transport algorithm to applications in radiotherapy;Estudo da evolucao do algoritmo de transporte de eletrons do GEANT4 para aplicacoes em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Malthez, Anna Luiza M.C.; Button, Vera L. da S.N. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Eletrica e de Computacao. Dept. de Engenharia Biomedica; Rocha, Jose R. de O. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Engenharia Biomedica

    2009-07-01

    In this work a bibliographic review was made about the GEANT4 applicability in radiotherapy, and also a study of electrons transport algorithm in order to establish the key points for future works with GEANT4. In papers already published, the GEANT4 version 4.6.1 was considered appropriated for photons simulations in applications of clinic significance in radiotherapy (accuracy {approx} 2%), however to electrons was checked that versions older than 8.3 present problems related to electrons transport algorithm, as size step artifact. The GEANT4 algorithm revision, version 8.3, resulted in substantial improvements of some values calculated in simulations, especially the loss energy per step and the boundary vicinity simulation of electrons, beyond better results stability, compared to versions 8.2. We concluded that electrons transport parameters within the following ranges: dRoverRange<0.3, RangeFactor=0.02, GeomFactor=3 and skin=1 is possible to get results with 1% accuracy to cavities simulations, although occur differences between simulated and theoretical doses, indicating that others parameters and the dose shift should be better evaluated. (author)

  12. Applications of Geant4 toolkit to implosion physics for inertial confinement fusion experiments%Geant4在惯性约束聚变内爆物理中的应用

    Institute of Scientific and Technical Information of China (English)

    苏明; 余波; 宋天明; 何小安; 郑建华; 黄天晅; 刘慎业; 江少恩

    2013-01-01

    基于Geant4建立了内爆物理实验多种诊断设备的全三维仿真模型,包括中子成像系统、用于硬X射线诊断的滤波应光谱仪、楔形滤片质子能谱仪、化学气相沉积金刚石探测器(CVD)等.根据Geant4仿真模拟的数据,建立了合适的解谱及图像还原算法,优化了系统设计,从理论上预估了诊断设备的诊断能力.此外仿真数据亦用于设计实验方案,建立诊断设备的标定方法等.%Several diagnostic systems used in implosion physics research were modeled by Geant4 toolkit,including the neutron imaging system,the filter-fluorescer spectrometer for hard X-ray diagnostic,the wedged-range filter spectrometer for proton diagnostic,the CVD diamond detector for neutron diagnostics,etc.The Geant4 simulation results were used to establish proper spectrum and images reconstructed algorithm,to optimize system design,and to estimate diagnostic system performance.Besides,based on the simulation,an experiment scheme was designed and calibration methods for the diagnostics were established.

  13. Photonique des Morphos

    CERN Document Server

    Berthier, Serge

    2010-01-01

    La photonique est déjà présente dans notre vie quotidienne, et on attend maintenant que la manipulation des photons permette aussi le traitement logique des informations. Cependant, l’élément de base qui permet cette manipulation de la lumière, le cristal photonique, est d’une réalisation complexe et mal contrôlée. Dans la course à la maîtrise de la lumière, les structures photoniques naturelles ont beaucoup à nous apprendre. C’est ce que nous montre Serge Berthier qui étudie dans ce livre la structure des écailles des Morphos. Tenant compte de l’essor récent des approches biomimétiques, il présente de manière détaillée plus de dix-huit techniques expérimentales utilisées pour ses analyses, ainsi que les diverses approches théoriques développées pour la modélisation de structures multi-échelles complexes. Première étude quasi-exhaustive des structures fines d’un genre et des propriétés optiques ainsi que colorimétriques générées, ce livre fournit aux entomologiste...

  14. Droit des organisations internationales

    CERN Document Server

    Sorel, Jean-Marc; Ndior, Valère

    2013-01-01

    Cet ouvrage collectif offre aux enseignants et chercheurs en droit international, aux praticiens et aux étudiants, une analyse actualisée du droit des organisations internationales. Il dresse en cinq parties un tableau, illustré par des exemples variés, des problématiques que soulève le phénomène polymorphe d institutionnalisation de la société internationale. La première partie est consacrée au phénomène des « organisations internationales », sous l angle à la fois de l institutionnalisation progressive des relations internationales et de la difficulté à cerner une catégorie unifiée. La deuxième partie rend compte de la création, de la disparition et des mutations des organisations internationales, ici envisagées comme systèmes institutionnels et ordres juridiques dérivés. La troisième partie analyse l autonomie que l acquisition de la personnalité juridique et de privilèges et immunités, un organe administratif intégré, un personnel ou un budget propres confèrent aux organi...

  15. Implementation of the n-body Monte-Carlo event generator into the Geant4 toolkit for photonuclear studies

    Science.gov (United States)

    Luo, Wen; Lan, Hao-yang; Xu, Yi; Balabanski, Dimiter L.

    2017-03-01

    A data-based Monte Carlo simulation algorithm, Geant4-GENBOD, was developed by coupling the n-body Monte-Carlo event generator to the Geant4 toolkit, aiming at accurate simulations of specific photonuclear reactions for diverse photonuclear physics studies. Good comparisons of Geant4-GENBOD calculations with reported measurements of photo-neutron production cross-sections and yields, and with reported energy spectra of the 6Li(n,α)t reaction were performed. Good agreements between the calculations and experimental data were found and the validation of the developed program was verified consequently. Furthermore, simulations for the 92Mo(γ,p) reaction of astrophysics relevance and photo-neutron production of 99Mo/99mTc and 225Ra/225Ac radioisotopes were investigated, which demonstrate the applicability of this program. We conclude that the Geant4-GENBOD is a reliable tool for study of the emerging experiment programs at high-intensity γ-beam laboratories, such as the Extreme Light Infrastructure - Nuclear Physics facility and the High Intensity Gamma-Ray Source at Duke University.

  16. A macroscopic and microscopic study of radon exposure using Geant4 and MCNPX to estimate dose rates and DNA damage

    Science.gov (United States)

    van den Akker, Mary Evelyn

    Radon is considered the second-leading cause of lung cancer after smoking. Epidemiological studies have been conducted in miner cohorts as well as general populations to estimate the risks associated with high and low dose exposures. There are problems with extrapolating risk estimates to low dose exposures, mainly that the dose-response curve at low doses is not well understood. Calculated dosimetric quantities give average energy depositions in an organ or a whole body, but morphological features of an individual can affect these values. As opposed to human phantom models, Computed Tomography (CT) scans provide unique, patient-specific geometries that are valuable in modeling the radiological effects of the short-lived radon progeny sources. Monte Carlo particle transport code Geant4 was used with the CT scan data to model radon inhalation in the main bronchial bifurcation. The equivalent dose rates are near the lower bounds of estimates found in the literature, depending on source volume. To complement the macroscopic study, simulations were run in a small tissue volume in Geant4-DNA toolkit. As an expansion of Geant4 meant to simulate direct physical interactions at the cellular level, the particle track structure of the radon progeny alphas can be analyzed to estimate the damage that can occur in sensitive cellular structures like the DNA molecule. These estimates of DNA double strand breaks are lower than those found in Geant4-DNA studies. Further refinements of the microscopic model are at the cutting edge of nanodosimetry research.

  17. A Geant4 simulation of the depth dose percentage in brain tumors treatments using protons and carbon ions

    Science.gov (United States)

    José A. Diaz, M.; Torres, D. A.

    2016-07-01

    The deposited energy and dose distribution of beams of protons and carbon over a head are simulated using the free tool package Geant4 and the data analysis package ROOT-C++. The present work shows a methodology to understand the microscopical process occurring in a session of hadron-therapy using advance simulation tools.

  18. Geant4 simulations of proton beam transport through a carbon or beryllium degrader and following a beam line

    NARCIS (Netherlands)

    van Goethem, M. J.; van der Meer, R.; Reist, H. W.; Schippers, J. M.

    2009-01-01

    Monte Carlo simulations based on the Geant4 simulation toolkit were performed for the carbon wedge degrader used in the beam line at the Center of Proton Therapy of the Paul Scherrer Institute (PSI). The simulations are part of the beam line studies for the development and understanding of the GANTR

  19. Evaluation on Geant4 Hadronic Models for Pion Minus, Pion Plus and Neutron Particles as Major Antiproton Annihilation Products.

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Mohammadi, Mohammad Mehdi; Reiazi, Reza; Jabbari, Keyvan

    2015-01-01

    Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 × 20 × 20 cm(3) water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in

  20. Evaluation on Geant4 Hadronic Models for Pion Minus, Pion Plus and Neutron Particles as Major Antiproton Annihilation Products

    Science.gov (United States)

    Tavakoli, Mohammad Bagher; Mohammadi, Mohammad Mehdi; Reiazi, Reza; Jabbari, Keyvan

    2015-01-01

    Geant4 is an open source simulation toolkit based on C++, which its advantages progressively lead to applications in research domains especially modeling the biological effects of ionizing radiation at the sub-cellular scale. However, it was shown that Geant4 does not give a reasonable result in the prediction of antiproton dose especially in Bragg peak. One of the reasons could be lack of reliable physic model to predict the final states of annihilation products like pions. Considering the fact that most of the antiproton deposited dose is resulted from high-LET nuclear fragments following pion interaction in surrounding nucleons, we reproduced depth dose curves of most probable energy range of pions and neutron particle using Geant4. We consider this work one of the steps to understand the origin of the error and finally verification of Geant4 for antiproton tracking. Geant4 toolkit version 9.4.6.p01 and Fluka version 2006.3 were used to reproduce the depth dose curves of 220 MeV pions (both negative and positive) and 70 MeV neutrons. The geometry applied in the simulations consist a 20 × 20 × 20 cm3 water tank, similar to that used in CERN for antiproton relative dose measurements. Different physic lists including Quark-Gluon String Precompound (QGSP)_Binary Cascade (BIC)_HP, the recommended setting for hadron therapy, were used. In the case of pions, Geant4 resulted in at least 5% dose discrepancy between different physic lists at depth close to the entrance point. Even up to 15% discrepancy was found in some cases like QBBC compared to QGSP_BIC_HP. A significant difference was observed in dose profiles of different Geant4 physic list at small depths for a beam of pions. In the case of neutrons, large dose discrepancy was observed when LHEP or LHEP_EMV lists were applied. The magnitude of this dose discrepancy could be even 50% greater than the dose calculated by LHEP (or LHEP_EMV) at larger depths. We found that effect different Geant4 physic list in

  1. Influence of thyroid volume reduction on absorbed dose in 131I therapy studied by using Geant4 Monte Carlo simulation

    Science.gov (United States)

    Ziaur, Rahman; Sikander, M. Mirza; Waheed, Arshed; Nasir, M. Mirza; Waheed, Ahmed

    2014-05-01

    A simulation study has been performed to quantify the effect of volume reduction on the thyroid absorbed dose per decay and to investigate the variation of energy deposition per decay due to β- and γ-activity of 131I with volume/mass of thyroid, for water, ICRP- and ICRU-soft tissue taken as thyroid material. A Monte Carlo model of the thyroid, in the Geant4 radiation transport simulation toolkit was constructed to compute the β- and γ-absorbed dose in the simulated thyroid phantom for various values of its volume. The effect of the size and shape of the thyroid on energy deposition per decay has also been studied by using spherical, ellipsoidal and cylindrical models for the thyroid and varying its volume in 1-25 cm3 range. The relative differences of Geant4 results for different models with each other and MCNP results lie well below 1.870%. The maximum relative difference among the Geant4 estimated results for water with ICRP and ICRU soft tissues is not more than 0.225%. S-values for ellipsoidal, spherical and cylindrical thyroid models were estimated and the relative difference with published results lies within 3.095%. The absorbed fraction values for beta particles show a good agreement with published values within 2.105% deviation. The Geant4 based simulation results of absorbed fractions for gammas again show a good agreement with the corresponding MCNP and EGS4 results (±6.667%) but have 29.032% higher values than that of MIRD calculated values. Consistent with previous studies, the reduction of the thyroid volume is found to have a substantial effect on the absorbed dose. Geant4 simulations confirm dose dependence on the volume/mass of thyroid in agreement with MCNP and EGS4 computed values but are substantially different from MIRD8 data. Therefore, inclusion of size/mass dependence is indicated for 131I radiotherapy of the thyroid.

  2. Magnetic resonance imaging (MRI) of liver and brain in haematologic-organic patients with fever of unknown origin; Magnetresonanztomographie (MRT) der Leber und des Gehirns bei haematologisch-onkologischen Patienten mit Fieber unbekannter Ursache

    Energy Technology Data Exchange (ETDEWEB)

    Heussel, C.P.; Kauczor, H.U.; Poguntke, M.; Schadmand-Fischer, S.; Mildenberger, P.; Thelen, M. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Heussel, G. [Mainz Univ. (Germany). 3. Medizinische Klinik und Poliklinik

    1998-08-01

    To examine the advantage of liver and brain MRI in clinically anomalous haematological patients with fever of unknown origin. Material and Methods: Twenty liver MRI (T{sub 2}-TSE, T{sub 2}-HASTE, T{sub 1}-FLASH{+-}Gd dynamic) and 16 brain MRI (T{sub 2}-TSE, FLAIR, T{sub 1}-TSE{+-}Gd) were performed searching for a focus of fever with a suspected organ system. Comparison with clinical follow-up. Results: suspected organ system. Comparison with clinical follow-up. Results: A focus was detected in 11/20 liver MRI. Candidiasis (n=3), mycobacteriosis (n=2), relapse of haematological disease (n=3), graft versus host disease (n=1), non-clarified (n=2). The remaining 9 cases with normal MRI were not suspicious of infectious hepatic disease during follo-wup. In brain MRI, 3/16 showed a focus (toxoplasmosis, aspergillosis, mastoiditis). Clinical indication for an infectious involvement of the brain was found in 4/16 cases 2--5 months after initially normal brain MRI. No suspicion of an infectious involvement of brain was present in the remaining 9/16 cases. Conclusion: In case of fever of unknown origin and suspicion of liver involvement, MRI of the liver should be performed due to data given in literature and its sensitivity of 100%. Because of the delayed detectability of cerebral manifestations, in cases of persisting suspicion even a previously normal MRI of the brain should be repeated. (orig.) [Deutsch] Untersuchung des Nutzens der MRT der Leber und des Gehirns bei klinisch auffaelligen haematologischen Patienten mit Fieber unbekannter Ursache. Material und Methoden: Es wurden 20 MRT der Leber (T{sub 2}-TSE, T{sub 2}-HASTE, T{sub 1}-FLASH{+-}Gd dynamisch) und 16 MRT des Gehirns (T{sub 2}-TSE, FLAIR, T{sub 1}-TSE{+-}Gd) zur Fokussuche bei Infektionsverdacht und Organhinweisen durchgefuehrt. Es erfolgte der Abgleich mit dem weiteren klinischen Verlauf. Ergebnisse: 11/20 MRT-Untersuchungen der Leber zeigten einen Herdbefund: Candidiasis (n=3), Mykobakteriose (n=2

  3. Contestation des Nobel une tradition aussi ancienne que leur attribution

    CERN Document Server

    Sevestre, G

    2003-01-01

    "La contestation des Nobel, avec cette annee la campagne lancee par un Americain afin de faire reconnaitre son role dans la mise au point de l'imagerie a resonance magnetique (IRM), constitue une tradition, quasiment aussi ancienne que l'attribution de ces distinctions" (1 page).

  4. Geant4 Simulation Study of Deep Underground Muons: Vertical Intensity and Angular Distribution

    Directory of Open Access Journals (Sweden)

    Halil Arslan

    2013-01-01

    Full Text Available Underground muon intensities up to 10000 m.w.e. and angular distribution up to 6500 m.w.e. in standard rock have been investigated using Geant4 simulation package. Muons with energies above 100 GeV were distributed from the ground level taking into account the muon charge ratio of ~1.3 at sea level. The simulated differential muon intensities are in good agreement with the intensities given in the literature. Furthermore, the simulation results for the integrated intensities are consistent with the experimental data, particularly at depths above 4000 m.w.e., where the simulation gives slightly smaller intensities than the experimental ones. In addition, the simulated exponent n at different underground depths agrees well with the experimental points, especially above ~2000 m.w.e.

  5. Geant4 Hadronic Cascade Models and CMS Data Analysis : Computational Challenges in the LHC era

    CERN Document Server

    Heikkinen, Aatos

    This work belongs to the field of computational high-energy physics (HEP). The key methods used in this thesis work to meet the challenges raised by the Large Hadron Collider (LHC) era experiments are object-orientation with software engineering, Monte Carlo simulation, the computer technology of clusters, and artificial neural networks. The first aspect discussed is the development of hadronic cascade models, used for the accurate simulation of medium-energy hadron-nucleus reactions, up to 10 GeV. These models are typically needed in hadronic calorimeter studies and in the estimation of radiation backgrounds. Various applications outside HEP include the medical field (such as hadron treatment simulations), space science (satellite shielding), and nuclear physics (spallation studies). Validation results are presented for several significant improvements released in Geant4 simulation tool, and the significance of the new models for computing in the Large Hadron Collider era is estimated. In particular, we es...

  6. Geant4 simulation of the nTOF-EAR2 neutron beam: Characteristics and prospects

    Energy Technology Data Exchange (ETDEWEB)

    Lerendegui-Marco, J.; Guerrero, C.; Cortes-Giraldo, M.A.; Quesada, J.M. [Universidad de Sevilla, Dpto. de Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); Lo Meo, S. [Research Centre ' ' Ezio Clementel' ' , ENEA, Bologna (Italy); INFN, Section of Bologna, Bologna (Italy); Massimi, C.; Vannini, G. [INFN, Section of Bologna, Bologna (Italy); University of Bologna, Physics and Astronomy Dept. ' ' Alma Mater Studiorum' ' , Bologna (Italy); Barbagallo, M.; Colonna, N. [INFN, Section of Bari, Bari (Italy); Mancusi, D.; Vlachoudis, V. [CEA-Saclay, Gif-sur-Yvette (France); Mingrone, F. [INFN, Section of Bologna, Bologna (Italy); Sabate-Gilarte, M. [Universidad de Sevilla, Dpto. de Fisica Atomica, Molecular y Nuclear, Sevilla (Spain); CEA-Saclay, Gif-sur-Yvette (France); Collaboration: nTOF Collaboration

    2016-04-15

    The characteristics of the neutron beam at the new nTOF-EAR2 facility have been simulated with the Geant4 code with the aim of providing useful data for both the analysis and planning of the upcoming measurements. The spatial and energy distributions of the neutrons, the resolution function and the in-beam γ-ray background have been studied in detail and their implications in the forthcoming experiments have been discussed. The results confirm that, with this new short (18.5 m flight path) beam line, reaching an instantaneous neutron flux beyond 10{sup 5} n/μs/pulse in the keV region, nTOF is one of the few facilities where challenging measurements can be performed, involving in particular short-lived radioisotopes. (orig.)

  7. Signal pulse emulation for scintillation detectors using Geant4 Monte Carlo with light tracking simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ogawara, R. [Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Kita-ku, Sapporo-shi, Hokkaido (Japan); Ishikawa, M., E-mail: masayori@med.hokudai.ac.jp [Graduate School of Health Science, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo-shi, Hokkaido (Japan)

    2016-07-15

    The anode pulse of a photomultiplier tube (PMT) coupled with a scintillator is used for pulse shape discrimination (PSD) analysis. We have developed a novel emulation technique for the PMT anode pulse based on optical photon transport and a PMT response function. The photon transport was calculated using Geant4 Monte Carlo code and the response function with a BC408 organic scintillator. The obtained percentage RMS value of the difference between the measured and simulated pulse with suitable scintillation properties using GSO:Ce (0.4, 1.0, 1.5 mol%), LaBr{sub 3}:Ce and BGO scintillators were 2.41%, 2.58%, 2.16%, 2.01%, and 3.32%, respectively. The proposed technique demonstrates high reproducibility of the measured pulse and can be applied to simulation studies of various radiation measurements.

  8. Scalable Parallel Implementation of GEANT4 Using Commodity Hardware and Task Oriented Parallel C

    CERN Document Server

    Cooperman, G; Grinberg, V; McCauley, T; Reucroft, S; Swain, J D; Cooperman, Gene; Anchordoqui, Luis; Grinberg, Victor; Cauley, Thomas Mc; Reucroft, Stephen; Swain, John

    2000-01-01

    We describe a scalable parallelization of Geant4 using commodity hardware in a collaborative effort between the College of Computer Science and the Department of Physics at Northeastern University. The system consists of a Beowulf cluster of 32 Pentium II processors with 128 MBytes of memory each, connected via ATM and fast Ethernet. The bulk of the parallelization is done using TOP-C (Task Oriented Parallel C), software widely used in the computational algebra community. TOP-C provides a flexible and powerful framework for parallel algorithm development, is easy to learn, and is available at no cost. Its task oriented nature allows one to parallelize legacy code while hiding the details of interprocess communications. Applications include fast interactive simulation of computationally intensive processes such as electromagnetic showers. General results motivate wider applications of TOP-C to other simulation problems as well as to pattern recognition in high energy physics.

  9. Thermal neutron response of a boron-coated GEM detector via GEANT4 Monte Carlo code.

    Science.gov (United States)

    Jamil, M; Rhee, J T; Kim, H G; Ahmad, Farzana; Jeon, Y J

    2014-10-22

    In this work, we report the design configuration and the performance of the hybrid Gas Electron Multiplier (GEM) detector. In order to make the detector sensitive to thermal neutrons, the forward electrode of the GEM has been coated with the enriched boron-10 material, which works as a neutron converter. A total of 5×5cm(2) configuration of GEM has been used for thermal neutron studies. The response of the detector has been estimated via using GEANT4 MC code with two different physics lists. Using the QGSP_BIC_HP physics list, the neutron detection efficiency was determined to be about 3%, while with QGSP_BERT_HP physics list the efficiency was around 2.5%, at the incident thermal neutron energies of 25meV. The higher response of the detector proves that GEM-coated with boron converter improves the efficiency for thermal neutrons detection.

  10. Validation of GEANT4 Monte Carlo models with a highly granular scintillator-steel hadron calorimeter

    Science.gov (United States)

    Adloff, C.; Blaha, J.; Blaising, J.-J.; Drancourt, C.; Espargilière, A.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Prast, J.; Vouters, G.; Francis, K.; Repond, J.; Schlereth, J.; Smith, J.; Xia, L.; Baldolemar, E.; Li, J.; Park, S. T.; Sosebee, M.; White, A. P.; Yu, J.; Buanes, T.; Eigen, G.; Mikami, Y.; Watson, N. K.; Mavromanolakis, G.; Thomson, M. A.; Ward, D. R.; Yan, W.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Dotti, A.; Folger, G.; Ivantchenko, V.; Uzhinskiy, V.; Benyamna, M.; Cârloganu, C.; Fehr, F.; Gay, P.; Manen, S.; Royer, L.; Blazey, G. C.; Dyshkant, A.; Lima, J. G. R.; Zutshi, V.; Hostachy, J.-Y.; Morin, L.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Göttlicher, P.; Günter, C.; Hermberg, B.; Karstensen, S.; Krivan, F.; Lucaci-Timoce, A.-I.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Vargas-Trevino, A.; Feege, N.; Garutti, E.; Marchesini, I.; Ramilli, M.; Eckert, P.; Harion, T.; Kaplan, A.; Schultz-Coulon, H.-Ch; Shen, W.; Stamen, R.; Bilki, B.; Norbeck, E.; Onel, Y.; Wilson, G. W.; Kawagoe, K.; Dauncey, P. D.; Magnan, A.-M.; Bartsch, V.; Wing, M.; Salvatore, F.; Calvo Alamillo, E.; Fouz, M.-C.; Puerta-Pelayo, J.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Kirikova, N.; Kozlov, V.; Smirnov, P.; Soloviev, Y.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Tikhomirov, V.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Amjad, M. S.; Bonis, J.; Callier, S.; Conforti di Lorenzo, S.; Cornebise, P.; Doublet, Ph; Dulucq, F.; Fleury, J.; Frisson, T.; van der Kolk, N.; Li, H.; Martin-Chassard, G.; Richard, F.; de la Taille, Ch; Pöschl, R.; Raux, L.; Rouëné, J.; Seguin-Moreau, N.; Anduze, M.; Boudry, V.; Brient, J.-C.; Jeans, D.; Mora de Freitas, P.; Musat, G.; Reinhard, M.; Ruan, M.; Videau, H.; Bulanek, B.; Zacek, J.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Ruzicka, P.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Belhorma, B.; Ghazlane, H.; Takeshita, T.; Uozumi, S.; Götze, M.; Hartbrich, O.; Sauer, J.; Weber, S.; Zeitnitz, C.

    2013-07-01

    Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

  11. Distributed Geant4 simulation in medical and space science applications using DIANE framework and the GRID

    CERN Document Server

    Moscicki, J T; Mantero, A; Pia, M G

    2003-01-01

    Distributed computing is one of the most important trends in IT which has recently gained significance for large-scale scientific applications. Distributed analysis environment (DIANE) is a R&D study, focusing on semiinteractive parallel and remote data analysis and simulation, which has been conducted at CERN. DIANE provides necessary software infrastructure for parallel scientific applications in the master-worker model. Advanced error recovery policies, automatic book-keeping of distributed jobs and on-line monitoring and control tools are provided. DIANE makes a transparent use of a number of different middleware implementations such as load balancing service (LSF, PBS, GRID Resource Broker, Condor) and security service (GSI, Kerberos, openssh). A number of distributed Geant 4 simulations have been deployed and tested, ranging from interactive radiotherapy treatment planning using dedicated clusters in hospitals, to globally-distributed simulations of astrophysics experiments using the European data g...

  12. Impact of the choice of physics list on GEANT4 simulations of hadronic showers in tungsten

    CERN Document Server

    Speckmayer, P

    2010-01-01

    The development of pion induced showers in a large block of matter (tungsten, lead, iron) is simulated for pions from 1 to 50GeV. Two GEANT4 physics lists (QGSP BERT and QGSP BERT HP) are compared. The deposited energy at each step of the simulation is identified as visible, invisible or escaped. It will be shown, that for tungsten in most of the hadronic showers more than 90% of the energy is deposited visibly if QGSP BERT is used. This fraction drops to only 60% for QGSP BERT HP. The latter fraction is similar to lead, even when QGSP BERT is used for the simulation. The impact of this behaviour on the energy resolution of a sampling calorimeter with scintillator as active material is shown. Although more energy is deposited visibly for QGSP BERT than for QGSP BERT HP, the reconstructed energy resolution is about 5 to 10% percent better for the latter.

  13. Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons

    CERN Document Server

    Makarova, Anastasia; Sauerwein, Wolfgang

    2016-01-01

    Usually, Monte Carlo models are validated against experimental data. However, models of multiple Coulomb scattering (MCS) in the Gaussian approximation are exceptional in that we have theories which are probably more accurate than the experiments which have, so far, been done to test them. In problems directly sensitive to the distribution of angles leaving the target, the relevant theory is the Moliere/Fano/Hanson variant of Moliere theory. For transverse spreading of the beam in the target itself, the theory of Preston and Koehler holds. Therefore, in this paper we compare Geant4 simulations, using the Urban and Wentzel models of MCS, with theory rather than experiment, revealing trends which would otherwise be obscured by experimental scatter. For medium-energy (radiotherapy) protons, and low-Z (water-like) target materials, Wentzel appears to be better than Urban in simulating the distribution of outgoing angles. For beam spreading in the target itself, the two models are essentially equal.

  14. Simulation loop between cad systems, GEANT-4 and GeoModel: Implementation and results

    Science.gov (United States)

    Sharmazanashvili, A.; Tsutskiridze, Niko

    2016-09-01

    Compare analysis of simulation and as-built geometry descriptions of detector is important field of study for data_vs_Monte-Carlo discrepancies. Shapes consistency and detalization is not important while adequateness of volumes and weights of detector components are essential for tracking. There are 2 main reasons of faults of geometry descriptions in simulation: (1) Difference between simulated and as-built geometry descriptions; (2) Internal inaccuracies of geometry transformations added by simulation software infrastructure itself. Georgian Engineering team developed hub on the base of CATIA platform and several tools enabling to read in CATIA different descriptions used by simulation packages, like XML->CATIA; VP1->CATIA; Geo-Model->CATIA; Geant4->CATIA. As a result it becomes possible to compare different descriptions with each other using the full power of CATIA and investigate both classes of reasons of faults of geometry descriptions. Paper represents results of case studies of ATLAS Coils and End-Cap toroid structures.

  15. Geant4 electromagnetic physics for high statistic simulation of LHC experiments

    CERN Document Server

    Allison, J; Bagulya, A; Champion, C; Elles, S; Garay, F; Grichine, V; Howard, A; Incerti, S; Ivanchenko, V; Jacquemier, J; Maire, M; Mantero, A; Nieminen, P; Pandola, L; Santin, G; Sawkey, D; Schalicke, A; Urban, L

    2012-01-01

    An overview of the current status of electromagnetic physics (EM) of the Geant4 toolkit is presented. Recent improvements are focused on the performance of large scale production for LHC and on the precision of simulation results over a wide energy range. Significant efforts have been made to improve the accuracy without compromising of CPU speed for EM particle transport. New biasing options have been introduced, which are applicable to any EM process. These include algorithms to enhance and suppress processes, force interactions or splitting of secondary particles. It is shown that the performance of the EM sub-package is improved. We will report extensions of the testing suite allowing high statistics validation of EM physics. It includes validation of multiple scattering, bremsstrahlung and other models. Cross checks between standard and low-energy EM models have been performed using evaluated data libraries and reference benchmark results.

  16. Simulation Loop between CAD systems, Geant4 and GeoModel: Implementation and Results

    CERN Document Server

    Sharmazanashvili, Alexander; The ATLAS collaboration

    2015-01-01

    Data_vs_MonteCarlo discrepancy is one of the most important field of investigation for ATLAS simulation studies. There are several reasons of above mentioned discrepancies but primary interest is falling on geometry studies and investigation of how geometry descriptions of detector in simulation adequately representing “as-built” descriptions. Shapes consistency and detalization is not important while adequateness of volumes and weights of detector components are essential for tracking. There are 2 main reasons of faults of geometry descriptions in simulation: 1/ Inconsistency to “as-built” geometry descriptions; 2/Internal inaccuracies of transactions added by simulation packages itself. Georgian Engineering team developed hub on the base of CATIA platform and several tools enabling to read in CATIA different descriptions used by simulation packages, like XML/Persint->CATIA; IV/VP1->CATIA; GeoModel->CATIA; Geant4->CATIA. As a result it becomes possible to compare different descriptions with each othe...

  17. A comparison between Geant4 PIXE simulations and experimental data for standard reference samples

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Z., E-mail: ziad.francis@gmail.com [Université Saint Joseph, Faculty of Science, Department of Physics, Beirut (Lebanon); The Open University, Faculty of Science, Department of Physical Sciences, Walton Hall, MK7 6AA Milton Keynes (United Kingdom); El Bast, M. [Ion Beam Analysis Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, Beirut (Lebanon); El Haddad, R. [Université Saint Joseph, Faculty of Science, Department of Mathematics, Beirut (Lebanon); Mantero, A. [Istituto Nazionale di Fisica Nucleare, sez. di Genova, via Dodecaneso 33, 16146 Genova (Italy); Incerti, S. [Université Bordeaux 1, CNRS/IN2P3, Centre d’Etudes Nucléaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, 33175 Gradignan (France); Ivanchenko, V. [Ecoanalytica, Moscow State University, 119899 Moscow (Russian Federation); Geant4 Associates International Ltd., Hebden Bridge (United Kingdom); El Bitar, Z. [Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3, 67037 Strasbourg Cedex (France); Champion, C. [Université Bordeaux 1, CNRS/IN2P3, Centre d’Etudes Nucléaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, 33175 Gradignan (France); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas-UNICAMP, SP 13083-859 (Brazil); Roumie, M. [Ion Beam Analysis Laboratory, Lebanese Atomic Energy Commission, National Council for Scientific Research, Beirut (Lebanon)

    2013-12-01

    The Geant4 PIXE de-excitation processes are used to simulate proton beam interactions with sample materials of known composition. Simulations involve four mono-elemental materials; Cu, Fe, Si and Al and three relatively complex materials: stainless steel, phosphor bronze and basal BE-N reference material composed of 25 different elements. The simulation results are compared to experimental spectra acquired for real samples analyzed using 3 MeV incident protons delivered by an ion tandem accelerator. Data acquisition was performed using a Si(Li) detector and an aluminum funny filter was added for the three last mentioned samples depending on the configuration to reduce the noise and obtain clear resulting spectrum. The results show a good agreement between simulations and measurements for the different samples.

  18. Geant4.10 simulation of geometric model for metaphase chromosome

    Energy Technology Data Exchange (ETDEWEB)

    Rafat-Motavalli, L., E-mail: rafat@um.ac.ir; Miri-Hakimabad, H.; Bakhtiyari, E.

    2016-04-01

    In this paper, a geometric model of metaphase chromosome is explained. The model is constructed according to the packing ratio and dimension of the structure from nucleosome up to chromosome. A B-DNA base pair is used to construct 200 base pairs of nucleosomes. Each chromatin fiber loop, which is the unit of repeat, has 49,200 bp. This geometry is entered in Geant4.10 Monte Carlo simulation toolkit and can be extended to the whole metaphase chromosomes and any application in which a DNA geometrical model is needed. The chromosome base pairs, chromosome length, and relative length of chromosomes are calculated. The calculated relative length is compared to the relative length of human chromosomes.

  19. Technical Note: Radiotherapy dose calculations using GEANT4 and the Amazon Elastic Compute Cloud

    CERN Document Server

    Poole, Christopher M; Trapp, Jamie V; Langton, Christian M

    2011-01-01

    Cloud computing allows for vast computational resources to be leveraged quickly and easily in bursts as and when required. Using the Amazon Elastic Compute Cloud and the Amazon Simple Storage Solution, we describe a technique that allows for Monte Carlo radiotherapy dose calculations to be performed using GEANT4 and executed in the cloud. Simulation cost and completion time was evaluated as a function of instance count using compute instances acquired via biding on the Elastic Compute Cloud spot market. Bidding for instances on the instance spot market was found to be 35-60% of the cost of on-demand instances of the same type. Using the technique, we demonstrate the potential usefulness of cloud computing as a solution for rapid Monte Carlo simulation for radiotherapy dose calculation.

  20. Geant4 calculations for space radiation shielding material Al2O3

    Science.gov (United States)

    Capali, Veli; Acar Yesil, Tolga; Kaya, Gokhan; Kaplan, Abdullah; Yavuz, Mustafa; Tilki, Tahir

    2015-07-01

    Aluminium Oxide, Al2O3 is the most widely used material in the engineering applications. It is significant aluminium metal, because of its hardness and as a refractory material owing to its high melting point. This material has several engineering applications in diverse fields such as, ballistic armour systems, wear components, electrical and electronic substrates, automotive parts, components for electric industry and aero-engine. As well, it is used as a dosimeter for radiation protection and therapy applications for its optically stimulated luminescence properties. In this study, stopping powers and penetrating distances have been calculated for the alpha, proton, electron and gamma particles in space radiation shielding material Al2O3 for incident energies 1 keV - 1 GeV using GEANT4 calculation code.

  1. Efficiency Calibration Measurement And Geant Simulation Of The Dragon Bgo Gamma Ray Array At Triumf

    CERN Document Server

    Gigliotti, D G

    2005-01-01

    A gamma ray array to detect the characteristic gammas emitted from astrophysically significant, radiative proton and alpha capture reactions, was built as part of the Detector of Recoils And Gammas Of Nuclear reactions (DRAGON) spectrometer at ISAC/TRIUMF. The DRAGON array consists of a collection of 30 hexagonal BGO detectors measuring 7.62 cm long by 5.58 cm across the face. A simulation was built with the particle-tracking program GEANT v3.21. The efficiency of the array was measured using calibrated sources of various gamma energies and compared to simulated results. For the cases where the activity of the source was not well known the sources were calibrated using a standard NaI detector of known efficiency. The agreement between simulation and measured differences is more than adequate for proposed DRAGON experiments. The analysis and results of the comparison between measured and simulated efficiency will be discussed in this thesis.

  2. Comparison of SRIM, MCNPX and GEANT simulations with experimental data for thick Al absorbers.

    Science.gov (United States)

    Evseev, Ivan G; Schelin, Hugo R; Paschuk, Sergei A; Milhoretto, Edney; Setti, João A P; Yevseyeva, Olga; de Assis, Joaquim T; Hormaza, Joel M; Díaz, Katherin S; Lopes, Ricardo T

    2010-01-01

    Proton computerized tomography deals with relatively thick targets like the human head or trunk. In this case precise analytical calculation of the proton final energy is a rather complicated task, thus the Monte Carlo simulation stands out as a solution. We used the GEANT4.8.2 code to calculate the proton final energy spectra after passing a thick Al absorber and compared it with the same conditions of the experimental data. The ICRU49, Ziegler85 and Ziegler2000 models from the low energy extension pack were used. The results were also compared with the SRIM2008 and MCNPX2.4 simulations, and with solutions of the Boltzmann transport equation in the Fokker-Planck approximation.

  3. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy

    Science.gov (United States)

    De Napoli, M.; Romano, F.; D'Urso, D.; Licciardello, T.; Agodi, C.; Candiano, G.; Cappuzzello, F.; Cirrone, G. A. P.; Cuttone, G.; Musumarra, A.; Pandola, L.; Scuderi, V.

    2014-12-01

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned. Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u-1 12C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  4. Validation of GEANT4 Monte Carlo Models with a Highly Granular Scintillator-Steel Hadron Calorimeter

    CERN Document Server

    Adloff, C; Blaising, J J; Drancourt, C; Espargiliere, A; Gaglione, R; Geffroy, N; Karyotakis, Y; Prast, J; Vouters, G; Francis, K; Repond, J; Schlereth, J; Smith, J; Xia, L; Baldolemar, E; Li, J; Park, S T; Sosebee, M; White, A P; Yu, J; Buanes, T; Eigen, G; Mikami, Y; Watson, N K; Mavromanolakis, G; Thomson, M A; Ward, D R; Yan, W; Benchekroun, D; Hoummada, A; Khoulaki, Y; Apostolakis, J; Dotti, A; Folger, G; Ivantchenko, V; Uzhinskiy, V; Benyamna, M; Cârloganu, C; Fehr, F; Gay, P; Manen, S; Royer, L; Blazey, G C; Dyshkant, A; Lima, J G R; Zutshi, V; Hostachy, J Y; Morin, L; Cornett, U; David, D; Falley, G; Gadow, K; Gottlicher, P; Gunter, C; Hermberg, B; Karstensen, S; Krivan, F; Lucaci-Timoce, A I; Lu, S; Lutz, B; Morozov, S; Morgunov, V; Reinecke, M; Sefkow, F; Smirnov, P; Terwort, M; Vargas-Trevino, A; Feege, N; Garutti, E; Marchesini, I; Ramilli, M; Eckert, P; Harion, T; Kaplan, A; Schultz-Coulon, H Ch; Shen, W; Stamen, R; Bilki, B; Norbeck, E; Onel, Y; Wilson, G W; Kawagoe, K; Dauncey, P D; Magnan, A M; Bartsch, V; Wing, M; Salvatore, F; Alamillo, E Calvo; Fouz, M C; Puerta-Pelayo, J; Bobchenko, B; Chadeeva, M; Danilov, M; Epifantsev, A; Markin, O; Mizuk, R; Novikov, E; Popov, V; Rusinov, V; Tarkovsky, E; Kirikova, N; Kozlov, V; Smirnov, P; Soloviev, Y; Buzhan, P; Ilyin, A; Kantserov, V; Kaplin, V; Karakash, A; Popova, E; Tikhomirov, V; Kiesling, C; Seidel, K; Simon, F; Soldner, C; Szalay, M; Tesar, M; Weuste, L; Amjad, M S; Bonis, J; Callier, S; Conforti di Lorenzo, S; Cornebise, P; Doublet, Ph; Dulucq, F; Fleury, J; Frisson, T; van der Kolk, N; Li, H; Martin-Chassard, G; Richard, F; de la Taille, Ch; Poschl, R; Raux, L; Rouene, J; Seguin-Moreau, N; Anduze, M; Boudry, V; Brient, J-C; Jeans, D; Mora de Freitas, P; Musat, G; Reinhard, M; Ruan, M; Videau, H; Bulanek, B; Zacek, J; Cvach, J; Gallus, P; Havranek, M; Janata, M; Kvasnicka, J; Lednicky, D; Marcisovsky, M; Polak, I; Popule, J; Tomasek, L; Tomasek, M; Ruzicka, P; Sicho, P; Smolik, J; Vrba, V; Zalesak, J; Belhorma, B; Ghazlane, H; Takeshita, T; Uozumi, S; Gotze, M; Hartbrich, O; Sauer, J; Weber, S; Zeitnitz, C

    2013-01-01

    Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8GeV to 100GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

  5. Monte Carlo Simulation of RPC-based PET with GEANT4

    CERN Document Server

    Weizheng, Zhou; Cheng, Li; Hongfang, Chen; Yongjie, Sun; Tianxiang, Chen

    2014-01-01

    The Resistive Plate Chambers (RPC) are low-cost charged-particle detectors with good timing resolution and potentially good spatial resolution. Using RPC as gamma detector provides an opportunity for application in positron emission tomography (PET). In this work, we use GEANT4 simulation package to study various methods improving the detection efficiency of a realistic RPC-based PET model for 511keV photons, by adding more detection units, changing the thickness of each layer, choosing different converters and using multi-gaps RPC (MRPC) technique. Proper balance among these factors are discussed. It's found that although RPC with materials of high atomic number can reach a higher efficiency, they may contribute to a poor spatial resolution and higher background level.

  6. ALGEBRA: ALgorithm for the heterogeneous dosimetry based on GEANT4 for BRAchytherapy.

    Science.gov (United States)

    Afsharpour, H; Landry, G; D'Amours, M; Enger, S; Reniers, B; Poon, E; Carrier, J-F; Verhaegen, F; Beaulieu, L

    2012-06-07

    Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry platforms. The scientific community has expressed the need for an accurate dosimetry platform in brachytherapy. The purpose of this paper is to present ALGEBRA, a Monte Carlo platform for dosimetry in brachytherapy which is sufficiently fast and accurate for clinical and research purposes. ALGEBRA is based on the GEANT4 Monte Carlo code and is capable of handling the DICOM RT standard to recreate a virtual model of the treated site. Here, the performance of ALGEBRA is presented for the special case of LDR brachytherapy in permanent prostate and breast seed implants. However, the algorithm is also capable of handling other treatments such as HDR brachytherapy.

  7. Geant4 based simulation of the Water Cherenkov Detectors of the LAGO Project

    CERN Document Server

    Calderón, R; Núñez, L A

    2015-01-01

    To characterize the signals registered by the different types of water Cherenkov detectors (WCD) used by the Latin American Giant Observatory (LAGO) Project, it is necessary to develop detailed simulations of the detector response to the flux of secondary particles at the detector level. These particles are originated during the interaction of cosmic rays with the atmosphere. In this context, the LAGO project aims to study the high energy component of gamma rays bursts (GRBs) and space weather phenomena by looking for the solar modulation of galactic cosmic rays (GCRs). Focus in this, a complete and complex chain of simulations is being developed that account for geomagnetic effects, atmospheric reaction and detector response at each LAGO site. In this work we shown the first steps of a GEANT4 based simulation for the LAGO WCD, with emphasis on the induced effects of the detector internal diffusive coating.

  8. Geant4 calculations for space radiation shielding material Al2O3

    Directory of Open Access Journals (Sweden)

    Capali Veli

    2015-01-01

    Full Text Available Aluminium Oxide, Al2O3 is the most widely used material in the engineering applications. It is significant aluminium metal, because of its hardness and as a refractory material owing to its high melting point. This material has several engineering applications in diverse fields such as, ballistic armour systems, wear components, electrical and electronic substrates, automotive parts, components for electric industry and aero-engine. As well, it is used as a dosimeter for radiation protection and therapy applications for its optically stimulated luminescence properties. In this study, stopping powers and penetrating distances have been calculated for the alpha, proton, electron and gamma particles in space radiation shielding material Al2O3 for incident energies 1 keV – 1 GeV using GEANT4 calculation code.

  9. TileCal Beam Test Simulation Application in the FADS/Goofy Framework (GEANT4)

    CERN Document Server

    Solodkov, A A

    2003-01-01

    A new application for the Tile Calorimeter (TileCal) beam test simulation has been developed in GEANT4 within the FADS/Goofy framework. The geometry and readout systems for all the different TileCal modules have been implemented in a quite detailed way. This application allows to simulate all the TileCal beam test setup configurations existing so far. Details of the development as well as instructions to install and run the program are presented. The first tests have been performed for a beam test setup consisting of five prototype modules using negative pions with different energies and results of comparison to the experimental data from TileCal TDR are presented as well.

  10. Dental Encounter System (DES)

    Data.gov (United States)

    Department of Veterans Affairs — Dental Encounter System (DES) is an automated health care application designed to capture critical data about the operations of VA Dental Services. Information on...

  11. Table des illustrations

    OpenAIRE

    2016-01-01

    Tableaux Dates d’inauguration des grands hôtels japonais entre 1860 et 1945… 19 Histoire, tourisme et hôtellerie en Corée depuis les années 1870… 59-60 Dates d’inauguration des grands hôtels chinois depuis 1863… 84 Les hôtels de luxe et leurs capacités d’hébergement en Corée en 2000… 103 Les flux de personnes suscités par les hôtels « super luxe » de Séoul en 2000… 105 L’activité des grands hôtels à Séoul en 1999 (en wons)… 106 Propriété et gestion des grands hôtels à Séoul en 1999…. 110 La c...

  12. Chimie des processus biologiques

    OpenAIRE

    Fontecave, Marc

    2010-01-01

    La chimie du vivant : enzymes et métalloenzymes, des biocatalyseurs fascinants La catalyse enzymatique, ce pouvoir que possèdent certaines protéines d’accélérer de façon extraordinaire et d’orienter avec une précision fascinante les réactions chimiques de la cellule, reste, encore aujourd’hui, l’un des grands mystères des systèmes vivants. Les réactions dont il est question vont de la simple hydrolyse de liaisons peptidiques à des processus poly-électroniques d’une très grande complexité, com...

  13. PDB4DNA: Implementation of DNA geometry from the Protein Data Bank (PDB) description for Geant4-DNA Monte-Carlo simulations

    Science.gov (United States)

    Delage, E.; Pham, Q. T.; Karamitros, M.; Payno, H.; Stepan, V.; Incerti, S.; Maigne, L.; Perrot, Y.

    2015-07-01

    This paper describes PDB4DNA, a new Geant4 user application, based on an independent, cross-platform, free and open source C++ library, so-called PDBlib, which enables use of atomic level description of DNA molecule in Geant4 Monte Carlo particle transport simulations. For the evaluation of direct damage induced on the DNA molecule by ionizing particles, the application makes use of an algorithm able to determine the closest atom in the DNA molecule to energy depositions. Both the PDB4DNA application and the PDBlib library are available as free and open source under the Geant4 license.

  14. Efficiency transfer using the GEANT4 code of CERN for HPGe gamma spectrometry.

    Science.gov (United States)

    Chagren, S; Ben Tekaya, M; Reguigui, N; Gharbi, F

    2016-01-01

    In this work we apply the GEANT4 code of CERN to calculate the peak efficiency in High Pure Germanium (HPGe) gamma spectrometry using three different procedures. The first is a direct calculation. The second corresponds to the usual case of efficiency transfer between two different configurations at constant emission energy assuming a reference point detection configuration and the third, a new procedure, consists on the transfer of the peak efficiency between two detection configurations emitting the gamma ray in different energies assuming a "virtual" reference point detection configuration. No pre-optimization of the detector geometrical characteristics was performed before the transfer to test the ability of the efficiency transfer to reduce the effect of the ignorance on their real magnitude on the quality of the transferred efficiency. The obtained and measured efficiencies were found in good agreement for the two investigated methods of efficiency transfer. The obtained agreement proves that Monte Carlo method and especially the GEANT4 code constitute an efficient tool to obtain accurate detection efficiency values. The second investigated efficiency transfer procedure is useful to calibrate the HPGe gamma detector for any emission energy value for a voluminous source using one point source detection efficiency emitting in a different energy as a reference efficiency. The calculations preformed in this work were applied to the measurement exercise of the EUROMET428 project. A measurement exercise where an evaluation of the full energy peak efficiencies in the energy range 60-2000 keV for a typical coaxial p-type HpGe detector and several types of source configuration: point sources located at various distances from the detector and a cylindrical box containing three matrices was performed.

  15. GATE - Geant4 Application for Tomographic Emission: a simulation toolkit for PET and SPECT

    Science.gov (United States)

    Jan, S.; Santin, G.; Strul, D.; Staelens, S.; Assié, K.; Autret, D.; Avner, S.; Barbier, R.; Bardiès, M.; Bloomfield, P. M.; Brasse, D.; Breton, V.; Bruyndonckx, P.; Buvat, I.; Chatziioannou, A. F.; Choi, Y.; Chung, Y. H.; Comtat, C.; Donnarieix, D.; Ferrer, L.; Glick, S. J.; Groiselle, C. J.; Guez, D.; Honore, P.-F.; Kerhoas-Cavata, S.; Kirov, A. S.; Kohli, V.; Koole, M.; Krieguer, M.; van der Laan, D. J.; Lamare, F.; Largeron, G.; Lartizien, C.; Lazaro, D.; Maas, M. C.; Maigne, L.; Mayet, F.; Melot, F.; Merheb, C.; Pennacchio, E.; Perez, J.; Pietrzyk, U.; Rannou, F. R.; Rey, M.; Schaart, D. R.; Schmidtlein, C. R.; Simon, L.; Song, T. Y.; Vieira, J.-M.; Visvikis, D.; Van de Walle, R.; Wieërs, E.; Morel, C.

    2012-01-01

    Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols, and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document, and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at the address http://www-lphe.ep.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects toward the gridification of GATE and its extension to other domains such as dosimetry are also discussed. PMID:15552416

  16. Geant4-DNA simulations using complex DNA geometries generated by the DnaFabric tool

    Science.gov (United States)

    Meylan, S.; Vimont, U.; Incerti, S.; Clairand, I.; Villagrasa, C.

    2016-07-01

    Several DNA representations are used to study radio-induced complex DNA damages depending on the approach and the required level of granularity. Among all approaches, the mechanistic one requires the most resolved DNA models that can go down to atomistic DNA descriptions. The complexity of such DNA models make them hard to modify and adapt in order to take into account different biological conditions. The DnaFabric project was started to provide a tool to generate, visualise and modify such complex DNA models. In the current version of DnaFabric, the models can be exported to the Geant4 code to be used as targets in the Monte Carlo simulation. In this work, the project was used to generate two DNA fibre models corresponding to two DNA compaction levels representing the hetero and the euchromatin. The fibres were imported in a Geant4 application where computations were performed to estimate the influence of the DNA compaction on the amount of calculated DNA damage. The relative difference of the DNA damage computed in the two fibres for the same number of projectiles was found to be constant and equal to 1.3 for the considered primary particles (protons from 300 keV to 50 MeV). However, if only the tracks hitting the DNA target are taken into account, then the relative difference is more important for low energies and decreases to reach zero around 10 MeV. The computations were performed with models that contain up to 18,000 DNA nucleotide pairs. Nevertheless, DnaFabric will be extended to manipulate multi-scale models that go from the molecular to the cellular levels.

  17. Vom Ort des Philosophierens

    OpenAIRE

    Damir Barbaric

    2002-01-01

    Im Aufsatz wird versucht, den ursprünglichen Sinn der Platonischen Bestimmung vom Staunen als Anfang der Philosophie zu ermitteln, und zwar durch eine kritischen Abhebung von ihrer Umdeutung bei Aristoteles, und dann insbesondere in der Stoa wie auch bei Spinoza und Hegel. Dabei wird auf die frühgriechische Erfahrung vom Staunen als _______ aufmerksam gemacht, wo es vor allem die Grundstimmung des Dabeiseins des Göttlichen und der menschlichen Teilnahme am Göttlichen bedeutet. Dem entspricht ...

  18. Liste des auteurs

    OpenAIRE

    2015-01-01

    Fariba Adelkhah est chargée de recherche à la Fondation nationale des sciences politiques, Centre d’études et de recherches internationales (CERI) [] Jean-Marie Bouissou est chargé de recherche à la Fondation nationale des sciences politiques, Centre d’études et de recherches internationales (CERI) [] Jean-Louis Briquet est chargé de recherche au CNRS, Centre d’études et de recherches internationales (CERI) [...

  19. La revolution des savants

    CERN Document Server

    Chavanne, A

    1989-01-01

    Premiere cassette : - 1666 : impact de la creation de l'Academie des Sciences par Colbert, trente ans apres le proces de Galile, et au moment des disparitions de Pascal, Descartes et Fermat. Elle dirigee par le hollandais Huyggens jusqu'a sa fuite de France au moment de la revocation de l'Edit de Nantes. - 1750 : l'Encyclopedie (ou "Dictionnaire raisonne des Sciences, des Arts et des Metiers") de Diderot et d'Alembert, soutenus par Malherbes, Buffon, Condorcet et Rousseau. - 1789 : Revolution francaise. - 8 aout 1793 : l'Assemblee, par une declaration de Marat, dissout l'Academie des Sciences. Celle-ci continue cependant ses travaux pour les poids et mesures jusqu'en 1795. - la Terreur : la condamnation a mort, pas au nom d'une "Revolution qui n'a pas besoin de savants" mais pour d'autres raisons, de trois grands hommes de science : Lavoisier, Bailly et Condorcet. - 1793-1794 : Au printemps 93, le Comite de Salut Publique s'inquiete du demi-million de soldats etrangers de toutes les pays frontaliers qui essai...

  20. Le dialogisme intertextuel des contes des Grimm

    OpenAIRE

    2013-01-01

    Loin d'être « purement allemands », nombre de contes des Grimm réécrivent les contes français largement diffusés en Allemagne au XVIIIe siècle en les « reconfigurant » selon leurs propres paradigmes esthétiques et idéologiques. L'étude introductive de la comparatiste Ute Heidmann montre que ce dialogisme européen est resté peu exploré en raison d’une « scénographie en trompe-l’œil » qui les présente comme issus du « terroir » hessois. Toutefois, les notes des Grimm (constituées en volume auto...

  1. Maladie des vibrations

    Science.gov (United States)

    Shen, Shixin (Cindy); House, Ronald A.

    2017-01-01

    Résumé Objectif Permettre aux médecins de famille de comprendre l’épidémiologie, la pathogenèse, les symptômes, le diagnostic et la prise en charge de la maladie des vibrations, une maladie professionnelle importante et courante au Canada. Sources d’information Une recherche a été effectuée sur MEDLINE afin de relever les recherches et comptes rendus portant sur la maladie des vibrations. Une recherche a été effectuée sur Google dans le but d’obtenir la littérature grise qui convient au contexte canadien. D’autres références ont été tirées des articles relevés. Message principal La maladie des vibrations est une maladie professionnelle répandue touchant les travailleurs de diverses industries qui utilisent des outils vibrants. La maladie est cependant sous-diagnostiquée au Canada. Elle compte 3 éléments : vasculaire, sous la forme d’un phénomène de Raynaud secondaire; neurosensoriel; et musculosquelettique. Aux stades les plus avancés, la maladie des vibrations entraîne une invalidité importante et une piètre qualité de vie. Son diagnostic exige une anamnèse minutieuse, en particulier des antécédents professionnels, un examen physique, des analyses de laboratoire afin d’éliminer les autres diagnostics, et la recommandation en médecine du travail aux fins d’investigations plus poussées. La prise en charge consiste à réduire l’exposition aux vibrations, éviter les températures froides, abandonner le tabac et administrer des médicaments. Conclusion Pour assurer un diagnostic rapide de la maladie des vibrations et améliorer le pronostic et la qualité de vie, les médecins de famille devraient connaître cette maladie professionnelle courante, et pouvoir obtenir les détails pertinents durant l’anamnèse, recommander les patients aux cliniques de médecine du travail et débuter les demandes d’indemnisation de manière appropriée. PMID:28292812

  2. La convergence des rôles respectifs des relationnistes et des journalistes influence-t-elle la perception qu'ils ont les uns des autres?

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    la convergence des rôles respectifs des praticiens des relations publiques et des journalistes a un effet favorable sur la perception qu’ils ont les uns des autres. L’effet est plus marqué chez les praticiens des relations publiques, car leur vision de la profession en journalisme correspond à celle...

  3. À propos des occasionnalismes

    Directory of Open Access Journals (Sweden)

    Dal Georgette

    2016-01-01

    Full Text Available Les occasionnalismes (nonce formations ou contextual formations dans la terminologie anglo-saxonne, qu’on définira provisoirement comme de “new complex word[s] created by a speaker/writer on the spur of the moment to cover some immediate need” (Bauer, 1983 : 45 ont, à notre connaissance, peu retenu l’attention des morphologues du domaine francophone. Pourtant, toutes les conditions sont désormais réunies pour que cet objet, invisible lorsqu’il s’agissait de décrire le système morphologique du français (ou d’autres langues à partir de ressources dictionnairiques, émerge en tant qu’observable dans une morphologie puisant ses données dans le réel langagier des locuteurs. Par définition en effet, on s’attend à ce qu’un occasionalisme soit absent des dictionnaires (nous verrons que, dans les faits, la situation est plus complexe que cela, et que ces contextual formations ne puissent pas être étudiées en dehors du contexte dans lequel elles ont été produites. À cet égard, la Toile et les produits qui en dérivent constituent des ressources de choix. C’est particulièrement vrai des forums, dans lesquels les internautes s’expriment librement, laissant libre cours à leur potentiel créatif (ou ce qu’ils pensent tel. Dans la présente communication, après avoir défini la notion d’occasionalisme, nous utiliserons un corpus constitué au fil d’autres recherches pour dégager des motifs récurrents propices à leur apparition, autrement dit pour établir une grammaire des occasionnalismes.

  4. Des Vents et des Jets Astrophysiques

    Science.gov (United States)

    Sauty, C.

    well expected result from the theory. Although, collimation may be conical, paraboloidal or cylindrical (Part 4), cylindrical collimation is the more likely to occur. The shape of outflows may then be used as a tool to predict physical conditions on the flows or on their source. L'éjection continue de plasma autour d'objets massifs est un phénomène largement répandu en astrophysique, que ce soit sous la forme du vent solaire, de vents stellaires, de jets d'étoiles en formation, de jets stellaires autour d'objets compacts ou de jets extra-galactiques. Cette zoologie diversifiée fait pourtant l'objet d'un commun effort de modélisation. Le but de cette revue est d'abord de présenter qualitativement le développement, depuis leur origine, des diverses théories de vents (Partie 1) et l'inter disciplinarité dans ce domaine. Il s'agit d'une énumération, plus ou moins exhaustive, des idées proposées pour expliquer l'accélération et la morphologie des vents et des jets, accompagnée d'une présentation sommaire des aspects observationnels. Cette partie s'abstient de tout aspect faisant appel au formalisme mathématique. Ces écoulements peuvent être décrits, au moins partiellement, en résolvant les équations magnétohydrodynamiques, axisymétriques et stationnaires. Ce formalisme, à la base de la plupart des théories, est exposé dans la Partie 2. Il permet d'introduire quantitativement les intégrales premières qu'un tel système possède. Ces dernières sont amenées à jouer un rôle important dans la compréhension des phénomènes d'accélération ou de collimation, en particulier le taux de perte de masse, le taux de perte de moment angulaire ou l'énergie du rotateur magnétique. La difficulté de modélisation réside dans l'existence de points critiques, propres aux équations non linéaires, qu'il faut franchir. La nature physique et la localisation de ces points critiques fait l'objet d'un débat important car ils sont la clef de voute de la r

  5. Validation of the coupling of mesh models to GEANT4 Monte Carlo code for simulation of internal sources of photons; Validacao do acoplamento de modelos mesh ao codigo Monte Carlo GEANT4 para simulacao de fontes de fotons internas

    Energy Technology Data Exchange (ETDEWEB)

    Caribe, Paulo Rauli Rafeson Vasconcelos, E-mail: raulycaribe@hotmail.com [Universidade Federal Rural de Pernambuco (UFRPE), Recife, PE (Brazil). Fac. de Fisica; Cassola, Vagner Ferreira; Kramer, Richard; Khoury, Helen Jamil [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

    2013-07-01

    The use of three-dimensional models described by polygonal meshes in numerical dosimetry enables more accurate modeling of complex objects than the use of simple solid. The objectives of this work were validate the coupling of mesh models to the Monte Carlo code GEANT4 and evaluate the influence of the number of vertices in the simulations to obtain absorbed fractions of energy (AFEs). Validation of the coupling was performed to internal sources of photons with energies between 10 keV and 1 MeV for spherical geometries described by the GEANT4 and three-dimensional models with different number of vertices and triangular or quadrilateral faces modeled using Blender program. As a result it was found that there were no significant differences between AFEs for objects described by mesh models and objects described using solid volumes of GEANT4. Since that maintained the shape and the volume the decrease in the number of vertices to describe an object does not influence so meant dosimetric data, but significantly decreases the time required to achieve the dosimetric calculations, especially for energies less than 100 keV.

  6. The comparison of GEANT 4.8.2 and 4.9.2 results for the 25MeV protons in thick polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Yevseyeva, Olga; Assis, Joaquim T. de; Ievsieieva, Ievgeniia [Universidade Estadual do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico; Evseev, Ivan G.; Schelin, Hugo R.; Ahmann, Francielle; Paschuk, Sergei A.; Milhoretto, Edney [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Diaz, Katherin S. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Havana (Cuba); Hormaza, Joel M. [Universidade Estadual Paulista (UNESP), Botucatu, SP (Brazil). Instituto de Biociencias; Lopes, Ricardo T. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2011-07-01

    Full text: The fidelity of Monte Carlo simulations is crucial, especially if for medical applications. Our earlier study has shown that the GEANT4 simulations of proton energy spectra after thick absorbers do not agree well with existing experimental data. Moreover, the spectra simulated for the Bethe-Bloch domain were showing an unexpected sensitivity to the choice of low-energy electromagnetic models during the code execution. These observations were done with the GEANT4 up to version 8.2 during our previous simulations for proton Computerized Tomography (pCT). As one of the probable reasons for these effects could be some specific feature in the code, or some specific implicit parameters in the GEANT4 manual, we have decided to continue our observations, but this time - with version 4.9.2 of the GEANT. This work describes in details the new simulations for 25 MeV protons passing through 6mm polyethylene absorber. As in our previous simulations, we have started from the Hadron therapy Example of GEANT4 official release by adjusting the geometry only. We have tested all available choices of the Electromagnetic Physics Models. The results are compared with our previous GEANT4, TRIM/SRIM and MCNPX simulations, with theoretical predictions and with experimental data. Some variations in comparison with our previous results were obtained. (author)

  7. Validation of GEANT4 simulations for {sup 62,63}Zn yield estimation in proton induced reactions of natural copper

    Energy Technology Data Exchange (ETDEWEB)

    Rostampour, Malihe [Department of Physics, Arak University, P.O. Box: 38156, Arak (Iran, Islamic Republic of); Sadeghi, Mahdi, E-mail: msadeghi@nrcam.org [Medical Physics Department, School of Medicine, Iran University of Medical Sciences, P.O. Box: 14155-6183, Tehran (Iran, Islamic Republic of); Aboudzadeh, Mohammadreza [Radiation Application Research School, Nuclear Science and Technology Research Institute, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of); Hamidi, Saeid [Department of Physics, Arak University, P.O. Box: 38156, Arak (Iran, Islamic Republic of); Hosseini, Seyedeh Fatemeh [Department of Physics, Payame Noor University, P.O. Box: 19395-3697, Tehran (Iran, Islamic Republic of)

    2017-03-01

    A useful approach to optimize of radioisotope production is the use of Monte Carlo simulations prior to experimentation. In this paper, the GEANT4 code was employed to calculate the saturation yields of {sup 62,63}Zn from proton-induced reactions of natural copper, enriched {sup 63}Cu and {sup 65}Cu. In addition, the saturation yields of the investigated radio-nuclides were calculated using the stopping power from the SRIM-2013 and reported experimental data for cross sections. The simulated saturation yields were compared with experimental values. Good agreement between the experimental and corresponding simulated data demonstrated that GEANT4 provides a suitable tool for radionuclide simulation production using proton irradiation.

  8. Gamma-gamma density and lithology tools simulation based on GEANT4 advanced low energy Compton scattering (GALECS) package

    Energy Technology Data Exchange (ETDEWEB)

    Esmaeili-sani, Vahid, E-mail: vaheed_esmaeely80@yahoo.com [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of); Moussavi-zarandi, Ali; Boghrati, Behzad; Afarideh, Hossein [Department of Nuclear Engineering and Physics, Amirkabir University of Technology, P.O. Box 4155-4494, Tehran (Iran, Islamic Republic of)

    2012-02-01

    Geophysical bore-hole data represent the physical properties of rocks, such as density and formation lithology, as a function of depth in a well. Properties of rocks are obtained from gamma ray transport logs. Transport of gamma rays, from a {sup 137}Cs point gamma source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The advanced Compton scattering concepts were used to gain better analyses about well formation. The simulation and understanding of advanced Compton scattering highly depends on how accurately the effects of Doppler broadening and Rayleigh scattering are taken into account. A Monte Carlo package that simulates the gamma-gamma well logging tools based on GEANT4 advanced low energy Compton scattering (GALECS).

  9. \\textsc{MaGe} - a {\\sc Geant4}-based Monte Carlo Application Framework for Low-background Germanium Experiments

    CERN Document Server

    Boswell, Melissa; Detwiler, Jason A; Finnerty, Padraic; Henning, Reyco; Gehman, Victor M; Johnson, Rob A; Jordan, David V; Kazkaz, Kareem; Knapp, Markus; Kröninger, Kevin; Lenz, Daniel; Leviner, Lance; Liu, Jing; Liu, Xiang; MacMullin, Sean; Marino, Michael G; Mokhtarani, Akbar; Pandola, Luciano; Schubert, Alexis G; Schubert, Jens; Tomei, Claudia; Volynets, Oleksandr

    2010-01-01

    We describe a physics simulation software framework, MAGE, that is based on the GEANT4 simulation toolkit. MAGE is used to simulate the response of ultra-low radioactive background radiation detectors to ionizing radiation, specifically the MAJORANA and GERDA neutrinoless double-beta decay experiments. MAJORANA and GERDA use high-purity germanium detectors to search for the neutrinoless double-beta decay of 76Ge, and MAGE is jointly developed between these two collaborations. The MAGE framework contains the geometry models of common objects, prototypes, test stands, and the actual experiments. It also implements customized event generators, GEANT4 physics lists, and output formats. All of these features are available as class libraries that are typically compiled into a single executable. The user selects the particular experimental setup implementation at run-time via macros. The combination of all these common classes into one framework reduces duplication of efforts, eases comparison between simulated data...

  10. Validation of GEANT3 simulation studies with a dual-head PMT ClearPET TM prototype

    CERN Document Server

    Ziemons, K; Streun, M; Pietrzyk, U

    2004-01-01

    The ClearPET TM project is proposed by working groups of the Crystal Clear Collaboration (CCC) to develop a 2/sup nd/ generation high performance small animal positron emission tomograph (PET). High sensitivity and high spatial resolution is foreseen for the ClearPET TM camera by using a phoswich arrangement combining mixed lutetium yttrium aluminum perovskite (LuYAP:Ce) and lutetium oxyorthosilicate (LSO) scintillating crystals. Design optimizations for the first photomultiplier tube (PMT) based ClearPET camera are done with a Monte-Carlo simulation package implemented on GEANT3 (CERN, Geneva, Switzerland). A dual-head prototype has been built to test the frontend electronics and was used to validate the implementation of the GEANT3 simulation tool. Multiple simulations were performed following the experimental protocols to measure the intrinsic resolution and the sensitivity profile in axial and radial direction. Including a mean energy resolution of about 27.0% the simulated intrinsic resolution is about (...

  11. A probability-conserving cross-section biasing mechanism for Monte-Carlo variance reduction with application to Geant4

    CERN Document Server

    Mendenhall, Marcus H

    2011-01-01

    In Monte-Carlo codes such as Geant4, it is often important to adjust reaction cross sections to reduce the variance of calculations of relatively rare events, in a technique known as non-analogous Monte-Carlo. We present the theory and sample code for a Geant4 process which allows the cross section of a G4VDiscreteProcess to be scaled, while adjusting track weights so as to mitigate the effects of altered primary beam depletion induced by the cross section change. This allows us to increase the cross section of nuclear reactions by factors exceeding 10^{4} (in appropriate cases), without distorting the results of energy deposition calculations or coincidence rates. The procedure is also valid for bias factors less than unity, which is useful, for example, in problems which involve computation of particle penetration deep into a target, such as occurs in atmospheric showers or in shielding.

  12. Geant4 simulations of the Gamma Reaction History Diagnostic at the NIF, Omega and HIGS calibration facility

    Science.gov (United States)

    Rubery, Michael; Horsfield, Colin; Herrmann, Hans; Kim, Yong Ho; Mack, Joseph; Young, Carlton; Caldwell, Steven; Evans, Scott; Sedillo, Tom; McEvoy, Aaron; Miller, Kirk; Stoeffl, Wolfgang; Ali, Zaheer; Grafil, Elliott

    2010-11-01

    This paper discusses the development of a Geant4 model of the Gamma Reaction History (GRH) diagnostic at NIF and Omega, Inertial Confinement Fusion (ICF) laser facilities. The GRH diagnostic has been developed to measure bang-time and burn-width parameters for ICF implosions at both facilities, further investigations have also shown that measurements, such as ablator aerial density and ion temperature, may also be possible. Absolute gamma calibration experiments have been performed at the High Intensity Gamma Source (HIGS) facility at Duke University to increase confidence in parameters supplied by simulation for the use in calculations at both laser facilities. A comparison between HIGS data, Geant4 and the ITS ACCEPT code will be presented along with other important GRH properties, such as temporal unit response function, peak-timing shift and Cherenkov production profile, all as a function of pressure and incident gamma energy.

  13. Evaluation of open MPI and MPICH2 performances for the computation time in proton therapy dose calculations with Geant4

    Science.gov (United States)

    Kazemi, M.; Afarideh, H.; Riazi, Z.

    2015-11-01

    The aim of this research work is to use a better parallel software structure to improve the performance of the Monte Carlo Geant4 code in proton treatment planning. The hadron therapy simulation is rewritten to parallelize the shared memory multiprocessor systems by using the Message-Passing Interface (MPI). The speedup performance of the code has been studied by using two MPI-compliant libraries including Open MPI and the MPICH2, separately. Despite the speedup, the results are almost linear for both the Open MPI and MPICH2; the latter was chosen because of its better characteristics and lower computation time. The Geant4 parameters, including the step limiter and the set cut, have been analyzed to minimize the simulation time as much as possible. For a reasonable compromise between the spatial dose distribution and the calculation time, the improvement in time reduction coefficient reaches about 157.

  14. Design and Construction of a Positron Emission Tomography (PET) Unit and Medical Applications with GEANT Detector Simulation Package

    Energy Technology Data Exchange (ETDEWEB)

    Karagoz, Muge [Bogazici Univ., Istanbul (Turkey)

    1998-01-01

    In order to investigate the possibility of the construction of a sample PET coincidence unit in our HEP laboratory, a setup with two face to face PMTs and two 2x8 Csi(Tl) scintillator matrices has been constructed. In this setup, 1-D projections of a pointlike 22 Na positron source at different angles have been measured. Using these projections a 2-D image has been formed. Monte Carlo studies of this setup have been implemented using the detector simulation tool in CERN program library, GEANT. Again with GEANT a sample human body is created to study the effects of proton therapy. Utilization of the simulation as a pretherapy tool is also investigated.

  15. Progress and Validation of Geant4 Based Radioactive Decay Simulation Using the Examples of Simbol-X and IXO

    CERN Document Server

    Hauf, S; Pia, M G; Bell, Z; Briel, U; Chipaux, R; Hoffmann, D H H; Kendziorra, E; Laurent, P; Strüder, L; Tenzer, C; Weidenspointer, G; Zoglauer, A

    2009-01-01

    The anticipated high sensitivity and the science goals of the next generation X-ray space missions, like the International X-ray Observatory or Simbol-X, rely on a low instrumental background, which in turn requires optimized shielding concepts. We present Geant4 based simulation results on the IXO Wide Field Imager cosmic ray proton induced background in comparison with previous results obtained for the Simbol-X LED and HED focal plane detectors. Our results show that an improvement in mean differential background flux compared to actually operating X-ray observatories may be feasible with detectors based on DEPFET technology. In addition we present preliminary results concerning the validation of Geant4 based radioactive decay simulation in space applications as a part of the Nano5 project.

  16. GEANT4 simulation of plastic scintillator strips with embedded optical fibers for a prototype of tomographic system

    Energy Technology Data Exchange (ETDEWEB)

    Riggi, S., E-mail: simone.riggi@ct.infn.i [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia (Italy); La Rocca, P. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Roma (Italy); Leonora, E.; Lo Presti, D. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy); Pappalardo, G.S. [INFN Section of Catania (Italy); Riggi, F.; Russo, G.V. [Department of Physics and Astronomy, University of Catania (Italy); INFN Section of Catania (Italy)

    2010-12-21

    The response to cosmic muons of plastic scintillator strips, with and without wavelength shifter fibers embedded, read out at both edges by photomultipliers has been studied through detailed GEANT4 simulations, with the aim of studying the light collection at the module ends under different conditions. The performed simulations, validated and tuned with data coming from a module prototype, could serve as an important guide for the design of a tomographic system based on cosmic ray muons.

  17. Influence of various geometries on detection efficiency of polystyrene, polyvinyl-toluene, and sodium iodide detectors using Geant4

    Directory of Open Access Journals (Sweden)

    Mirza Sikander M.

    2015-01-01

    Full Text Available In this work, comparative study on energy dependence of absorbed, intrinsic, photo-peak and absolute total efficiency of polystyrene plastic scintillation fiber and polyvinyl-toluene detectors with NaI(Tl scintillation detectors has been performed using Geant4 version 9.6 toolkit. The effects of geometry parameters on various efficiencies were investigated by varying detector radii, thickness and various source-to-detector configurations. These studies were carried out for both cylindrical and slab geometries for photon energy range of 10 keV-20 MeV using point isotropic sources and parallel beams of photons. Comparisons of the Geant4.9.6 based simulations for polystyrene scintillation fiber intrinsic efficiency as a function of photon energy and corresponding results obtained by earlier versions Geant4 (version 5.1 and Geant4 (version 8.1 show good agreements. The variation of the intrinsic efficiency with energy for polyvinyltoluene is also found to match very well with respective earlier results. This work confirms that the plastic scintillator based fibers and slab detectors are suitable for X-ray and low energy g-ray applications with energies typically below 50 keV with the optimum length of polystyrene scintillation fiber equal to 10 cm. For high energy range, cross talk remains an issue for polystyrene scintillation fiber and it is prominent in fibers having longer lengths and small diameters. Also, until the fiber radius is smaller than the incident photon beam, the fiber intrinsic efficiency increases with an increase in the radius.

  18. Table des illustrations

    OpenAIRE

    2015-01-01

    Intégrer les Tsiganes Hongrie, 1970 (photo DR) 34 Discuter entretient la fraternité. (photo M. Stewart) 35 La veille du mariage (photo M. Stewart) 36 Le « salon » (photo M. Stewart) 37 Les activités économiques des Tsiganes sont conçues comme des jeux. (photo M. Stewart) 39 Lev cheval (photo I. Nemeth) 41 Le cortège d’un mariage (photo M. Stewart) 43 Avant le mariage (photo M. Stewart) 43 C’est par le chant (photo M. Stewart) 45 Des « frères » boivent en harmonie (photo M. Stewart) 46 Les che...

  19. Geschichte des SIN

    CERN Document Server

    Pritzker, Andreas

    2013-01-01

    Dieses Buch erzählt die Geschichte des Schweizerischen Instituts für Nuklearforschung (SIN). Das Institut wurde 1968 gegründet und ging 1988 ins Paul Scherrer Institut (PSI) über. Die Gründung des SIN erfolgte in einer Zeit, als die Physik weitherum als Schlüsseldisziplin für die technologische und gesellschaftliche Entwicklung galt. Der Schritt war für ein kleines Land wie die Schweiz ungewöhnliche und zeugte von Mut und Weitsicht. Ungewöhnlich waren der Folge die Leistungen des SIN im weltweiten Vergleich sowie sein Einfluss auf die schweizerische, teils auf die internationale Wissenschaftspolitik.

  20. Les lueurs des sables

    CERN Multimedia

    Les lueurs des sables

    2013-01-01

    Two CERN ladies are getting ready for the “Trophée Roses des Sables” rally adventure: Julie and Laetitia are finalizing the last details before setting off on Monday 7th October 2013. Julie from EN-MEF group and Laetitia from DGS-SEE group, met at the CERN Rugby club. This year, they are participating in the 100 % female rally which will take place in Morocco from 10 to 20 October. They will be carrying along 100 kg of humanitarian donation for children such as some clothes, books and medical material. Do not hesitate to show your support at their farewell party to be held on Monday 7 October, from 4 to 6 pm in front of the St Genis-Pouilly Mairie (city Hall). Follow their exciting adventure on the blog leslueursdessables.trophee-roses-des-sables.org and on their association’s Facebook page Les Lueurs des Sables.

  1. GEANT4 simulation of photo-peak efficiency of small high purity germanium detectors for nuclear power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Shakeel Ur; Mirza, Sikander M. [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan); Mirza, Nasir M., E-mail: nmm@pieas.edu.p [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan); Siddique, Muhammad Tariq [Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)

    2011-01-15

    GEANT4 - based Monte Carlo simulations have been carried out for the determination of photo-peak efficiency of heavily shielded small high purity germanium detector (HPGe) used for monitoring radiation levels in nuclear power plants. The GEANT4 simulated values of HPGe detector efficiency for point as well as for disk sources, for two different values of collimator diameter, have been found in good agreement with the corresponding published results obtained by using the MCNP code. The work has been extended to study the effect of radial displacement of a source relative to a detector on photo-peak efficiency for both point and disk source, and at various values of {gamma}-ray energies. Also the effect of disk source radius on photo-peak efficiency has been studied. Besides the results of different available physics models in GEANT4 have also been compared. The computed values of efficiency for point as well as for disk sources using the Penelope and Livermore physics models have been found correspondingly consistent for various values of {gamma}-ray energies while some differences (e.g., Penelope model yields 6.3% higher values of photo-peak efficiency for E{gamma} = 1.332 MeV, 10 mm collimator diameter) have been observed in the corresponding valued obtained by using the Standard physics model.

  2. Validation of the Geant4 Monte Carlo package for X-ray fluorescence spectroscopy in triaxial geometry

    Science.gov (United States)

    Amaro, Pedro; Santos, José Paulo; Samouco, Ana; Adão, Ricardo; Martins, Luís Souto; Weber, Sebastian; Tashenov, Stanislav; Carvalho, Maria Luisa; Pessanha, Sofia

    2017-04-01

    In this study, we investigated the potential of the Geant4 Monte Carlo simulation package for retrieving accurate elemental concentrations from energy dispersive X-ray fluorescence spectra. For this purpose, we implemented a Geant4 code that simulates an energy dispersive X-ray fluorescence spectrometer in a triaxial geometry. In parallel, we also performed measurements in a spectrometer with the same geometry, for validation of the present code. This spectrometer allows low limits of detection and permits an effective comparison of elemental concentrations down to tens of part-per-million. Several standard reference materials of both light, medium and heavy matrices were employed in order to attest the validity of simulations for several values of averaged atomic number. We observed good agreement of better than 25% for most fluorescence lines of interest, and for all materials. Discrepancies were observed at the multiple Compton scattering tail. We thus concluded from this experimental and theoretical study that the present Geant4 code can be incorporated in a quantitative method for the determination of trace elements in a triaxial-type spectrometer.

  3. Des Groupes et des Œuvres

    OpenAIRE

    Grojnowski, Daniel

    2015-01-01

    À la fin du xixe siècle, les groupes de bohèmes se multiplient et se diversifient, des salons privés aux tavernes ou cabarets. Une étude aussi attentive que possible de trois d’entre eux (les Zutiques, les Hydropathes, les Incohérents) montre la diversité de leurs configurations, ainsi que l’importance déterminante que leurs productions revêt au regard de la postérité.

  4. Differentialdiagnose des Ulcus cruris

    Directory of Open Access Journals (Sweden)

    Binder B

    2010-01-01

    Full Text Available Das Ulcus cruris ist eine Erkrankung vor allem des höheren Lebensalters. Ungefähr 1 % der Bevölkerung leidet an einer chronischen Wunde. An die 90 % der Ulzera sind vaskulärer Genese, doch gibt es vielfältige weitere Ursachen. Die Kenntnis der relevanten Differentialdiagnosen ist insbesondere bei therapierefraktären Verläufen von Bedeutung. Dazu gehören Neuropathien, myeloproliferative Erkrankungen, Infektionen, Medikamente oder Hauttumore. Für eine erfolgreiche Behandlung des Ulcus cruris ist die Identifikation der Genese von entscheidender Bedeutung, um eine kausale, interdisziplinäre Therapie zu ermöglichen.

  5. Liste des Auteurs

    OpenAIRE

    2014-01-01

    Amor Hakima, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Angeli Aurora, Universita degli studi di Bologna, Dipartimento di scienze statiche “Paolo Fortunati”, Bologne, Italie. Baali Abdellatif, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Bachtarzi T., Hôpital Ibn Sina, CHU Annaba, Algérie. Baudot Patrick, Université de Proven...

  6. Liste des Auteurs

    OpenAIRE

    2014-01-01

    Amor Hakima, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Angeli Aurora, Universita degli studi di Bologna, Dipartimento di scienze statiche “Paolo Fortunati”, Bologne, Italie. Baali Abdellatif, Université Cadi Ayyad, Faculté des sciences Semlalia, Département de biologie, Laboratoire d’écologie humaine, Marrakech, Maroc. Bachtarzi T., Hôpital Ibn Sina, CHU Annaba, Algérie. Baudot Patrick, Université de Proven...

  7. GEANT4 Simulations of Gamma-Gamma Angular Correlations with GRIFFIN

    Science.gov (United States)

    Natzke, Connor; Griffin Collaboration

    2016-09-01

    The structure of very neutron rich isotopes has been of recent experimental interest for both nuclear astrophysics and fundamental nuclear structure investigations. In beta-minus decay specifically, beta-delayed gamma cascades can help to shed light on the spin and parity of the states involved. One of the world's most powerful decay spectroscopy tool is the Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN) spectrometer at TRIUMF-ISAC in Vancouver, Canada. To investigate the feasibility of these experimental studies, GEANT4 simulations of neutron-rich nuclei are critical, as they are able to provide realistic estimates of what the experimental results may look like. The first such nucleus investigated was 44P, and both the temporal and angular γγ correlations were extracted. Furthermore the simulations were used to model various multipole decay possibilities which provide a powerful tool analyzing collected data from such facilities. In the future, the Facility for Rare Isotope Beams (FRIB) at MSU will be an ideal site for such studies on the most exotic nuclei.

  8. New Standard Evaluated Neutron Cross Section Libraries for the GEANT4 Code and First Verification

    CERN Document Server

    Mendoza, Emilio; Koi, Tatsumi; Guerrero, Carlos

    2014-01-01

    The Monte Carlo simulation of the interaction of neutrons with matter relies on evaluated nuclear data libraries and models. The evaluated libraries are compilations of measured physical parameters (such as cross sections) combined with predictions of nuclear model calculations which have been adjusted to reproduce the experimental data. The results obtained from the simulations depend largely on the accuracy of the underlying nuclear data used, and thus it is important to have access to the nuclear data libraries available, either of general use or compiled for specific applications, and to perform exhaustive validations which cover the wide scope of application of the simulation code. In this paper we describe the work performed in order to extend the capabilities of the GEANT4 toolkit for the simulation of the interaction of neutrons with matter at neutron energies up to 20 MeV and a first verification of the results obtained. Such a work is of relevance for applications as diverse as the simulation of a n...

  9. Geant4 simulation study of Indian National Gamma Array at TIFR

    Science.gov (United States)

    Saha, S.; Palit, R.; Sethi, J.; Biswas, S.; Singh, P.

    2016-03-01

    A Geant4 simulation code for the Indian National Gamma Array (INGA) consisting of 24 Compton suppressed clover high purity germanium (HPGe) detectors has been developed. The calculated properties in the energy range that is of interest for nuclear γ-ray spectroscopy are spectral distributions for various standard radioactive sources, intrinsic peak efficiencies and peak-to-total (P/T) ratios in various configurations such as singles, add-back and Compton suppressed mode. The principle of operation of the detectors in add-back and Compton suppression mode have been reproduced in the simulation. The reliability of the calculation is checked by comparison with the experimental data for various γ-ray energies up to 5 MeV. The comparison between simulation results and experimental data demonstrate the need of incorporating the exact geometry of the clover detectors, Anti-Compton Shield and other surrounding materials in the array to explain the detector response to the γ-ray. Several experimental effects are also investigated. These include the geometrical correction to angular distribution, crosstalk probability and the impact of heavy metal collimators between the target and the array on the P/T ratio.

  10. Modeling Monte Carlo of multileaf collimators using the code GEANT4

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Alex C.H.; Lima, Fernando R.A., E-mail: oliveira.ach@yahoo.com, E-mail: falima@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Lima, Luciano S.; Vieira, Jose W., E-mail: lusoulima@yahoo.com.br [Instituto Federal de Educacao, Ciencia e Tecnologia de Pernambuco (IFPE), Recife, PE (Brazil)

    2014-07-01

    Radiotherapy uses various techniques and equipment for local treatment of cancer. The equipment most often used in radiotherapy to the patient irradiation is linear accelerator (Linac). Among the many algorithms developed for evaluation of dose distributions in radiotherapy planning, the algorithms based on Monte Carlo (MC) methods have proven to be very promising in terms of accuracy by providing more realistic results. The MC simulations for applications in radiotherapy are divided into two parts. In the first, the simulation of the production of the radiation beam by the Linac is performed and then the phase space is generated. The phase space contains information such as energy, position, direction, etc. of millions of particles (photons, electrons, positrons). In the second part the simulation of the transport of particles (sampled phase space) in certain configurations of irradiation field is performed to assess the dose distribution in the patient (or phantom). Accurate modeling of the Linac head is of particular interest in the calculation of dose distributions for intensity modulated radiation therapy (IMRT), where complex intensity distributions are delivered using a multileaf collimator (MLC). The objective of this work is to describe a methodology for modeling MC of MLCs using code Geant4. To exemplify this methodology, the Varian Millennium 120-leaf MLC was modeled, whose physical description is available in BEAMnrc Users Manual (20 11). The dosimetric characteristics (i.e., penumbra, leakage, and tongue-and-groove effect) of this MLC were evaluated. The results agreed with data published in the literature concerning the same MLC. (author)

  11. Validation of Geant4 Physics Using the CMS HCAL Test Beam 2002 Experiment

    CERN Document Server

    Elvira, Victor Daniel

    2004-01-01

    High energy physics measurements relay to a great extent on the accuracy of physics generators and detector simulations. The size of systematic uncertainties associated with particle discoveries, mass, or cross section measurements is tightly associated with how accurately the simulations describe the actual performance of the detector in measuring physics objects. Physics validation studies of Geant4 using physics lists LHEP-3.6 and QGSP-2.7, and based on HCAL test beam taken in 2002, are presented in this note. The pion energy resolution and response linearity as a function of incident energy derived from the simulations are in good agreement with the data measurement within the large systematics uncertainties in the latter. Below 30GeV, the uncertaintiesin the data are too large to provide information about deviationsof the Monte Carlo model with respect to the data measurements. Tr ansverse and longitudinal shower profiles are also studied in the Monte Carlo, but no data were analyzed. In particular, long...

  12. Energy Response and Longitudinal Shower Profiles Measured in CMS HCAL and Comparison With Geant4

    CERN Document Server

    Baiatian, G; Emeliantchik, Igor; Massolov, V; Shumeiko, Nikolai; Stefanovich, R; Damgov, Jordan; Dimitrov, Lubomir; Genchev, Vladimir; Piperov, Stefan; Vankov, Ivan; Litov, Leander; Bencze, Gyorgy; Laszlo, Andras; Pal, Andras; Vesztergombi, Gyorgy; Zálán, Peter; Fenyvesi, Andras; Bawa, Harinder Singh; Beri, Suman Bala; Bhatnagar, Vipin; Kaur, Manjit; Kohli, Jatinder Mohan; Kumar, Arun; Singh, Jas Bir; Acharya, Bannaje Sripathi; Banerjee, Sunanda; Banerjee, Sudeshna; Chendvankar, Sanjay; Dugad, Shashikant; Kalmani, Suresh Devendrappa; Katta, S; Mazumdar, Kajari; Mondal, Naba Kumar; Nagaraj, P; Patil, Mandakini Ravindra; Reddy, L; Satyanarayana, B; Sharma, Seema; Sudhakar, Katta; Verma, Piyush; Hashemi, Majid; Mohammadi-Najafabadi, M; Paktinat, S; Golutvin, Igor; Kalagin, Vladimir; Kosarev, Ivan; Ladygin, Vladimir; Mescheryakov, G; Moissenz, P; Petrosian, A; Sergeyev, S; Smirnov, Vitaly; Vishnevskiy, Alexander; Volodko, Anton; Zarubin, Anatoli; Gavrilov, Vladimir; Gershtein, Yuri; Ilyina, N; Kaftanov, Vitali; Kisselevich, I; Kolossov, V; Krokhotin, Andrey; Kuleshov, Sergey; Litvintsev, Dmitri; Ulyanov, A; Safronov, Grigory; Semenov, Sergey; Stolin, Viatcheslav; Demianov, A; Gribushin, Andrey; Kodolova, Olga; Petrushanko, Sergey; Sarycheva, Ludmila; Teplov, V; Vardanyan, Irina; Yershov, A; Abramov, Victor; Goncharov, Petr; Kalinin, Alexey; Khmelnikov, Alexander; Korablev, Andrey; Korneev, Yury; Krinitsyn, Alexander; Kryshkin, V; Lukanin, Vladimir; Pikalov, Vladimir; Ryazanov, Anton; Talov, Vladimir; Turchanovich, L; Volkov, Alexey; Camporesi, Tiziano; De Visser, Theo; Vlassov, E; Aydin, Sezgin; Bakirci, Mustafa Numan; Cerci, Salim; Dumanoglu, Isa; Eskut, Eda; Kayis-Topaksu, A; Koylu, S; Kurt, Pelin; Onengüt, G; Ozkurt, Halil; Polatoz, A; Sogut, Kenan; Topakli, Huseyin; Vergili, Mehmet; Yetkin, Taylan; Cankocak, Kerem; Esendemir, Akif; Gamsizkan, Halil; Güler, M; Ozkan, Cigdem; Sekmen, Sezen; Serin-Zeyrek, M; Sever, Ramazan; Yazgan, Efe; Zeyrek, Mehmet; Deliomeroglu, Mehmet; Dindar, Kamile; Gülmez, Erhan; Isiksal, Engin; Kaya, Mithat; Ozkorucuklu, Suat; Levchuk, Leonid; Sorokin, Pavel; Senchishin, V; Hauptman, John M; Abdullin, Salavat; Elias, John E; Elvira, D; Freeman, Jim; Green, Dan; Los, Serguei; O'Dell, Vivian; Ronzhin, Anatoly; Suzuki, Ichiro; Vidal, Richard; Whitmore, Juliana; Arcidy, M; Hazen, Eric; Heering, Arjan Hendrix; Lawlor, C; Lazic, Dragoslav; Machado, Emanuel; Rohlf, James; Varela, F; Wu, Shouxiang; Baden, Drew; Bard, Robert; Eno, Sarah Catherine; Grassi, Tullio; Jarvis, Chad; Kellogg, Richard G; Kunori, Shuichi; Mans, Jeremy; Skuja, Andris; Podrasky, V; Sanzeni, Christopher; Winn, Dave; Akgun, Ugur; Ayan, S; Duru, Firdevs; Merlo, Jean-Pierre; Mestvirishvili, Alexi; Miller, Michael; Norbeck, Edwin; Olson, Jonathan; Onel, Yasar; Schmidt, Ianos; Akchurin, Nural; Carrell, Kenneth Wayne; Gumus, Kazim; Kim, Heejong; Spezziga, Mario; Thomas, Ray; Baarmand, Marc M; Mermerkaya, Hamit; Ralich, Robert; Vodopiyanov, Igor; Kramer, Laird; Linn, Stephan; Markowitz, Pete; Cushman, Priscilla; Ma, Yousi; Sherwood, Brian; Cremaldi, Lucien Marcus; Reidy, Jim; Sanders, David A; Karmgard, Daniel John; Ruchti, Randy; Fisher, Wade Cameron; Tully, Christopher; Bodek, Arie; De Barbaro, Pawel; Budd, Howard; Chung, Yeon Sei; Haelen, T; Hagopian, Sharon; Hagopian, Vasken; Johnson, Kurtis F; Barnes, Virgil E; Laasanen, Alvin T

    2007-01-01

    The response of the CMS combined electromagnetic and hadron calorimeter to beams of pions with momenta in the range 5-300 GeV/c has been measured in the H2 test beam at CERN. The raw response with the electromagnetic compartment calibrated to electrons and the hadron compartment calibrated to 300 GeV pions may be represented by sigma = (1.2) sqrt{E} oplus (0.095) E. The fraction of energy visible in the calorimeter ranges from 0.72 at 5 GeV to 0.95 at 300 GeV, indicating a substantial nonlinearity. The intrinsic electron to hadron ratios are fit as a function of energy and found to be in the range 1.3-2.7 for the electromagnetic compartment and 1.4-1.8 for the hadronic compartment. The fits are used to correct the non-linearity of the e pi response to 5% over the entire measured range resulting in a substantially improved resolution at low energy. Longitudinal shower profile have been measured in detail and compared to Geant4 models, LHEP-3.7 and QGSP-2.8. At energies below 30 GeV, the data, LHEP and QGSP are...

  13. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Mahdipour, Seyed Ali [Physics Department, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); Mowlavi, Ali Asghar, E-mail: amowlavi@hsu.ac.ir [Physics Department, Hakim Sabzevari University, Sabzevar (Iran, Islamic Republic of); ICTP, Associate Federation Scheme, Medical Physics Field, Trieste (Italy)

    2016-07-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth−dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8 MeV proton, 190.1 MeV alpha, and 1060 MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam's Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors.

  14. Simulating Neutron Interactions in the MoNA-LISA/Sweeper Setup with Geant4

    Science.gov (United States)

    McArthur, Magdalene

    2012-10-01

    The sweeper magnet is a superconducting dipole designed to bend charged particles of 4 Tm rigidity 43 degrees at a radius of approximately one meter. In a typical experiment neutron-unbound states are populated in a reaction in front of the magnet and emitted neutrons are subsequently detected with the high-efficiency position sensitive neutron detector arrays, MoNA and LISA. Before the neutrons interact in MoNA or LISA, they have to pass through the walls of the sweeper magnet chamber. A Monte Carlo simulation was written using Geant 4 which included MoNA and LISA, as well as the geometry of the sweeper magnet and the chamber. In a recent experiment LISA was positioned at large angles were the neutrons passed through the sidewalls of the chamber. The impact of the sidewalls on the neutron spectra was explored for neutrons from the decay of 12Li -> 11Li + n produced from 50 MeV/u 14B beams on a beryllium target.

  15. Benchmarking GEANT4 nuclear models for carbon-therapy at 95 MeV/A

    CERN Document Server

    Dudouet, J; Durand, D; Labalme, M

    2013-01-01

    In carbon-therapy, the interaction of the incoming beam with human tissues may lead to the production of a large amount of nuclear fragments and secondary light particles. An accurate estimation of the biological dose deposited into the tumor and the surrounding healthy tissues thus requires sophisticated simulation tools based on nuclear reaction models. The validity of such models requires intensive comparisons with as many sets of experimental data as possible. Up to now, a rather limited set of double di erential carbon fragmentation cross sections have been measured in the energy range used in hadrontherapy (up to 400 MeV/A). However, new data have been recently obtained at intermediate energy (95 MeV/A). The aim of this work is to compare the reaction models embedded in the GEANT4 Monte Carlo toolkit with these new data. The strengths and weaknesses of each tested model, i.e. G4BinaryLightIonReaction, G4QMDReaction and INCL++, coupled to two di fferent de-excitation models, i.e. the generalized evaporat...

  16. Geant4 simulation of the CERN-EU high-energy reference field (CERF) facility.

    Science.gov (United States)

    Prokopovich, D A; Reinhard, M I; Cornelius, I M; Rosenfeld, A B

    2010-09-01

    The CERN-EU high-energy reference field facility is used for testing and calibrating both active and passive radiation dosemeters for radiation protection applications in space and aviation. Through a combination of a primary particle beam, target and a suitable designed shielding configuration, the facility is able to reproduce the neutron component of the high altitude radiation field relevant to the jet aviation industry. Simulations of the facility using the GEANT4 (GEometry ANd Tracking) toolkit provide an improved understanding of the neutron particle fluence as well as the particle fluence of other radiation components present. The secondary particle fluence as a function of the primary particle fluence incident on the target and the associated dose equivalent rates were determined at the 20 designated irradiation positions available at the facility. Comparisons of the simulated results with previously published simulations obtained using the FLUKA Monte Carlo code, as well as with experimental results of the neutron fluence obtained with a Bonner sphere spectrometer, are made.

  17. Tuning of the GEANT4 FRITIOF (FTF) Model Using NA61/SHINE Experimental Data

    CERN Document Server

    Uzhinsky, V

    2011-01-01

    The NA61/SHINE collaboration measured inclusive cross sections of \\pi^+ and \\pi^- meson production in the interactions of 31 GeV/c protons with carbon nuclei at forward emission angles (0 - 420 mrad). The collaboration also presented predictions of Monte Carlo models - FLUKA, VENUS and UrQMD, in comparison with the data. A careful analysis shows that deviations of the FLUKA and VENUS predictions from the data have different tendencies. The worst description of the data was observed for the UrQMD model results. All the models assume the creation of quark-gluon strings in the interactions, but it is complicated to analyze the models in order to find the source of the deviations. Thus, the quark-gluon string model - FRITIOF (FTF) - was implemented in the GEANT4 toolkit and is used to understand the deviations mentioned above. It was found that the most important factor influencing the FTF calculations is the sampling of quark-gluon string masses. The other factors/parameters are not essential for a description o...

  18. Monte Carlo study of a 3D Compton imaging device with GEANT4

    CERN Document Server

    Lenti, M; 10.1016/j.nima.2011.06.060

    2011-01-01

    In this paper we investigate, with a detailed Monte-Carlo simulation based on Geant4, the novel approach [Nucl. Instrum. Methods A588 (2008) 457] to 3D imaging with photon scattering. A monochromatic and well collimated gamma beam is used to illuminate the object to be imaged and the photons Compton scattered are detected by means of a surrounding germanium strip detector. The impact position and the energy of the photons are measured with high precision and the scattering position along the beam axis is calculated. We study as an application of this technique the case of brain imaging but the results can be applied as well to situations where a lighter object, with localized variations of density, is embedded in a denser container. We report here the attainable sensitivity in the detection of density variations as a function of the beam energy, the depth inside the object and size and density of the inclusions. Using a 600 keV gamma beam, for an inclusion with a density increase of 30% with respect to the so...

  19. Physical Modelling of Proton and Heavy Ion Radiation using Geant4

    Directory of Open Access Journals (Sweden)

    Douglass M.

    2012-10-01

    Full Text Available Protons and heavy ion particles are considered to be ideal particles for use in external beam radiotherapy due to superior properties of the dose distribution that results when these particles are incident externally and due to their relative biological effectiveness. While significant research has been performed into the properties and physical dose characteristics of heavy ions, the nuclear reactions (direct and fragmentation undergone by He4, C12 and Ne20 nuclei used in radiotherapy in materials other than water is still largely unexplored. In the current project, input code was developed for the Monte Carlo toolkit Geant 4 version 9.3 to simulate the transport of several mono-energetic heavy ions through water. The relative dose contributions from secondary particles and nuclear fragments originating from the primary particles were investigated for each ion in both water and dense bone (ICRU media. The results indicated that the relative contribution to the total physical dose from nuclear fragments increased with both increasing particle mass and with increasing medium density. In the case of 150 MeV protons, secondary particles were shown to contribute less than 0.5% of the peak dose and as high as 25% when using 10570 MeV neon ions in bone. When water was substituted for a bone medium, the contributions from fragments increased by more than 6% for C12 and Ne20.

  20. Geant4 simulation of the solar neutron telescope at Sierra Negra, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, L.X., E-mail: xavier@geofisica.unam.m [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, 04510 D.F. (Mexico); Sanchez, F. [Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); Valdes-Galicia, J.F. [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, 04510 D.F. (Mexico)

    2010-02-01

    The solar neutron telescope (SNT) at Sierra Negra (19.0 deg. N, 97.3 deg. W and 4580 m.a.s.l) is part of a worldwide network of similar detectors (Valdes-Galicia et al., (2004)). This SNT has an area of 4 m{sup 2}; it is composed by four 1 mx1 mx30 cm plastic scintillators (Sci). The Telescope is completely surrounded by anti-coincidence proportional counters (PRCs) to separate charged particles from the neutron flux. In order to discard photon background it is shielded on its sides by 10 mm thick iron plates and on its top by 5 mm lead plates. It is capable of registering four different channels corresponding to four energy deposition thresholds: E>30, >60, >90 and >120 MeV. The arrival direction of neutrons is determined by gondolas of PRCs in electronic coincidence, four layers of these gondolas orthogonally located underneath the SNT, two in the NS direction and two in the EW direction. We present here simulations of the detector response to neutrons, protons, electrons and gammas in range of energies from 100 to 1000 MeV. We report on the detector efficiency and on its angular resolution for particles impinging the device with different zenith angles. The simulation code was written using the Geant4 package (Agostinelli et al., (2003)), taking into account all relevant physical processes.

  1. VIDA: a voxel-based dosimetry method for targeted radionuclide therapy using Geant4.

    Science.gov (United States)

    Kost, Susan D; Dewaraja, Yuni K; Abramson, Richard G; Stabin, Michael G

    2015-02-01

    We have developed the Voxel-Based Internal Dosimetry Application (VIDA) to provide patient-specific dosimetry in targeted radionuclide therapy performing Monte Carlo simulations of radiation transport with the Geant4 toolkit. The code generates voxel-level dose rate maps using anatomical and physiological data taken from individual patients. Voxel level dose rate curves are then fit and integrated to yield a spatial map of radiation absorbed dose. In this article, we present validation studies using established dosimetry results, including self-dose factors (DFs) from the OLINDA/EXM program for uniform activity in unit density spheres and organ self- and cross-organ DFs in the Radiation Dose Assessment Resource (RADAR) reference adult phantom. The comparison with reference data demonstrated agreement within 5% for self-DFs to spheres and reference phantom source organs for four common radionuclides used in targeted therapy ((131)I, (90)Y, (111)In, (177)Lu). Agreement within 9% was achieved for cross-organ DFs. We also present dose estimates to normal tissues and tumors from studies of two non-Hodgkin Lymphoma patients treated by (131)I radioimmunotherapy, with comparison to results generated independently with another dosimetry code. A relative difference of 12% or less was found between methods for mean absorbed tumor doses accounting for tumor regression.

  2. GEANT4 simulation of water volume fraction measurement in dehydrated crude oil

    Institute of Scientific and Technical Information of China (English)

    JING Chunguo; XING Guangzhong; LIU Bin

    2007-01-01

    Online measurement of water volume fraction (WVF) in dehydrated crude oil is a difficult task due to very little water in dehydrated crude oil and high precision requirements. We presents a method to measure water volume fraction in dehydrated crude oil with γ-ray densitometry. The Monte Carlo computer simulation packet GEANT4 was used to analyze the WVF measuring sensitivity of the γ-ray densitometry at different γ-ray energies, and effects of temperature, pressure, salinity and oil components on WVF measurement. The results show that the γ-ray densitome-try has high sensitivity in γ-ray energy ranges of 16~25 keV, and it can distinguish WVF changes of 0.0005. The calculated WVF decreases about 0.0002 with 1 ℃ of temperature increase and they have approximately linear relation with temperature when water volume fraction remains the same. Effects of pressure, salinity and oil components on water volume fraction can be neglected. Experiments were done to analyze sensitivity of the γ-ray densitometry. The results, as compared with simulations, demonstrate that simulation method is reliable and it is feasible to gauge low water volume fraction using low energy γ-rays.

  3. Simulation of ultrasoft X-rays induced DNA damage using the Geant4 Monte Carlo toolkit

    Science.gov (United States)

    Tajik, Marjan; Rozatian, Amir S. H.; Semsarha, Farid

    2015-01-01

    In this study, the total yields of SSB and DSB induced by monoenergetic electrons with energies of 0.28-4.55 keV, corresponding to ultrasoft X-rays energies, have been calculated in Charlton and Humm volume model using the Geant4-DNA toolkit and compared with theoretical and experimental data. A reasonable agreement between the obtained results in the present study and experimental and theoretical data of previous studies showed the efficiency of this model in estimating the total yield of strand breaks in spite of its simplicity. Also, it has been found that in the low energy region, the yield of the total SSB remains nearly constant while the DSB yield increases with decreasing energy. Moreover, a direct dependency between DSB induction, RBE value and the mean lineal energy as a microdosimetry quantity has been observed. In addition, it has become clear that the use of the threshold energy of 10.79 eV to calculate the total strand breaks yields results in a better agreement with the experiments, while the threshold of 17.5 eV shows a big difference.

  4. Radial dose distributions from protons of therapeutic energies calculated with Geant4-DNA

    Science.gov (United States)

    Wang, He; Vassiliev, Oleg N.

    2014-07-01

    Models based on the amorphous track structure approximation have been successful in predicting the biological effects of heavy charged particles. Development of such models remains an active area of research that includes applications to hadrontherapy. In such models, the radial distribution of the dose deposited by delta electrons and directly by the particle is the main characteristic of track structure. We calculated these distributions with Geant4-DNA Monte Carlo code for protons in the energy range from 10 to 100 MeV. These results were approximated by a simple formula that combines the well-known inverse square distance dependence with two factors that eliminate the divergence of the radial dose integral at both small and large distances. A clear physical interpretation is given to the asymptotic behaviour of the radial dose distribution resulting from these two factors. The proposed formula agrees with the Monte Carlo data within 10% for radial distances of up to 10 μm, which corresponds to a dose range covering over eight orders of magnitude. Differences between our results and those of previously published analytical models are discussed.

  5. Optimization of a general-purpose, actively scanned proton beamline for ocular treatments: Geant4 simulations.

    Science.gov (United States)

    Piersimoni, Pierluigi; Rimoldi, Adele; Riccardi, Cristina; Pirola, Michele; Molinelli, Silvia; Ciocca, Mario

    2015-03-08

    The Italian National Center for Hadrontherapy (CNAO, Centro Nazionale di Adroterapia Oncologica), a synchrotron-based hospital facility, started the treatment of patients within selected clinical trials in late 2011 and 2012 with actively scanned proton and carbon ion beams, respectively. The activation of a new clinical protocol for the irradiation of uveal melanoma using the existing general-purpose proton beamline is foreseen for late 2014. Beam characteristics and patient treatment setup need to be tuned to meet the specific requirements for such a type of treatment technique. The aim of this study is to optimize the CNAO transport beamline by adding passive components and minimizing air gap to achieve the optimal conditions for ocular tumor irradiation. The CNAO setup with the active and passive components along the transport beamline, as well as a human eye-modeled detector also including a realistic target volume, were simulated using the Monte Carlo Geant4 toolkit. The strong reduction of the air gap between the nozzle and patient skin, as well as the insertion of a range shifter plus a patient-specific brass collimator at a short distance from the eye, were found to be effective tools to be implemented. In perspective, this simulation toolkit could also be used as a benchmark for future developments and testing purposes on commercial treatment planning systems.

  6. Ion therapy for uveal melanoma in new human eye phantom based on GEANT4 toolkit.

    Science.gov (United States)

    Mahdipour, Seyed Ali; Mowlavi, Ali Asghar

    2016-01-01

    Radiotherapy with ion beams like proton and carbon has been used for treatment of eye uveal melanoma for many years. In this research, we have developed a new phantom of human eye for Monte Carlo simulation of tumors treatment to use in GEANT4 toolkit. Total depth-dose profiles for the proton, alpha, and carbon incident beams with the same ranges have been calculated in the phantom. Moreover, the deposited energy of the secondary particles for each of the primary beams is calculated. The dose curves are compared for 47.8MeV proton, 190.1MeV alpha, and 1060MeV carbon ions that have the same range in the target region reaching to the center of tumor. The passively scattered spread-out Bragg peak (SOBP) for each incident beam as well as the flux curves of the secondary particles including neutron, gamma, and positron has been calculated and compared for the primary beams. The high sharpness of carbon beam׳s Bragg peak with low lateral broadening is the benefit of this beam in hadrontherapy but it has disadvantages of dose leakage in the tail after its Bragg peak and high intensity of neutron production. However, proton beam, which has a good conformation with tumor shape owing to the beam broadening caused by scattering, can be a good choice for the large-size tumors.

  7. Modeling of x-ray fluorescence using MCNPX and Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Rajasingam, Akshayan [Los Alamos National Laboratory; Hoover, Andrew S [Los Alamos National Laboratory; Fensin, Michael L [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory

    2009-01-01

    X-Ray Fluorescence (XRF) is one of thirteen non-destructive assay techniques being researched for the purpose of quantifying the Pu mass in used fuel assemblies. The modeling portion of this research will be conducted with the MCNPX transport code. The research presented here was undertaken to test the capability of MCNPX so that it can be used to benchmark measurements made at the ORNL and to give confidence in the application of MCNPX as a predictive tool of the expected capability of XRF in the context of used fuel assemblies. The main focus of this paper is a code-to-code comparison between MCNPX and Geant4 code. Since XRF in used fuel is driven by photon emission and beta decay of fission fragments, both terms were independently researched. Simple cases and used fuel cases were modeled for both source terms. In order to prepare for benchmarking to experiments, it was necessary to determine the relative significance of the various fission fragments for producing X-rays.

  8. Simulation of ultrasoft X-rays induced DNA damage using the Geant4 Monte Carlo toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Tajik, Marjan; Rozatian, Amir S.H. [Department of Physics, University of Isfahan, Hezar Jarib Street, Isfahan 81746-73441 (Iran, Islamic Republic of); Semsarha, Farid, E-mail: Semsarha@ibb.ut.ac.ir [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box: 13145-1384, Tehran (Iran, Islamic Republic of)

    2015-01-01

    In this study, the total yields of SSB and DSB induced by monoenergetic electrons with energies of 0.28–4.55 keV, corresponding to ultrasoft X-rays energies, have been calculated in Charlton and Humm volume model using the Geant4-DNA toolkit and compared with theoretical and experimental data. A reasonable agreement between the obtained results in the present study and experimental and theoretical data of previous studies showed the efficiency of this model in estimating the total yield of strand breaks in spite of its simplicity. Also, it has been found that in the low energy region, the yield of the total SSB remains nearly constant while the DSB yield increases with decreasing energy. Moreover, a direct dependency between DSB induction, RBE value and the mean lineal energy as a microdosimetry quantity has been observed. In addition, it has become clear that the use of the threshold energy of 10.79 eV to calculate the total strand breaks yields results in a better agreement with the experiments, while the threshold of 17.5 eV shows a big difference.

  9. Benchmarking geant4 nuclear models for hadron therapy with 95 MeV/nucleon carbon ions

    Science.gov (United States)

    Dudouet, J.; Cussol, D.; Durand, D.; Labalme, M.

    2014-05-01

    In carbon therapy, the interaction of the incoming beam with human tissue may lead to the production of a large amount of nuclear fragments and secondary light particles. An accurate estimation of the biological dose on the tumor and the surrounding healthy tissue thus requires sophisticated simulation tools based on nuclear reaction models. The validity of such models requires intensive comparisons with as many sets of experimental data as possible. Up to now, a rather limited set of double differential carbon fragmentation cross sections has been measured in the energy range used in hadron therapy (up to 400 MeV/nucleon). However, new data have been recently obtained at intermediate energy (95 MeV/nucleon). The aim of this work is to compare the reaction models embedded in the geant4 Monte Carlo toolkit with these new data. The strengths and weaknesses of each tested model, i.e., G4BinaryLightIonReaction, G4QMDReaction, and INCL++, coupled to two different de-excitation models, i.e., the generalized evaporation model and the Fermi break-up model, are discussed.

  10. Geant4 simulation of the response of phosphor screens for X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Pistrui-Maximean, S.A. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France)]. E-mail: simona.pistrui@insa-lyon.fr; Freud, N. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France); Letang, J.M. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France); Koch, A. [Thales Electron Devices, 38430 Moirans (France); Munier, B. [Thales Electron Devices, 38430 Moirans (France); Walenta, A.H. [Department of Detectors and Electronics, FB Physik, University of Siegen, 57068 Siegen (Germany); Montarou, G. [Corpuscular Physics Laboratory, Blaise Pascal University, 63177 Aubiere Cedex (France); Babot, D. [Laboratory of Nondestructive Testing using Ionizing Radiation, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint Exupery, 69621 Villeurbanne Cedex (France)

    2006-07-01

    In order to predict and optimize the response of phosphor screens, it is important to understand the role played by the different physical processes inside the scintillator layer. A simulation model based on the Monte Carlo code Geant4 was developed to determine the Modulation Transfer Function (MTF) of phosphor screens for energies used in X-ray medical imaging and nondestructive testing applications. The visualization of the dose distribution inside the phosphor layer gives an insight into how the MTF is progressively degraded by X-ray and electron transport. The simulation model allows to study the influence of physical and technological parameters on the detector performances, as well as to design and optimize new detector configurations. Preliminary MTF measurements have been carried out and agreement with experimental data has been found in the case of a commercial screen (Kodak Lanex Fine) at an X-ray tube potential of 100 kV. Further validation with other screens (transparent or granular) at different energies is under way.

  11. Geant4 simulation of gamma conversion to muon pair for dark matter searches

    CERN Document Server

    Sokolov, Anton

    2017-01-01

    There is a direct evidence from different astronomical observations and CMB spectrum that 26% of the visible part of the Universe consists of so-called dark matter. There are many models explaining the phenomenon of dark matter, however none of them has been confirmed experimentally. It justifies the further searches for the dark matter that involve more and more various experiments, such as, for instance, SHiP experiment [1] at CERN or LDMX project [2] at SLAC. LDMX (Light Dark Matter eXperiment) is an electron fixedtarget missing momentum search for light dark matter. The main process that LDMX looks for is dark bremsstrahlung (i.e. emitting a light dark matter particle) by the several GeV electrons scattered off the target. This process is contaminated by the background of ordinary bremsstrahlung, that consists of many different processes which can be accounted for and vetoed by various counters. The experiment designs are studied with the Geant4 toolkit. Recently, one of the important background pro...

  12. An example of scientific application of APL language: the simulation of magnetic resonance spectra: or the practical role of APL language to write efficient programs; Un exemple d`application scientifique d`APL: la simulation des spectres de resonance magnetique: ou le role pratique d`APL pour l`ecriture de programmes efficaces

    Energy Technology Data Exchange (ETDEWEB)

    Chachaty, C.

    1995-12-31

    This article has been published to show that the APL area is bigger that it is generally thought and can make the science progress in fields where EPR (electron paramagnetic resonance) and NMR (nuclear magnetic resonance) have and will have important repercussions, especially in medicine. (N.C.).

  13. GEANT4 used for neutron beam design of a neutron imaging facility at TRIGA reactor in Morocco

    Science.gov (United States)

    Ouardi, A.; Machmach, A.; Alami, R.; Bensitel, A.; Hommada, A.

    2011-09-01

    Neutron imaging has a broad scope of applications and has played a pivotal role in visualizing and quantifying hydrogenous masses in metallic matrices. The field continues to expand into new applications with the installation of new neutron imaging facilities. In this scope, a neutron imaging facility for computed tomography and real-time neutron radiography is currently being developed around 2.0MW TRIGA MARK-II reactor at Maamora Nuclear Research Center in Morocco (Reuscher et al., 1990 [1]; de Menezes et al., 2003 [2]; Deinert et al., 2005 [3]). The neutron imaging facility consists of neutron collimator, real-time neutron imaging system and imaging process systems. In order to reduce the gamma-ray content in the neutron beam, the tangential channel was selected. For power of 250 kW, the corresponding thermal neutron flux measured at the inlet of the tangential channel is around 3×10 11 ncm 2/s. This facility will be based on a conical neutron collimator with two circular diaphragms with diameters of 4 and 2 cm corresponding to L/D-ratio of 165 and 325, respectively. These diaphragms' sizes allow reaching a compromise between good flux and efficient L/D-ratio. Convergent-divergent collimator geometry has been adopted. The beam line consists of a gamma filter, fast neutrons filter, neutron moderator, neutron and gamma shutters, biological shielding around the collimator and several stages of neutron collimator. Monte Carlo calculations by a fully 3D numerical code GEANT4 were used to design the neutron beam line ( http://www.info.cern.ch/asd/geant4/geant4.html[4]). To enhance the neutron thermal beam in terms of quality, several materials, mainly bismuth (Bi) and sapphire (Al 2O 3) were examined as gamma and neutron filters respectively. The GEANT4 simulations showed that the gamma and epithermal and fast neutron could be filtered using the bismuth (Bi) and sapphire (Al 2O 3) filters, respectively. To get a good cadmium ratio, GEANT 4 simulations were used to

  14. Die lebensvision des semonides

    Directory of Open Access Journals (Sweden)

    Milivoj Sironić

    1980-12-01

    Full Text Available Der Autor analysiert die Weibersatire des Semonides und andere seiner kurzen Fragmente. Dabei kommt er zu der Schlussfolgerung, dass sich die Verse der Satire durch eine gute Technik auszeich­ nen, dass aber auch eine unnötige Weitschweifigkeit nicht zu Ubersehen ist. Trotzdem kann man jedoch dem Dichter nicht die künstlerische Überzeugungskraft absprechen, wie auch die Ten­ denz nach Detailschilderungen und die Feinheit geistreicher Charakterisierungen. Die Aussage beinhaltet manchmal eine be­ stimmte innere Ironie in der Einfachheit der Wörter.In kurzen Fragmenten wird die Fähigkeit des Semonides sichtbar, sich sehr präzise auszudrücken. Seine ironisch-epische Sprache ist sehr reich  und verdient vom linguistischen Standpunkt aus Auf­ merksamkeit wegen ihres reichhaltigen lexischen und termino­ logischen Materials, insbesondere was die Bereiche der Tier­ welt und des Essens anbelangt.Die Weltanschauung des Dichters ist in dem ersten Fragment recht deutlich erkennbar. Da sieht man, dass er düster und pessimistisch auf das Leben blickt. Das Fehlen jeglicher positiven Einstellung hat dann den Sar­ kasmus zur Folge, mit dem der Dichter die Darstellung der Weiber einkleidet, ihn aber auch auf die Menschen schlechthin ausweitet.

  15. La physique des infinis

    CERN Document Server

    Bernardeau, Francis; Laplace, Sandrine; Spiro, Michel

    2013-01-01

    Écrire l'histoire de l'Univers, tel est l'objectif commun des physiciens des particules et des astrophysiciens. Pour y parvenir, deux approches s'épaulent : la voie de l'infiniment petit, que l'on emprunte via de gigantesques accélérateurs de particules, et celle de l'infiniment grand, dont le laboratoire est l'Univers. Un Univers qui est bien loin d'avoir livré tous ses secrets. On connaît à peine 4,8 % de la matière qui le constitue, le reste étant composé de matière noire (25,8 %) et d'énergie noire (69,4 %), toutes deux de nature inconnue. Et si la récente découverte du boson de Higgs valide le Modèle standard de la physique des particules, celui-ci est toujours incomplet et doit être étendu à ou dépassé. Est-on arrivé au bout du jeu de poupées russes de la matière ? Quelles sont les particules manquantes ? Faut-il revoir les lois fondamentales ? Quels instruments faut-il mettre en œuvre pour accéder à cette « nouvelle physique » ? Comment parler de Super Big Science aux citoye...

  16. CHAINE DES ROTISSEUR @ HILTON

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The annual gala dinner of Chaine des Rotisseurs was hosted by Hilton Beijing. The “Ballet Dinner” - a great creation for both art and fine dining lovers was taken place in varies places within the hotel, including hotel lobby, 3rd floor and lobby lounge.

  17. REPRISE DES COURS - Yoga

    CERN Multimedia

    Club de Yoga

    2015-01-01

    REPRISE DES COURS – Venez nombreux ! Yoga, Sophrologie, Tai Chi La liste des cours pour le semestre allant du 1er septembre 2015 au 31 janvier 2016 est disponible sur notre site web : http://club-yoga.web.cern.ch Lieu Les cours ont lieu dans la salle des clubs, à l’entresol du restaurant No 2, Bât. 504 (dans la salle no 3 pour la Sophrologie). Prix des cours Le prix pour le semestre (environ 18 leçons) est fixé à 220 CHF plus 10 CHF d’adhésion annuelle au Club. Couple : 200 CHF par personne. 2 cours par semaine : 400 CHF. Inscriptions Les inscriptions aux cours seront prises directement auprès du professeur, lors de la 1ère séance. Avant de s’inscrire pour le semestre, il est possible d’essayer une séance gratuitement. Informations : http://club-yoga.web.cern.ch ----------------------------------------- cern.ch/club-yoga/

  18. Potenziale des Mobile Commerce

    OpenAIRE

    Turowski, Klaus

    2004-01-01

    Potenziale des Mobile Commerce / B. Bazijanec, K. Turowski. - In: Mobile economy : 4. Workshop Mobile Commerce, 02.-03. Februar 2004, Univ. Augsburg / Key Pousttchi ... (Hrsg.). - Bonn : Ges. für Informatik, 2004. - S. 7-11. - (GI-Edition : Proceedings ; 42)

  19. Vom Ort des Philosophierens

    Directory of Open Access Journals (Sweden)

    Damir Barbaric

    2002-12-01

    Full Text Available Im Aufsatz wird versucht, den ursprünglichen Sinn der Platonischen Bestimmung vom Staunen als Anfang der Philosophie zu ermitteln, und zwar durch eine kritischen Abhebung von ihrer Umdeutung bei Aristoteles, und dann insbesondere in der Stoa wie auch bei Spinoza und Hegel. Dabei wird auf die frühgriechische Erfahrung vom Staunen als _______ aufmerksam gemacht, wo es vor allem die Grundstimmung des Dabeiseins des Göttlichen und der menschlichen Teilnahme am Göttlichen bedeutet. Dem entspricht die bei Platon stark hervorgehobene Rolle des “Pathetischen” am Staunen, das in der nachkommenden Tradition grundsätzlich verlorengegangen ist. Für Platon entspringt das Staunen einem nie zu überwindenden Zustand der wesentlichen philosophischen “Weglosigkeit” (_____, welche schon bei Aristoteles nur noch im Sinne eines unbedingt zu verlassenden Ausgangspunkts der methodisch sicher fortfahrenden philosophischen Wissenschaft verstanden wird. Durch ein Zurückgreifen auf die Diotimas Lehre im Dialog Symposion wird dementgegen die Sokratisch-Platonische “Weglosigkeit” als der einzig angemessene “Ort” des echten Philosophierens bestimmt, welchen es, als das “Zwischen” für das Weltspiel der Unsterblichen und Sterblichen, um jeden Preis zu bewahren und offen zu halten gilt.

  20. Injectabilite des coulis de ciment dans des milieux fissures

    Science.gov (United States)

    Mnif, Thameur

    Le travail presente ici est un bilan du travaux de recherche effectues sur l'injectabilite des coulis de ciment dans lu milieux fissures. Un certain nombre de coulis a base de ciment Portland et microfin ont ete selectionnes afin de caracteriser leur capacite a penetrer des milieux fissures. Une partie des essais a ete menee en laboratoire. L'etude rheologique des differents melanges a permis de tester l'influence de l'ajout de superplastifiant et/ou de fumee de silice sur la distribution granulometrique des coulis et par consequent sur leur capacite a injecter des colonnes de sable simulant un milieu fissure donne. La classe granulometrique d'un coulis, sa stabilite et sa fluidite sont apparus comme les trois facteurs principaux pour la reussite d'une injection. Un facteur de finesse a ete defini au cours de cette etude: base sur la classe granulometrique du ciment et sa stabilite, il peut entrer dans la formulation theorique du debit d'injection avant application sur chantier. La deuxieme et derniere partie de l'etude presente les resultats de deux projets de recherche sur l'injection realises sur chantier. L'injection de dalles de beton fissurees a permis le suivi de l'evolution des pressions avec la distance au point d'injection. L'injection de murs de maconnerie a caractere historique a montre l'importance de la definition de criteres de performance des coulis a utiliser pour traiter un milieu donne et pour un objectif donne. Plusieurs melanges peuvent ainsi etre predefinis et mis a disposition sur le chantier. La complementarite des ciments traditionnels et des ciments microfins devient alors un atout important. Le choix d'utilisation de ces melanges est fonction du terrain rencontre. En conclusion, cette recherche etablit une methodologie pour la selection des coulis a base de ciment et des pressions d'injection en fonction de l'ouverture des fissures ou joints de construction.

  1. Identification et prise en charge des femmes ayant des antécédents familiaux de cancer du sein

    Science.gov (United States)

    Heisey, Ruth; Carroll, June C.

    2016-01-01

    Résumé Objectif Résumer les meilleures données portant sur les stratégies d’identification et de prise en charge des femmes qui présentent des antécédents familiaux de cancer du sein. Sources d’information Une recherche a été effectuée sur PubMed à l’aide des mots-clés anglais suivants : breast cancer, guidelines, risk, family history, management et magnetic resonance imaging screening, entre 2000 et 2016. La plupart des données sont de niveau II. Message principal Une bonne anamnèse familiale est essentielle lors de l’évaluation du risque de cancer du sein afin d’identifier les femmes qui sont candidates à une recommandation en counseling génétique pour un éventuel test génétique. On peut sauver des vies en offrant aux femmes porteuses d’une mutation au gène BRCA des interventions chirurgicales de réduction des risques (mastectomie bilatérale prophylactique, salpingo-ovariectomie bilatérale). Il faut encourager toutes les femmes qui présentent des antécédents familiaux de cancer du sein à demeurer actives et à limiter leur consommation d’alcool à moins de 1 verre par jour; certaines femmes sont admissibles à la chimioprévention. Il faut offrir aux femmes dont le risque à vie de cancer du sein est de 20 à 25 % ou plus un dépistage poussé par imagerie par résonance magnétique en plus d’une mammographie. Conclusion Une vie saine et la chimioprévention (chez les candidates) pourraient réduire l’incidence du cancer du sein; le dépistage poussé pourrait entraîner une détection plus précoce. Le fait d’aiguiller des femmes porteuses d’une mutation au BRCA vers la chirurgie de réduction des risques sauve des vies. PMID:27737991

  2. Dopage et protection des jeunes sportifs : Loin des affaires

    OpenAIRE

    Guy, Daniel

    2002-01-01

    National audience; Loin des affaires et des révélations polémiques de la presse, les jeunes plébiscitent massivement les activités sportives. Sport compétition, sport participation, sport détente... Pourtant, quand la pratique devient intense, que les entraînements et les compétitions s'enchaînent à un rythme soutenu, l'ombre des conduites dopantes vient déchirer la quiétude des uns et des autres. Or, que savons-nous réellement de la pratique des jeunes sportifs ? Comment préparent-ils les co...

  3. Neutron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gunsing, F

    2005-06-15

    The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)

  4. Determination of intensity and position of the extracted electron beam at ELSA by means of high-frequency resonators; Bestimmung von Intensitaet und Position des extrahierten Elektronenstrahls an ELSA mittels Hochfrequenzresonatoren

    Energy Technology Data Exchange (ETDEWEB)

    Pusch, Thorsten

    2012-06-15

    The electron stretcher facility ELSA provides an electron beam of a few hundred pA used for the generation of bremsstrahlung photons probing the nucleon structure in a detector setup. For the correct interpretation of the events registered, the persistence of the beam position over time is crucial. Its continuous monitoring has been enabled by setting up a measurement system based on resonant cavities. Position signals at a frequency of 1.5 GHz and below one aW of power can be abstracted from the beam without degrading its quality. After frequency down-conversion to a few kHz, a narrow bandwidth detection performed by lock-in amplifiers separates them from noise. A maximum sample rate of 9 Hz and a resolution of one tenth of a millimeter could be achieved. The position signals have to be normalized to the beam current which is monitored by another dedicated resonator. The measurement precision down to a few pA allows for the accelerator extraction mechanism to be controlled by a feedback loop in order to obtain the respective requested current. (orig.)

  5. Optimization of {sup 6}LiF:ZnS(Ag) Scintillator Light Yield Using Geant4

    Energy Technology Data Exchange (ETDEWEB)

    Yehuda-Zada, Y. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ben-Gurion University (Israel); Pritchard, K.; Ziegler, J.B.; Cooksey, C.; Siebein, K. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Jackson, M.; Hurlbut, C. [Eljen Technology, Sweetwater Texas (United States); Kadmon, Y.; Cohen, Y.; Maliszewskyj, N.C. [Nuclear Research Center Negev, Beer-Sheva (Israel); Ibberson, R.M.; Majkrzak, C.F. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Orion, Y. [Ben-Gurion University (Israel); Osovizky, A. [National Institute of Standards and Technology, Gaithersburg, Maryland (United States); Rotem Industries Ltd, Rotem Industrial Park (Israel); University of Maryland (United States)

    2015-07-01

    Neutrons provide an effective tool to probe materials structure. Neutron diffraction is a method to determine the atomic and magnetic structure of a material based on neutron scattering. By this method a collimated incident beam of thermal neutrons heat the examined sample and based on the obtained diffraction pattern information on the structure of the material is provided. Research for developing a novel cold neutron detector for Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is underway at the NIST center for neutron research. The system unique design is aimed to provide over ten times fold faster analysis of materials than conventional system. In order to achieve the fast analysis a large number of neutron detectors is required. A key design constraint for this detector is the thickness of the neutron sensitive element. This is met using {sup 6}LiF:ZnS(Ag) scintillation material with embedded wavelength shifting (WLS) fibers conducting scintillation light to silicon photomultiplier photo-sensors. The detector sensitivity is determined by both the neutron capture probability ({sup 6}Li density) and the detectable light output produced by the ZnS(Ag) ionization, the latter of which is hindered by the fluorescence absorption of the scintillation light by the ZnS. Tradeoffs between the neutron capture probability, stimulated light production and light attenuation for determining the optimal stoichiometry of the {sup 6}LiF and ZnS(Ag) as well as the volume ratio of scintillator and fiber. Simulations performed using the GEANT4 Monte Carlo package were made in order to optimize the detector design. GEANT4 enables the investigation of the neutron interaction with the detector, the ionization process and the light transfer process following the nuclear process. The series of conversions required for this detector were modelled: - A cold neutron enters the sensor and is captured by {sup 6}Li in the scintillator mixture ({sup 6}Li (n,α) {sup 3}H

  6. MRI of the fetal abdomen; MRT des fetalen Abdomens

    Energy Technology Data Exchange (ETDEWEB)

    Hoermann, M.; Brugger, P.C.; Witzani, L.; Prayer, D. [Medizinische Universitaet Wien (Austria). Universitaetsklinik fuer Radiodiagnostik

    2006-02-15

    Magnetic resonance imaging (MRI) is an important diagnostic component for central nervous system and thoracic diseases during fetal development. Although ultrasound remains the method of choice for observing the fetus during pregnancy, fetal MRI is being increasingly used as an additional technique for the accurate diagnosis of abdominal diseases. Recent publications confirm the value of MRI in the diagnosis of fetal gastrointestinal tract and urogenital system diseases. The following report provides an overview of MRI-examination techniques for the most frequent diseases of the abdomen. (orig.) [German] Die MRT ist ein wichtiger Bestandteil zur Diagnostik des zentralen Nervensystems und thorakaler Erkrankungen in der fetalen Entwicklung. Wenngleich der Ultraschall die Methode der Wahl zur Ueberwachung des Feten in der Schwangerschaft bleibt, bekommt die fetale MRT als zusaetzliche Untersuchungstechnik zur akkuraten Diagnostik abdomineller Erkrankungen immer groessere Bedeutung. Die neueren Publikationen bestaetigen v. a. den Stellenwert der MRT in der Diagnose von Erkrankungen des fetalen Gastrointestinaltrakts und des Urogenitalsystems. Im Folgenden soll ein Ueberblick ueber die MR-Untersuchungstechnik der haeufigsten Erkrankungen des Abdomens gegeben werden. (orig.)

  7. The GEANT4 toolkit capability in the hadron therapy field: simulation of a transport beam line

    Science.gov (United States)

    Cirrone, G. A. P.; Cuttone, G.; Di Rosa, F.; Raffaele, L.; Russo, G.; Guatelli, S.; Pia, M. G.

    2006-01-01

    At Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare of Catania (Sicily, Italy), the first Italian hadron therapy facility named CATANA (Centro di AdroTerapia ed Applicazioni Nucleari Avanzate) has been realized. Inside CATANA 62 MeV proton beams, accelerated by a superconducting cyclotron, are used for the radiotherapeutic treatments of some types of ocular tumours. Therapy with hadron beams still represents a pioneer technique, and only a few centers worldwide can provide this advanced specialized cancer treatment. On the basis of the experience so far gained, and considering the future hadron-therapy facilities to be developed (Rinecker, Munich Germany, Heidelberg/GSI, Darmstadt, Germany, PSI Villigen, Switzerland, CNAO, Pavia, Italy, Centro di Adroterapia, Catania, Italy) we decided to develop a Monte Carlo application based on the GEANT4 toolkit, for the design, the realization and the optimization of a proton-therapy beam line. Another feature of our project is to provide a general tool able to study the interactions of hadrons with the human tissue and to test the analytical-based treatment planning systems actually used in the routine practice. All the typical elements of a hadron-therapy line, such as diffusers, range shifters, collimators and detectors were modelled. In particular, we simulated the Markus type ionization chamber and a Gaf Chromic film as dosimeters to reconstruct the depth (Bragg peak and Spread Out Bragg Peak) and lateral dose distributions, respectively. We validated our simulated detectors comparing the results with the experimental data available in our facility.

  8. Geant4 Analysis of a Thermal Neutron Real-Time Imaging System

    Science.gov (United States)

    Datta, Arka; Hawari, Ayman I.

    2017-07-01

    Thermal neutron imaging is a technique for nondestructive testing providing complementary information to X-ray imaging for a wide range of applications in science and engineering. Advancement of electronic imaging systems makes it possible to obtain neutron radiographs in real time. This method requires a scintillator to convert neutrons to optical photons and a charge-coupled device (CCD) camera to detect those photons. Alongside, a well collimated beam which reduces geometrical blurriness, the use of a thin scintillator can improve the spatial resolution significantly. A representative scintillator that has been applied widely for thermal neutron imaging is 6LiF:ZnS (Ag). In this paper, a multiphysics simulation approach for designing thermal neutron imaging system is investigated. The Geant4 code is used to investigate the performance of a thermal neutron imaging system starting with a neutron source and including the production of charged particles and optical photons in the scintillator and their transport for image formation in the detector. The simulation geometry includes the neutron beam collimator and sapphire filter. The 6LiF:ZnS (Ag) scintillator is modeled along with a pixelated detector for image recording. The spatial resolution of the system was obtained as the thickness of the scintillator screen was varied between 50 and 400 μm. The results of the simulation were compared to experimental results, including measurements performed using the PULSTAR nuclear reactor imaging beam, showing good agreement. Using the established model, further examination showed that the resolution contribution of the scintillator screen is correlated with its thickness and the range of the neutron absorption reaction products (i.e., the alpha and triton particles). Consequently, thinner screens exhibit improved spatial resolution. However, this will compromise detection efficiency due to the reduced probability of neutron absorption.

  9. The simulation of the LANFOS-H food radiation contamination detector using Geant4 package

    Science.gov (United States)

    Piotrowski, Lech Wiktor; Casolino, Marco; Ebisuzaki, Toshikazu; Higashide, Kazuhiro

    2015-02-01

    Recent incident in the Fukushima power plant caused a growing concern about the radiation contamination and resulted in lowering the Japanese limits for the permitted amount of 137Cs in food to 100 Bq/kg. To increase safety and ease the concern we are developing LANFOS (Large Food Non-destructive Area Sampler)-a compact, easy to use detector for assessment of radiation in food. Described in this paper LANFOS-H has a 4 π coverage to assess the amount of 137Cs present, separating it from the possible 40K food contamination. Therefore, food samples do not have to be pre-processed prior to a test and can be consumed after measurements. It is designed for use by non-professionals in homes and small institutions such as schools, showing safety of the samples, but can be also utilized by specialists providing radiation spectrum. Proper assessment of radiation in food in the apparatus requires estimation of the γ conversion factor of the detectors-how many γ photons will produce a signal. In this paper we show results of the Monte Carlo estimation of this factor for various approximated shapes of fish, vegetables and amounts of rice, performed with Geant4 package. We find that the conversion factor combined from all the detectors is similar for all food types and is around 37%, varying maximally by 5% with sample length, much less than for individual detectors. The different inclinations and positions of samples in the detector introduce uncertainty of 1.4%. This small uncertainty validates the concept of a 4 π non-destructive apparatus.

  10. BC404 scintillators as gamma locators studied via Geant4 simulations

    Science.gov (United States)

    Cortés, M. L.; Hoischen, R.; Eisenhauer, K.; Gerl, J.; Pietralla, N.

    2014-05-01

    In many applications in industry and academia, an accurate determination of the direction from where gamma rays are emitted is either needed or desirable. Ion-beam therapy treatments, the search for orphan sources, and homeland security applications are examples of fields that can benefit from directional sensitivity to gamma-radiation. Scintillation detectors are a good option for these types of applications as they have relatively low cost, are easy to handle and can be produced in a large range of different sizes. In this work a Geant4 simulation was developed to study the directional sensitivity of different BC404 scintillator geometries and arrangements. The simulation includes all the physical processes relevant for gamma detection in a scintillator. In particular, the creation and propagation of optical photons inside the scintillator was included. A simplified photomultiplier tube model was also simulated. The physical principle exploited is the angular dependence of the shape of the energy spectrum obtained from thin scintillator layers when irradiated from different angles. After an experimental confirmation of the working principle of the device and a check of the simulation, the possibilities and limitations of directional sensitivity to gamma radiation using scintillator layers was tested. For this purpose, point-like sources of typical energies expected in ion-beam therapy were used. Optimal scintillator thicknesses for different energies were determined and the setup efficiencies calculated. The use of arrays of scintillators to reconstruct the direction of incoming gamma rays was also studied. For this case, a spherical source emitting Bremsstrahlung radiation was used together with a setup consisting of scintillator layers. The capability of this setup to identify the center of the extended source was studied together with its angular resolution.

  11. Geant4 simulations on medical Linac operation at 18 MV: Experimental validation based on activation foils

    Science.gov (United States)

    Vagena, E.; Stoulos, S.; Manolopoulou, M.

    2016-03-01

    The operation of a medical linear accelerator was simulated using the Geant4 code regarding to study the characteristics of an 18 MeV photon beam. Simulations showed that (a) the photon spectrum at the isocenter is not influenced by changes of the primary electron beam's energy distribution and spatial spread (b) 98% of the photon energy fluence scored at the isocenter is primary photons that have only interacted with the target (c) the number of contaminant electrons is not negligible since it fluctuated around 5×10-5 per primary electron or 2.40×10-3 per photon at the isocenter (d) the number of neutrons that are created by (γ, n) reactions is 3.13×10-6 per primary electron or 1.50×10-3 per photon at the isocenter (e) a flattening filter free beam needs less primary electrons in order to deliver the same photon fluence at the isocenter than a normal flattening filter operation (f) there is no significant increase of the surface dose due to the contaminant electrons by removing the flattening filter (g) comparing the neutron fluences per incident electron for the flattened and unflattened beam, the neutron fluencies is 7% higher for the unflattened beams. To validate the simulations results, the total neutron and photon fluence at the isocenter field were measured using nickel, indium, and natural uranium activation foils. The percentage difference between simulations and measurements was 1.26% in case of uranium and 2.45% in case of the indium foil regarding photon fluencies while for neutrons the discrepancy is higher up to 8.0%. The photon and neutron fluencies of the simulated experiments fall within a range of ±1 and ±2 sigma error, respectively, compared to the ones obtained experimentally.

  12. 基于Geant4模拟质子在半导体Si材料中的NIEL值%Simulation of proton NIEL in silicon by using GEANT4

    Institute of Scientific and Technical Information of China (English)

    路伟; 王同权; 王兴功; 刘雪林

    2011-01-01

    利用蒙特卡洛软件GEANT4模拟了质子对半导体Si材料的位移损伤效应的能量损失.根据反冲原子的能量,引入反冲原子能量Lindbard-Robinson-Akkerman分离函数,模拟结果表明10MeV-1 GeV能量范围内的质子位移能量损失值和Jun、Summers等结果吻合较好.

  13. Le corps des anges

    OpenAIRE

    Margel,Serge

    2017-01-01

    Ce séminaire fait suite à un cycle de conférences données en 2014 sur la notion de corps de chair dans le premier christianisme. Cette année la recherche a porté sur le corps spécifique des anges dans la patristique grecque et latine. Sur la base d’un corpus de textes délimité, j’ai essayé de montrer deux choses principales : d’un côté, on ne peut pas comprendre la spécificité du corps des anges sans l’inscrire dans le champ de l’angélologie chrétienne, qui assimile l’ange et l’âme, et d’un a...

  14. Typologie des Accidents Cyclistes

    OpenAIRE

    Amoros, Emmanuelle; BILLOT-GRASSET, Alice; Hours, Martine

    2015-01-01

    L'usage du vélo est en hausse en ville ; cette pratique est encouragée dans le cadre du développement durable et de la lutte contre la sédentarité. Pour accompagner cela, il faut réduire les risques d'accident, et pour ce faire, mieux les connaître. Nous utilisons le Registre des victimes de la circulation routière du Rhône, basé sur les services hospitaliers (dont les urgences) ; il est quasi-exhaustif : env. 1100 blessés à vélo/an versus 120 dans les données officielles. L'ensemble des cycl...

  15. Table des tableaux

    OpenAIRE

    2014-01-01

    Présentation schématique de la production et de la transformation de l’acier 16 Chronologie des nationalisations en France 33 Importations de coke de la France 48 Comparaison entre les prix de l’acier en Allemagne et en France, août 1949 99 Prix du marché intérieur et du marché mondial pour les laminés marchands (qualité Thomas) 101 Évolution de la production allemande et française d’acier brut 119 Comparaison des coûts de l’extraction de charbon en Allemagne et en France, 1949 138 Évolution ...

  16. Table des illustrations

    OpenAIRE

    2017-01-01

    Illustration de couverture : Dolmen n° 2 des Géandes avec le Mont Ventoux en arrière-plan, octobre 2006 (cliché Wolfgang Pape). Illustration de la quatrième de couverture : René Gilles sur le dolmen n° 5 des Géandes en mars 1989 (cliché Wolfgang Pape). Fig. 1 - Gorges de l’Ardèche au niveau de la grotte de Saint-Marcel (cliché Bernard Gély) 21 Fig. 2 - Doline de Bidon (cliché Wolfgang Pape) 21 Fig. 3 - Paysage de garrigue (cliché Wolfgang Pape) 22 Fig. 4 - Données radio-chronométriques de l’A...

  17. Direction des Publications

    African Journals Online (AJOL)

    Synthese

    accroissement des pressions sur les écosystèmes et les espèces qu‟ils renferment. La pollution de ... Exacerbée par le changement climatique, cette anthropisation .... majeure partie de son aire de répartition. .... de cette région. .... savoir les impacts à plus grande échelle et ..... habitats et la totalité de l'aire géographique.

  18. Lo calized surface plasmon resonance mo des in Ag nanowires with p entagonal cross sections%五边形截面的Ag纳米线局域表面等离子体共振模式∗

    Institute of Scientific and Technical Information of China (English)

    徐天宁; 李翔; 贾文旺; 隋成华; 吴惠桢

    2015-01-01

    Ag nanowires have attracted much attention due to their potential applications in spontaneous emission amplifiers, logic gates, single photon sources, and biomolecule detection. Single crystal Ag nanowires are prepared by chemical method. The Ag nanowires exhibit pentagonal cross sections with an average radius of 80 nm. Two enhanced emission peaks (345 and 383 nm) are observed in ZnO quantum dots when mixing with Ag nanowires. To explore the origination of the enhancement, the localized surface plasmon resonance modes of Ag nanowires are investigated theoretically by the finite difference time domain method. The extinction spectrum, electric field distribution and electric field enhancement factor versus excitation wavelength of Ag nanowires are simulated. The results show that the Ag nanowires have two extinction peaks in the ultraviolet region: the 340 nm peak originating from the transverse dipole resonance (DR) and the 375 nm peak belonging to the transverse quadrupole resonance (QR). The same extinction peaks are also observed in the experimental measurement, which are consistent with the emission enhancement peaks of ZnO quantum dots. Compared with that of the DR peak, the red shift of the QR peak becomes more obvious with the increase of Ag nanowire radius. The resonance mode of the extinction peak depends on the cross sectional shape of the Ag nanowire. In the case of the traditional Ag nanowire with circular cross section, DR is excited by long wavelength light while QR is excited by short wavelength light. According to the curves of electric field enhancement factor vs excitation wavelength, the maximum enhanced electric field is observed at the apex of the pentagonal section of Ag nanowire, and the enhancement factor reaches 180 times for excitation wavelength of 377 nm. However, the electric field at the pentagon edge is enhanced only by several times. The simulation results give a reasonable explanation to the emission enhancement in Ag nanowire

  19. Le vernis des apparences

    Directory of Open Access Journals (Sweden)

    Grazia Nicosia

    2010-04-01

    Full Text Available Le but de cet article est de comprendre l’incidence sémiotique du nettoyage d’un tableau ainsi que la résultante cognitive induite sur l’observateur. Cette étude confronte l’analyse des phénomènes visuels engendrés par le jaunissement du vernis et son retrait, à des entretiens réalisés à dessein. Le retrait d’un vernis jauni change considérablement l’image. L’heure, le climat, la saison et l’activité même des personnages s’en trouvent ainsi modifié. La patine peut être perçue, soit comme un obstacle à l’exploration, soit pour ceux qui l’apprécient, comme le medium d’une relation plus intime entre l’œuvre et l’observateur.The purpose of this article is to understand the semiotic impact of the cleaning of a painting and the cognitive effects induced on the observer. This study analyses conjointly the visual phenomenon generated by yellowing varnish and its removal and controlled interviews of observers.The removal of yellowing varnish modifies considerably the perception of the picture. Daytime, climate, season and characters activities are modified. The patina may be perceived either as an obstacle to the painting exploration, or, for those who appreciate it, as a medium for a closer relationship between the painting and the observer.

  20. Dictionnaire des risques psychosociaux

    CERN Document Server

    Zawieja, Philippe

    2014-01-01

    Stress, suicide, harcèlement, épuisement professionnel, workaholism... Au-delà de la souffrance qu'elles désignent, ces notions souvent récentes constituent une approche inédite, et demandent à mieux être comprises, dans leur ensemble et isolément. C'est tout l'enjeu de ce dictionnaire, pionnier en son genre. Le lecteur y trouvera représentés, avec les 314 entrées (rédigées par 251 contributeurs) qui le composent, tous les champs disciplinaires s'intéressant à la souffrance au travail : psychologie du travail et des organisations, psychologie sociale et psychosociologie, psychanalyse, psychopathologie et psychiatrie, ergonomie, sociologie du travail et des organisations, médecine du travail, droit du travail et de la sécurité sociale, sciences de gestion, philosophie... Y sont détaillés les principaux concepts, notions, approches, méthodes, théories, outils, études, etc., ayant cours dans l'étude des risques psychosociaux, mais aussi certaines professions emblématiques (infirmières,...

  1. Grundlagen des Tissue Engineering

    Science.gov (United States)

    Mayer, Jörg; Blum, Janaki; Wintermantel, Erich

    Die Organtransplantation stellt eine verbreitete Therapie dar, um bei krankheitsoder unfallbedingter Schädigung eines Organs die Gesamtheit seiner Funktionen wieder herzustellen, indem es durch ein Spenderorgan ersetzt wird. Organtransplantationen werden für die Leber, die Niere, die Lunge, das Herz oder bei schweren grossflächigen Verbrennungen der Haut vorgenommen. Der grosse apparative, personelle und logistische Aufwand und die Risiken der Transplantationschirurgie (Abstossungsreaktionen) sowie die mangelnde Verfügbarkeit von immunologisch kompatiblen Spenderorganen führen jedoch dazu, dass der Bedarf an Organtransplantaten nur zu einem sehr geringen Teil gedeckt werden kann. Sind Spenderorgane nicht verfügbar, können in einzelnen Fällen lebenswichtige Teilfunktionen, wie beispielsweise die Filtrationsfunktion der Niere durch die Blutreinigung mittels Dialyse ersetzt oder, bei mangelnder Funktion der Bauchspeicheldrüse (Diabetes), durch die Verabreichung von Insulin ein normaler Zustand des Gesamtorganismus auch über Jahre hinweg erhalten werden. Bei der notwendigen lebenslangen Anwendung apparativer oder medikamentöser Therapie können für den Patienten jedoch häufig schwerwiegende, möglicherweise lebensverkürzende Nebenwirkungen entstehen. Daher werden in der Forschung Alternativen gesucht, um die Funktionen des ausgefallenen Organs durch die Implantation von Zellen oder in vitro gezüchteten Geweben möglichst umfassend wieder herzustellen. Dies erfordert biologisch aktive Implantate, welche die für den Stoffwechsel des Organs wichtigen Zellen enthalten und einen organtypischen Stoffwechsel entfalten.

  2. SU-E-T-427: Feasibility Study for Evaluation of IMRT Dose Distribution Using Geant4-Based Automated Algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Choi, H; Shin, W; Testa, M; Min, C [Yonsei University, Wonju (Korea, Republic of); Kim, J [Seoul National University Hospital, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: For intensity-modulated radiation therapy (IMRT) treatment planning validation using Monte Carlo (MC) simulations, a precise and automated procedure is necessary to evaluate the patient dose distribution. The aim of this study is to develop an automated algorithm for IMRT simulations using DICOM files and to evaluate the patient dose based on 4D simulation using the Geant4 MC toolkit. Methods: The head of a clinical linac (Varian Clinac 2300 IX) was modeled in Geant4 along with particular components such as the flattening filter and the multi-leaf collimator (MLC). Patient information and the position of the MLC were imported from the DICOM-RT interface. For each position of the MLC, a step- and-shoot technique was adopted. PDDs and lateral profiles were simulated in a water phantom (50×50×40 cm{sup 3}) and compared to measurement data. We used a lung phantom and MC-dose calculations were compared to the clinical treatment planning used at the Seoul National University Hospital. Results: In order to reproduce the measurement data, we tuned three free parameters: mean and standard deviation of the primary electron beam energy and the beam spot size. These parameters for 6 MV were found to be 5.6 MeV, 0.2378 MeV and 1 mm FWHM respectively. The average dose difference between measurements and simulations was less than 2% for PDDs and radial profiles. The lung phantom study showed fairly good agreement between MC and planning dose despite some unavoidable statistical fluctuation. Conclusion: The current feasibility study using the lung phantom shows the potential for IMRT dose validation using 4D MC simulations using Geant4 tool kits. This research was supported by Korea Institute of Nuclear safety and Development of Measurement Standards for Medical Radiation funded by Korea research Institute of Standards and Science. (KRISS-2015-15011032)

  3. Desarrollos y aplicaciones de GEANT4 para radioterapia y microdosimetría en detectores y circuitos integrados

    OpenAIRE

    Cortes Giraldo, Miguel Antonio

    2011-01-01

    El objetivo general de este proyecto es abrir nuevas líneas de investigación en el Departamento de Física Atómica, Molecular y Nuclear de la Universidad de Sevilla, relacionadas con el estudio del transporte de radiación a través de la materia mediante ... simulaciones Monte Carlo. En esta memoria, se presentan las aplicaciones desarrolladas con el código GEANT4 en diversos campos de investigación.Este documento se divide en cuatro partes. En la primera, se realiza una breve introducción sobr...

  4. Creation of a Geant4 Muon Tomography Package for Imaging of Nuclear Fuel in Dry Cask Storage

    Energy Technology Data Exchange (ETDEWEB)

    Tsoukalas, Lefteri H. [Purdue Univ., West Lafayette, IN (United States)

    2016-03-01

    This is the final report of the NEUP project “Creation of a Geant4 Muon Tomography Package for Imaging of Nuclear Fuel in Dry Cask Storage”, DE-NE0000695. The project started on December 1, 2013 and this report covers the period December 1, 2013 through November 30, 2015. The project was successfully completed and this report provides an overview of the main achievements, results and findings throughout the duration of the project. Additional details can be found in the main body of this report and on the individual Quarterly Reports and associated Deliverables of the project, uploaded in PICS-NE.

  5. Investigation of behavior of scintillator detector of Alborz observatory array using Monte Carlo method with Geant4 code

    Directory of Open Access Journals (Sweden)

    M. Abbasian Motlagh

    2014-04-01

    Full Text Available For their appropriate temporal resolution, scintillator detectors are used in the Alborz observatory. In this work, the behavior of the scintillation detectors for the passage of electrons with different energies and directions were studied using the simulation code GEANT4. Pulse shapes of scintillation light, and such characteristics as the total number of photons, the rise time and the falling time for the optical pulses were computed for the passage of electrons with energies of 10, 100 and 1000 MeV. Variations of the characteristics of optical pulse of scintillation with incident angle and the location of electrons were also investigated

  6. Comparison of the neutron ambient dose equivalent and ambient absorbed dose calculations with different GEANT4 physics lists

    Science.gov (United States)

    Ribeiro, Rosane Moreira; Souza-Santos, Denison

    2017-10-01

    A comparison between neutron physics lists given by GEANT4, is made in the calculation of the ambient dose equivalent, and ambient absorbed dose, per fluence conversion coefficients (H* (10) / ϕ and D* (10) / ϕ) for neutrons in the range of 10-9 MeV to 15 MeV. Physics processes are included for neutrons, photons and charged particles, and calculations are made for neutrons and secondary particles. Results obtained for QBBC, QGSP_BERT, QGSP_BIC and Neutron High Precision physics lists are compared with values published in ICRP 74 and previously published articles. Neutron high precision physics lists showed the best results in the studied energy range.

  7. Desarrollos y aplicaciones de GEANT4 para radioterapia y microdosimetría en detectores y circuitos integrados

    OpenAIRE

    Cortes Giraldo, Miguel Antonio

    2011-01-01

    El objetivo general de este proyecto es abrir nuevas líneas de investigación en el Departamento de Física Atómica, Molecular y Nuclear de la Universidad de Sevilla, relacionadas con el estudio del transporte de radiación a través de la materia mediante ... simulaciones Monte Carlo. En esta memoria, se presentan las aplicaciones desarrolladas con el código GEANT4 en diversos campos de investigación.Este documento se divide en cuatro partes. En la primera, se realiza una breve introducción sobr...

  8. Comparison of experimental proton-induced fluorescence spectra for a selection of thin high-Z samples with Geant4 Monte Carlo simulations

    Energy Technology Data Exchange (ETDEWEB)

    Incerti, S., E-mail: sebastien.incerti@tdt.edu.vn [Division of Nuclear Physics, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Barberet, Ph.; Dévès, G.; Michelet, C. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France); Francis, Z. [Université Saint Joseph, Science Faculty, Department of Physics, Beirut (Lebanon); Ivantchenko, V. [Ecoanalytica, Moscow (Russian Federation); Geant4 Associates International Ltd, Hebden Bridge (United Kingdom); Mantero, A. [SWHARD srl, via Greto di Cornigliano 6r, 16152 Genova (Italy); El Bitar, Z. [Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3, 67037 Strasbourg Cedex (France); Bernal, M.A. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, SP (Brazil); Tran, H.N. [Division of Nuclear Physics, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Karamitros, M.; Seznec, H. [Univ. Bordeaux, CENBG, UMR 5797, F-33170 Gradignan (France); CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan (France)

    2015-09-01

    The general purpose Geant4 Monte Carlo simulation toolkit is able to simulate radiative and non-radiative atomic de-excitation processes such as fluorescence and Auger electron emission, occurring after interaction of incident ionising radiation with target atomic electrons. In this paper, we evaluate the Geant4 modelling capability for the simulation of fluorescence spectra induced by 1.5 MeV proton irradiation of thin high-Z foils (Fe, GdF{sub 3}, Pt, Au) with potential interest for nanotechnologies and life sciences. Simulation results are compared to measurements performed at the Centre d’Etudes Nucléaires de Bordeaux-Gradignan AIFIRA nanobeam line irradiation facility in France. Simulation and experimental conditions are described and the influence of Geant4 electromagnetic physics models is discussed.

  9. Reticulation des fibres lignocellulosiques

    Science.gov (United States)

    Landrevy, Christel

    Pour faire face à la crise économique la conception de papier à valeur ajoutée est développée par les industries papetières. Le but de se projet est l'amélioration des techniques actuelles de réticulation des fibres lignocellulosiques de la pâte à papier visant à produire un papier plus résistant. En effet, lors des réactions de réticulation traditionnelles, de nombreuses liaisons intra-fibres se forment ce qui affecte négativement l'amélioration anticipée des propriétés physiques du papier ou du matériau produit. Pour éviter la formation de ces liaisons intra-fibres, un greffage sur les fibres de groupements ne pouvant pas réagir entre eux est nécessaire. La réticulation des fibres par une réaction de « click chemistry » appelée cycloaddition de Huisgen entre un azide et un alcyne vrai, catalysée par du cuivre (CuAAC) a été l'une des solutions trouvée pour remédier à ce problème. De plus, une adaptation de cette réaction en milieux aqueux pourrait favoriser son utilisation en milieu industriel. L'étude que nous désirons entreprendre lors de ce projet vise à optimiser la réaction de CuAAC et les réactions intermédiaires (propargylation, tosylation et azidation) sur la pâte kraft, en milieu aqueux. Pour cela, les réactions ont été adaptées en milieu aqueux sur la cellulose microcristalline afin de vérifier sa faisabilité, puis transférée à la pâte kraft et l'influence de différents paramètres comme le temps de réaction ou la quantité de réactifs utilisée a été étudiée. Dans un second temps, une étude des différentes propriétés conférées au papier par les réactions a été réalisée à partir d'une série de tests papetiers optiques et physiques. Mots Clés Click chemistry, Huisgen, CuAAC, propargylation, tosylation, azidation, cellulose, pâte kraft, milieu aqueux, papier.

  10. Etude des cas: Gestion alternatîves des conflits

    OpenAIRE

    Lo, H.

    2006-01-01

    Metadata only record Pour mieux consolider les acquis consensuels pour la gestion alternative des conflits, il nous paraît essentiel de maîtriser un certain nombre de facteurs ayant trait au "partage" des gommeraies entre autres: Available in SANREM office, FS

  11. GEANT 4.8.2, 9.2 and 9.4 simulations versus experimental proton energy loss in thick absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Evseev, Ivan; Schelin, Hugo R.; Ahmann, Francielle; Milhoretto, Edney; Paschuk, Sergei A., E-mail: evseev@utfpr.edu.b, E-mail: schelin@utfpr.edu.b, E-mail: sergei@utfpr.edu.b [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Yevseyeva, Olga; Assis, Joaquim T. de; Ievsieieva, Ievgeniia, E-mail: yevseveva@iprj.uerj.b, E-mail: joaquim@iprj.uerj.b [Instituto Politecnico do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Dept. de Modelagem Computacional; Hormaza, Joel M., E-mail: jmesa@ibb.unesp.b [Universidade Estadual Paulista (IBB/UNESP), Botucatu, SP (Brazil). Inst. de Biociencias; Diaz, Katherin S. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Havana (Cuba); Lopes, Ricardo T. [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LIN/COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

    2011-07-01

    Monte Carlo simulations are a powerful tool to estimate the proton energy loss and straggling in medical applications. The physics of proton interaction with matter for thick absorbers (like a human body) has a well-established theory for the so-called Bethe-Bloch domain, and the basic principles of Monte Carlo simulation for such processes are well known since the middle of the past century. However, in spite of GEANT4 has been validated against proton stopping powers from the NIST PSTAR, the evolution of the code leads to some result instability within the various code releases. In this work, we present the recent results for the comparison of our GEANT4 simulations against experimental proton energy loss for some thick absorbers. All the simulations were performed using the GEANT4 Hadrontherapy Advanced Example. The GEANT4 versions 4.8.2, 4.9.2, and 4.9.4 were tested with different simulation parameters, such as varied cut values. In addition to the Standard model, some other models for the electromagnetic processes from the GEANT4 Low Energy Extension Pack were tested as well. Experimental data were taken from for polyethylene, and from for aluminum and gold absorbers. The theoretical predictions for the spectra were calculated using the self-consistent Gaussian solution of the Boltzmann kinetic equation in the Fokker-Plank form. In order to compare the GEANT4 simulations with other popular codes, the same spectra were simulated by TRIM/SRIM2011 and MCNPX2.4.0. The simultaneous comparison of the results obtained for different materials at various initial proton energies were done using the reduced calibration curve approach. (author)

  12. Technical Note: Improvements in GEANT4 energy-loss model and the effect on low-energy electron transport in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Kyriakou, I., E-mail: ikyriak@cc.uoi.gr [Medical Physics Laboratory, University of Ioannina Medical School, Ioannina 45110 (Greece); Incerti, S. [Centre d’Etudes Nucléaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, Université de Bordeaux, Gradignan 33175, France and Centre d’Etudes Nucléaires de Bordeaux-Gradignan, CENBG, Chemin du Solarium, CNRS/IN2P3, Gradignan 33175 (France); Francis, Z. [Department of Physics, Faculty of Sciences, Saint Joseph University, Mkalles, Beirut (Lebanon)

    2015-07-15

    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 binding 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.

  13. The Energy Compensation Study of Geiger -Mueller Tube Based on Geant4%基于Geant4的盖革计数管能量补偿研究

    Institute of Scientific and Technical Information of China (English)

    龚玉巍; 刘明健; 张燕; 贾铭椿; 龚军军

    2011-01-01

    The energy response of Geiger - Mueller (GM) tube to ga mma radiation in wide energy range is mainly researched, and characteristics of energy response are briefly explained in theory. Some factors that influence energy response are analysed in the model of J4403 tube by Geant4. The analysis obtains energy response of compensated tube with various compensation shields, which provides the foundation for energy compensation.%重点研究了盖革计数管对于较宽能量范围的各能量γ射线的响应情况,从理论上简要说明了盖革计数管的能量响应特点,并针对国产的J4403型计数管使用蒙特卡罗软件Geant4分析了实际情况下能量补偿的各个影响因素,得到不同结构参数下计数管的能量响应情况,为计数管的能量补偿提供了依据.

  14. 4He和12C离子Rutherford背散射的Geant4模拟%Geant4-Based Simulation of 4 He and 12C Ions Rutherford Backscattering on Thin Films

    Institute of Scientific and Technical Information of China (English)

    王振超; 马玉刚; 杨海芳; 牛璐莹; 周庆; 赵广义; 宋明珠

    2013-01-01

    The Rutherford backscattering spectra (RBS) of 4 He and 12C normally incident on Au,Ag,Cu thin films at 270 keV and 500 keV were simulated via Geant4.Effects of different materials,thickness and energy of incident ions on RBS were discussed.The characters of 4He,12C RBS were analyzed.It was found that the mass resolution is much better for 12C RBS than that for 4He RBS.%利用Geant4程序模拟270,500 keV 4 He和12C离子垂直入射Au,Ag,Cu薄膜上的Rutherford背散射谱(RBS),并讨论材料、厚度和入射离子能量对背散射谱的影响.结果表明,能量较大的12C离子具有较好的质量分辨率.

  15. Integration of three-dimensional magnetic resonance spectrometry to the irradiation treatment plan for glioblastomas: definition of new target volumes; Integration de la spectrometrie par resonance magnetique tridimensionnelle au plan de traitement par irradiation des glioblastomes: definition de nouveaux volumes cibles

    Energy Technology Data Exchange (ETDEWEB)

    Ken, S.; Vieillevigne, L.; Cohen-Jonathan, E.M.; Laprie, A. [Departement de radiotherapie, institut Claudius-Regaud, 31 - Toulouse (France); Ken, S.; Franceries, X.; Lotterie, J.A.; Lubrano, V.; Catalaa, I.; Celsis, P.; Berry, I.; Laprie, A. [Inserm UMR 825 Imagerie cerebrale et handicaps neurologiques, 31 - Toulouse (France); Lotterie, J.A.; Lubrano, V.; Berry, I. [Departement de biophysique, centre hospitalier universitaire de Rangueil, 31 - Toulouse (France); Catalaa, I. [Departement de radiologie, centre hospitalier universitaire de Purpan, 31 - Toulouse (France)

    2010-10-15

    Based on a clinic trial, the authors report the definition of a new reliable and reproducible method to delimit and integrate targets to the treatment plan which are specific to magnetic resonance spectrometry imagery for the radiotherapy of glioblastomas, in order to perform a treatment by intensity-modulated conformational radiotherapy (IMRT). A weighted conventional MRI has been performed before radiotherapy. The importation of anatomic-metabolic images into the dose planning system comprises two steps: normalization on the whole volume of magnetic resonance spectrometry imagery, and segmentation of target volumes specific to spectrometry anomalies. This integration of target volumes is thus facilitated. Short communication

  16. Assessment of predictive indices for glioblastomas radiation therapy: comparison of perfusion MRI and spectrometric imagery by magnetic resonance; Evaluation d'indices predictifs pour la radiotherapie des glioblastomes: comparaison de l'IRM de perfusion et de l'imagerie de spectrometrie par resonance magnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lemoine, J.M.; Laprie, A.; Moyal Cohen-Jonathan, E.; Ken, S. [Departement de radiotherapie, institut Claudius-Regaud, 31 - Toulouse (France); Lemoine, J.M.; Laprie, A.; Franceries, X.; Lotterie, J.A.; Celsis, P.; Lubrano, V.; Berry, I.; Ken, S. [Inserm, UMR 825, imagerie cerebrale et handicaps neurologiques, 31 - Toulouse (France); Lemoine, J.M.; Franceries, X. [Universite Paul-Sabatier, 31 - Toulouse (France); Lotterie, J.A.; Berry, I. [Departement de biophysique, CHU Rangueil, 31 - Toulouse (France); Lubrano, V. [Departement de neurochirurgie, CHU Rangueil, 31 - Toulouse (France)

    2010-10-15

    The authors report the comparison of several imagery modalities: anatomic imagery (T1-weighted MRI after gadolinium injection and T2-weighted MRI), metabolic imagery (spectrometric imagery by magnetic resonance) and functional imagery (perfusion MRI). This comparison has been performed within the frame of a prospective clinic test associating a radiosensitizer concomitant with a radiation therapy of glioblastomas. It appears that the integration of data of spectrometric imagery by magnetic resonance and of perfusion MRI is a promising method to overcome the resistance of glioblastomas. Short communication

  17. GEANT4 simulation of the ACE beam line : Measurement of the energy distribution of degraded Antiproton beam and the ToF signal of generated pions.

    CERN Document Server

    BRAHIMI, Nihel

    2014-01-01

    The present document describes my 8 weeks work project as a summer student at the AEgIS experiment under the supervision of Michael Doser and what i have learned during this period . It can be devided into three main tasks which are: Theoretical preparations concerning low energy antiproton physics. Learning the basic principles of GEANT4 simu- lation toolkit. Using GEANT4 platform to follow up the work of two technical students (Logan and Conrad) in designing an experiment (ACE beam line ) which aims at improving the methods of detect- ing matter-antimatter annihilations vertices at low energies in terms of resolution and accuracy using hybrid detectors .

  18. Missile Aerodynamics (Aerodynamique des Missiles)

    Science.gov (United States)

    1998-11-01

    guerre froide la production des missiles a baisse’, avec pour consequence une diminution des budgets de d6veloppement. Les nouveaux types de conflits ...Roma) Directeur - Gestion de l’information LUXEMBOURG (Recherche et developpement) - DRDGI 3 Voir Belgique Ministbre de la Difense nationale NORVEGE

  19. Study of the excited {Delta} resonance ways of decay in {sup 4}He and other nuclei with the ({sup 3}He,T) reaction at 2 GeV; Etude des voies de decroissance de la resonance {Delta} excitee dans l`{sup 4}He et d`autres noyaux par la reaction ({sup 3}He,T) a 2 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Tarle-Rousteau, S.

    1995-05-10

    This thesis describes the ({sup 3}He,t) experiment carried out at 2 GeV at the Saturne National Laboratory (CEA Saclay, France) on {sup 1}H, {sup 2}H, {sup 4}He, {sup 12}C and {sup 208}Pb targets. The charged particles (pions and/or protons) from the {Delta} resonance deexcitation are detected in coincidence with triton using the Diogene large angle detector. New informations are obtained on the ways of {Delta} resonance decay in nuclei. Three modes of decay are investigated: the quasi-free decay, the {Delta}N into NN absorption and the coherent pions production. Modifications of {Delta} resonance properties in nuclei with respect to those of free {Delta} are analysed using the experimental results about pions diffusion, photons absorption, charge exchange reaction and {Delta}-hole model conclusions. The quasi-deuteron absorption process on {sup 4}He is studied using a Monte-Carlo simulation. Coherent pions production is also analysed in detail on {sup 4}He and {sup 12}C target nuclei. The process is very sensitive to {Delta}-hole correlations involved in the longitudinal spin canal which shifts the nucleus response in the {Delta} resonance region towards the low transferred energies. (J.S.). 85 refs., 72 figs., 10 tabs., 1 annexe.

  20. First GEANT4-based simulation investigation of a Li-coated resistive plate chamber for low-energy neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, J.T. [Institute for Advanced Physics, Department of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Jamil, M., E-mail: mjamil@konkuk.ac.kr [Institute for Advanced Physics, Department of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Division of International Studies, University College, Konkuk University, Seoul 143-701 (Korea, Republic of); Jeon, Y.J. [LCD Research Lab, Department of Chemistry, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2013-08-01

    A simulation study of the performance of a single-gap resistive plate chamber coated with Li-layer for the detection of low energy neutrons was performed by means of GEANT4 Monte Carlo code. Low energy neutrons were detected via {sup 7}Li(n, α) {sup 3}He nuclear reaction. To make the detector sensitive to low energy neutrons, Li- coating was employed both on the forward and backward electrodes of the converter. Low energy neutrons were transported onto the Li-coating RPC by GEANT4 MC code. A detector with converter area of 5×5 cm{sup 2} was utilized for this work. The detection response was evaluated as a function of incident low energy neutrons in the range of 25 MeV–100 MeV. The evaluated results predicted higher detection response for the backward-coated converter detector than that of forward coated converter RPC setup. This type of detector can be useful for the detection of low energy neutrons.

  1. Commissioning of a Geant4 based treatment plan simulation tool: linac model and dicom-rt interface

    CERN Document Server

    Cornelius, Iwan; Middlebrook, Nigel; Poole, Christopher; Oborn, Brad; Langton, Christian

    2011-01-01

    A Geant4 based simulation tool has been developed to perform Monte Carlo modelling of a 6 MV VarianTM iX clinac. The computer aided design interface of Geant4 was used to accurately model the LINAC components, including the Millenium multi-leaf collimators (MLCs). The simulation tool was verified via simulation of standard commissioning dosimetry data acquired with an ionisation chamber in a water phantom. Verification of the MLC model was achieved by simulation of leaf leakage measurements performed using GafchromicTM film in a solid water phantom. An absolute dose calibration capability was added by including a virtual monitor chamber into the simulation. Furthermore, a DICOM-RT interface was integrated with the application to allow the simulation of treatment plans in radiotherapy. The ability of the simulation tool to accurately model leaf movements and doses at each control point was verified by simulation of a widely used intensity-modulated radiation therapy (IMRT) quality assurance (QA) technique, the...

  2. Inhomogeneity effect in Varian Trilogy Clinac iX 10 MV photon beam using EGSnrc and Geant4 code system

    Science.gov (United States)

    Yani, S.; Rhani, M. F.; Haryanto, F.; Arif, I.

    2016-08-01

    Treatment fields consist of tissue other than water equivalent tissue (soft tissue, bones, lungs, etc.). The inhomogeneity effect can be investigated by Monte Carlo (MC) simulation. MC simulation of the radiation transport in an absorbing medium is the most accurate method for dose calculation in radiotherapy. The aim of this work is to evaluate the effect of inhomogeneity phantom on dose calculations in photon beam radiotherapy obtained by different MC codes. MC code system EGSnrc and Geant4 was used in this study. Inhomogeneity phantom dimension is 39.5 × 30.5 × 30 cm3 and made of 4 material slices (12.5 cm water, 10 cm aluminium, 5 cm lung and 12.5 cm water). Simulations were performed for field size 4 × 4 cm2 at SSD 100 cm. The spectrum distribution Varian Trilogy Clinac iX 10 MV was used. Percent depth dose (PDD) and dose profile was investigated in this research. The effects of inhomogeneities on radiation dose distributions depend on the amount, density and atomic number of the inhomogeneity, as well as on the quality of the photon beam. Good agreement between dose distribution from EGSnrc and Geant4 code system in inhomogeneity phantom was observed, with dose differences around 5% and 7% for depth doses and dose profiles.

  3. Simulation and Digitization of a Gas Electron Multiplier Detector Using Geant4 and an Object-Oriented Digitization Program

    Science.gov (United States)

    McMullen, Timothy; Liyanage, Nilanga; Xiong, Weizhi; Zhao, Zhiwen

    2017-01-01

    Our research has focused on simulating the response of a Gas Electron Multiplier (GEM) detector using computational methods. GEM detectors provide a cost effective solution for radiation detection in high rate environments. A detailed simulation of GEM detector response to radiation is essential for the successful adaption of these detectors to different applications. Using Geant4 Monte Carlo (GEMC), a wrapper around Geant4 which has been successfully used to simulate the Solenoidal Large Intensity Device (SoLID) at Jefferson Lab, we are developing a simulation of a GEM chamber similar to the detectors currently used in our lab. We are also refining an object-oriented digitization program, which translates energy deposition information from GEMC into electronic readout which resembles the readout from our physical detectors. We have run the simulation with beta particles produced by the simulated decay of a 90Sr source, as well as with a simulated bremsstrahlung spectrum. Comparing the simulation data with real GEM data taken under similar conditions is used to refine the simulation parameters. Comparisons between results from the simulations and results from detector tests will be presented.

  4. Beta-efficiency of a typical gas-flow ionization chamber using GEANT4 Monte Carlo simulations

    Directory of Open Access Journals (Sweden)

    Hussain Abid

    2011-01-01

    Full Text Available GEANT4 based Monte Carlo simulations have been carried out for the determination of efficiency and conversion factors of a gas-flow ionization chamber for beta particles emitted by 86 different radioisotopes covering the average-b energy range of 5.69 keV-2.061 MeV. Good agreements were found between the GEANT4 predicted values and corresponding experimental data, as well as with EGS4 based calculations. For the reported set of b-emitters, the values of the conversion factor have been established in the range of 0.5×1013-2.5×1013 Bqcm-3/A. The computed xenon-to-air conversion factor ratios have attained the minimum value of 0.2 in the range of 0.1-1 MeV. As the radius and/or volume of the ion chamber increases, conversion factors approach a flat energy response. These simulations show a small, but significant dependence of ionization efficiency on the type of wall material.

  5. Microdosimetry of alpha particles for simple and 3D voxelised geometries using MCNPX and Geant4 Monte Carlo codes.

    Science.gov (United States)

    Elbast, M; Saudo, A; Franck, D; Petitot, F; Desbrée, A

    2012-07-01

    Microdosimetry using Monte Carlo simulation is a suitable technique to describe the stochastic nature of energy deposition by alpha particle at cellular level. Because of its short range, the energy imparted by this particle to the targets is highly non-uniform. Thus, to achieve accurate dosimetric results, the modelling of the geometry should be as realistic as possible. The objectives of the present study were to validate the use of the MCNPX and Geant4 Monte Carlo codes for microdosimetric studies using simple and three-dimensional voxelised geometry and to study their limit of validity in this last case. To that aim, the specific energy (z) deposited in the cell nucleus, the single-hit density of specific energy f(1)(z) and the mean-specific energy were calculated. Results show a good agreement when compared with the literature using simple geometry. The maximum percentage difference found is MCNPX for calculation time is 10 times higher with Geant4 than MCNPX code in the same conditions.

  6. Validation of nuclear models in Geant4 using the halo of a proton pencil beam stopping in water

    CERN Document Server

    Hall, David C; Paganetti, Harald; Gottschalk, Bernard

    2015-01-01

    A proton pencil beam is associated with a surrounding low-dose envelope, originating from nuclear interactions. It is important for treatment planning systems to accurately model this envelope when performing dose calculations for pencil beam scanning treatments, and Monte Carlo (MC) codes are commonly used for this purpose. This work aims to validate the nuclear models employed by the Geant4 MC code, by comparing the simulated absolute dose distribution to a recent experiment of a 177 MeV proton pencil beam stopping in water. Impressive agreement is observed over five orders of magnitude, with both the shape and normalisation well modelled. The normalisations of two depth dose curves are lower than experiment, though this could be explained by an experimental positioning error. The Geant4 neutron production model is also verified in the distal region. The entrance dose is poorly modelled, suggesting an unaccounted upstream source of low-energy protons. Recommendations are given for a follow-up experiment whi...

  7. Reconstruction and identification of muons in the experiment DO, study of the resonant production of s-leptons; Reconstruction et identification des muons dans l'experience DO etude de la production resonnante de s-leptons

    Energy Technology Data Exchange (ETDEWEB)

    Deliot, F

    2002-04-01

    In the framework of supersymmetric models with R-parity violation, supersymmetric particles can be singly produced. If the {lambda}'{sub 211} coupling is the dominant one, muon s-neutrino or a s-muon can be resonantly produced at the Tevatron and lead to tri-lepton (with two muons) or like sign dimuon final states. In this thesis, the discovery potential for these signals at Tevatron Run II has been studied in the framework of the minimal supergravity model. Those processes reach a high sensitivity on the model parameters m{sub 0} and m{sub 1/2} and allow to reconstruct the masses for the superparticles involved in the decay chain. Tevatron Run II has begun in 2001 after important upgrades in the accelerator complex and in the D0 experiment. In particular the muon spectrometer has been modified. The D0 experiment is in the calibration and alignment phase. The second part of the work presented in this thesis covers the muon reconstruction and identification. The track reconstruction in the muon spectrometer is performed with a fit taking into account magnetic field, energy loss and multiple scattering in the iron toroid. This method gives a momentum resolution limited for low momentum tracks at 20% due to multiple scattering in the toroid. These tracks and its error matrix are then propagated through the calorimeter and combined with the inner tracker tracks. The first Run II data recorded by D0 has allowed to compute the trigger efficiency and to valid the muon identification algorithms which were, for this thesis, entirely based on muon spectrometer informations. The first J/{psi} studies show that the reconstruction works correctly and that the identification criteria are preferment. (author)

  8. Application of the laser induced fluorescence to the investigation of highly magnetized plasmas, heated by ion cyclotron resonance; Fluorescence induite par laser sur des plasmas fortement magnetises, chauffes par resonnance cyclotron ionique

    Energy Technology Data Exchange (ETDEWEB)

    Pailloux, A. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes d`Enrichissement]|[Universite Louis Pasteur, 67 - Strasbourg (France)

    1997-12-31

    This work has been achieved in the frame of isotopic separation studies by in cyclotron resonance. For this purpose, in a highly magnetized (2 to 3 Tesla) and non-collisional (10{sup 12} ions/cm{sup 3}) plasma, composed of metallic ions, a wave near the ion cyclotron frequency is thrown in order to heat selectively a given species. A laser induced fluorescence (LIP) has been developed on barium and gadolinium plasmas. The Larmor gyration of ions greatly modifies the interaction, which has been modelled through the time-dependent Schroedinger equation. The obtained excitation probably has been integrated over all the ions excited in the measurement volume in order to check that the LIF still leads to the distribution function of ion velocities. The influence of the Larmor motion of ions on the spectral distribution of LIF has been derived both theoretically and experimentally. The LIF diagnostics has been achieved with a dye O`ring laser. The barium ion has been excited on the transition 6142 angstrom, using rhodamine 6G dye, and the gadolinium ion on the pseudo-triplet 3861 angstrom, using exalite dye. Data treatment has been developed taking into account the Zeeman effect and the different heating of isotopes. The ionic temperature (from 1 eV to some hundreds eV) has been measured as a function of radiofrequency heating. Our experimental results are in good agreement with the selective heating theory. Also, the ion velocity distribution function has been found locally Maxwellian. And the behaviour of the plasma has been studied as a function of control parameters of the plasma source. (author) 62 refs.

  9. Therapie des Status epilepticus

    Directory of Open Access Journals (Sweden)

    Trinka E

    2009-01-01

    Full Text Available Der Status epilepticus (SE ist nach dem Schlaganfall der häufigste neurologische Notfall. Er stellt als generaliserter konvulsiver SE (GKSE die schwerste Ausprägung eines epileptischen Anfalls dar, der mit einer signifikanten Morbidität und einer ca. 20%igen Letalität verbunden ist. Nur bei der Hälfte der Patienten mit SE besteht zuvor eine Epilepsie; die meisten Fälle sind symptomatisch, wobei Schädel- Hirn-Traumata, zerebrovaskuläre Erkrankungen, ZNS-Infektionen und metabolische Ursachen führend sind. Bei Patienten mit vorbestehender Epilepsie lässt sich eine frühe Phase des GKSE erkennen, in der die Anfälle crescendoartig zunehmen, bis sie in kontinuierliche Anfallsaktivität münden (etablierte Phase. Das Management eines GKSE verlangt rasches und beherztes Vorgehen. Neben der sofort einzuleitenden Therapie muss gleichzeitig die artdiagnostische Zuordnung des SE und die Ursache erkannt und behandelt werden. Als Therapie der ersten Wahl sind Benzodiazepine etabliert, wobei intravenösem (i.v. Lorazepam gegenüber Diazepam der Vorzug zu geben ist. Versagt die Therapie mit Benzodiazepinen, muss rasch und konsequent nach einem Stufenschema vorgegangen werden. Phenytoin/Fosphenytoin, Valproinsäure, Levetiracetam und Lacosamid sind als i.v. Formulierung erhältliche Antiepileptika. Obwohl Vergleichsstudien hier fehlen, wird Phenytoin bevorzugt. Valproat und Levetiracetam sind nicht sedierend und kardiovaskulär gut verträglich, sodass hier Alternativen zu Phenytoin vorhanden sind. Lacosamid ist eine neue Therapieoption, deren Stellenwert erst bestimmt werden muss. Versagt auch die zweite Therapiestufe, so muss der Patient intubiert und in Allgemeinanästhesie intensivmedizinisch behandelt werden. Dafür stehen Thiopental, Propofol oder hoch dosiertes Midazolam zu Verfügung. Durch den eklatanten Mangel an randomisierten Studien bleibt die Therapie des GKSE empirisch und durch den Off-label-Einsatz gekennzeichnet.

  10. Mécanique des fluides

    CERN Document Server

    Cengel, Y A

    2017-01-01

    La mécanique des fluides est un outil performant qui permet d'expliquer les phénomènes qui nous entourent de l'échelle microscopique à l'échelle macroscopique. Elle est aussi à la base du développement de nombreuses technologies. Cet ouvrage à destination des étudiants donne une vision complète de la mécanique des fluides. Bien que la mécanique des fluides puisse souvent paraître rébarbative aux yeux des étudiants, cet ouvrage valorise ce domaine d'enseignement en l'illustrant de nombreux exemples issus de l'ingénierie navale, l'aéronautique, la météorologie, etc.

  11. Does the individual adaption of standardized speech paradigmas for clinical functional Magnetic Resonance Imaging (fMRI) effect the localization of the language-dominant hemisphere and of Broca's and Wernicke's areas; Beeinflusst die individuelle Anpassung standardisierter Sprachparadigmen fuer die klinische funktionelle Magnetresonanztomographie (fMRT) die Lokalisation der sprachdominanten Hemisphaere, des Broca- und des Wernicke-Sprachzentrums?

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, F.; Nennig, E.; Kress, B.; Sartor, K.; Stippich, C. [Abteilung Neuroradiologie, Neurologische Klinik, Universitaetsklinikum Heidelberg (Germany); Ochmann, H. [Neurochirurgische Klinik, Universitaetsklinikum Heidelberg (Germany)

    2005-03-01

    Purpose: Functional magnetic resonance imaging (fMRI) localizes Broca's area (B) and Wernicke's area (W) and the hemisphere dominant for language. In clinical fMRI, adapting the stimulation paradigms to each patient's individual cognitive capacity is crucial for diagnostic success. To interpret clinical fMRI findings correctly, we studied the effect of varying frequency and number of stimuli on functional localization, determination of language dominance and BOLD signals. Materials and Methods: Ten volunteers (VP) were investigated at 1.5 Tesla during visually triggered sentence generation using a standardized block design. In four different measurements, the stimuli were presented to each VP with frequencies of (1/1)s, (1/2)s,(1/3)s and (1/6)s. Results: The functional localizations and the correlations of the measured BOLD signals to the applied hemodynamic reference function (r) were almost independent from frequency and number of the stimuli in both hemispheres, whereas the relative BOLD signal changes ({delta}S) in B and W increased with the stimulation rate, which also changed the lateralization indices. The strongest BOLD activations were achieved with the highest stimulation rate or with the maximum language production task, respectively. Conclusion: The adaptation of language paradigms necessary in clinical fMRI does not alter the functional localizations but changes the BOLD signals and language lateralization which should not be attributed to the underlying brain pathology. (orig.)

  12. Molekulare Formen des PSA in der Diagnostik des Prostatakarzinoms

    Directory of Open Access Journals (Sweden)

    Lein M

    2003-01-01

    Full Text Available Das prostataspezifische Antigen ist die wichtigste Kenngröße in der Diagnostik und Therapieüberwachung des Prostatakarzinoms. Zur besseren Abgrenzung zwischen Männern mit und ohne Prostatakarzinom, aber auch zur Früherkennung, haben sich die molekularen Formen des PSA als wertvolle Entscheidungshilfen erwiesen. Es wird eine Übersicht über bisher vorliegende Informationen zur Aussagekraft des freien PSA, des an alpha 1-Antichymotrypsin gebundenen PSA und des komplexierten PSA (cPSA zusammen mit eigenen Resultaten gegeben. Der Quotient aus freiem und Gesamt-PSA hat sich als eine wichtige Entscheidungsgröße in der urologischen Praxis etabliert, mit der Sensitivität und Spezifität der Prostatakarzinomdiagnostik verbessert werden. Die Zahl von Prostatastanzbiopsien im Gesamt-PSA-Bereich von 4–10 ng/ml kann damit reduziert werden. Ein diagnostischer Vorteil der alleinigen Bestimmung des komplexierten PSA bzw. der entsprechenden Quotienten im Vergleich zum Gesamt-PSA und des Quotienten freies PSA zu Gesamt-PSA konnte bisher nicht sicher nachgewiesen werden.

  13. Pancreatic neuroendocrine neoplasms; Neuroendokrine Neoplasien des Pankreas

    Energy Technology Data Exchange (ETDEWEB)

    Beiderwellen, K.; Lauenstein, T.C. [Universitaetsklinikum Essen, Institut fuer Diagnostische und Interventionelle Radiologie und Neuroradiologie, Essen (Germany); Sabet, A.; Poeppel, T.D. [Universitaetsklinikum Essen, Klinik fuer Nuklearmedizin, Essen (Germany); Lahner, H. [Universitaetsklinikum Essen, Klinik fuer Endokrinologie und Stoffwechselerkrankungen, Essen (Germany)

    2016-04-15

    Pancreatic neuroendocrine neoplasms (NEN) account for 1-2 % of all pancreatic neoplasms and represent a rare differential diagnosis. While some pancreatic NEN are hormonally active and exhibit endocrine activity associated with characteristic symptoms, the majority are hormonally inactive. Imaging techniques such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) or as combined PET/CT play a crucial role in the initial diagnosis, therapy planning and control. Endoscopic ultrasound (EUS) and multiphase CT represent the reference methods for localization of the primary pancreatic tumor. Particularly in the evaluation of small liver lesions MRI is the method of choice. Somatostatin receptor scintigraphy and somatostatin receptor PET/CT are of particular value for whole body staging and special aspects of further therapy planning. (orig.) [German] Neuroendokrine Neoplasien (NEN) des Pankreas stellen mit einem Anteil von 1-2 % aller pankreatischen Tumoren eine seltene Differenzialdiagnose dar. Ein Teil der Tumoren ist hormonell aktiv und faellt klinisch durch charakteristische Symptome auf, wohingegen der ueberwiegende Anteil hormonell inaktiv ist. Bildgebende Verfahren wie Sonographie, Computertomographie (CT), Magnetresonanztomographie (MRT) und nicht zuletzt Positronenemissionstomographie (PET oder kombiniert als PET/CT) spielen eine zentrale Rolle fuer Erstdiagnose, Therapieplanung und -kontrolle. Die Endosonographie und die multiphasische CT stellen die Referenzmethoden zur Lokalisation des Primaertumors dar. Fuer die Differenzierung insbesondere kleiner Leberlaesionen bietet die MRT die hoechste Aussagekraft. Fuer das Ganzkoerperstaging und bestimmte Aspekte der Therapieplanung lassen sich die Somatostatinrezeptorszintigraphie und v. a. die Somatostatinrezeptor-PET/CT heranziehen. (orig.)

  14. Mécanique des sols et des roches

    CERN Document Server

    Vullier, Laurent; Zhao, Jian

    2016-01-01

    La mécanique des sols et la mécanique des roches sont des disciplines généralement traitées séparément dans la littérature. Pour la première fois, un traité réunit ces deux spécialités, en intégrant également les connaissances en lien avec les écoulements souterrains et les transferts thermiques. A la fois théorique et pratique, cet ouvrage propose tout d'abord une description détaillée de la nature et de la composition des sols et des roches, puis s'attache à la modélisation de problèmes aux conditions limites et présente les essais permettant de caractériser les sols et les roches, tant d'un point de vue mécanique qu'hydraulique et thermique. La problématique des sols non saturés et des écoulements multiphasiques est également abordée. Une attention particulière est portée aux lois de comportement mécanique et à la détermination de leurs paramètres par des essais in situ et en laboratoire, et l'ouvrage offre également une présentation détaillée des systèmes de classi...

  15. Le silence des agneaux

    Directory of Open Access Journals (Sweden)

    BERNARD ROY

    2012-01-01

    Full Text Available Ce texte est avant tout une réflexion sur la notion d'obéissance, initiée à partir de deux évènements impliquant étroitement des membres de la profession infirmière. L'auteur se réjouit de la prise de parole et de l'implication directe d'infirmières dans le contexte du printemps érable. Il estime que la posture de ces infirmières s'inscrit dans ce que l'éthicien Guy Durand, appelle une obéissance autonome qui peut, du coup, mener à la désobéissance civile, à l'objection de conscience. En prenant exemple sur le silence des infirmières dans le contexte de la fermeture de postes d'infirmières en Minganie, l'auteur estime que cette posture est marginale chez les infirmières qui, majoritairement, adoptent une position de soumission et d'obéissance hétéronome.

  16. La médicalisation des humeurs des enfants

    OpenAIRE

    Monzée, Joël

    2015-01-01

    Les enfants qui ont des comportements dérangeants ou qui souffrent de problèmes neurologiques, comme le trouble déficitaire de l’attention avec ou sans hyperactivité (TDAH), remettent en question nos moyens d’intervention pour les aider. Alors que le contexte européen tend à privilégier une intervention psychoéducative, les milieux nord-américains recourent davantage aux psychostimulants pour réduire les effets des problèmes comportementaux des enfants. Cet article aborde quelques problématiq...

  17. Analysis methods of neutrons induced resonances in the transmission experiments by time-of-flight and automation of these methods on IBM 7094 II computer; Methode d'analyse des resonances induites par les neutrons dans les experiences de transmission par temps-de-vol et automatisation de ces methodes sur ordinateur IBM-7094 II

    Energy Technology Data Exchange (ETDEWEB)

    Corge, C

    1967-07-01

    The neutron induced resonances analysis aims to determine the neutrons characteristics, leading to the excitation energies, de-excitation probabilities by gamma radiation emission, by neutron emission or by fission, their spin, their parity... This document describes the methods developed, or adapted, the calculation schemes and the algorithms implemented to realize such analysis on a computer, from data obtained during time-of-flight experiments on the linear accelerator of Saclay. (A.L.B.)

  18. The promises of fuel cells seduce the electronics manufacturers; Les promesses des piles a combustible seduisent les geants de l'electronique

    Energy Technology Data Exchange (ETDEWEB)

    Chalmet, E.; Maridet, R.

    2001-07-01

    The cell using the hydrogen seems to be an attractive alternative energy source. Useful for the portable telephones, the automobiles or in the houses, it may cover a market of 60 milliards of dollars in 2010. (A.L.B.)

  19. Background neutron in the endcap and barrel regions of resistive plate chamber for compact muon solenoid/large hadron collider using GEANT4

    Indian Academy of Sciences (India)

    J T Rhee; M Jamil; Christopher Joen; Bingzhu Yin; Y J Jeon

    2007-09-01

    In this study the performance of double gap RPC has been tested by GEANT4 Monte Carlo simulation code. The detector response calculations taken as a function of the neutron energy in the range of 0.01 eV–1 GeV have been simulated through RPC set-up. In order to evaluate the response of detector in the LHC background environment, the neutron spectrum expected in the CMS muon endcap and barrel region were taken into account. A hit rate of about 165.5 Hz cm-2, 34 Hz cm-2, 33.6 Hz cm-2, and 27.0 Hz cm-2 due to an isotropic neutron source is calculated using GEANT4 standard electromagnetic package for a 20 × 20 cm2 RPC in the ME1, ME2, ME3 and ME4, respectively. While for the same neutron source and using GEANT4 package a hit rate of about 0.42 Hz cm-2, 0.7182 Hz cm-2 was measured for the MB1 and MB4 stations respectively. Similar characteristics of hit rates have been observed for GEANT4 low electromagnetic package.

  20. Transport de paires EPR dans des structures mesoscopiques

    Science.gov (United States)

    Dupont, Emilie

    Dans cette these, nous nous sommes particulierement interesses a la propagation de paires EPR1 delocalisees et localisees, et a l'influence d'un supraconducteur sur le transport de ces paires. Apres une introduction de cette etude, ainsi que du cadre scientifique qu'est l'informatique quantique dans lequel elle s'inscrit, nous allons dans le chapitre 1 faire un rappel sur le systeme constitue de deux points quantiques normaux entoures de deux fils supraconducteurs. Cela nous permettra d'introduire une methode de calcul qui sera reutilisee par la suite, et de trouver egalement le courant Josephson produit par ce systeme transforme en SQUID-dc par l'ajout d'une jonction auxiliaire. Le SQUID permet de mesurer l'etat de spin (singulet ou triplet), et peut etre forme a partir d'autres systemes que nous etudierons ensuite. Dans le chapitre 2, nous rappellerons l'etude detaillee d'un intricateur d'Andreev faite par un groupe de Bale. La matrice T, permettant d'obtenir le courant dans les cas ou les electrons sont separes spatialement ou non, sera etudiee en detail afin d'en faire usage au chapitre suivant. Le chapitre 3 est consacre a l'etude de l'influence du bruit sur le fonctionnement de l'intricateur d'Andreev. Ce bruit modifie la forme du courant jusqu'a aboutir a d'autres conditions de fonctionnement de l'intricateur. En effet, le bruit present sur les points quantiques peut perturber le transport des paires EPR par l'intermediaire des degres de liberte. Nous montrerons que, du fait de l'"intrication" entre la charge de la paire et le bruit, la paire est detruite pour des temps longs. Cependant, le resultat le plus important sera que le bruit perturbe plus le transport des paires delocalisees, qui implique une resonance de Breit-Wigner a deux particules. Le transport parasite n'implique pour sa part qu'une resonance de Breit-Wigner a une particule. Dans le chapitre 4, nous reviendrons au systeme constitue de deux points quantiques entoures de deux fils

  1. Habilitations à diriger des recherches

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available Pierre Corbin, Avec des dictionnaires pour compagnons.Habilitation à diriger des recherches soutenue le 24 novembre 2006.Composition du juryHenri Béjoint (Lyon 2Franz Josef Hausmann (Erlangen-NürnbergBenoît Habert (Paris 10Pierre Rézeau (CNRSMichel Roché (Toulouse 2Danièle Van de Velde (Lille 3, UMR STL, Directrice d'habilitation.Philippe Sabot, La philosophie, entre pratiques de lecture et pratiques d'écritureHabilitation à diriger des recherches soutenue le 24 novembre 2006.Compositio...

  2. Des cartes dans la classe…

    Directory of Open Access Journals (Sweden)

    R. Gimeno

    1990-09-01

    Full Text Available La majorité des enseignants qui veulent faire des cartes — et les faire réaliser aux élèves — pour répondre aux exigences des instructions officielles, doivent surmonter leur manque de compétences en cartographie et en didactique ainsi que les difficultés propres aux logiciels de cartographie encore peu performants. Ces compétences et la réflexion qui les accompagne sont pourtant accessibles aux enfants de l’école élémentaire…

  3. Wider die Verherrlichung des Weiblichen : Kritik des Ökofeminismus

    OpenAIRE

    Attia, Iman

    1991-01-01

    Die Studie ist eine Kritik am Frauen- und Gesellschaftsbild des Ökofeminismus. Nach der Darstellung wesentlicher theoretischer Kategorien des Ökofeminismus, die sich zentrieren im Ideal der Hausarbeit als wichtigste Form von Subsistenzarbeit, stellt die Autorin zusammenfassend fest, daß der Ökofeminismus die gesellschaftlichen Unterschiede und historischen Veränderungen ignoriert, indem er den Weiblichkeitsbegriff aus der Gebärfähigkeit ableitet. Jede Ausbeutungsform wird reduziert auf biolog...

  4. γ全吸收型探测装置中子束流监视器的Geant4模拟%Geant4 Simulation of Neutron Beam Monitor in Gamma-Ray Total Absorption Facility

    Institute of Scientific and Technical Information of China (English)

    苏明; 仲启平; 郑玉来; 张奇玮; 阮锡超; 周祖英; 孔祥忠

    2009-01-01

    The relative detection efficiency of a lithium glass detector used as a neutron beam monitor in gamma-ray total absorption facility was simulated by Geant4. The neutron detection efficiency of the lithium glass detector was obtained between 10 keV and 1 MeV. Some factors affecting the efficiency were analyzed. The effect of the time delay caused by the elastic scattering upon TOF (time-of-flight) measurement, and the n-γ discrimination in different thickness lithium glass were discussed. The work will be helpful to understand better the neutron time of flight spectrum and energy spectrum from Li-glass detector which is used as a monitor of keV neutron source.%利用Geant4模拟了γ全吸收型探测装置中用于中子束流监视的锂玻璃探测器的相对探测效率,给出了锂玻璃探测器在10 keV~1 MeV区间的中子探测效率,并对影响探测效率的相关因素进行了分析,讨论了弹性散射引起的时间滞后对TOF(time-of-flight)测量的影响和不同厚度锂玻璃探测器的n-γ分辨效果.在未来使用锂玻璃探测器作为keV中子源监视器时,这项工作将为更好地理解相关中子飞行时间谱和能谱提供依据.

  5. Behaviors of the percentage depth dose curves along the beam axis of a phantom filled with different clinical PTO objects, a Monte Carlo Geant4 study

    Science.gov (United States)

    EL Bakkali, Jaafar; EL Bardouni, Tarek; Safavi, Seyedmostafa; Mohammed, Maged; Saeed, Mroan

    2016-08-01

    The aim of this work is to assess the capabilities of Monte Carlo Geant4 code to reproduce the real percentage depth dose (PDD) curves generated in phantoms which mimic three important clinical treatment situations that include lung slab, bone slab, bone-lung slab geometries. It is hoped that this work will lead us to a better understanding of dose distributions in an inhomogeneous medium, and to identify any limitations of dose calculation algorithm implemented in the Geant4 code. For this purpose, the PDD dosimetric functions associated to the three clinical situations described above, were compared to one produced in a homogeneous water phantom. Our results show, firstly, that the Geant4 simulation shows potential mistakes on the shape of the calculated PDD curve of the first physical test object (PTO), and it is obviously not able to successfully predict dose values in regions near to the boundaries between two different materials. This is, surely due to the electron transport algorithm and it is well-known as the artifacts at interface phenomenon. To deal with this issue, we have added and optimized the StepMax parameter to the dose calculation program; consequently the artifacts due to the electron transport were quasi disappeared. However, the Geant4 simulation becomes painfully slow when we attempt to completely resolve the electron artifact problems by considering a smaller value of an electron StepMax parameter. After electron transport optimization, our results demonstrate the medium-level capabilities of the Geant4 code to modeling dose distribution in clinical PTO objects.

  6. La fabrique des extraterrestres

    OpenAIRE

    Poulain, Sébastien

    2012-01-01

    Grâce à différentes stratégies discursives et médiatiques, Radio Ici et Maintenant joue un rôle dans la fabrication de la rumeur de l’existence des extraterrestres. Cette rumeur, teintée de complot, doit servir à légitimer l’utopie messianique et millénariste de cette radio New Age qui dispose de 5 000 auditeurs au quotidien. Cette radio prophétique et thérapeutique participe donc, jusqu’à un certain degré, au renouvellement de l’espace du politico-religieux. Thanks to various media and di...

  7. Therapie des Harnwegsinfekts

    Directory of Open Access Journals (Sweden)

    Stoiser B

    2010-01-01

    Full Text Available Harnwegsinfektionen gehören zu den häufigsten entzündlichen Erkrankungen im niedergelassenen Bereich. Eine intelligente Therapiestrategie stellt damit nicht nur eine klinische Herausforderung dar, sondern ermöglicht rasche Heilung, Vermeidung von Resistenzbildungen sowie oft unnötiger, teurer diagnostischer Schritte. Der erste entscheidende Schritt ist die genaue Klassifizierung des Harnweginfektes – asymptomatische Bakteriurie bis zur komplizierten Pyelonephritis. Hier entscheiden sich bereits Aggressivität der Behandlung sowie diagnostischer Aufwand. Für die Entwicklung einer empirischen antimikrobiellen Therapie ist die Kenntnis der häufigsten Erreger sowie lokaler Resistenzmuster wichtig. Bei gezieltem Vorgehen können die meisten Harnwegsinfekte ohne erhöhten diagnostischen Aufwand therapiert werden.

  8. LA TRADUCTION DES PREPOSITIONS

    Directory of Open Access Journals (Sweden)

    Samira MOUTAKIL

    2013-05-01

    Full Text Available L’idée de cet article nous est venue d’un cours qu’on assure pour les futurs guides touristiques en Jordanie. En traduisant des textes - français-arabe ou arabe-français, les étudiants se heurtent à certains problèmes pour rendre le texte vers la langue cible et qui soit convenable syntaxiquement et sémantiquement. On a remarqué donc que la traduction des prépositions vers l’une ou l’autre langue présente un dilemme pour les apprenants. On a décidé de composer un corpus de phrases contenant les propositions en français, « à » avec toutes ses formes, « dans et sur » et de l'arabe "على", "في" . Dans un premier temps, on a constitué le corpus avec 25 phrases dans les deux langues et on les a soumises aux étudiants, la liste en français aux étudiants du niveau A2 et la liste ne arabe aux étudiants du niveau A1. Par la suite, on a dégagé ce qui ressort de leurs traductions ce qui nous a permis de faire une analyse sémantico-syntaxique assez détaillée. En conclusion de cet article, on présente les résultats de cette expérience très intéressante.

  9. Photothermal resonance

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates to an ap......The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates...... to an apparatus for detecting photo-thermal absorbance of a sample....

  10. Marais Des Cygnes Wildlife Area

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This brochure is for the Marais des Cygnes Wildlife Area, managed by Kansas Department of Wildlife, Parks and Tourism, and located in the floodplain of the Marais...

  11. Digitalisierung des Kulturellen Erbes (Europas)

    NARCIS (Netherlands)

    Gruber, Marion

    2011-01-01

    Gruber, M. R. (2011, 13 December). Digitalisierung des Kulturellen Erbes (Europas). Guest lecture at the IPMZ - Institute of Mass Communication and Media Research, Devision Media Change & Innovation, University of Zurich, Switzerland.

  12. Monte Carlo Simulation of Electron Beams for Radiotherapy - EGS4, MCNP4b and GEANT3 Intercomparison

    CERN Document Server

    Trindade, A; Alves, C M; Chaves, A; Lopes, C; Oliveira, C; Peralta, L

    2000-01-01

    In medical radiation physics, an increasing number of Monte Carlo codes are being used, which requires intercomparison between them to evaluated the accuracy of the simulated results against benchmark experiments. The Monte Carlo code EGS4, commonly used to simulate electron beams from medical linear accelerators, was compared with GEANT3 and MCNP4b. Intercomparison of electron energy spectra, angular and spatial distribution were carried out for the Siemens KD2 linear accelerator, at beam energies of 10 and 15 MeV for a field size of 10x10 cm2. Indirect validation was performed against electron depth doses curves and beam profiles measured in a MP3-PTW water phantom using a Markus planar chamber. Monte Carlo isodose lines were reconstructed and compared to those from commercial treatment planning systems (TPS's) and with experimental data.

  13. Spallation Source Modelling for an ADS Using the MCNPX and GEANT4 Packages for Sensitivity Analysis of Reactivity

    Science.gov (United States)

    Antolin, M. Q.; Marinho, F.; Palma, D. A. P.; Martinez, A. S.

    2014-04-01

    A simulation for the time evolution of the MYRRHA conceptual reactor was developed. The SERPENT code was used to simulate the nuclear fuel depletion and the spallation source which drives the system was simulated using both MCNPX and GEANT4 packages. The obtained results for the neutron energy spectrum from the spallation are coherent with each other and were used as input for the SERPENT code which simulated a constant power operation regime. The obtained results show that the criticality of the system is not sensitive to the spallation models employed and only relative small deviations with respect to the inverse kinetic model coming from the point kinetic equations proposed by Gandini were observed.

  14. Simulation of the Production of Secondary Particles from a Neutron Beam on Polyethylene Targets using the GEANT4 Simulation Tool

    CERN Document Server

    Ilgner, C

    2003-01-01

    In view of a beam test of RadFET semiconductor detectors and optically stimulated luminescence (OSL) detectors as on-line dosimeters for radiation monitoring purposes in the caverns of the Large Hadron Collider (LHC) experiments, a simulation on the production of secondary particles from a neutron beam on a polyethylene target was carried out. We describe the yield of recoil protons, scattered neutrons as well as electrons, positrons and photons, when neutrons of an average energy of 20 MeV hit polyethylene targets of several thicknesses. The simulation was carried out using the latest release 5.2 of the GEANT4 detector description and simulation tool, including advanced hadron interaction models.

  15. The effect of heavy metal in CMOS on neutron induced single event upset simulated with Geant4

    CERN Document Server

    Zhang, Huan; Chen, Wei; Yang, Shan-chao

    2015-01-01

    Local metal interconnection is widely used in modern complementary metal oxide semiconductor (CMOS) technology. The most frequently used local materials are some heavy metals, such as tungsten (W) or copper (Cu). It's well known that single event upset (SEU) could occur in a CMOS under neutron exposure. In this paper the rectangular parallelepiped (RPP) method is used to investigate the SEU response of a typical CMOS. SEU induced by 1$\\sim$14\\:MeV neutrons are simulated with Geant4 and the cross sections are calculated. The results show that only in the structure with W, secondary particle $\\alpha$ is created and SEUs are generated when the energy of neutron is less than $4$\\:MeV.

  16. The radiation environment on the surface of Mars - Numerical calculations of the galactic component with GEANT4/PLANETOCOSMICS

    Science.gov (United States)

    Matthiä, Daniel; Berger, Thomas

    2017-08-01

    Galactic cosmic radiation and secondary particles produced in the interaction with the atmosphere lead to a complex radiation field on the Martian surface. A workshop (;1st Mars Space Radiation Modeling Workshop;) organized by the MSL-RAD science team was held in June 2016 in Boulder with the goal to compare models capable to predict this radiation field with each other and measurements from the RAD instrument onboard the curiosity rover taken between November 15, 2015 and January 15, 2016. In this work the results of PLANETOCOSMICS/GEANT4 contributed to the workshop are presented. Calculated secondary particle spectra on the Martian surface are investigated and the radiation field's directionality of the different particles in dependence on the energy is discussed. Omnidirectional particle fluxes are used in combination with fluence to dose conversion factors to calculate absorbed dose rates and dose equivalent rates in a slab of tissue.

  17. Yields of positron and positron emitting nuclei for proton and carbon ion radiation therapy: a simulation study with GEANT4.

    Science.gov (United States)

    Lau, Andy; Chen, Yong; Ahmad, Salahuddin

    2012-01-01

    A Monte Carlo application is developed to investigate the yields of positron-emitting nuclei (PEN) used for proton and carbon ion range verification techniques using the GEANT4 Toolkit. A base physics list was constructed and used to simulate incident proton and carbon ions onto a PMMA or water phantom using pencil like beams. In each simulation the total yields of PEN are counted and both the PEN and their associated positron depth-distributions were recorded and compared to the incident radiation's Bragg Peak. Alterations to the physics lists are then performed to investigate the PEN yields dependence on the choice of physics list. In our study, we conclude that the yields of PEN can be estimated using the physics list presented here for range verification of incident proton and carbon ions.

  18. Geant4 Simulation Study of Dose Distribution and Energy Straggling for Proton and Carbon Ion Beams in Water

    Directory of Open Access Journals (Sweden)

    Zhao Qiang

    2016-01-01

    Full Text Available Dose distribution and energy straggling for proton and carbon ion beams in water are investigated by using a hadrontherapy model based on the Geant4 toolkit. By gridding water phantom in N×N×N voxels along X, Y and Z axes, irradiation dose distribution in all the voxels is calculated. Results indicate that carbon ion beams have more advantages than proton beams. Proton beams have bigger width of the Bragg peak and broader lateral dose distribution than carbon ion beams for the same position of Bragg peaks. Carbon ion has a higher local ionization density and produces more secondary electrons than proton, so carbon ion beams can achieve a higher value of relative biological effectiveness.

  19. The performance of a new Geant4 Bertini intra-nuclear cascade model in high throughput computing (HTC) cluster architecture

    Energy Technology Data Exchange (ETDEWEB)

    Aatos, Heikkinen; Andi, Hektor; Veikko, Karimaki; Tomas, Linden [Helsinki Univ., Institute of Physics (Finland)

    2003-07-01

    We study the performance of a new Bertini intra-nuclear cascade model implemented in the general detector simulation tool-kit Geant4 with a High Throughput Computing (HTC) cluster architecture. A 60 node Pentium III open-Mosix cluster is used with the Mosix kernel performing automatic process load-balancing across several CPUs. The Mosix cluster consists of several computer classes equipped with Windows NT workstations that automatically boot, daily and become nodes of the Mosix cluster. The models included in our study are a Bertini intra-nuclear cascade model with excitons, consisting of a pre-equilibrium model, a nucleus explosion model, a fission model and an evaporation model. The speed and accuracy obtained for these models is presented. (authors)

  20. A free-parameter theoretical model for describing the electron elastic scattering in water in the Geant4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Champion, C. [Universite Paul Verlaine-Metz, Laboratoire de Physique Moleculaire et des Collisions, 1 Boulevard Arago, Technopole 2000, 57078 Metz (France)], E-mail: champion@univ-metz.fr; Incerti, S. [CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux-Gradignan, UMR 5797, Gradignan F-33175 (France); Universite de Bordeaux, Centre d' Etudes Nucleaires de Bordeaux-Gradignan, UMR 5797, Gradignan F-33175 (France); Aouchiche, H.; Oubaziz, D. [Universite M. Mammeri, Laboratoire de Mecanique, Structure et Energetique, BP 17, Tizi-Ouzou 15000 (Algeria)

    2009-09-15

    The present work provides an accurate description of the elastic scattering process for low-energy electrons (10 eV-10 keV) in liquid water by means of a free-parameter quantum-mechanical treatment. The calculations are performed in the partial-wave formalism by means of a total interaction potential taking into account a static contribution as well as fine effects like exchange and polarization contributions. The obtained results in terms of singly differential and total cross sections exhibit relatively good agreement with available experimental data (in gaseous water). They have been incorporated into the Geant4 toolkit, which has been recently extended with physics processes for microdosimetry applications in liquid water down to the electronvolt scale. They offer an improved alternative to the semi-empirical and to the screened Rutherford models already available in this very low-energy extension.

  1. A GEANT4 study on the time resolution of a fast plastic scintillator read out by a G-APD

    Energy Technology Data Exchange (ETDEWEB)

    Sedlak, K., E-mail: kamil.sedlak@psi.ch [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Stoykov, A.; Scheuermann, R. [Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland)

    2012-12-22

    The time resolution of a fast scintillation counter, consisting of a plastic scintillator read out by a Geiger-mode Avalanche Photodiode, is studied over a wide range of the number of detected photons (primary photoelectrons) using the GEANT4 simulation toolkit. Different timing definitions such as first photon detection, leading edge and constant fraction discrimination are considered. In the latter case the predictions are compared with the existing experimental data. We also show that due to the finite scintillation rise time, finite scintillator dimensions and also due to the finite single photon time resolution in G-APD cells, the time resolution for the first detected photon in real detectors substantially deviates from the {sigma}{approx}1/N{sub phe} dependence, theoretically predicted for a scintillator with zero rise time.

  2. A GEANT4 study on the time resolution of a fast plastic scintillator read out by a G-APD

    Science.gov (United States)

    Sedlak, K.; Stoykov, A.; Scheuermann, R.

    2012-12-01

    The time resolution of a fast scintillation counter, consisting of a plastic scintillator read out by a Geiger-mode Avalanche Photodiode, is studied over a wide range of the number of detected photons (primary photoelectrons) using the GEANT4 simulation toolkit. Different timing definitions such as first photon detection, leading edge and constant fraction discrimination are considered. In the latter case the predictions are compared with the existing experimental data. We also show that due to the finite scintillation rise time, finite scintillator dimensions and also due to the finite single photon time resolution in G-APD cells, the time resolution for the first detected photon in real detectors substantially deviates from the σ˜1/Nphe dependence, theoretically predicted for a scintillator with zero rise time.

  3. Detailed studies of hadronic showers and comparison to GEANT4 simulations with data from highly granular calorimeters

    CERN Document Server

    van der Kolk, Naomi

    2015-01-01

    The highly granular calorimeter prototypes of the CALICE collaboration have provided large data samples with precise three-dimensional information on hadronic showers with steel and tungsten absorbers and silicon, scintillator and gas detector readout. From these data sets, detailed measurements of the spatial structure, including longitudinal and lateral shower profiles and of the shower substructure and time structure are extracted. Recent analyses have extended these studies to different particle species in calorimeters with scintillator readout and steel and tungsten absorbers, to energies below 10 GeV in a silicon tungsten calorimeter and have provided first studies of the shower substructure with gaseous readout and unprecedented granularity of $1\\times1$~cm$^{2}$ over a full cubic meter. These results are confronted with Geant4 simulations with different hadronic physics models. They present new challenges to the simulation codes and provide the possibility to validate and improve the simulation of had...

  4. The performance of a new Geant4 Bertini intra-nuclear cascade model in high throughput computing (HTC) cluster architecture

    Energy Technology Data Exchange (ETDEWEB)

    Aatos, Heikkinen; Andi, Hektor; Veikko, Karimaki; Tomas, Linden [Helsinki Univ., Institute of Physics (Finland)

    2003-07-01

    We study the performance of a new Bertini intra-nuclear cascade model implemented in the general detector simulation tool-kit Geant4 with a High Throughput Computing (HTC) cluster architecture. A 60 node Pentium III open-Mosix cluster is used with the Mosix kernel performing automatic process load-balancing across several CPUs. The Mosix cluster consists of several computer classes equipped with Windows NT workstations that automatically boot, daily and become nodes of the Mosix cluster. The models included in our study are a Bertini intra-nuclear cascade model with excitons, consisting of a pre-equilibrium model, a nucleus explosion model, a fission model and an evaporation model. The speed and accuracy obtained for these models is presented. (authors)

  5. Performance evaluation of multi sampling ionization chamber for heavy ion beams by comparison with GEANT4 simulation

    Science.gov (United States)

    Kanke, Yuki; Himac H093 Collaboration

    2014-09-01

    In high-energy heavy-ion accelerator facilities, multi sampling ionization chambers are often used for the identification of the atomic number Z by detecting the energy deposit in it. In the study at GSI, the picture of the escape of secondary electrons, δ rays, from the ionization chamber explains the experimental data of pulse-height resolution. If this picture is correct, the pulse-height resolution should depend on the effective area of the ionization chamber. The experiment have been performed at NIRS-HIMAC. The pulse-height resolutions of two ionization chambers with different effective area were compared by using a 400-MeV/u Ni beam and their fragments. The difference in the pulse-height resolutions was observed. By comparison with the GEANT4 simulation including the δ-rays emission, the performance of the ionization chamber have been evaluated.

  6. Monte Carlo Simulation of Electron Beams for Radiotherapy - EGS4, MCNP4b and GEANT3 Intercomparison

    Science.gov (United States)

    Trindade, A.; Rodrigues, P.; Alves, C.; Chaves, A.; Lopes, M. C.; Oliveira, C.; Peralta, L.

    In medical radiation physics, an increasing number of Monte Carlo codes are being used, which requires intercomparison between them to evaluated the accuracy of the simulated results against benchmark experiments. The Monte Carlo code EGS4, commonly used to simulate electron beams from medical linear accelerators, was compared with GEANT3 and MCNP4b. Intercomparison of electron energy spectra, angular and spatial distribution were carried out for the Siemens KD2 linear accelerator, at beam energies of 10 and 15 MeV for a field size of 10x10 cm2. Indirect validation was performed against electron depth doses curves and beam profiles measured in a MP3-PTW water phantom using a Markus planar chamber. Monte Carlo isodose lines were reconstructed and compared to those from commercial treatment planning systems (TPS's) and with experimental data.

  7. ROSI and GEANT4 – A comparison in the context of high energy X-ray physics

    Energy Technology Data Exchange (ETDEWEB)

    Kiunke, Markus [Chair of X-ray Microscopy, University Würzburg, Josef-Martin-Weg 63, 97074 Würzburg (Germany); Stritt, Carina, E-mail: Carina.Stritt@empa.ch [Empa, Swiss Federal Laboratories for Material Science and Technology, Reliability Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Schielein, Richard [Chair of X-ray Microscopy, University Würzburg, Josef-Martin-Weg 63, 97074 Würzburg (Germany); Sukowski, Frank; Hölzing, Astrid [Fraunhofer Development Center for X-ray Technology EZRT, Flugplatzstr. 75, 90768 Fürth (Germany); Zabler, Simon [Chair of X-ray Microscopy, University Würzburg, Josef-Martin-Weg 63, 97074 Würzburg (Germany); Fraunhofer Development Center for X-ray Technology EZRT, Flugplatzstr. 75, 90768 Fürth (Germany); Hofmann, Jürgen; Flisch, Alexander [Empa, Swiss Federal Laboratories for Material Science and Technology, Center for X-ray Analytics, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Kasperl, Stefan [Fraunhofer Development Center for X-ray Technology EZRT, Flugplatzstr. 75, 90768 Fürth (Germany); Sennhauser, Urs [Empa, Swiss Federal Laboratories for Material Science and Technology, Reliability Science and Technology, Überlandstrasse 129, 8600 Dübendorf (Switzerland); and others

    2016-06-15

    This work compares two popular MC simulation frameworks ROSI (Roentgen Simulation) and GEANT4 (Geometry and Tracking in its fourth version) in the context of X-ray physics. The comparison will be performed with the help of a parameter study considering energy, material and length variations. While the total deposited energy as well as the contribution of Compton scattering show a good accordance between all simulated configurations, all other physical effects exhibit large deviations in a comparison of data-sets. These discrepancies between simulations are shown to originate from the different cross sectional databases used in the frameworks, whereas the overall simulation mechanics seem to not have an influence on the agreement of the simulations. A scan over energy, length and material shows that the two parameters energy and material have a significant influence on the agreement of the simulation results, while the length parameter shows no noticeable influence on the deviations between the data-sets.

  8. In-beam quality assurance using induced β+ activity in hadrontherapy: a preliminary physical requirements study using Geant4

    Science.gov (United States)

    Lestand, L.; Montarou, G.; Force, P.; Pauna, N.

    2012-10-01

    Light and heavy ions particle therapy, mainly by means of protons and carbon ions, represents an advantageous treatment modality for deep-seated and/or radioresistant tumours. An in-beam quality assurance principle is based on the detection of secondary particles induced by nuclear fragmentations between projectile and target nuclei. Three different strategies are currently under investigation: prompt γ rays imaging, proton interaction vertex imaging and in-beam positron emission tomography. Geant4 simulations have been performed first in order to assess the accuracy of some hadronic models to reproduce experimental data. Two different kinds of data have been considered: β+-emitting isotopes and prompt γ-ray production rates. On the one hand simulations reproduce experimental β+ emitting isotopes production rates to an accuracy of 24%. Moreover simulated β+ emitting nuclei production rate as a function of depth reproduce well the peak-to-plateau ratio of experimental data. On the other hand by tuning the tolerance factor of the photon evaporation model available in Geant4, we reduce significantly prompt γ-ray production rates until a very good agreement is reached with experimental data. Then we have estimated the total amount of induced annihilation photons and prompt γ rays for a simple treatment plan of ∼1 physical Gy in a homogenous equivalent soft tissue tumour (6 cm depth, 4 cm radius and 2 cm wide). The average annihilation photons emitted during a 45 s irradiation in a 4 π solid angle are ∼2 × 106 annihilation photon pairs and 108 single prompt γ whose energy ranges from a few keV to 10 MeV.

  9. In-beam quality assurance using induced β(+) activity in hadrontherapy: a preliminary physical requirements study using Geant4.

    Science.gov (United States)

    Lestand, L; Montarou, G; Force, P; Pauna, N

    2012-10-21

    Light and heavy ions particle therapy, mainly by means of protons and carbon ions, represents an advantageous treatment modality for deep-seated and/or radioresistant tumours. An in-beam quality assurance principle is based on the detection of secondary particles induced by nuclear fragmentations between projectile and target nuclei. Three different strategies are currently under investigation: prompt γ rays imaging, proton interaction vertex imaging and in-beam positron emission tomography. Geant4 simulations have been performed first in order to assess the accuracy of some hadronic models to reproduce experimental data. Two different kinds of data have been considered: β(+)-emitting isotopes and prompt γ-ray production rates. On the one hand simulations reproduce experimental β(+) emitting isotopes production rates to an accuracy of 24%. Moreover simulated β(+) emitting nuclei production rate as a function of depth reproduce well the peak-to-plateau ratio of experimental data. On the other hand by tuning the tolerance factor of the photon evaporation model available in Geant4, we reduce significantly prompt γ-ray production rates until a very good agreement is reached with experimental data. Then we have estimated the total amount of induced annihilation photons and prompt γ rays for a simple treatment plan of ∼1 physical Gy in a homogenous equivalent soft tissue tumour (6 cm depth, 4 cm radius and 2 cm wide). The average annihilation photons emitted during a 45 s irradiation in a 4 π solid angle are ∼2 × 10(6) annihilation photon pairs and 10(8) single prompt γ whose energy ranges from a few keV to 10 MeV.

  10. Assessment and improvements of Geant4 hadronic models in the context of prompt-gamma hadrontherapy monitoring

    Science.gov (United States)

    Dedes, G.; Pinto, M.; Dauvergne, D.; Freud, N.; Krimmer, J.; Létang, J. M.; Ray, C.; Testa, E.

    2014-04-01

    Monte Carlo simulations are nowadays essential tools for a wide range of research topics in the field of radiotherapy. They also play an important role in the effort to develop a real-time monitoring system for quality assurance in proton and carbon ion therapy, by means of prompt-gamma detection. The internal theoretical nuclear models of Monte Carlo simulation toolkits are of decisive importance for the accurate description of neutral or charged particle emission, produced by nuclear interactions between beam particles and target nuclei. We assess the performance of Geant4 nuclear models in the context of prompt-gamma emission, comparing them with experimental data from proton and carbon ion beams. As has been shown in the past and further indicated in our study, the prompt-gamma yields are consistently overestimated by Geant4 by a factor of about 100% to 200% over an energy range from 80 to 310 MeV/u for the case of 12C, and to a lesser extent for 160 MeV protons. Furthermore, we focus on the quantum molecular dynamics (QMD) modeling of ion-ion collisions, in order to optimize its description of light nuclei, which are abundant in the human body and mainly anticipated in hadrontherapy applications. The optimization has been performed by benchmarking QMD free parameters with well established nuclear properties. In addition, we study the effect of this optimization on charged particle emission. With the usage of the proposed parameter values, discrepancies reduce to less than 70%, with the highest values being attributed to the nucleon-ion induced prompt-gammas. This conclusion, also confirmed by the disagreement we observe in the case of proton beams, indicates the need for further investigation on nuclear models which describe proton and neutron induced nuclear reactions.

  11. An investigation on the radiation sensitivity of DNA conformations to {sup 60}Co gamma rays by using Geant4 toolkit

    Energy Technology Data Exchange (ETDEWEB)

    Semsarha, F. [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Goliaei, B., E-mail: goliaei@ibb.ut.ac.ir [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Raisali, G.; Khalafi, H. [Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Mirzakhanian, L. [Medical Physics Unit, McGill University, 1650 Cedar Avenue, Montreal, Quebec (Canada)

    2014-03-15

    To investigate the impact of conformational properties of genetic material of living cells on radiation-induced DNA damage, single strand breaks (SSB), double strand breaks (DSB) and some microdosimetric quantities of A, B and Z-DNA conformations caused by {sup 60}Co gamma rays, have been calculated. Based on a previous B-DNA geometrical model, models of A and Z forms have been developed. Simple 34 base pairs segments of each model repeated in high number and secondary electron spectrum of {sup 60}Co gamma rays have been simulated in a volume of a typical animal cell nucleus. All simulations in this study have been performed by using the Geant4 (GEometry ANd Tracking 4)-DNA extension of the Geant4 toolkit. The results showed that, B-DNA has the lowest yield of simple strand breaks with 2.23 × 10{sup −10} Gy{sup −1} Da{sup −1} and 1.0 × 10{sup −11} Gy{sup −1} Da{sup −1} for the SSB and DSB damage yield, respectively. The A-DNA has the highest SSB yield with 3.59 × 10{sup −10} Gy{sup −1} Da{sup −1} and the Z-DNA has the highest DSB yields with 1.8 × 10{sup −11} Gy{sup −1} Da{sup −1}. It has been concluded that there is a direct correlation between the hit probability, mean specific imparted energy and SSB yield in each model of DNA. Moreover, there is a direct correlation between the DSB yield and both the mean lineal energy and topological characteristics of each model.

  12. Synovial sarcoma of the foot; Synovialsarkom des Fusses

    Energy Technology Data Exchange (ETDEWEB)

    Beus, J. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Kreitner, K.F. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie; Rompe, J.D. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Orthopaedie; Riehle, H.M. [Mainz Univ. (Germany). Inst. fuer Pathologie

    1996-09-01

    The case of a 29 year-old female patient who had experienced pain in the right midfoot for 5 years which was diagnosed as a degenerative or rheumatic change and treated by physiotherapy and medication. By means of magnetic resonance imaging we identified a soft-tissue tumor of the midfoot. Histology provided the findings of a monophasic fibrous synovial sarcoma. The case history is reported together with a presentation of the disease and its radiological diagnosis. (orig.) [Deutsch] Es wird ueber den Fall einer 29jaehrigen Patientin berichtet, die 5 Jahre lang wegen Schmerzen im rechten Mittelfuss unter der Diagnose degenerativer oder rheumatischer Veraenderungen physikalisch und medikamentoes behandelt wurde. Magnetresonanztomographisch wurde ein Weichteiltumor des Mittelfusses diagnostiziert. Die histologische Untersuchung erbrachte den Befund eines monophasisch-fibroesen Synovialsarkoms. Mit der Kasuistik verbunden ist eine Darstellung des Krankheitsbildes und dessen radiologischer Diagnostik. (orig.)

  13. Bolometric detection of magnetoplasma resonances in microwave absorption by two-dimensional electron systems based on doping layer conductivity measurements in GaAs/AlGaAs heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Dorozhkin, S. I., E-mail: dorozh@issp.ac.ru; Sychev, D. V.; Kapustin, A. A. [Institute of Solid State Physics RAS, 142432 Chernogolovka, Moscow district (Russian Federation)

    2014-11-28

    We have implemented a new bolometric method to detect resonances in magneto-absorption of microwave radiation by two-dimensional electron systems (2DES) in selectively doped GaAs/AlGaAs heterostructures. Radiation is absorbed by the 2DES and the thermally activated conductivity of the doping layer supplying electrons to the 2DES serves as a thermometer. The resonant absorption brought about by excitation of the confined magnetoplasma modes appears as peaks in the magnetic field dependence of the low-frequency impedance measured between the Schottky gate and 2DES.

  14. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  15. Study of a continuous plasma generated by electron bombardment and its mixing with a laser induced plasma. Influence of collisions on resonance cone phenomenon; Contribution a l`etude d`un plasma cree de facon continue par bombardement electronique et de son melange avec un photo-plasma pulse. Influence des collisions sur les cones de resonance

    Energy Technology Data Exchange (ETDEWEB)

    Besuelle, E.

    1997-02-25

    This thesis deals with three different fields of plasma physics. In the first part, we studied free expansion of an ionised uranium vapour generated in an electron beam evaporator. The electron temperature and the electron density of the expanding plasma have been measured by a Langmuir probe. The experimental results have been compared with the ones obtained by numerical simulation using a fluid code. The calculated points are in the error bars. We observe that there are two electron populations with different temperatures, which undergo a mixing during the plasma expansion. The neutral density influence on the electron temperature by collisional relaxation is also studied. The second part deals with a plasma diagnostic which can replace Langmuir probe in the case of a cold magnetized plasma: the resonance cone phenomenon. After recalling the wave propagation theory in a cold plasma, we introduce a new calculation of the potential radiated by an antenna in a collisional magnetized plasma. The domain where the resonance cone exists in considerably reduced because of collisions. More of that, the cone angle is reduced by this phenomenon too. The experiments performed show that we must take into account a wave turbulence phenomenon to explain the High collision frequency that we observe. The third part is about the study of the expansion of a plasma into another one. We solve this problem with fluid codes and Particle-In-Cell (PIC) code. THe electron families have a counter stream motion locally. Then, we study the electrostatic extraction of two plasmas-one pulsed, one continuous-in which we observe electron unfurling. (author).

  16. Nuclear magnetic resonance imaging of the head. Kernspintomographie des Kopfes

    Energy Technology Data Exchange (ETDEWEB)

    Uhlenbrock, D. (Sankt-Vincenz-Krankenhaus, Paderborn (Germany, F.R.). Abt. fuer Radiologie); Higer, H.P. (Stiftung Deutsche Klinik fuer Diagnostik, Wiesbaden (Germany, F.R.)); Lukas, P. (Klinikum rechts der Isar, Muenchen (Germany, F.R.). Inst. und Poliklinik fuer Strahlentherapie und Radiologische Onkologie); Sehlen, S. (Goettingen Univ. (Germany, F.R.). Klinik und Poliklinik fuer Strahlentherap

    1990-01-01

    This pocket book is a clearly arranged and amply illustrated textbook presenting practice-oriented information for readers who seek a concise but nevertheless complete introduction to the complex subject: The technical aspects and physical principles are explained, and a catalogue of reference data and principles for image interpretation is given. The specific information refers to the clinical neuroanatomy and neuropathology of the most frequent lesions (intracranial tumors; cerebrovascular, inflammatory and degenerative lesions; hydrocephalus, multiple sclerosis, traumata, post-surgical changes, radiation effects). There also is a chapter discussing neuropediatric lesions. (orig.) With 257 ill. covering 401 figs., 15 tabs.

  17. GEANT4 simulation diagram showing the architecture of the ATLAS test line: the detectors are positioned to receive the beam from the SPS. A muon particle which enters the magnet and crosses all detectors is shown (blue line).

    CERN Multimedia

    2004-01-01

    GEANT4 simulation diagram showing the architecture of the ATLAS test line: the detectors are positioned to receive the beam from the SPS. A muon particle which enters the magnet and crosses all detectors is shown (blue line).

  18. Terre des hommes

    CERN Multimedia

    Staff Association

    2012-01-01

    Transformez votre téléphone portable en geste de solidarité ! Collecte du 12 au 23 novembre 2012   Faites un geste simple et utile en déposant vos téléphones portables inutilisés dans les urnes installées dans les trois restaurants du CERN. En Suisse, une personne change tous les 12 à 18 mois de téléphone portable. La plupart de nos vieux appareils sont simplement laissés à l’abandon avec comme seule fonction de parer une éventuelle panne à venir. On  estime ainsi que 8 millions de portables sont inutilisés, alors qu'entre 30 et 50% peuvent être réutilisés. L'action Solidarcomm leur offre une deuxième vie ! Terre des Hommes Suisse, dans le cadre de la campagne Solidarcomm, collecte et valorise vos téléphones inutilis&...

  19. Onlinespieler abseits des Mainstreams

    Directory of Open Access Journals (Sweden)

    Harald Baumgartlinger

    2012-12-01

    Full Text Available MMO(RPGs „Massively Multiplayer Online (Role-Playing Games“ nehmen einen Sonderstatus unter den Onlinespielen ein, welcher durch den wachsenden wirtschaftlichen Erfolg, insbesondere durch den „breakthrough hit“ (Duchenaut et al. 2006: 407 World of Warcraft (WoW, auch an Bedeutung für die Medien- und Kommunikationswissenschaft gewinnt (vgl. Inderst 2009: 15; vgl. Seifert/Jöckel 2008: 297. Der Primus des Genres, WoW, repräsentiert gemeinsam mit einigen nahezu identen Titeln insgesamt 85 Prozent der gespielten MMOGs (vgl. Williams et al. 2008: 999. Daher befasst sich auch die Mehrheit der vorliegenden Studien mit eben diesen Spielen. Neue Formen von MMO(Gs können jedoch zu ebenso neuartigen Spielerfahrungen führen und damit unterschiedliche Nutzungsmotive befriedigen (vgl. Seifert/Jöckel 2008: 309 und folglich zu einem gänzlich anderen Spielerleben führen. Während im Mainstream die kooperativen Spielerbeziehungen überwiegen, dominiert in Darkfall Online der soziale Wettbewerb. Der von Williams et al. 2008 verwendete Fragebogen diente als Rohling für die Kreation eines für die speziellen Anforderungen adaptierten Erhebungstools zur Erforschung der Spielertypologie und der Motive der Darkfall-Online-SpielerInnen. Die in der Onlinebefragung (N = 506 gesammelten Daten belegen, dass sich sowohl die Spielerdemographie, als auch die Motive der Spieler von den Mainstream MMOs unterscheiden. Zudem konnten realweltliche Eigenschaften der Spieler als signifikante Einflussfaktoren für die Spielzuwendung identifiziert werden.

  20. Peste des petits ruminants.

    Science.gov (United States)

    Parida, S; Muniraju, M; Mahapatra, M; Muthuchelvan, D; Buczkowski, H; Banyard, A C

    2015-12-14

    Peste des petits ruminants virus causes a highly infectious disease of small ruminants that is endemic across Africa, the Middle East and large regions of Asia. The virus is considered to be a major obstacle to the development of sustainable agriculture across the developing world and has recently been targeted by the World Organisation for Animal Health (OIE) and the Food and Agriculture Organisation (FAO) for eradication with the aim of global elimination of the disease by 2030. Fundamentally, the vaccines required to successfully achieve this goal are currently available, but the availability of novel vaccine preparations to also fulfill the requisite for differentiation between infected and vaccinated animals (DIVA) may reduce the time taken and the financial costs of serological surveillance in the later stages of any eradication campaign. Here, we overview what is currently known about the virus, with reference to its origin, updated global circulation, molecular evolution, diagnostic tools and vaccines currently available to combat the disease. Further, we comment on recent developments in our knowledge of various recombinant vaccines and on the potential for the development of novel multivalent vaccines for small ruminants. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Effect of Different Geant4 Physical Models on Simulation of Radiotherapy Proton Beam%Geant4不同物理模型对放疗质子束模拟的影响

    Institute of Scientific and Technical Information of China (English)

    林辉; 谢聪; 张拥军; 熊桢宇; 吴东升; 曹瑞芬; FDS团队

    2015-01-01

    The Monte Carlo method is usually used to simulate the feature of the exter‐nal radiotherapy of proton beam to optimize the clinical therapy scenario .T he selection of a suitable physical model is very critical to ensure the correction and the efficiency of the simulation .This work studied nine Geant4 physical models ,which are often used in the simulation of radiotherapy of proton beam with energy of 60‐250 MeV .The dosage features and the microcosmic secondary yields in different materials were compared .The result show s that ,although the standard EM ,the low energy Penelope model and the low energy Livermore model can output the right dose distribution ,they can’t simulate the baryon yields .The parametrization driven model LHEP and the Quark gluon string‐pre‐compound model both can’ t simulate the complex ion transportation . Thus the above five models are not enough for the research calculation in the radiation protection and the radiation damage .The QGSP_BIC_EMY model in Geant4 hadron therapy exam‐ple is very bad for underestimating the dose ratio of Bragg peak to entrance and absolute dose .The QGSP_BERT model ,QGSP_BIC model and FTFP_BERT model are suitable for the radiotherapy proton beam with energy of 60‐250 MeV .%Monte Carlo方法常用于质子束剂量模拟以优化质子束临床治疗,合适的物理模型选择关系到M onte Carlo模拟结果的可靠性及模拟效率。本工作选取9个可用于质子模拟的Geant4物理模型,计算比较了质子束在多种介质中的剂量及次级粒子产额。结果表明:标准电磁物理模型、低能电磁Penel‐ope模型和Livermore模型虽在模拟质子整体剂量分布上可接受,但在微观上缺失重粒子生成。参数化驱动模型LHEP的模拟时间最短,但与QGSP相同,均不能产生复杂重离子。QGSP_BIC_EMY模型较其他模型明显低估Bragg峰‐入口剂量比和绝对剂量。QGSP_BERT 模型、QGSP_BIC模型和 FT FP

  2. CCC/WPA study : Des Lacs NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of the Civilian Conservation Corps (CCC) camp at Des Lacs National Wildlife Refuge from July 1935-May 1942 to carry on restoration and development of Des...

  3. Current algebra; Algebre des courants

    Energy Technology Data Exchange (ETDEWEB)

    Jacob, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-07-01

    The first three chapters of these lecture notes are devoted to generalities concerning current algebra. The weak currents are defined, and their main properties given (V-A hypothesis, conserved vector current, selection rules, partially conserved axial current,...). The SU (3) x SU (3) algebra of Gell-Mann is introduced, and the general properties of the non-leptonic weak Hamiltonian are discussed. Chapters 4 to 9 are devoted to some important applications of the algebra. First one proves the Adler- Weisberger formula, in two different ways, by either the infinite momentum frame, or the near-by singularities method. In the others chapters, the latter method is the only one used. The following topics are successively dealt with: semi leptonic decays of K mesons and hyperons, Kroll- Ruderman theorem, non leptonic decays of K mesons and hyperons ( {delta}I = 1/2 rule), low energy theorems concerning processes with emission (or absorption) of a pion or a photon, super-convergence sum rules, and finally, neutrino reactions. (author) [French] La premiere partie de ce cours (trois premiers chapitres), traite des generalites concernant l'algebre de courants. Apres une definition rapide des courants faibles et un rappel de leurs proprietes (hypothese V-A, conservation du courant vecteur, regles de selection, courant axial partiellement conserve,...), l'on introduit l'algebre de Gell-Mann SU (3) x SU (3), et discute les proprietes generales de l'Hamiltonien faible non leptonique. Les chapitres IV a IX sont consacres a des applications importantes de l'algebre des courants. En premier lieu l'on demontre la formule de Adler et Weisberger, par deux methodes differentes, celle dite du repere de moment infini et celle des singularites proches. Cette derniere est seule utilisee dans la suite. Puis, l'on traite successivement les problemes suivants: desintegrations semi-leptoniques des mesons K et des hyperons, theoreme de Kroll

  4. La théorie des industries culturelles (et informationnelles, composante des SIC

    Directory of Open Access Journals (Sweden)

    Bernard Miège

    2012-09-01

    Full Text Available Inaugurer le Cahier central de la Revue des SIC est certes une forme de reconnaissance, mais cela comporte des obligations, au premier rang desquelles la nécessité d’intéresser des lecteurs a priori pas immédiatement concernés par la thématique.Si la théorie des industries culturelles est devenue progressivement une approche marquante des SIC, en France, en Europe et plus largement encore (avec des dénominations variables et des modalités spécifiques, ce n’est en effet ni en le proclamant ha...

  5. Numerical solution of the Maxwell-Vlasov equations in the periodic regime. Application to the study of isotope separation by ion cyclotron resonance; Resolution numerique des equations de Maxwell-Vlasov en regime periodique. Application a l'etude de la separation isotopique par resonance cyclotron ionique

    Energy Technology Data Exchange (ETDEWEB)

    Omnes, P

    1999-01-25

    This work is dedicated to the study of the behaviour of a magnetic confined plasma that is excited by a purely sinusoidal electric current delivered by an antenna. The response of the electrons to the electromagnetic field is considered as linear,whereas the ions of the plasma are represented by a non-relativistic Vlasov equation. In order to avoid transients, the coupled Maxwell-Vlasov equations are solved in a periodic mode and in a bounded domain. An equivalent electric conductivity tensor has been defined, this tensor is a linear operator that links the electric current generated by the movement of the particles to the electromagnetic field. Theoretical considerations can assure the existence and uniqueness of a periodical solution to Vlasov equations and of a solution to Maxwell equations in harmonic mode. The system of equations is periodical and has been solved by using an iterative method. The application of this method to the simulation of a isotopic separation device based on ionic cyclotron resonance has shown that the convergence is reached in a few iterations and that the solution is valid. Furthermore a method based on a finite-volume formulation of Maxwell equations in the time domain is presented. 2 new variables are defined in order to better take into account the Gauss' law and the conservation of the magnetic flux, the new system is still hyperbolic. The parallelization of the process has been successfully realized. (A.C.)

  6. Study of the J/{Psi} resonance suppression as a function of reaction centrality and dimuon transverse momentum in the Pb+Pb and S+U collisions; Etude dans les collisions Pb + Pb et S + U de la suppression de la resonance J/{Psi} en fonction de la centralite de la reaction et de l`impulsion transverse des dimuons

    Energy Technology Data Exchange (ETDEWEB)

    Mourgues, Sandrine [Ecole Doctorale des Science Fondamentales, Universite Blaise Pascal, U.F.R. de Recherche Scientifique et Technique, F-63177 Aubiere Cedex (France)

    1997-12-18

    This work is a contribution to the search of quark-gluon plasma. It is devoted to the study of J/{psi} meson production in S + U (NA38 experiment) and Pb + Pb collision (NA50 experiment). The ratio of J/{psi} to Drell-Yan cross section is studied as a function of the centrality of the collision in two transverse momentum bins. The results show a strong transverse momentum dependence of J/{psi} suppression. In high transverse momentum bin, an important discontinuity appears between S + U and Pb + Pb systems. On the other hand, J/{psi} survival probability decreases continuously from S + U to Pb + Pb collisions in low transverse momentum range. We also studied the transverse momentum distribution of J/{psi} as a function of the centrality of the collision. In S + U collisions the mean squared transverse momentum as a function of centrality is in agreement with a theoretical model taking into account both initial state parton scattering and the absorption of a pre-resonant state before J/{psi} formation. This analysis has been done for Pb + Pb collisions. The comparison of our results with theoretical models does not allow a clear-cut conclusion about the medium created in Pb + Pb collision (confined or deconfined medium). (author) 40 refs., 103 figs., 35 tabs.

  7. Study of irradiation effects in the silicon carbide cubic polytype by photoluminescence and electron spin resonance spectroscopies; Etude des effets d'irradiation dans le polytype cubique du carbure de silicium par les techniques spectroscopiques de photoluminescence et de resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, J

    2008-01-15

    This experimental work has consisted in the study of point defects induced by an electronic irradiation in the cubic crystallographic structure of silicon carbide with low temperature photoluminescence and electron spin resonance spectroscopies. The first one of these measurement tools has allowed to estimate the displacement threshold energy in the silicon sub-lattice and then to analyze the thermal stability of the irradiation defects in the low temperature range: (10-300 K) and then in the high temperature range: (300-1400 K). Besides, on the base of a recent theoretical model, this thesis has confirmed the proposition of the isolated silicon antisite for the D1 center whose running beyond the nominal running temperature of fission nuclear reactors (generation IV), for which SiC is in part intended, seems to be particularly problematic. Measurements carried out by ESR under lighting have at last allowed to detect a new defect in its metastable spin state S=1, possibly associated to a silicon interstitial configuration. (O.M.)

  8. Breast cancer imaging; Bildgebende Diagnostik des Mammakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Funke, M. [Stadtklinik Baden-Baden, Brustzentrum Klinikum Mittelbaden, Radiologische Klinik, Baden-Baden (Germany); Villena, C. [Stadtklinik Baden-Baden, Brustzentrum Klinikum Mittelbaden, Frauenklinik, Baden-Baden (Germany)

    2008-06-15

    Advances in female breast imaging have substantially influenced the diagnosis, therapy, and prognosis of breast cancer in the past few years. Mammography using conventional or digital technique is considered the gold standard for the early detection of breast cancer. Other modalities such as breast ultrasound and contrast-enhanced magnetic resonance imaging of the breast play an important role in diagnostic imaging, staging, and follow-up of breast cancer. Percutaneous needle biopsy is a faster, less invasive, and more cost-effective method than surgical biopsy for verifying the histological diagnosis. New methods such as breast tomosynthesis, contrast-enhanced mammography, and positron emission tomography promise to further improve breast imaging. Further studies are mandatory to adapt these new methods to clinical needs and to evaluate their performance in clinical practice. (orig.) [German] Die Fortschritte bei den bildgebenden Verfahren der weiblichen Brust haben in den letzten Jahren die Diagnostik, die Therapie und die Prognose des Mammakarzinoms erheblich beeinflusst. Die Frueherkennungsmammographie in traditioneller oder digitaler Technik gilt heute als der ''Goldstandard'' fuer die fruehzeitige Detektion von Brustkrebs. Weitere Modalitaeten wie die Mammasonographie und die kontrastmittelgestuetzte MR-Mammographie spielen bei der bildgebenden Diagnostik, im Staging sowie in der Nachsorge des Mammakarzinoms eine wichtige Rolle. Die perkutane Nadelbiopsie stellt eine schnellere, weniger invasive und kostenguenstigere Methode dar als die diagnostische Exzision fuer die histologische Sicherung der Diagnose. Neue Modalitaeten wie Tomosynthese der Brust, kontrastverstaerkte Mammographie und Positronenemissionstomographie erheben den Anspruch, zu einer weiteren Verbesserung der Bildgebung beizutragen. Weitere Studien sind notwendig, um diese neuen Methoden an die klinischen Beduerfnisse zu adaptieren und ihren Stellenwert im klinischen Alltag

  9. Neologismen des Lettischen anhand des schriftstellerischen Werkes von Zigmunds Skujins

    OpenAIRE

    Javojss, Skaidrite

    2010-01-01

    Untersuchung: Aus acht Werken des zeitgenössischen Schriftstellers Zigmunds Skujins wurden 500 lettische Wörter untersucht, die in den drei umfangreichsten lettischen Wörterbüchern nicht verzeichnet und somit möglicherweise Neologismen des Autors sind. Analysiert werden die Wortarten, die Komposita, die Herkunft der assimilierten Lehnwörter, orthographische und andere Varianten bereits lexikalisierter Wörter, die Arten der Diminutivbildung und der Präfigierung. Außerdem werden Aussagen über d...

  10. Calculation of lineal energies for water and DNA bases using the Rudd model cross sections integrated within the Geant4-DNA processes

    Science.gov (United States)

    Francis, Z.; El Bitar, Z.; Incerti, S.; Bernal, M. A.; Karamitros, M.; Tran, H. N.

    2017-07-01

    This study presents new parameters for proton ionisation cross sections in guanine, adenine, thymine, and cytosine based upon the semi-empirical Rudd model. The same model was used to find differential electron cross sections considering a speed scaling procedure. To accelerate computation, the total electron cross sections were obtained using the binary-encounter-Bethe approximation instead of the integrated Rudd formula. The cross sections were implemented in the Geant4 simulation toolkit as Geant4-DNA processes, and simulations were carried out measuring protons lineal energies in spherical micrometric volumes filled with water, adenine, thymine, guanine, and cytosine. Large differences were seen in the lineal energies evaluated for the different materials, with the lineal energy measured in guanine being sometimes twice that of water. This suggests that the cross sections developed here should be considered in biological simulations where cellular substructures are modelled, in contrast to the current approach which approximates these volumes as consisting of liquid water.

  11. Development of a Geant4 application to characterise a prototype neutron detector based on three orthogonal (3)He tubes inside an HDPE sphere.

    Science.gov (United States)

    Gracanin, V; Guatelli, S; Prokopovich, D; Rosenfeld, A B; Berry, A

    2017-01-01

    The Bonner Sphere Spectrometer (BSS) system is a well-established technique for neutron dosimetry that involves detection of thermal neutrons within a range of hydrogenous moderators. BSS detectors are often used to perform neutron field surveys in order to determine the ambient dose equivalent H*(10) and estimate health risk to personnel. There is a potential limitation of existing neutron survey techniques, since some detectors do not consider the direction of the neutron field, which can result in overly conservative estimates of dose in neutron fields. This paper shows the development of a Geant4 simulation application to characterise a prototype neutron detector based on three orthogonal (3)He tubes inside a single HDPE sphere built at the Australian Nuclear Science and Technology Organisation (ANSTO). The Geant4 simulation has been validated with respect to experimental measurements performed with an Am-Be source.

  12. Evaluer des études de gestion des entreprises : combiner des éléments principales avec des éléments pratiques

    NARCIS (Netherlands)

    Pennink, B.J.W.

    2002-01-01

    Evaluer la recherche de gestion demande une combinaison des critères classiques et des critères pratiques. Par cette combinaison il est possible de trouver une réponse cerrecte concernant la validité et l'effet de la recherche. Dans cet article nous allons décrire comment une combinaison des

  13. GEANT4 simulation and evaluation of a time-of-flight spectrometer for nuclear cross section measurements in particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gruenwald, Oxana

    2011-06-08

    In 2007 a new project has been launched in a cooperation between the RWTH Aachen Physics Department, the University Hospital Aachen and the Philips Research Laboratories. The project aim is to validate and improve GEANT4 nuclear interaction models for use in proton and ion therapy. The method chosen here is the measurement of nuclear reaction cross sections which will not only provide a comparison to the simulation but will also allow to improve some of the parameters in the nuclear models. In the first phase of the project 200 MeV protons are used as a projectile in combination with a thin graphite target. For use in particle therapy the excitation functions of the most frequently produced isotopes need to be measured with an accuracy of 10% or less. For this purpose a dedicated detector system has been designed and implemented in GEANT4. The detection of target fragments produced by protons in graphite is achieved via time-of-flight spectrometry. In the setup presented here the primary beam first hits the Start detector and initiates the time-of-flight measurement before it passes through the apertures of two Veto detectors and impinges on the target. Successively, the secondary particles emanating from the target travel a short distance of 70/80 cm through vacuum (0.1 mbar) before they hit one of the 20 Stop detectors which end the time-of-flight measurement and record the energy deposited by the particle. The dissertation at hand describes the underlying detector concept and presents a detailed GEANT4 simulation of the setup which allows to evaluate the detector performance with respect to target fragment identification at a projectile energy of 200 MeV. At first, correlations of time-of-flight and energy deposition are built from simulated data and are subsequently used to reconstruct mass spectra of the detected fragments. Such influences on the detection performance as the target thickness, the residual pressure within the detector chamber, the Veto system

  14. Alimentation des tortues terrestres herbivores

    OpenAIRE

    Morin, Nicolas

    2015-01-01

    Chez les tortues, la plupart des affections rencontrées sont directement ou indirectement liées à un défaut dans les conditions d’entretien et notamment à une alimentation inadéquate. Les ouvrages de référence ne proposent généralement que des rations qualitatives déterminées empiriquement. Ce travail se veut une synthèse bibliographique des différents travaux qui ont été menés sur les tortues terrestres herbivores, dont le but est de dégager les paramètres physiologiques sous-jacents au ...

  15. LES APPROCHES PSYCHOSOCIOLOGIQUES DES ORGANISATIONS

    Directory of Open Access Journals (Sweden)

    Deaconu Alecxandrina

    2008-05-01

    Full Text Available Les préoccupations pour bien comprendre la complexité des organisations sont bien connues dans la théorie et la pratique du management. La motivation la plus fréquente pour toutes les recherches et les investigationes faites a été fondée sur le besoin de savoir gérer les situations diverses en vue de maximiser la performance organisationnelle. En ce qui nous concerne, pour enrichir les informations disponibles, nous voulons élargir, dans notre communication, les approches traditionelles, focaliser l’attention sur la dimension psychologiques des organisations et présenter les mécanismes qui favorisent l’implication des salariés.

  16. L’Internet des objets

    OpenAIRE

    Benghozi, Pierre-Jean; Bureau, Sylvain; Massit-Folléa, Françoise

    2012-01-01

    L’ « internet des objets » est une dimension majeure de l’internet du futur. Mais tout le monde ne s’accorde pas encore sur sa définition, ni sur la mesure de son importance économique ou des risques qu’il induit. L’étude de nombreux rapports prospectifs et l’observation des innovations d’ores et déjà engagées a permis de mettre en relief les incertitudes techniques, économiques et socio-politiques qui pèsent sur cette véritable mutation programmée de l’internet et de proposer une approche eu...

  17. L’Internet des objets

    OpenAIRE

    Benghozi, Pierre-Jean; Bureau, Sylvain; Massit-Folléa, Françoise

    2012-01-01

    L’ « internet des objets » est une dimension majeure de l’internet du futur. Mais tout le monde ne s’accorde pas encore sur sa définition, ni sur la mesure de son importance économique ou des risques qu’il induit. L’étude de nombreux rapports prospectifs et l’observation des innovations d’ores et déjà engagées a permis de mettre en relief les incertitudes techniques, économiques et socio-politiques qui pèsent sur cette véritable mutation programmée de l’internet et de proposer une approche eu...

  18. Géographie des cryptarchies

    Directory of Open Access Journals (Sweden)

    Gilles Fumey

    2002-06-01

    Full Text Available Si toute la surface du globe est appropriée, certains territoires sont encore revendiqués par des personnes ou petits groupes usurpateurs, conquérants ou aventuriers. Leur «conquête» porte sur des espaces physiques ou virtuels (internet. Elle traduit avec constance dans l'histoire le rôle considérable de l'ancrage territorial qui reste, pour l'homme, un antidote à toutes les formes d'organisation qui le dépassent.

  19. Cardiotoxicité des psychotropes

    OpenAIRE

    TAHIRI, Abdallah

    2013-01-01

    Même à dose thérapeutique, les médicaments psychotropes sont susceptibles d'engendrer des troubles du rythme cardiaque graves avec risque létal concourant à expliquer la pré valence de la mort subite dans la population psychiatrique. Les situations cliniques à risque telles que poly médication (des psychotropes entre eux ou d'un psychotrope avec un non psychotrope allongeur de QTc), interactions médicamenteuses aussi bien pharmacodynamiques que pharmacocinétiques, traitement pa...

  20. Physique statistique des Fluides Classiques

    OpenAIRE

    Aslangul, Claude

    2006-01-01

    0 - Préambule.Préambule, table des matières1 - Rappels sur la description d'un système à l'équilibre thermodynamiqueQuelques propriétés des systèmes macroscopiques. Nature statistique de l'entropie. Grandeurs internes et grandeurs externes. Relations thermodynamiques fondamentales. Potentiels thermodynamiques. Ensembles microcanonique, canonique, grand-canonique et isotherme - isobare. Exemple: fonction de partition d'un fluide classique. Principe variationnel pour l'énergie libre.2 - Stabili...