Deterministic and Monte Carlo codes for multiple scattering photon transport (original) (raw)
2012, Applied Radiation and Isotopes
https://doi.org/10.1016/J.APRADISO.2011.11.046
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Abstract
AI
This paper explores deterministic and Monte Carlo methods for photon transport in contexts involving multiple scattering phenomena. Significant biases in Compton profile simulations at low energies using traditional algorithms were identified, necessitating corrections through unbiased algorithms and coupled photon-electron simulations. Results indicate that adjustments for inner shell impact ionization are essential for accurate photon scattering models.
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Radiation Physics and Chemistry, 2010
This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are
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MCSHAPE is a general purpose Monte Carlo code developed at the University of Bologna to simulate the diffusion of X- and gamma-ray photons with the special feature of describing the full evolution of the photon polarization state along the interactions with the target. The prevailing photon-matter interactions in the energy range 1–1000 keV, Compton and Rayleigh scattering and photoelectric effect, are considered. All the parameters that characterize the photon transport can be suitably defined: (i) the source intensity, (ii) its full polarization state as a function of energy, (iii) the number of collisions, and (iv) the energy interval and resolution of the simulation. It is possible to visualize the results for selected groups of interactions. MCSHAPE simulates the propagation in heterogeneous media of polarized photons (from synchrotron sources) or of partially polarized sources (from X-ray tubes). In this paper, the main features of MCSHAPE are illustrated with some examples and a comparison with experimental data.
Compton Scattering: A Theory and Experiments
Introduction: Compton scattering is a technique for determining the momentum distribution of electrons in condensed matter. When monochromatic photons are Compton scattered (inelastically scattered) in a fixed direction, the observed energy spectrum of the scattered photons is Doppler-broadened due to the motion of the target electrons. The objective of this review is to present the Compton scattering theory to researchers generally unfamiliar with this phenomenon and to lead the researchers to understanding of the fundamental principles of the Compton Scattering Theory and of the way in which they are employed in logical deductions and analyses. In this review, the theoretical and experimental considerations and energy limitations of the Compton scattering method are discussed. The method for extracting information about ground-state electron momentum densities through an analysis of the Compton line shape is presented. The various Compton sources and Compton scattering in current use are reviewed. Since 1970 Compton profile measurements have become more frequent and the experimental results for many Z-elements reported in the literature have been quoted to an accuracy of better than 1% for the total profiles. Today the Compton scattering is acknowledged as an important technique for investing the electronic structure of materials; it provides a sensitive test for the accuracy of the resulting electron wave functions obtained from different theoretical models. This has been demonstrated in view of the Compton scattering experiments successfully performed over a wide range of incident photon energies (10-662 KeV) used in various Compton spectrometer systems distributed around the world.
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Max Kircher, Florian Trinter, 3 Sven Grundmann, Isabel Vela-Perez, Simon Brennecke, Nicolas Eicke, Jonas Rist, Sebastian Eckart, Salim Houamer, Ochbadrakh Chuluunbaatar, 7 Yuri V. Popov, 6 Igor P. Volobuev, Kai Bagschick, M. Novella Piancastelli, 10 Manfred Lein, Till Jahnke, Markus S. Schöffler, and Reinhard Dörner ∗ Institut für Kernphysik, J. W. Goethe Universität, Max-von-Laue-Str. 1, D-60438 Frankfurt, Germany FS-PETRA-S, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, D-22607 Hamburg, Germany Molecular Physics, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany Institut für Theoretische Physik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany LPQSD, Department of Physics, Faculty of Science, University Sétif-1, 19000, Setif, Algeria Joint Institute for Nuclear Research, Dubna, Moscow region 141980, Russia Institute of Mathematics, National University of Mongolia, Ulan-Bator, Mongolia Skobeltsyn Institute of Nuclea...
Energy and intensity distributions in double photon Compton scattering
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The scattering process of a single incident photon by an electron into a final state consisting of two simultaneously emitted photons IS called double-photon Compton scattering. The theory and elementary featules of this higher order process are described. The reported experimental measurements so far on this higher order process, demonstrate conclusively its existence. Some elementary features of the theory of this process have also been conrirmed in some of the measurements.
Compton and Rayleigh double scattering of unpolarized radiation
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Analytical expressions describing double-scattering intensities of the Compton and Rayleigh effects (Compton-Compton, Compton-Rayleigh, Rayleigh-Compton, and Rayleigh-Rayleigh contributions), are deduced in the framework of the transport theory for an infinitely thick sample irradiated with collimat-ed monochromatic radiation. An orders-of-interaction solution of the integro-differential Boltzmann equation for unpolarized photons is used to separate the multiple-order terms. Interaction kernels for coherent and incoherent scattering include atomic form factors describing the effect of the electronic distribution in multielectron atoms. The total attenuation coefficient of the target takes into account, besides the mentioned scattering processes, the photoelectric effect, important in the x-ray regime. First-order Compton and Rayleigh interactions give monochromatic peaks according to the theoretical model that neglects electron motion. In contrast, Compton-Compton, Compton-Rayleigh, and Rayleigh-Compton contribute asymmetric continuous spectra whose wavelength breadths are the DuMond width and 2A, z (A, ~ is the Compton wavelength), respectively. Single-and double-scattering intensities of the Rayleigh and Compton effects are computed for pure and composite materials as a function of the exci-tation energy and the angular orientations of the incident and takeoff beams. Since absorption in the target is considered, computations can be straightforwardly compared with experimental data and with realistic Monte Carlo simulations. The agreement is good for low excitation energies because the second-order term remains dominant in multiple scattering and bremsstrahlung emission is weaker. However, for higher excitation energies the probability of higher orders of multiple scattering increases, and they cannot be neglected. Although analytical calculations are performed up to the second order in this work, a Monte Carlo simulation is used to show the importance of higher orders in light elements.
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