Deterministic and Monte Carlo codes for multiple scattering photon transport (original) (raw)
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Multiple scattering in the Compton effect. II. Analytic and numerical treatment of energy profiles
Physical Review A, 1976
Energy profiles are calculated for photons scattered twice from stationary electrons in a cylindrical sample of infinite radius. Both double-Compton (inelastic) and one-Rayleigh (elastic), one-Compton events are treated. Klein-Nishina, Thomson, and isotropic differential cross sections are employed. It is found that at the energies typically used in y-ray experiments, the different cross sections result in significantly different energy profiles and angular distributions, while at x-ray energies the form of the cross section is (as expected) considerably less important. Sample thickness and choice of primary scattering angle are found to have major effects on the shapes of the double-scattered profiles.
Unbiased Monte Carlo simulation of the compton profile
Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms, 2007
Recent comparisons between analytical (deterministic) computations using the code SHAPE, and Monte Carlo (MC) simulations of Compton scattering using different codes show discrepancies in the shape of the Compton peak (the so-called Compton profile), specially for medium-low energy X-ray excitation. Considering the analytical computations as a reference model, the standard approach adopted for generating the Compton profile in different MC codes (EGSnrc, MCNP, MCSHAPE) has been studied comparatively in order to discover a reason for the difference. Apparently there is a bias in the profile generation which is common to all the codes and is related to the assumption of completely populated atomic orbitals contributing to the scattering. Such an assumption does not agree with the equivalence condition between the integrated Compton profile in the Impulse Approximation (IA) and the Waller-Hartree (WH) scattering function.
Simulation of inverse Compton scattering and its implications on the scattered linewidth
Physical Review Accelerators and Beams
Rising interest in inverse Compton sources has increased the need for efficient models that properly quantify the behavior of scattered radiation given a set of interaction parameters. The current state-of-theart simulations rely on Monte Carlo-based methods, which, while properly expressing scattering behavior in high-probability regions of the produced spectra, may not correctly simulate such behavior in lowprobability regions (e.g. tails of spectra). Moreover, sampling may take an inordinate amount of time for the desired accuracy to be achieved. In this paper, we present an analytic derivation of the expression describing the scattered radiation linewidth and propose a model to describe the effects of horizontal and vertical emittance on the properties of the scattered radiation. We also present an improved version of the code initially reported in Krafft et al. [Phys. Rev. Accel. Beams 19, 121302 (2016)], that can perform the same simulations as those present in CAIN and give accurate results in low-probability regions by integrating over the emissions of the electrons. Finally, we use these codes to carry out simulations that closely verify the behavior predicted by the analytically derived scaling law.
McShape: A Monte Carlo Code for Simulation of Polarized Photon Transport
2000
MCSHAPE, a new Monte Carlo code based on the recent analytical solution of the vector transport equations in plane geometry including polarization effects, was developed to provide a proper description of the polarization state evolution of photons through multiple scattering collisions. The code considers a detailed description of the prevailing interactions in the X-ray regime (Rayleigh and Compton scattering, and
Validation of Compton Scattering Monte Carlo Simulation Models
2014
Abstract—Several models for the Monte Carlo simulation of Compton scattering on electrons are quantitatively evaluated with respect to a large collection of experimental data retrieved from the literature. Some of these models are currently implemented in general purpose Monte Carlo systems; some have been implemented and evaluated for possible use in Monte Carlo particle transport for the first time in this study. Here we present first and preliminary results concerning total and differential Compton scattering cross sections. I.
Generation of primary photons through inverse Compton scattering using a Monte Carlo simulation code
2022
Photon sources based on inverse Compton scattering, namely, the interaction between relativistic electrons and laser photons, are emerging as quasimonochromatic energy-tunable sources either as compact alternatives to synchrotron facilities for the production of low-energy (10-100 keV) x rays or to reach the 1-100 MeV photon energy range, which is inaccessible at synchrotrons. Different interaction layouts are possible for electron and laser beams, and several applications are being studied, ranging from fundamental research in nuclear physics to advanced x-ray imaging in the biomedical field, depending on the radiation energy range, intensity, and bandwidth. Regardless of the specific application, a reliable tool for the simulation of the radiation produced is essential for the design, the commissioning, and, subsequently, the study and optimization of this kind of source. Different computational tools have been developed for this task, based on both a purely analytical treatment and Monte Carlo simulation codes. Each of these tools has strengths and weaknesses. Here, we present a novel Monte Carlo code based on GEANT4 for the simulation of inverse Compton scattering in the linear regime. The code produces results in agreement with CAIN, one of the most used Monte Carlo tools, for a wide range of interaction conditions at a computational time reduced by 2 orders of magnitude. Furthermore, the developed tool can be easily embedded in a GEANT4 user application for the tracking of photons generated through inverse Compton scattering in a given experimental setup.
Radiation Physics and Chemistry, 2010
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The Monte Carlo code MCSHAPE: Main features and recent developments
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015
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.