Cross sections for electron and photon processes required by electrontransport calculations

by James Mack Peek

Publisher: Dept. of Energy, Sandia Laboratories, Publisher: for sale by the National Technical Information Service] in Albuquerque, N.M, [Springfield, Va

Written in English
Published: Pages: 121 Downloads: 57
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Subjects:

  • Electron transport.,
  • Photons.

Edition Notes

StatementJames M. Peek, Theoretical Division 4221, Sandia Laboratories ; prepared by Sandia Laboratories for the United States Department of Energy.
SeriesSAND ; 79-0772, SAND (Series) (Albuquerque, N.M.) -- 79-0772.
ContributionsUnited States. Dept. of Energy., Sandia Laboratories., Sandia Laboratories. Theoretical Division 4231.
The Physical Object
Pagination121 p. :
Number of Pages121
ID Numbers
Open LibraryOL17650714M

Thomson scattering is the elastic scattering of electromagnetic radiation by a free charged particle, as described by classical is the low-energy limit of Compton scattering: the particle's kinetic energy and photon frequency do not change as a result of the scattering. This limit is valid as long as the photon energy is much smaller than the mass energy of the particle. AN EVALUATION OF BREMSSTRAHLUNG CROSS-SECTIONS FOR keV TO GeV ELECTRONS By AN EVALUATION OF BREMSSTRAHLUNG CROSS-SECTIONS FOR keV TO GeV ELECTRONS By Anne-Sophie T. Leclère Bremsstrahlung process is the primary source of x-ray production in electron-photon transport codes. A discussion of the electron transport modeling including both. It can be found in any quantum electrodynamics book that the cross section for electron-positron scattering in the high energy limit is \begin{equation} \dfrac{\mathrm{d} \sigma}{\sin \theta \, \. Description: More details of photon interactions are revealed, and a couple of mistakes from the previous day are corrected. The Klein-Nishina cross section is introduced to explain the angle-energy dependence of Compton scattering. A “from-scratch” gamma counting spectrum is created from the individual photon interactions.

The formula of the differential bremsstrahlung cross section was integrated over all angles, except the angle between the direction of the incident electron and that of emitted photon. The comparison of the differential and integral cross sections of the bremsstrahlung with the corresponding Bethe-Heitler formulas was made. Photon transport mode I Photon transport mode was introduced in version in I Photon transport can be used for elements Z= 1 to 99 I Energy range of photons from 1 keV to MeV I No electron transport, bremsstrahlung production is taken into account with the thick-target bremsstrahlung (TTB) approximation I Data: Most of the interaction data is from ENDF-B-VII.1 (form factors File Size: 1MB. Abstract. The kinematics of electron-positron pair production and annihilation, i.e., the determination and transformation of the momenta and energies of particles and photons upon the transition from an arbitrary reference frame to the center-of-mass frame of the particles and back, is analyzed in by: 1. For comparison, according to section in the same book, the cross-section for Compton scattering is $$ \sigma \sim \frac{\alpha^2}{m^2}. \tag{2} $$ So the cross-section for photon-photon scattering is smaller than the cross-section for photon-electron scattering by a factor of $$ \sim \alpha^2\,\left(\frac{\omega}{m}\right)^6.

@article{osti_, title = {The TORT three-dimensional discrete ordinates neutron/photon transport code (TORT version 3)}, author = {Rhoades, W A and Simpson, D B}, abstractNote = {TORT calculates the flux or fluence of neutrons and/or photons throughout three-dimensional systems due to particles incident upon the system`s external boundaries, due to fixed internal sources, or due to. @article{osti_, title = {Status of electron transport in MCNP{trademark}}, author = {Hughes, H G}, abstractNote = {The latest version of MCNP, the Los Alamos Monte Carlo transport code, has now been officially released. A variety of new features are available in MCNP4B. Among these are differential operator perturbations, cross section plotting capabilities, enhanced diagnostics for. MCNP5 is a general-purpose Monte Carlo N–Particle code that can be used for neutron, photon, electron, or coupled neutron/photon/electron transport, including the capability to calculate eigenvalues for critical systems. Some of the new features of MCNP include: o Adjoint-weighted Tallies for Point Kinetics Parameters. Charge-changing processes include one electron loss from He 2+ and He +, two electron loss from He 2+, one electron capture by He 0 and He +, and two electron capture by He 0. In both cases, all cross sections below 1 MeV are based on semi-empirical models and Cited by:

Cross sections for electron and photon processes required by electrontransport calculations by James Mack Peek Download PDF EPUB FB2

Electron transport calculations rely on a large collection of electron-atom and photon-atom cross section data to represent the response characteristics of the target medium.

These basic atomic-physics quantities and certain qualities derived from them that are now commonly in use, are critically reviewed. Get this from a library. Cross sections for electron and photon processes required by electrontransport calculations.

[James Mack Peek; United States. Department of Energy.; Sandia Laboratories.; Sandia Laboratories. Theoretical Division ]. Electron transport codes require extensive information on the cross sections that govern electron interactions with the atoms that make up the medium.

These processes include bremsstrahlung production in the atomic field, excitation and ionization of atomic electrons, and elastic scattering by screened atomic by: This paper describes the rather accurate Monte Carlo model and cross sections that have been used to calculate effects from electrons and photons on measurement, electronic and biological systems in space.

A number of applications are illustrated, with emphasis Author: Stephen M. Seltzer. James M. Peek, “Cross-sections for Electron and Photon Processes Required by Electron-Transport Calculations,” Sandia National Laboratories report SAND (Albuquerque, New Mexico, November ).Cited by: 1.

The scope our work included: development and implementation of: 1) discrete ordinates electron transport calculations for electron sources both within and incident of solid structures; 2) discrete Author: Stanley Woolf.

electron-volts to tens of mega-electron-volts. In Section II.B we review how the interaction cross sections vary with energy and atomic number in order to make clear which processes are relevant in a given simulation. Detailed formulas for cross sections and angular distributions are left to code documentation and textbooks.

Photons. provides analytic expressions for the elastic cross sections of group I and II elements that are quite precise in a wide energy range. This is the main theme of the present paper.

The incentive for this undertaking stems from the long-standing need to simplify the calculation of electron transport coefficients. In fact this workCited by: 2. Multigroup data produced by the CEPXS cross-section-generating code is needed to operate the BFP codes in adjoint electron-photon mode.

cross-section (e.g., for the calculation of the radiative stopping power), or in the cross-section differential in one variable (e.g., differential in the photon energy to get the spectrum of. MCNPX is a general purpose three dimensional Monte Carlo code that can be used for neutron, photon, electron and heavy ion transport.

It is released with the required libraries for neutrons, photons, electrons, protons and photonuclear interactions [9].Cited by: PHOTON TRANSPORT LOGIC 13 10− 2 10− 1 Incident γ energy (MeV) 10− 2 10− 1 σ (cm 2 /g) Total photon σ vs γ− energy Hydrogen Water Lead energy.

processes are much smaller than cross sections for charged particles undergoing inelastic electron collisions •photons are not degraded in energy as they pass through matter •the processes either absorb the photon or scatter them out of the beam •thus, the photon that. The experimental and theoretical study of atomic inner-shell ionization cross- sections by electron impact, a subject of scientific study for many years, is important both for understanding the.

This is a database primarily of total ionization cross sections of molecules by electron impact. The database also includes cross sections for some atoms and energy distributions of ejected electrons for H, He, and H 2.

The cross sections were calculated using the Binary-Encounter-Bethe (BEB) model. The various features of electron/photon transport and its applications have been organized into four main categories. These are (a) Input Data (cross sections for the physical interactions which we discussed in 2), (b) Mathematical Methods and Models, (c) Benchmark Experimental Data, and (d) Applications.

Excitation cross sections. Summary This document is part of Subvolume C ‘Interactions of Photons and Electrons with Molecules’ of Volume 17 ‘Photon and Electron Interactions with Atoms, Molecules and Ions’ of Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms.

Cross sections and energy deposition. The electron pseudo-cross sections used in MultiTrans calculations were created by CEPXS program (Lorence et al., ). Multigroup photon–electron cross sections in 35 photon groups and 35 electron groups were Cited by: 5.

A fast electron was released with kinetic energy AF (g) which was also followed to its degradation. MORSE-ESDM produced condensed histories of electron energy degradation since the fractional energy loss for group advance was calculated as an Monte Carlo electron-transport calculations Eo E -~Emod + E E o/2 E 'o ~~ ~Ecat Eo/2 Fig.

by: 1. Figure 1 presents a summary of the photon cross section data as used by the EGS3 system. Note the % discontinuity in the gamma mean free path at 50 MeV which occurs because the data of Storm and Israel (8t70) are used for the pair production cross sections below 50 MeV and a different normalization is used above Size: 1MB.

If instead of a neutral atom, how- ever, the electron interacts with a positively charged ion, D. Mueller / Electron - ion collision cross sections V(r) 4 - it is generally accepted that direct measurement of the cross section using the colliding beams technique can provide the most definitive by: 2.

Research on photon and electron collisions with atomic and molecular targets and their ions has seen a rapid increase in interest, both experimentally and theoretically, in recent years.

the dynamics of many particle systems at a fundamental level and partly because their detailed understanding is required in many other fields, particularly. From the photon–electron scattering cross-section, find the bremsstrahlung cross-section in a collision between a fast electron and a nucleus.

Solution. In the frame of reference K 1 in which the electron is at rest before the collision, the process may be regarded as the scattering by the electron of the equivalent photons of the field of. The generation of high-order neutron scattering cross sections consistent with high-fidelity simulations remains an area of active research.

Popular options include generating cross sections from continuous energy Monte Carlo calculations or generating cross sections from a deterministic neutron transport calculation with high-fidelity tabulated cross sections.

A significant advance came with the atomic photoeffect cross section calculations by Rakavy and Ron (, ) for not only the K shell, but also for all the significantly contributing higher subshells (L I–III, M I–V, N I–VII, and O I–III) over the energy range 1 keV to Cited by: Review of photon interaction cross section data R5 to =ˆD.˙pe + ˙incoh + ˙coh + ˙pair + ˙trip/=uA (7) referring back to equation (5) for the meaning and units of the conversion factor 1=uA.

The cross sections for the individual processes are discussed in section 3, particularly the cross. For photoionization both include cross sections for all subshells. 3) Both include data up to GeV.

4) Both use the same atomic parameters, in particular for consistency with the Livermore Evaluated Electron Data Library (EEDL) [5], both use the same photoionization subshell binding by: photon disapp ears and an electron is ejected from atom. The electron carries a w y all of the energy absorb ed photon, min us binding the electron to atom.

The K-shell electrons are most tigh tly b ound, and are imp ortan t con tributions to the atomic photo e ect cross-section in most cases.

Ho w ev er, if the photon energy drops b elo w the File Size: KB. Contents Abstract Statement Acknowledgements Symbols and Abbreviations Preface 1 Photon and Electron Physics at Therapeutic Energies Introduction I.2 Photon interactions L Introduction I Compton scattering I Photoelectric absorption Pair production.

I Attenuation coefrcients tx xl xlll xv)(TK 1 t 2 2 2 3 4 b I Fluence 7File Size: 8MB. multi-group differential photon scattering cross section, electron-to-photon production cross section, electron scat-tering cross section, and photon-to-electron production cross section, respectively. These scattering or production cross sections are provided by the CEPXS in multi-group Legendre form.

Estimating the lifetime of an electron on a virtual level with the photon energy of about 1 eV 0 ~ s and assuming the absorption cross section of excited electrons in all virtual levels to be equal to 1, one obtains two-photon absorption cross section to be 2 = 1 Cited by: 1.In this article the general methodology for continuous-energy adjoint Monte Carlo neutron transport is reviewed and extended for photon and coupled neutron-photon transport.

In the latter cases the discrete photons generated by annihilation or by neutron capture or inelastic scattering prevent a direct application of the general by: Absorption cross section is a measure for the probability of an absorption process.

More generally, the term cross section is used in physics to quantify the probability of a certain particle-particle interaction, e.g., scattering, electromagnetic absorption, etc. (Note that light in this context is described as consisting of particles, i.e., photons.).