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Title: Poster - 18: New features in EGSnrc for photon cross sections

Abstract

Purpose: To implement two new features in the EGSnrc Monte Carlo system. The first is an option to account for photonuclear attenuation, which can contribute a few percent to the total cross section at the higher end of the energy range of interest to medical physics. The second is an option to use exact NIST XCOM photon cross sections. Methods: For the first feature, the photonuclear total cross sections are generated from the IAEA evaluated data. In the current, first-order implementation, after a photonuclear event, there is no energy deposition or secondary particle generation. The implementation is validated against deterministic calculations and experimental measurements of transmission signals. For the second feature, before this work, if the user explicitly requested XCOM photon cross sections, EGSnrc still used its own internal incoherent scattering cross sections. These differ by up to 2% from XCOM data between 30 keV and 40 MeV. After this work, exact XCOM incoherent scattering cross sections are an available option. Minor interpolation artifacts in pair and triplet XCOM cross sections are also addressed. The default for photon cross section in EGSnrc is XCOM except for the new incoherent scattering cross sections, which have to be explicitly requested. The photonuclear,more » incoherent, pair and triplet data from this work are available for elements and compounds for photon energies from 1 keV to 100 GeV. Results: Both features are implemented and validated in EGSnrc.Conclusions: The two features are part of the standard EGSnrc distribution as of version 4.2.3.2.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
22689326
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 8; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ENERGY ABSORPTION; ENERGY LOSSES; EVALUATED DATA; GEV RANGE 10-100; IMPLEMENTATION; KEV RANGE 01-10; KEV RANGE 10-100; MEV RANGE 10-100; MONTE CARLO METHOD; PHOTONS

Citation Formats

Ali, Elsayed, Mainegra-Hing, Ernesto, and Rogers, Davi. Poster - 18: New features in EGSnrc for photon cross sections. United States: N. p., 2016. Web. doi:10.1118/1.4961792.
Ali, Elsayed, Mainegra-Hing, Ernesto, & Rogers, Davi. Poster - 18: New features in EGSnrc for photon cross sections. United States. doi:10.1118/1.4961792.
Ali, Elsayed, Mainegra-Hing, Ernesto, and Rogers, Davi. Mon . "Poster - 18: New features in EGSnrc for photon cross sections". United States. doi:10.1118/1.4961792.
@article{osti_22689326,
title = {Poster - 18: New features in EGSnrc for photon cross sections},
author = {Ali, Elsayed and Mainegra-Hing, Ernesto and Rogers, Davi},
abstractNote = {Purpose: To implement two new features in the EGSnrc Monte Carlo system. The first is an option to account for photonuclear attenuation, which can contribute a few percent to the total cross section at the higher end of the energy range of interest to medical physics. The second is an option to use exact NIST XCOM photon cross sections. Methods: For the first feature, the photonuclear total cross sections are generated from the IAEA evaluated data. In the current, first-order implementation, after a photonuclear event, there is no energy deposition or secondary particle generation. The implementation is validated against deterministic calculations and experimental measurements of transmission signals. For the second feature, before this work, if the user explicitly requested XCOM photon cross sections, EGSnrc still used its own internal incoherent scattering cross sections. These differ by up to 2% from XCOM data between 30 keV and 40 MeV. After this work, exact XCOM incoherent scattering cross sections are an available option. Minor interpolation artifacts in pair and triplet XCOM cross sections are also addressed. The default for photon cross section in EGSnrc is XCOM except for the new incoherent scattering cross sections, which have to be explicitly requested. The photonuclear, incoherent, pair and triplet data from this work are available for elements and compounds for photon energies from 1 keV to 100 GeV. Results: Both features are implemented and validated in EGSnrc.Conclusions: The two features are part of the standard EGSnrc distribution as of version 4.2.3.2.},
doi = {10.1118/1.4961792},
journal = {Medical Physics},
number = 8,
volume = 43,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}