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Title: Gamma-Ray Interaction in Ge: A Monte Carlo Simulation

Abstract

The interaction of X-ray and gamma-ray photons with materials is of fundamental interest to many fields. The interaction of these primary photons with atoms results in the creation of fast electrons. Electron-solid interaction can be determined experimentally by measuring physical quantities, such as scattering cross section, but the partitioning of energy loss into different quantum mechanical processes is important to determine the mean energy required to create an electron-hole pair, W, and the intrinsic variance (or Fano factor, F) for radiation detectors. In the present work, a Monte Carlo (MC) method previously developed has been employed to simulate the interaction of photons with Ge over the energy range from 50 eV to ~1 MeV and the subsequent electron cascades. Various quantum mechanical processes for energy loss of fast electrons, which control the broadening of Fano factor, are investigated in detail. At energies lower than 1 keV, W generally decreases with increasing photon energy from 2.95 to 2.75 in Ge, whereas it has a constant value of 2.64 eV for higher energies. Also, the function, F, decreases with increasing photon energy. Above the L shell edge, F has a value of 0.11 that is smaller than that in Si (0.14). However,more » F exhibits a sawtooth variation, and discontinuities at the shell edges follow the photoionization cross section. These results are in good agreement with experimental measurements. The simulated distribution indicates that the interband transition and plasmon excitation are the most important mechanisms of electron-hole pair creation in Ge, while core shell ionization appears to be significant only at high energies.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
901165
Report Number(s):
PNNL-SA-50972
TRN: US0702523
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms, 255(1):286-290; Journal Volume: 255; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ATOMS; CROSS SECTIONS; DISTRIBUTION; ELECTRONS; ENERGY RANGE; EXCITATION; FANO FACTOR; IONIZATION; L SHELL; PHOTOIONIZATION; PHOTONS; PLASMONS; RADIATION DETECTORS; SCATTERING; SIMULATION; Monte Carlo simulation; Fano factor; W value; Ge

Citation Formats

Gao, Fei, Campbell, Luke W., Devanathan, Ram, Xie, YuLong, Zhang, Yanwen, Peurrung, Anthony J., and Weber, William J.. Gamma-Ray Interaction in Ge: A Monte Carlo Simulation. United States: N. p., 2007. Web. doi:10.1016/j.nimb.2006.11.031.
Gao, Fei, Campbell, Luke W., Devanathan, Ram, Xie, YuLong, Zhang, Yanwen, Peurrung, Anthony J., & Weber, William J.. Gamma-Ray Interaction in Ge: A Monte Carlo Simulation. United States. doi:10.1016/j.nimb.2006.11.031.
Gao, Fei, Campbell, Luke W., Devanathan, Ram, Xie, YuLong, Zhang, Yanwen, Peurrung, Anthony J., and Weber, William J.. Fri . "Gamma-Ray Interaction in Ge: A Monte Carlo Simulation". United States. doi:10.1016/j.nimb.2006.11.031.
@article{osti_901165,
title = {Gamma-Ray Interaction in Ge: A Monte Carlo Simulation},
author = {Gao, Fei and Campbell, Luke W. and Devanathan, Ram and Xie, YuLong and Zhang, Yanwen and Peurrung, Anthony J. and Weber, William J.},
abstractNote = {The interaction of X-ray and gamma-ray photons with materials is of fundamental interest to many fields. The interaction of these primary photons with atoms results in the creation of fast electrons. Electron-solid interaction can be determined experimentally by measuring physical quantities, such as scattering cross section, but the partitioning of energy loss into different quantum mechanical processes is important to determine the mean energy required to create an electron-hole pair, W, and the intrinsic variance (or Fano factor, F) for radiation detectors. In the present work, a Monte Carlo (MC) method previously developed has been employed to simulate the interaction of photons with Ge over the energy range from 50 eV to ~1 MeV and the subsequent electron cascades. Various quantum mechanical processes for energy loss of fast electrons, which control the broadening of Fano factor, are investigated in detail. At energies lower than 1 keV, W generally decreases with increasing photon energy from 2.95 to 2.75 in Ge, whereas it has a constant value of 2.64 eV for higher energies. Also, the function, F, decreases with increasing photon energy. Above the L shell edge, F has a value of 0.11 that is smaller than that in Si (0.14). However, F exhibits a sawtooth variation, and discontinuities at the shell edges follow the photoionization cross section. These results are in good agreement with experimental measurements. The simulated distribution indicates that the interband transition and plasmon excitation are the most important mechanisms of electron-hole pair creation in Ge, while core shell ionization appears to be significant only at high energies.},
doi = {10.1016/j.nimb.2006.11.031},
journal = {Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms, 255(1):286-290},
number = 1,
volume = 255,
place = {United States},
year = {Fri Feb 16 00:00:00 EST 2007},
month = {Fri Feb 16 00:00:00 EST 2007}
}
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