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Exposure Buildup Factors of High-Energy Gamma Rays for Water, Concrete, Iron, and Lead
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Exposure Buildup Factors of High-Energy Gamma Rays for Water, Concrete, Iron, and Lead
作者:
HirayamaHideo,
期刊:
Nuclear Technology
(Taylor Available online 1987)
卷期:
Volume 77,
issue 1
页码: 60-67
ISSN:0029-5450
年代: 1987
DOI:10.13182/NT87-A33952
出版商: Taylor&Francis
数据来源: Taylor
摘要:
AbstractExposure buildup factors for plane normal sources have been calculated with an electron gamma shower Monte Carlo code, EGS4, for water, concrete, iron, and lead in the 10 to 100 MeV range. Electron reactions like multiple scattering, collision, and continuous energy loss are taken into account together with bremsstrahlung. The buildup factors in this energy region are affected very much by the energy loss mechanism of electrons and positrons in the medium. The energy of electrons or positrons in lead is mainly converted to photons via the bremsstrahlung reaction; therefore, buildup factors increase rapidly with the increase of the photon energy. In the case of water, the energy of electrons or positrons is mainly spent in ionization or excitation. Buildup factors for water decrease gradually to 40 MeV and increase gradually above that energy. The buildup factors in each medium are calculated for eight-source energy from 10 to 100 MeV for penetration depths as great as 10 mfp.
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