New Photon Exposure Buildup Factors

Journal Article · Thu Feb 15 04:00:00 EST 2001 · Nuclear Science and Engineering

OSTI ID:20804698

Chibani, Omar

A New Monte Carlo code (EBUF) is developed to calculate improved point isotropic photon exposure buildup factors in media. Variance reduction techniques are used to perform calculations up to 60 mean free paths. EBUF accounts for coherent scattering and bound-electron Compton scattering. Bremsstrahlung photons and annihilation gamma rays as well as K and L X-rays are considered. The most recent cross-section data are used. The EBUF exposure buildup factors compare very well with those from the ANS-6.4.3 Working Group (ANS-6.4.3) when the same initial conditions are assumed: no coherent scattering, free-electron Compton scattering, and only K X-ray fluorescence. Next, a detailed physics treatment is used to calculate a representative set of exposure buildup factors in aluminum, iron, lead, water, air, and concrete over a large energy range (20 keV to 10 MeV). The effects of L X-rays are shown for lead at low energy. The EBUF factors are in good agreement with the SN1D code results for low-Z media. Finally, total exposure values from EBUF and ANS-6.4.3 are compared. Quite significant differences are observed because the ANS-6.4.3 calculations do not account for binding effects in Compton scattering, L X-ray fluorescence, and coherent scattering in mixtures.

• OSTI ID: 20804698
• Journal Information: Nuclear Science and Engineering, Journal Name: Nuclear Science and Engineering Journal Issue: 2 Vol. 137; ISSN NSENAO; ISSN 0029-5639
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
AIR
ALUMINIUM
ANNIHILATION
BREMSSTRAHLUNG
BUILDUP
COHERENT SCATTERING
COMPTON EFFECT
CONCRETES
CROSS SECTIONS
ELECTRONS
FLUORESCENCE
GAMMA RADIATION
IRON
KEV RANGE
LEAD
MEAN FREE PATH
MEV RANGE
MONTE CARLO METHOD
PHOTONS
PHOTONUCLEAR REACTIONS
WATER
X RADIATION