نتایج جستجو برای: buildup factors
تعداد نتایج: 1080843 فیلتر نتایج به سال:
exposure buildup factors have been calculated by monte carlo method for point isotropic gamma ray sources, penetrating a two-layer spherical shield of water surrounded by lead, and the effect of bremsstrahlung radiation on buildup factors has, in particular, been investigated, the results of which are in good agreement with previous works. the buildup factors were then calculated for various co...
This paper presents the study on the effect of detector type in estimating gamma rays buildup factor. In this regard, the flux buildup factors of gamma rays emitted by an isotropic point 60Co source in mean energy 1.253 MeV was evaluated after passing through the Pb, W, Zn, and Ti sample in thickness of 1-5 cm by MCNPX. Four common detector types in simulation of measurement was defined to esti...
Neutron dose-equivalent buildup factors were calculated for point isotropic neutron sources irradiating infinite slablike shields of lead, iron and water using the MCNP code. The factors are presented for some source neutron energies in the range from 0.025 eV to 14 MeV, and for shield thicknesses from 0.5 to 10 mfp. Since the MCNP code considers all kinds of neutron interactions with matter, a...
The exposure buildup factors are important for determining the shield thickness of gamma and X-ray. Without taking this factor into account, the estimated thickness of the shield is less than what is expected which leads to an excessive received radiation exposure of staffs or patients. Given that the exposure buildup factor for the monoenergetic homogenous point sources have been calculated by...
The point-kernel method is a widely used practical tool for gamma-ray shielding calculations. However, application of that neutron transport simulations very limited. accuracy the strongly depends on buildup factors in Buildup are usually obtained using appropriate computer codes, either based discrete ordinates or Monte Carlo approach. Since these codes put strong demands resources, they appli...
The purpose of this study is to select the best place for the detector towards shield and the gamma source which have the least flux buildup factor of the photon. In this research, the flux buildup factor of gamma rays was calculated by using of MCNP-4C code for cylindrical sources 137Cs, 60Co, 16N coaxial shields made up of aluminum, iron and lead with a constant thickness 1.55 cm in detec...
the effects of including incoherent (bound-electron) and coherent (rayleigh) scattering in exposure buildup factor calculations for point isotropic gamma ray sources, penetrating a two-layer water-lead shield have been investigated in the gamma ray energy (e?) range of 40 kev to 3 mev. incoherent scattering decreases the values of these factors in both layers up to e? ~ 200 kev and the effect i...
Exposure buildup factors for water and lead have been calculated by the Monte-Carlo method for an isotropic point source in an infinite homogeneous medium, using the latest cross secions available on the Internet. The types of interactions considered are ,photoelectric effect, incoherent (or bound-electron Compton). Scattering, coherent (or Rayleigh) scattering and pair production. Fluorescen...
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