نتایج جستجو برای: neutron moderation
تعداد نتایج: 51301 فیلتر نتایج به سال:
Background: In neutron interaction with matter and reduction of neutron energy due to multiple scatterings to the thermal energy range, increasing the probability of thermal neutron capture by neutron captures makes dose enhancement in the tumors loaded with these materials. Objective: The purpose of this study is to evaluate dose distribution in the presence of 10B, 157Gd and 33S neutron...
Introduction: Neutrons have many applications in various fields, such as medicine. The important application of neutron in medical science is in Boron Neutron Capture Therapy (BNCT). Because of this, determination of neutron dose and flux is critical for the health maintaining of workers and patients exposed to this beam. The neutron radioisotope sources produce gamma rays in ...
One of the important neutron sources for Boron Neutron Capture Therapy (BNCT) is a nuclear reactor. It needs a high flux of epithermal neutrons. The optimum conditions of the neutron spectra for BNCT are provided by the International Atomic Energy Agency (IAEA). In this paper, Miniature Neutron Source Reactor (MNSR) as a neutron source for BNCT was investigated. For this purpose, we designed a ...
Background: Monte Carlo simulations play a vital role in the calculation of the necessary shielding both for neutrons and photons. Advanced and simple shielding materials against neutron and gamma rays were compared by simulation using the MCNB4B Monte Carlo code. The simulations were carried out for the three common neutron sources, namely the 252Cf, the 241Am/Be and the DD neutron generator w...
Background: Several landmine detection methods, based on nuclear techniques, have been suggested up to now. Neutron-induced gamma emission, neutron and gamma attenuation, and fast neutron backscattering are the nuclear methods used for landmine detection. In this paper an optimized (safe and effective) moderating structure using an 241Am-Be neutron source for detecting landmines has been invest...
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...
introduction bnct is an effective method to destroy brain tumoral cells while sparing the healthy tissues. the recommended flux for epithermal neutrons is 109 n/cm2s, which has the most effectiveness on deep-seated tumors. in this paper, it is indicated that using d-t neutron source and optimizing of beam shaping assembly (bsa) leads to treating brain tumors in a reasonable time where all iaea ...
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