نتایج جستجو برای: gamma and fast neutron doses
تعداد نتایج: 16894404 فیلتر نتایج به سال:
In order to gain the neutron spectrum with proper components specification for BNCT, it is necessary to design a Beam Shape Assembling (BSA), including moderator, collimator, reflector, gamma filter and thermal neutrons filter, in front of the initial radiation beam from the source. According to the result of MCNP4Csimulation, the Northwest beam tube has the most optimized neutron flux between ...
Background: The trabecular bone changes in the bia of C3H/HeN mice were measured 12 weeks a er whole body irradia on with various doses of fast neutrons (0-2.4 Gy) or 137 Cs-generated gamma-rays (0-6 Gy). Materials and Methods: Serum calcium, phosphorus, estradiol concentra on and alkaline phosphatase ac vity were measured. Tibiae were analyzed using microcomputed tomography. Biomechanical prop...
An epithermal neutron beam has been designed for Boron neutron Capture Therapy (BNCT) at the thermal column of Tehran Research Reactor (TRR) recently. In this paper the whole body effective dose, as well as the equivalent doses of several organs have been calculated in this facility using MCNPX Monte Carlo code. The effective dose has been calculated by using the absorbed doses determined for e...
Monte Carlo Method is used to simulate a double layer gadolinium-amorphous silicon thermal neutron detector. The detector fabricated in pixel array configuration has various applications including neutron imaging. According to the simulation results, a detector consisting of a gadolinium (Gd) film with thickness of 2-4 ~m, sandwiched properly with two layers of sufficiently thick (-30 ?µm) hydr...
An . in vivo micronucleus assay using mouse bone marrow for identifying radioprotective effect of cimetidine is described. The influence of cimetidine, an antagonist to histamine H2 receptor, on the kinetics of low and high LET radiations such as gamma rays and neutron induced micronuclei as well as the clastogenic effects of chemicals such as benzene, ara C and mitomycin C was tested in Swiss ...
Recently, polymeric nanocomposites have been used in dosimetry and detection of gamma rays, but due to their low photon absorption cross section, they exhibit a small sensitivity to gamma rays. In order to overcome this problem, metal oxide particles with a high atomic number are added to the polymer matrix. For this purpose, in this work, tungsten oxide particles (WO3) were distributed in poly...
Abstract Prompt gamma rays induced by inelastic scattering of fast neutrons on aluminum, titanium and copper were measured at an angle 90 o between neutron beam detector the instrument FaNGaS, operated Jülich Centre Neutron Science Heinz-Maier-Leibnitz Zentrum in Garching. The flux was 1.40 10 8 cm −2 s −1 with average energy 2.30 MeV. Intensities spectrum averaged isotopic partial cross sectio...
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 ...
Background : Performing successful BNCT experiments needs a suitable neutron source. Important factors of the neutron beam are flux and energy that are very important in the selection of neutron source. In most centers that use this method for treatment, reactor is a neutron source, which according to characteristics of the reactor appropriated neutrons are very high. High cost of constructin...
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