نتایج جستجو برای: neutron
تعداد نتایج: 46140 فیلتر نتایج به سال:
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 ...
In this research, the applicability of several metal hydrides as neutron moderator and shielding for D-D fusion sources has been investigated by MCNPX code. The results have been investigated in three steps to find the materials with lower thermal, fast and total neutron fluxes than conventional shielding materials. The results show relative advantages of LaNi5H6, VH, TiH2, TaH, Mg (BH4)2, YH2,...
Introduction: Recently head and neck cancer has pay attention to many researchers. Its therapeutic methods include surgery, chemotherapy, radiotherapy and Boron neutron capture therapy (BNCT). BNCT is better than conventional radiotherapy because it targets the tumor cell. This method involves two steps of infusion of stable 10B and then neutron radiation with a suitable intens...
چکیده ندارد.
Background: The amount of average dose enhancement in tumor loaded with 10B may vary due to various factors in boron neutron capture therapy.Objective: This study aims to evaluate dose enhancement in tumor loaded with 10B under influence of various factors and investigate the dependence of this dose enhancement on neutron spectra changes.Material and Methods: In this simulation stud...
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A new model is presented herein to calculate optimal value for ultra-cold neutron (UCN) production rate of a UCN source. The cold neutron (CN) converter is the main component of UCN source. In this paper, we study the UCN source which contains the D2O neutron moderator, the sD2 converter, 590 Mev proton beam, and the spallation target (a mixture of Pb, D2O and Zr). In order to determine the qua...
Employing High-energy photons in medical linear accelerators can lead to neutron contamination. The relative biological effect of neutrons is 20 times higher than photons. Consequently, its damage to the biological tissue is much higher and unobtrusive. In this study, we calculated neutron equivalent dose in a medical linear accelerator by the FLUKA Monte Carlo code system. The results show tha...
Boron neutron capture therapy (BNCT) is an effective method for treatment of deep seated brain tumors. This method consists of two stages: injection of boron compound in the patient body, and then irradiation of the region tumors with the neutron beam. It allows for delivery of high linear energy transfer (LET) radiation (particles 4He and 7Li nuclei) to tumors at the cellular level whilst avoi...
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