نتایج جستجو برای: neutron
تعداد نتایج: 46140 فیلتر نتایج به سال:
Neutron diffraction analysis was employed to measure residual stresses near welds in used anhydrous ammonia nurse tanks. Tensile residual stresses contribute to stress corrosion cracking of nurse tanks, which can cause tanks to release toxic ammonia vapor. The analysis showed that tensile residual stresses were present in the tanks measured, and the magnitudes of these stresses approached the y...
Monte Carlo calculation of shielding parameters for fast neutrons in newly developed heavy concretes
Introduction: The role of radiotherapy as a part of cancer management increases every year around the world. Thus, Radiation protection in the design of radiotherapy rooms are of great importance. Materials and Methods: In present study using Monte Carlo method, MCNPX code, fourteen types of developed high density concretes with densities ranging from 2.45 ...
The potential of using Cf-252 to treat cancer patients was first described by Shlea and Stoddard in 1965 as a source of neutrons using brachytherapy procedures [Stoddard, 1986]. In the late 1960’s and early 1970’s, the United States and England initiated human clinical trials of Cf-252 neutron brachytherapy (NBT) for treating patients of various cancer types. These earlier trials treated only v...
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...
The most important part of neutron therapy treatment (NCT1) is to achieve a beam of neutrons with suitable energy and intensity, as well as the least pollution and damage. In this study, in order to correct the neutron spectrum from D-D fusion and its use in neutron therapy, a set of different materials which are called the Beam Shaping Assembly (BSA) was placed in the direction of energy 2.45 ...
The silver activation counters are commonly used for pulsed-neutron yield measurements especially in plasma focus devices. The counter normally consists of a Geiger-Muller tube along with silver foils and polyethylene (as a moderator), which is calibrated against an Am-Be radioisotope neutron source. The neutrons, after being slowed-down in the polyethylene, activate the silver foils. By measur...
Bi-based and Ag-doped superconductors were irradiated by neutrons. Experimental result showed that XRD patern-intensity of irradiated Bi-based sample was decreased and The Tc of these samples were decreased by 7-10 K. The neutron irradiated sample was also found to decrease by 50% the normal state resistivity of samples. Therefore, neutron irradiation is a useful method to improve the supercon...
Introduction: One of the concerns about using of high energy photons in radiotherapy is neutron contamination production. The threshold energy of photoneutron production in most materials with high atomic number is about 7MeV. Therefore, it seems to be logical that the main components with high atomic number elements used in the LINAC head have a large contribution to the neutr...
Neutron individual dosimetry is challenging subject in dosimetry field. Thermoluminescent dosimeter (TLD) is one of the types of personal dosimeters that is extremely used to determine the doses of neutron sources. Typically, this type of dosimeter is used in different centers with a variety of applications after calibration with a standard neutron radiation sources. Usually, materials of TL cr...
In this project the neutron spectra from the reaction of deutron on beryllium muclei is measured. The energies of deuterons were 7, 10, 13 and 15 MeV, and these measurements are performed at 10, 30 and 50 degrees relative to the beam of deutrons. The detector used is 76 by 76 mm right circular cylender of NE-213 liquid scintillator. The zero crossing technique is used for gamma discriminatin....
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