نتایج جستجو برای: neutron contamination

تعداد نتایج: 98839  

Journal: :international journal of nanoscience and nanotechnology 2013
sh. sohrabnezhad* d. rezaei ochbelgh n. morsali golboos

in this research, cobalt and nickel sulfide nanoparticles (nps) were grown on almcm-41 matrix by using ion exchange method. the prepared samples were irradiated by thermalized neutron that emitted from am-be source up to fluencies (7.9+e9n/cm2). after that, x-ray diffraction (xrd), uv-vis spectroscopy, fourier transform infrared (ftir), scanning electron microscopy (sem) and transmission electr...

ژورنال: سنجش و ایمنی پرتو 2020

Neutron Generators (NG) are used as a neutron source for different applications. During recent years, major efforts are underway to develop a high yield compact NG. In this way, radiation protection aspects need to be considered during the operation of these high yield NGs. In this paper the neutron effective dose of a NG operator has been calculated using MCNPX Monte Carlo code. The results sh...

ژورنال: سنجش و ایمنی پرتو 2015

In this study, a mixture of waste lead mine Nakhlak and cement with different percentages of boric acid are used to construct a proper shield for gamma and neutron radiations emitted from the Am-Be source. Neutron dose rate reduction ​​by the prepared samples was investigated by thermal neutron irradiation system of Isfahan University, TLD 600 and TLD 700. Neutron dose rate changes, compressive...

2011
M. E. Christy W. Melnitchouk

Over the past decade measurements of unpolarized structure functions with unprecedented precision have significantly advanced our knowledge of nucleon structure. These have for the first time allowed quantitative tests of the phenomenon of quark-hadron duality, and provided a deeper understanding of the transition from hadron to quark degrees of freedom in inclusive scattering. Dedicated Rosenb...

2004
Martin C. Weisskopf Eileen Collins

We present here an overview of the status of the Chandra X-ray Observatory which has now been operating for five years. The Observatory is running smoothly, and the scientific return continues to be outstanding. We provide some details on the molecular contamination of the ACIS filters and its impact on observations. We review the observations with Chandra of the pulsar in the Crab Nebula and a...

Journal: :The Astrophysical journal 2000
Qian

I show that recent observations of r-process abundances in metal-poor stars are difficult to explain if neutron star mergers (NSMs) are the major r-process sources. In contrast, such observations and meteoritic data on 182Hf and 129I in the early solar system support a self-consistent picture of r-process enrichment by supernovae (SNe). While further theoretical studies of r-process production ...

2009
H.J.M. Hanley Howard J. M. Hanley

Small angle neutron scattering (SANS) data are reported from a system that models the contamination of a clay/organic matter soil from a fuel spillage. The soil was represented as an aqueous dispersion of the synthetic clay mineral Laponite coated with lysine, and the contaminant was a representative jet fuel, quadricyclane, mixed with the detergent cetyltrimethylammonium bromide (CTAB). The ad...

Journal: :iranian journal of astronomy and astrophysic 0
mohsen bigdeli department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran nariman roohi department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran mina zamani department of physics, university of zanjan, p.o. box 45195-313, zanjan, iran

in the present work, we have obtained the equation of state for neutron star matter considering the in uence of the ferromagnetic and antiferromagnetic spin state. we have also investigated the structure of neutron stars. according to our results, the spin asymmetry sti ens the equation of state and leads to high mass for the neutron star.

Journal: :journal of biomedical physics and engineering 0
m m firoozabadi university of birjand gh izadi vasafi k karimi-sh university of birjand m ghorbani

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  10 b ,  157 gd  and  33 s  ne...

A. Vejdani-Noghreiyan, H. Miri-Hakimabad, H. Panjeh,

Background: Prompt gamma neutron activation analysis (PGNAA) is known as a non-invasive technique capable of measuring elemental concentration in voluminous samples in a short period of time. Also it is a valuable diagnostic tool for total body elemental measurements. 252Cf and 241Am-Be sources which are usually used in this method, generate not only neutrons, but also emit high-energy and unwa...

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