scholarly journals Shielding Properties Enhancement of Bentonite Clay Nano Particles Coated by Polyvinyl Alcohol Polymer

Author(s):  
Fawzy Hammad Sallam ◽  
Eman Mohamed Ibrahim ◽  
Sayed Fahmy Hassan ◽  
Ahmed Omar

Abstract Calcination process is a method used for gamma rays mass attenuation coefficient enhancement of natural bentonite clay nano-particles. This process eliminates water and organic matter from bentonite clay structure which have low mass attenuation coefficient values. There are two opposite effects on mass attenuation coefficient values; oxides content increases after calcination process which enhances mass attenuation coefficient values and particle size of calcinated bentonite increases which decreases mass attenuation coefficient values. In order to enhance mass attenuation coefficient value for natural bentonite, a physical ball milling must introduced after calcination process that decreases particle size. Calcination process is done at 700 ̊C for two hours because dehydration is completed above 500 ˚C while dehydroxylation observed at 700 ˚C. Mass attenuation coefficients are measured for calcinated and ball milled bentonite clay at different energies (662, 1173 and 1332 keV) and different pressing pressures (50, 100 and 150 bar). Narrow beam transmission technique and two different sources (Cs-137 and Co-60) are used for mass attenuation coefficient measurements, also particle size are measured by two different methods dynamic light scattering and Williamson-Hall size analyses using XRD patterns. All samples are coated by polyvinyl alcohol polymer.

Author(s):  
F Kazemi ◽  
S Malekie ◽  
M A Hosseini

Background : In recent years, there has been an increased interest toward non-lead radiation shields consisting of small-sized filler particles doped into polymer matrices. In this paper, we study a new polyvinyl alcohol (PVA)/WO3 composite in the presence of high-energy gamma photons through simulation via the Monte Carlo N-Particle (MCNP) simulation code.Materials and Methods: An MCNP geometry was first designed in the software based on real-life conditions, and the generated geometry was validated by calculating the mass attenuation coefficient and making relative comparisons with standard tables. Using the lattice card in the MCNP input file, WO3 was considered as a filler dispersed in a PVA polymer at sizes of 10 µm and 30 nm with a weight concentration of 50 wt%. By defining 106-photons emitted from point sources corresponding to 662, 778, 964, 1112, 1170, 1130 and 1407 keV energy levels, and the F4 tally used to estimate the cell average flux, the values for mass attenuation coefficient and half-value layer (HVL) were calculated.Results: The results show that PVA/WO3 composite can be considered to shield X and γ-rays in the mentioned energies. However, nano-WO3 has a better ability to shield in comparison with the micro-WO3 fillers. The differences in attenuation changed at different energy levels, ascribed to the dominance of pair production occurrence and photon interactions in the composite, which was in good agreement with previous studies.Conclusion: Our finding showed that the composite can be considered as a lead-free shielding material.


2016 ◽  
Vol 675-676 ◽  
pp. 730-733
Author(s):  
Chumphon Khobkham ◽  
W. Chaiphaksa ◽  
P. Limkitjaroenporn ◽  
P. Prongsamrong ◽  
P. Wiwatkanjana ◽  
...  

In this work, the total mass attenuation coefficient and partial interactions of the zirconium alloy have been calculated by WinXCom program at 1 keV-100 MeV gamma ray energies. Zr2(Fe,Ni) alloys was studied for the mass attenuation coefficients, photoelectric absorption, incoherent, coherent and pair production processes. The effective atomic numbers and electron densities were also calculated. The calculated results show that the total mass attenuation coefficient decreased with increasing of gamma rays energy. The value of total mass attenuation coefficient of each material was different, which depend on chemical compositions of alloy. The partials interactions, effective atomic numbers and electron densities were also calculated and discussed.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
J. A. R. Borges ◽  
L. F. Pires ◽  
J. C. Costa

With increasing demand for better yield in agricultural areas, soil physical property representative measurements are more and more essential. Nuclear techniques such as computerized tomography (CT) and gamma-ray attenuation (GAT) have been widely employed with this purpose. The soil mass attenuation coefficient (μs) is an important parameter for CT and GAT analysis. When experimentally determined (μes), the use of suitable sized samples enable to evaluate it precisely, as well as to reduce measurement time and costs. This study investigated the representative elementary length (REL) of sandy and clayey soils forμesmeasurements. Two radioactive sources were employed (241Am and137Cs), three collimators (2–4 mm diameters), and 14 thickness (x) samples (2–15 cm). Results indicated ideal thickness intervals of 12–15 and 2–4 cm for the sources137Cs and241Am, respectively. The application of such results in representative elementary area (REA) evaluations in clayey soil clods via CT indicated thatμesaverage values obtained forx > 4 cm and source241Am might induce to the use of samples which are not large enough for soil bulk density evaluations (ρs). As a consequence,ρsmight be under- or overestimated, generating inaccurate conclusions about the physical quality of the soil under study.


Author(s):  
Ayano Shanko, MD, Et. al.

The aim of the research is to estimate the X-ray shielding properties of different glass systems using Monte Carlo Simulation. X-ray glass is also known as radiation shielding glass. Glass provides protection against the absorption of energy radiation. The shielding layer is formed by a high concentration of lead and barium. The mass attenuation coefficient, the effective atomic number and the effective electron density are used to determine the position of gamma-ray photons in matter. Shield characterization in terms of mass attenuation coefficient (μm), transmission fraction (T), effective atomic numbers (Zeff), half-value layer (HVL) and exposure build-up. factor (EBF) of a glass system is estimated by the Monte Carlo Simulation. The random sampling and statistical analysis are computed using the monte carlo simulation. Various external factors are considered as the input parameters. The different composition of the glass will be examined using the Monte Carlo simulation and the shielding capability would be determined for the various samples.


2021 ◽  
Vol 19 (6) ◽  
pp. 107-114
Author(s):  
Mohammed Yahya Hadi ◽  
Ali Hussein F. Alnasraui ◽  
Ali Adil Turki Aldalawi

The purpose of this paper is to determine the mass attenuation coefficient (μ/ρ), of a sample. In this work used (C16H32O2) fatty acid, exposed to gamma rays (γ), emitted from various sources 57Co, 133Ba, 22Na, 137Cs, 54Mn, and sCo with energies from 0.122 to 1.330 MeV. It exposes the compound to gamma rays and discloses the radiation force that passes through the sample, the rest of the gamma radiation attenuated. A NaI fluorescence detector (Tl) with an accuracy of 8.2% (at 662 kV) was used for the gamma ray detector beam. An advantage of using (μ/ρ) coefficient data can be obtained effective atomic numbers, atomic cross-section and effective electron densities.


2020 ◽  
Vol 393 (1) ◽  
pp. 2000095
Author(s):  
A. Manjunath ◽  
A. Ashwini ◽  
B. R. Kerur ◽  
G. M. Pushpanjali

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