Study the Effect of Weight Fractions of Different Powders on the Attenuation Performances of the Epoxy Composite

2021 ◽  
Vol 19 (9) ◽  
pp. 142-151
Author(s):  
Khaled W. Yahya ◽  
Edrees E. Khadeer
Keyword(s):  
Free Path ◽  
Attenuation Coefficient ◽  
Lead Oxide ◽  
High Weight ◽  
Weight Fraction ◽  
Mean Free Path ◽  
X Rays ◽  
X Ray ◽  
Industry Research ◽  
Medical Facilities

Among all types of radiation, X-ray has always garnered the most interest, owing to the growing availability of X-ray tubes in industry, research institutions, and medical facilities. In this research, the linear (μl) and mass (μm) attenuation coefficient, half value layer (HVL) and mean free path (λ) of the epoxy polymer-based composites which includes both lead oxide (Pb3O4), mixture of (Fe2O3 + Pb3O4) and barium sulfate (BaSO4) with different weight percentages were determined experimentally for the incident photon energies of (29-35 kV) emitted from (X-rays) source. The dispersion of the filler was also investigated using a scanning electron microscope to examine the composites morphology. The obtained results showed that adding these powders to epoxy has an effect on the X-ray shielding abilities of the prepared composites, meaning that there is a direct relationship between the weight ratios of the composite material with the linear (μl) and mass (μm) attenuation coefficient, and an inverse relationship with the half value layer (HVL) and free path rate (λ). While changing the X-ray shield with applied voltages showed a behavior opposite to what was mentioned above. The result also shows that the lead oxide (Pb3O4) composites yield better attenuation performance than the pure epoxy and the other two composites, especially at high weight fraction (50 Wt.%) of this filler, which due to the high density of these fillers and fine dispensability in the polymer matrix.

scholarly journals Study the effect of addition Rockwool fibers on the Shielding Radiation  for the X-ray of Low Density Polyethylene (LDPE): دراسة تأثير إضافة ألياف الصوف الصخري على الحجب الإشعاعي للأشعة السينية للبولي اثيلين واطىئ الكثافة

2020 ◽  
Vol 4 (2) ◽  
Author(s):  
Shaymaa H. Jasim, Wisam A. Radhi, Riyadh M. Ramadhan, Raed M
Keyword(s):  
Free Path ◽  
Attenuation Coefficient ◽  
Mean Free Path ◽  
Weight Percent ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
X Ray ◽  
Minimum Value ◽  
Maximum Value ◽  
The Mean

The extinction of X-rays (radiation attenuation) was studied using the low-density samples of polyethylene polymer to which the rockwool fibers powder is added as filled filler. This latter was blended with (weight percent) and with a micro-filler (filler particle) the sizes equal to or less than<212 μm. Furthermore, the free path average and linear attenuation coefficient were calculated.  Experimental results showed that the rockwool fibers powder act to reduce the spaces between polymer chains particularly when the weight percent is more than (10%), which implies the capability of the polymer/filler to make, the X-rays applied to the samples; disappear at these rates used in this study. The experimental work was conducted by applying a radiation beam having an energy of 30 kV based on the use of the X-ray unit with two tubes which are; X-ray generating tube and G-M detector with an energy of VG.M =600. The magnitudes of the mean free path are inversely proportional to the weight percent of the compound material whereas the proportionality of these percentages which are particularly the high ones which occur at experimental values of the linear attenuation coefficient. The value of the mean free path of 1.28 cm is the maximum value obtained at a weight percent of 1 %, whereas the minimum value of the mean path was 0.877 cm at a weight percent of 10 %. In addition, the maximum value of the attenuation coefficient obtained is 4.754 cm-1 at a weight percent of 10% and its minimum value at a weight percent of 1% was 0.7 cm-1. The maximum value of transmittance and the minimum value of absorbance were obtained at a weight percent of 10%, are (31.8) and (68.2) respectively. Through the practical results that we obtained that are better suited to high percentages more additive proportions can be used than the percentages used in this research to shielding X-rays more.

A Universal Equation for the Emission Range of X Rays from Bulk Specimens

2007 ◽  
Vol 13 (5) ◽  
pp. 354-357 ◽  
Author(s):  
Raynald Gauvin
Keyword(s):  
Electron Beam ◽  
Free Path ◽  
Beam Energy ◽  
Mean Free Path ◽  
Electron Beam Energy ◽  
X Rays ◽  
Bulk Materials ◽  
Universal Equation ◽  
Electron Trajectories ◽  
X Ray

The derivation of a universal equation to compute the range of emitted X rays is presented for homogeneous bulk materials. This equation is based on two fundamental assumptions: the φ(ρz) curve of X-ray generation is constant and the ratio of the emitted to the generated X-ray range is equal to the ratio of the emitted to the generated X-ray intensity. An excellent agreement is observed with data obtained from Monte Carlo simulations of 200,000 electron trajectories in C, Al, Cu, Ag, Au, and an Fe–B alloy with boron weight fractions equal to 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.99, performed with the electron beam energy varied from 1 to 30 keV in 1-keV steps. When the ratio of the generated X-ray range to the photon mean free path is much smaller than one, the emission X-ray range is equal to the generated X-ray range, but when this ratio is much greater than one, the emission X-ray range is constant and is given by the product of the effective photon mean free path multiplied by the sine of the take-off angle.

scholarly journals ‘Diffuse scattering" of the Fermi electrons in monovalent metals in relation to their electrical resistivities

1948 ◽  
Vol 194 (1037) ◽  
pp. 185-205 ◽  
Keyword(s):  
Form Factor ◽  
Free Path ◽  
Attenuation Coefficient ◽  
Structure Factor ◽  
Diffuse Scattering ◽  
Wave Length ◽  
Mean Free Path ◽  
X Rays ◽  
Electrical Resistivities ◽  
The Mean

The main step in the calculation of the electrical resistivities of monovalent metals, in which the conduction electrons are almost completely degenerate, is the calculation of the relaxation time τ of the electrons at the Fermi surface, which in these metals is a sphere, and is well inside the first Brillouin zone. Since the wave-length λ , and hence the group velocity v , of the Fermi electrons is known, the calculation of τ means also the calculation of the mean free path l = vτ of these electrons. Now the finite mean free path of these electrons arises from the scattering—particularly the large-angle scattering—of these electrons in their passage through the crystal, by the thermally agitated atoms. Hence a detailed knowledge of the scattering coefficient of the crystal for the Fermi electrons, incident and scattered along different directions in the crystal, will enable us to calculate τ or l . Now the scattering coefficient depends on two factors. 1. The atom form factor for scattering, which in monovalent metals may be taken to be isotropic, i.e. independent of the direction of incidence or of scattering separately, but dependent on the angle of scattering ɸ between them, and on λ . (Extensive measurements are available on the scattering of slow electrons by the rare gases, which give us information regarding the atom form factors for the scattering of the Fermi electrons in the corresponding alkali metals, and the variation of these factors with ɸ .) 2. The structure factor of the crystal, which, besides being a function of λ , will vary, even in a cubic crystal, with the direction of incidence and of scattering, but will, however, be independent of the nature of the waves, i.e. independent of whether they are X-rays, or electron or neutron waves. (The ‘diffuse scattering’ of X-rays of long wave-lengths in crystals has been studied in great detail, both theoretically and experimentally, from which one can calculate the structure factors of the monovalent metals for their respective Fermi wave-lengths, for different directions of incidence and of scattering in the crystals.) Using these data for the atom form factor and for the structure factor of the crystal, the mean free path of the Fermi electrons is calculated in detail in the present paper for different directions of incidence, for one typical monovalent metal, namely sodium crystal. The free path l is given by 1/ l = ψv 2 kTβσ , where v is the number of atoms per unit volume, σ is the cross-section of the atom for total scattering in all directions, β is the compressibility, and ψ is a numerical factor which varies from a maximum of about 2.2 for incidence along [110] to a minimum of about 0.9 for incidence along [100], its average value being close to the minimum, and nearly unity. With ψ actually unity, the right-hand side of the above expression for 1/ l can be seen to be just the Einstein-Smoluchowski expression for the attenuation coefficient of a liquid medium for long waves: which shows that in sodium, and presumably in the other monovalent metals also, the mean free path of the Fermi electrons may be taken roughly as the reciprocal of the attenuation coefficient of the crystal due to scattering, and the scattering may be regarded as due almost wholly to the local thermal fluctuations in density, and the Fermi wave-length as long enough for the Einstein-Smoluchowski formula for density-scattering to be applicable.

scholarly journals Calculate the Attenuation of X-ray radiation for low density polyethylene composites with oyster shells powder extracted from the Caspian Sea in Iran: حساب الحجب الإشعاعي للأشعة السينية لبوليمر البولي اثيلين واطئ الكثافة والمطعم بمسحوق قشور المحار المستخرج من بحر قزوين

2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Ahmed Jassim Mohammed, Riad Manadi Ramadan, Raed Muslim Shab
Keyword(s):  
Free Path ◽  
Attenuation Coefficient ◽  
Caspian Sea ◽  
Mean Free Path ◽  
Low Density Polyethylene ◽  
Linear Attenuation Coefficient ◽  
Low Density ◽  
The Caspian Sea ◽  
X Ray ◽  
The Mean

In this research, Calculation the Attenuation of X-ray radiation for low density polyethylene composites with oyster shells powder (extracted from the Caspian Sea in Iran), low density polyethylene production in the form of powder by the State Company for Petrochemical Industries (Basra-Iraq), the range of the added of oyster shells powder (extracted from the Caspian sea in Iran) has the values (0%, 2.5%, 5%, 10%, 15%, 20%, and 25%) for low density polyethylene weight and the added oyster shells powder with the particular size (≤ 250 μm). were investigated through several variables, such as, linear attenuation coefficient(μ) and mean free path(λ). The obtained results were appeared that the added oyster to reduce the spaces between the polymer chains, which reflects the high ability of the polymer as (10%-20%), and this increase will give further property that increase the attenuation x-ray of the prepared specimens. Where the practical study and the beam of intensity of energy (30 kv) and)VG.M = 600 voit(. The results showed that when increasing filler content, the total linear attenuation coefficient increases while the mean free path decreases. The mean free path (λ) at (2.5%) is (2.1 cm (, while at (20%) is (0.40 cm). The value of the linear attenuation coefficient (μ) at (20%) is)2.44 cm-1(, while at (2.5%) is) 0.49 cm-1(.

scholarly journals Diffusive transport of energetic electrons in the solar corona: X-ray and radio diagnostics

2018 ◽  
Vol 610 ◽  
pp. A6 ◽  
Author(s):  
S. Musset ◽  
E. P. Kontar ◽  
N. Vilmer
Keyword(s):  
Solar Corona ◽  
Free Path ◽  
Electron Distribution ◽  
Transport Model ◽  
Imaging Spectroscopy ◽  
Mean Free Path ◽  
Diffusive Transport ◽  
X Rays ◽  
Energetic Electrons ◽  
X Ray

Context. Imaging spectroscopy in X-rays with RHESSI provides the possibility to investigate the spatial evolution of X-ray emitting electron distribution and therefore, to study transport effects on energetic electrons during solar flares. Aims. We study the energy dependence of the scattering mean free path of energetic electrons in the solar corona. Methods. We used imaging spectroscopy with RHESSI to study the evolution of energetic electrons distribution in various parts of the magnetic loop during the 2004 May 21 flare. We compared these observations with the radio observations of the gyrosynchrotron radiation of the same flare and with the predictions of a diffusive transport model. Results. X-ray analysis shows a trapping of energetic electrons in the corona and a spectral hardening of the energetic electron distribution between the top of the loop and the footpoints. Coronal trapping of electrons is stronger for radio-emitting electrons than for X-ray-emitting electrons. These observations can be explained by a diffusive transport model. Conclusions. We show that the combination of X-ray and radio diagnostics is a powerful tool to study electron transport in the solar corona in different energy domains. We show that the diffusive transport model can explain our observations, and in the range 25–500 keV, the scattering mean free path of electrons decreases with electron energy. We can estimate for the first time the scattering mean free path dependence on energy in the corona.

scholarly journals X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2212
Author(s):  
Worawat Poltabtim ◽  
Ekachai Wimolmala ◽  
Teerasak Markpin ◽  
Narongrit Sombatsompop ◽  
Vichai Rosarpitak ◽  
...  
Keyword(s):  
Impact Strength ◽  
Water Absorption ◽  
Attenuation Coefficient ◽  
Bismuth Oxide ◽  
Morphological Properties ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
Equivalent Thickness ◽  
X Ray ◽  
The Impact

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

scholarly journals 1/4 Ke V Diffuse Background and the Local Interstellar Medium

1989 ◽  
Vol 120 ◽  
pp. 536-536
Author(s):  
S.L. Snowden
Keyword(s):  
Interstellar Medium ◽  
Filling Factor ◽  
Thermal Emission ◽  
Mean Free Path ◽  
Physical Parameters ◽  
X Rays ◽  
Local Interstellar Medium ◽  
X Ray ◽  
Diffuse Background ◽  
X Ray Background

The 1/4 keV diffuse X-ray background (SXRB) is discussed in relation to the local interstellar medium (LISM). The most likely source for these soft X-rays is thermal emission from a hot diffuse plasma. The existence of a non-zero flux from all directions and the short ISM mean free path of these X-rays (1020HI cm-2), coupled with ISM pressure constraints, imply that the plasma has a local component and that it must, at least locally (nearest hundred parsecs), have a large filling factor. Our understanding of the geometry and physical parameters of the LISM is therefore directly tied to our understanding of the SXRB.

Routine Determination of X-Ray Detector Efficiencies Using Submicron Spheres of Pure Materials

1985 ◽  
Vol 43 ◽  
pp. 416-417
Author(s):  
Thomas F. Kelly
Keyword(s):  
Electron Microscope ◽  
Energy Range ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Characteristic Line ◽  
X Rays ◽  
Detector Efficiency ◽  
X Ray ◽  
Transmission Electron

The purpose of this paper is to outline an approach to routine determination of x-ray detector efficiencies over the entire applicable energy range that may be used on any transmission electron microscope.BACKGROUNDThe quantification of x-ray intensities using the ratio technique can be accomplished [see, for example, 1] using a relation of the form:Here, for element A, CA is the composition in the sample as a weight fraction, kA is the x-ray generation constant (see below) which contains only sample-dependent information, eA is the detector efficiency for characteristic x-rays which contains only detector-dependent information, and lA is the measured x-ray intensity in a characteristic line.

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