Γ-ray Attenuation Research Articles

Evaluation of gamma-ray attenuation characteristics of some thermoplastic polymers: Experimental, WinXCom and MCNPX studies

In this work, the γ-ray attenuation properties of some thermoplastic polymers as widely used materials in nuclear medical diagnosis and treatment have been studied. The mass attenuation coefficient (μm) of all selected polymer samples have been measured using NaI (Tl) detector, WinXCom Program and MCNPX simulation at photon energies 122-1332 keV. Further, μm values were used to estimate other related parameters including linear attenuation coefficient, total molecular, atomic, and electronic cross-sections, effective atomic number, effective electron density, relaxation length, HVL and TVL. Results show that the theoretical and simulation values of attenuation parameters are in satisfactory agreement with experimental results. However, the experimental values of μm have been found to be closer to those calculated by MCNPX than the values obtained by WinXCom. In addition, the effectiveness of well-known thermoplastic polymer materials in nuclear medicine application at different photon energies has been compared and discussed.

Investigation of γ-ray attenuation coefficients, effective atomic number and electron density for ZnO/HDPE composite

Bulk and nano ZnO/HDPE composite with different weight fractions (10, 20, 30 and 40%) of ZnO as a filler were prepared and studied for radiation shielding properties against γ-ray. The structural, morphological and functional properties of the composites were identified using x-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared specrtroscopy (FTIR). The results confirmed the formation of ZnO nanoparticles with crystallite size of 27 nm and revealed their good dispersion within the polymer matrix compared to bulk ZnO as well as interaction mechanism between the filler and the polymer matrix. The mass attenuation coefficient (μm) for the composite was measured experimentally using a well calibrated high purity germanium cylindrical detector (HPGe) at energies (59.54, 356.01, 661.66, 1173.33 and 1332.50 keV) for different radioactive point sources (241Am, 133Ba, 137Cs and 60Co). The obtained attenuation coefficients were used to determine the values of total molecular cross section σmol, the total atomic cross section σatm (cm2/atom), total electronic cross-section σel (cm2/electron) effective atomic number Zeff, and effective electron number Neff. Using NIST XCOM photon cross section database, the theoretical radiation parameters were calculated for bulk ZnO/HDPE composite and compared with the experimental results of both bulk and nano ZnO/HDPE composite. The obtained results revealed good agreement compared to theoretical values. μm, σmol, and σatm values decreased with incident photon energy and increased with weight percentage of both bulk and nano ZnO filler. However, these values were greater for nano ZnO/HDPE composite compared to bulk ZnO/HDPE composite with the same weight percentage. Whereas, σel, Zeff and Neff values decreased with weight percentage and revealed a plateau region which appeared with further increase in energy.

(59.5–x) P2O5–30Na2O–10Al2O3–0.5CoO–xNd2O3 glassy system: an experimental investigation on structural and gamma-ray shielding properties

In this study, five different glasses encoded ND1, ND2, ND3, ND4 and ND5 based on (59.5–x) P2O5–30Na2O–10Al2O3–0.5CoO–xNd2O3 (x = 1, 2, 3, 4 and 5 mol%) glass system were fabricated. Using two γ- ray energies emitted from point sources, 356 keV (133Ba) and 662 keV (137Cs), γ-ray attenuation coefficients were measured as a function of the Nd2O3 concentration. The theoretical values of the mass attenuation coefficient were calculated using the XCOM program at 0.015–15-MeV photon energies. As it is underlined in the results section, the mass attenuation coefficient increases as the Nd2O3 concentration increases. X-ray diffraction (XRD) was characterized for fabricated glasses. Moreover, different shielding parameters such as half-value layer (HVL), mean free path (MFP), effective atomic numbers (Zeff), basic gamma-ray attenuation properties such as exposure buildup factors (EBF) and energy absorption buildup factors (EABF) at different penetration depths were calculated. With increasing Nd2O3 additive in glass samples, half-value layer (HVL), average free path (MFP), exposure and energy absorption buildup factor (EBF and EABF) values decrease. On the other hand, Zeff values increase with increasing Nd2O3 additive in glass samples at the photon energy 0.015–15 MeV. The results highlighted that ND5 sample with highest value of Nd2O3 (5 mol%) showed excellent nuclear radiation shielding properties.

Study on the Effect of the addition of Synthesized Nano scale Lead Oxide for Concrete Samples used in Gamma-Ray Shielding

Our goal in this research is to investigate the effect ofconcrete incorporated with nanoparticles of lead oxide inpowder form by different percentages on Gamma-ray shieldingcharacteristics. The lead oxide nanostructure was synthesizedthrough the reaction of citric acid (C6H7O8.H2O) solution andlead acetate (Pb (C2H3O2)) solution as stabilizer and precursor,respectively. In this synthesis, the prepared lead oxidenanostructure was characterized by X-Ray Diffraction (XRD)and Scanning Electron Microscopy (SEM) techniques. Theprepared PbO consists of the crystallites about 50 nm. Theconcrete samples were prepared according to the localstandards of building materials and doped with PbO nanopowders by different percentages, 0%, 5%and 10% (by weight)by replacing cement and keeping constant w/c ratio. Moreover,commercial PbO bulk powder additive was used to check theeffect of particle size on concrete attenuation properties. The γ-rays attenuation coefficients were measured as a function of theadditive percentage of nanoparticles of lead oxides and using γ-ray point source,126Ra with different energies in the range(0.295- 1.73) MeV. The results were compared with that fornormal concrete incorporated with the same percentage of bulklead oxide. It was found that the γ-ray attenuation coefficientfor concrete doped with nanoparticles of PbO was slightlyimproved.

Attenuation parameters of polyvinyl alcohol-tungsten oxide composites at the photon energies 5.895, 6.490, 59.54 and 662 keV

Abstract The growing demand for lightweight, non-toxic and effective X- and γ-ray shielding materials in various fields has led to the exploration of various polymer composites for shielding applications. In this study, tungsten filled polyvinyl alcohol (PVA) composites of varying WO3 concentrations (0 - 50 wt%) were prepared by solution cast technique. The structural, morphological, and thermal properties of the prepared composite films were studied using X-ray diffraction technique (XRD), Scanning electron microscopy (SEM) and Thermogravimetric analysis (TGA). The AC conductivity studies showed the low conductivity property of the composites. The X-ray (5.895 and 6.490 keV) and γ-ray (59.54 and 662 keV) attenuation studies performed using CdTe and NaI(Tl) detector spectrometers revealed a noticeable increase in shielding efficiency with increase in filler wt%. The effective atomic number (Zeff) calculated by the direct method agreed with the values obtained using Auto-Zeff software. The % heaviness showed that tungsten filled polyvinyl alcohol composites are lighter than traditional shielding materials.

Experimental and Monte Carlo investigations of gamma ray transmission and buildup factors for inorganic nanoparticle/epoxy composites

The integration of inorganic nanoparticles into a polymer matrix presents a category of advanced materials, known as polymer inorganic nanocomposites (PINCs). In present work, the γ-ray shielding parameters of epoxy resin loaded with two different proportions (5 and 25 wt%) of Pb, Zn, ZnO, Ti and TiO2 inorganic nanoparticles have been investigated. The prepared samples were characterized through structural investigations including SEM, EDS, XRD and FT-IR analyses. Furthermore, mechanical properties of the nanocomposites were evaluated on the basis of compressive strength. To evaluate the γ-ray attenuation performance of the nanocomposites, the transmission and flux buildup factors have been measured experimentally. The 59.54 and 662 keV γ-rays emitted from 241Am and 137Cs point sources were counted by a 2″ × 2″ NaI(Tl) detector. In addition, experimental results has been confirmed by a theoretical study using MCNPX code. The results showed that γ-ray shielding effectiveness was enhanced by the increment of the filler loading. The experimental and theoretical calculations of transmission and buildup factors were found to be in a good agreement. As expected, 25 wt% Pb/epoxy nanocomposites indicated better shielding properties than their counterparts. However, it has to be notices that the mechanical strength of Pb/epoxy nanocomposites were determined significantly lower than those of Zn, ZnO, Ti and TiO2/epoxy nanocomposites. To design and choose an appropriate shielding material, therefore, a number of factors have to be considered.

Novel neutron activation analysis scheme for determination of trace elements in medicinal plants infusion

This work is concerned with the development of a simple and accurate procedure for trace elements determination in infusion of medicinal plants using neutron activation analysis. The developed scheme involves irradiation of herb (tea in the present work) before immersion into boiled water and then analyzing the induced radioactivity in the infusion using HPGe detector to determine the concentration levels of the extracted elements. Results were corrected for geometry and γ-ray attenuation effects using Monte Carlo simulation. The effects of irradiation dose and infusion period on the extraction process were also evaluated. The developed method proved its efficiency and capability for evaluation of the daily intake of elements reach our body through consumption of medicinal plants.

TeO2–B2O3–ZnO–La2O3 glasses: γ-ray and neutron attenuation characteristics analysis by WinXCOM program, MCNP5, Geant4, and Penelope simulation codes

γ-ray, fast and thermal neutrons shielding features for five Pb-free {[(TeO2)0.70(B2O3)0.30]0.7 (ZnO)0.30}(1-x)(La2O3)x (x = 0.01, 0.02, 0.03, 0.04, and 0.05 mol%) glasses have been inspected in this work. For all samples, within the photon energy range of 0.015–15 MeV, linear attenuation coefficients (μ) and mass attenuation coefficients (μ/ρ) were estimated using WinXCOM program (theoretical approach), and obtained μ/ρ values are in fine agreement with computed μ/ρ results of respective MCNP5, Geant4, and Penelope codes. By utilizing μ/ρ values of WinXCOM, γ-ray attenuation parameters like effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), and mean free path (MFP) were assessed within 0.015–15 MeV photon energy range, for all samples. Additionally, exposure buildup factors (EBFs) and energy absorption buildup factors (EABFs) were calculated for all samples by applying a five parameter geometric progression (G‒P) fitting method as a function of various penetration depths (1, 5, 10, 15, 20, 25, 30, 35, and 40 mfp) within 0.015–15 MeV photon energy range. The derived radiation protection efficiency (RPE) results indicate all samples' effective attenuation competence for lower energy γ-rays. Among all glasses, 46.55TeO2-19.95B2O3-28.5ZnO–5La2O3 (mol%) sample, by having relatively bigger μ/ρ and Zeff, minimal HVL and MFP, and lowest EBF and EABF, endorse its' excellent γ-ray shielding effectiveness. Further, neutron shielding parameters such as macroscopic removal cross-section for fast neutrons (ΣR), coherent and incoherent scattering cross-sections (σcs & σics), absorption cross-section (σA), and total cross-section (σT) for thermal neutrons were explored. By using the Geant4 code, ‘σT’ values have been deduced within 10−4‒10−8 MeV neutron energy range. The 46.55TeO2-19.95B2O3-28.5ZnO–5La2O3 (mol%) glass owns relatively larger ΣR (0.1474 cm−1) for fast neutrons attenuation and ‘σT’ (10.1444 cm−1 at 0.0253 eV neutron energy, 15.9824 cm−1 → 0.551 cm−1 from 1 × 10−8 MeV →1 × 10−4 MeV neutron energy) for thermal neutrons absorption, respectively, revealing its' superior neutrons shielding ability.

Investigation of physical, mechanical and gamma-ray shielding properties using ceramic tiles incorporated with powdered lead oxide

Standard ceramic tiles doped with powdered, micro-sized lead oxide (PbO) were manufactured with weight fractions (2.5%, 5%, 7.5% and 10%) and investigated for γ-ray shielding ability. Several methods were used to characterize the newly fabricated ceramic samples. These included Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), energy dispersive X-ray (EDX), scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM). The mechanical properties of assembled ceramic composites were examined and their modulus of rupture (MOR) was calculated. Results revealed that the values of MOR varied between 1.884 and 2.158 MPa, as the content of PbO increased from 0.0 to 10.0 wt% in the ceramic body. Physical properties, such as density and percentage of water adsorption, were determined. To evaluate γ-ray attenuation coefficients (μm) of the investigated samples, different energies in the range of 59.53–1332.50 keV were applied and a NaI detector was used to measure photon intensities, as a function of the weight percentage of PbO. Confirmation of the accuracy of these results was performed, when a comparison was made with the theoretical values obtained from the XCOM simulation code. Two more parameters were tested to ensure the shielding capabilities of the new composites, namely the half value layer (HVL) and the mean free path (MFP). These values were calculated to reveal that the ceramic composite containing 10 wt% PbO exhibited the highest μm and lowest MFP and HVL values of all other tested composites. The outlined results confirm the significant improvement in γ-ray shielding properties of ceramic tiles as the wt% of PbO increased from 0.0 to 10.0 wt%.

Physicomechanical and gamma-ray shielding properties of high-strength heavyweight concrete containing steel furnace slag aggregate

An extensive review of literature on heavyweight concrete (HWC) reveals that this material is not economical to produce due to the required use of expensive special heavyweight aggregates and high water-to-cement (W/C) ratios. This study aimed to develop the utilization of steel furnace slag (SFS), as an aggregate to produce high-strength HWC with optimized water content for gamma (γ) ray shielding. A method was established for the optimization of the volumetric ratio of fine and coarse SFS aggregates and their influence on the cement content. Meanwhile, the optimum W/C ratio was determined to improve the performance of concrete. Thirteen concrete mixes were prepared by utilizing SFS as fine and coarse aggregates with the addition of a superplasticizer very-high-range water reducer admixture [VHRWRA] as a modern chemical admixture to achieve high strength after extensive mix design development. An investigation program was implemented in two parts. Firstly, compressive strength and density were determined after 7, 28, 56 and 90 days for the first six mixes with various W/C ratios between 0.2 and 0.45. Secondly, the properties of concrete mixes with different binder and aggregate ratios (C1S2G4, C1S1.5G3, C1S2G3, C1S2.5G3, C1S2.5G2.5, C1S2.5G2, and C1S3G2) were examined in terms of fresh density and workability in fresh concrete. The mechanical strength, durability and γ-ray shielding properties of the hardened concrete were also evaluated. Results showed that the use of third-generation VHRWRA reduced the W/C ratio to 0.23 whilst maintaining desirable workability. The concrete's compressive strength reached 106 MPa at 28 days, and all of the concretes' mechanical, durability and the γ-ray attenuation properties were improved. These observations show SFS is suitable to be used as aggregates (fine and coarse) in HWC to provide protection from radioactive rays.

B2O3–Bi2O3–TeO2–BaO and TeO2–Bi2O3–BaO glass systems: a comparative assessment of gamma-ray and fast and thermal neutron attenuation aspects

For Pb-free 35B2O3‒35Bi2O3‒(30–x)TeO2‒(x)BaO (x = 5, 10, 15, 20, and 25 mol%) and (90–x)TeO2‒10Bi2O3‒(x)BaO (x = 10, 15, and 20 mol%) glass systems, gamma and neutron (both fast and thermal neutron) radiation shielding features were examined and compared. Within 0.015–15 MeV photon energy, mass attenuation coefficients (μ/ρ), for all samples, which have been assessed using WinXCOM program are in fair agreement with deduced MCNP5 simulation code μ/ρ results. For all selected samples, at the lowest energy, μ/ρ has bigger values whereas at higher energy regions possess lower values. Furthermore, by employing μ/ρ values, effective atomic number (Zeff), effective electron density (Neff), half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP) are figured out for both glass systems. For studied samples, with the gradual replacement of TeO2 content with BaO, the derived values of Zeff, HVL, TVL, and MFP revealed improved γ-ray shielding potentiality. Besides, within photon energy range of 0.015–15 MeV, exposure build-up factors (EBFs) and energy absorption build-up factors (EABFs) were estimated for all samples by utilizing G‒P fitting method as a function of different penetration depths (0.5, 1, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 35, and 40 mfp). The 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) glass relatively larger μ/ρ and Zeff values, lower HVL, TVL, and MFP values, and minimal EBF and EABF values confirm its superior γ-ray attenuation competence among all samples. Additionally, in comparison, HVL and MFP values of 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) sample are lower than the respective values of some commercial γ-ray shielding glasses and different types of standard concretes, signifying its better shielding features than them. Moreover, macroscopic removal cross-section for fast neutrons (ΣR), coherent scattering cross-section (σcs), incoherent scattering cross-section (σics), absorption cross-section (σA), and total cross-section (σT) for thermal neutrons absorption were derived for both glass systems. Among all selected glasses, 35B2O3–35Bi2O3–5TeO2–25BaO (mol%) sample possesses relatively higher ΣR (0.106 cm−1) and ‘σT’ (8.809 cm−1 at 0.0253 eV neutron energy) values for fast and thermal neutrons attenuation, respectively, demonstrating its favorable absorption capability for neutrons.

A New Measurement of the Hubble Constant and Matter Content of the Universe Using Extragalactic Background Light γ-Ray Attenuation

Abstract The Hubble constant H 0 and matter density Ω m of the universe are measured using the latest γ-ray attenuation results from Fermi-LAT and Cerenkov telescopes. This methodology is based upon the fact that the extragalactic background light supplies opacity for very high energy photons via photon–photon interaction. The amount of γ-ray attenuation along the line of sight depends on the expansion rate and matter content of the universe. This novel strategy results in a value of km s−1 Mpc−1 and . These estimates are independent and complementary to those based on the distance ladder, cosmic microwave background (CMB), clustering with weak lensing, and strong lensing data. We also produce a joint likelihood analysis of our results from γ-rays and those from more mature methodologies, excluding the CMB, yielding a combined value of H 0 = 66.6 ± 1.6 km s−1 Mpc−1 and Ω m = 0.29 ± 0.02.

Fabrication and characterization of phosphotungstic acid - Copper oxide nanoparticles - Plastic waste nanocomposites for enhanced radiation-shielding

A novel (R-HDPE/CuO-NP-PTA) nanocomposite was designed based on doping recycled high-density polyethylene (R-HDPE) with phosphotungstic acid (PTA) and copper oxide nanoparticles (CuO NPs). It was prepared and investigated for the ability to shield γ-rays. The composite samples were fabricated using the compression molding technique and their characteristics were identified using the Fourier transform infrared spectrophotometer (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and a high-resolution transmission electron microscope (HR-TEM). The assembled nanocomposites were found to be highly protective from γ-rays due to the presence of high-density materials, such as phosphotungstic acid and copper oxide nanoparticles. The γ-rays attenuation coefficients were measured as a function of the percentage of PTA and CuO NPs using several γ-ray energies with point sources; 356 keV from 133Ba, 662 keV from 137Cs, 1173 and 1332 keV from 60Co. When comparing between the addition of phototungstic acid (PTA) and that of CuO NPs to R-HDPE, it was found that PTA increased the electron density (Nel), mass attenuation coefficient (μm), and effective atomic number (Zeff) of the prepared composites more than CuO NPs. The theoretical values of the mass attenuation coefficient were calculated using the XCOM program.

Excitation functions and yield measurements for Proton Induced Reactions in Stainless Steel: Special relevance to Proton Activation Analysis

In this work, the excitation functions for protons induced nuclear reactions with stainless steel's constituent elements were measured and the results were used in Proton Activation Analysis (PAA) of 18/10 steel samples which was carried out at Egyptian MGC-20 cyclotron. The elemental concentrations were also checked using the EDX technique. The reactions natFe(p,x)56Co, natNi(p,α)55Co and natCr(p,x)52gMn were studied from threshold up to 14.3 MeV proton energy. TALYS-1.6 and EMPIRE-3.2.2 codes were used to model the excitation functions of the investigated reactions. For quantitative analysis using PAA, the apparent reaction yields (i.e. not corrected for the γ-ray attenuation), were measured for each reaction along the proton energy range as well as the target thickness, and normalization factors were given.

Study of the TiO2 effect on the heavy metals oxides borosilicate glasses structure using gamma-ray spectroscopy and positron annihilation technique

Fourier transform infrared (FTIR), γ-ray attenuation and positron annihilation lifetime (PAL) spectroscopies were performed to study the physical and nanostructure properties of prepared Na2O-B2O3–PbO–SiO2–Bi2O3 (NBSi) glasses with different concentration of TiO2. The FTIR spectra of alkali lead titanate borosilicate glasses had different ratios of Bi2O3 are analyzed. The detailed examination revealed a creation of BO4 on the expense of BO3 and BiO3 structural units. This process with the increment of Bi2O3 polymerized the network of the studied glasses. The decrease in the fraction N4 indicates this process. It was found that the γ-ray attenuation parameters [the half value layer HVL, the tenth value layer TVL, the mean free path MFP, the linear attenuation coefficient μ and the mass attenuation coefficient μm] at the energy of 661.7 keV and the density ρ decreases with increasing the TiO2 contents on the prepared glasses. The size of the ortho-positronium hole volume (o-Ps) (obtained from PAL) with its contents decrease with increasing the TiO2 concentration as a result of filling the hole with TiO2. There is a fair agreement between density, relative fractional of the o-Ps open hole size and mass attenuation coefficient μm of the glass samples. The acquired results indicated a formation of non-bridging oxygens associated with the borosilicate network, which decreases its rigidity and thus, decreases its preceding physical parameters.

High energy spatially radiative properties of Vela X pulsar wind nebula

Context. Vela X is a middle-aged pulsar wind nebula (PWN) that has been detected in radio, X-ray, and γ-ray bands. The observations indicate that that photon index and flux density of the inner regions of the nebula have obvious changes as the radial distance increases in the X-ray band, and the surface brightness has been discovered to decrease with the increase of radial distance in γ-ray band. Aims. The multi-band photon emission and high energy spatially radiative properties of Vela X are investigated in the framework of a spatially dependent particle transport model. Methods. Electron distribution inside the PWN was described by a spatially dependent particle transport equation and the evolution of the non-thermal photon was described as a photon conservation equation under the assumption of a spherically symmetric system with dynamical evolution. In this model, the dynamical and particle evolution equations were simultaneously solved, and the γ-ray attenuation by the supernova remnant (SNR) photon fields in the PWN were taken into account. Results. The observed spectral energy distributions of Vela X, including X-ray spectra of the inner regions and γ-ray spectra observed at GeV and TeV bands, are well reproduced. The radial variations of the photon index in X-ray band and the surface brightness in the TeV energy range as well as the γ-ray spectra of the inner region and ring extension can also be well reproduced in the framework of our model. The spatial variations of photon indices at GeV and TeV bands are predicted and show that the photon index in GeV band increases with the increase of radial distance while there is only a slight change in the TeV band. Moreover, the modelling results reveal that the γ-ray attenuation by the SNR photon fields is important for modifying very high energy γ-ray spectrum of Vela X.

An investigation on physical, mechanical, leaching and radiation shielding behaviors of barite concrete containing recycled cathode ray tube funnel glass aggregate

In order to explore the feasibility of using hazardous waste cathode ray tube (CRT) funnel glass to replace high density mineral aggregates in the radiation shielding concrete, various barite concrete samples were prepared with portland cement, ground funnel glass sand as the substitute for barite aggregates, and fly ash as mineral admixtures, and the rates of funnel glass for fine and coarse (5–10 mm) barite aggregate were 25%, 50%, 75%, 100% and 10%, 20%, 30%, respectively. The work performance, mechanical properties, dry shrinkage, alkali-silica reaction (ASR) expansion and lead leaching were investigated, and the γ-ray attenuation coefficients were obtained by experiment, XCOM program and MCNP code. The results show that the slump, ASR expansion and lead leaching of the concrete increase while its apparent density, mechanical properties, dry shrinkage, and γ-ray shielding properties decrease with the increase of the rate of funnel glass. Adding fly ash to the concrete can inhibit the leaching of Pb, and reduce the ASR expansion. The concrete samples with 25–50% fine funnel glass sand or 10–20% 5–10 mm coarse aggregate have good performances. The results show that it’s efficient, economical and environmental-benign to use funnel glass to produce the high density radiation shielding concrete.

Study of some γ-ray attenuation parameters for new shielding materials composed of nano ZnO blended with high density polyethylene

The extensive utilization of radiation is rapidly developing worldwide involving abundant fields like medical, industrial, research, and nuclear facilities. This makes the need for studying radiation shielding materials and their properties more urgent than ever. In the present study, bulk and nano ZnO were mixed by the same ratio each time (10, 20, 30, and 40 wt.%), with high-density polyethylene as a polymer matrix and characterized by X-ray diffraction. The results confirmed the good dispersion of bulk and nano ZnO particles within the polymer matrix. The prepared composite samples were used in different thicknesses as gamma ray shielding materials, and the heaviness was calculated and compared to lead. Using HPGe detector at specific energies (59.53, 356.01, 661.66, 1173.33, and 1332.50 keV) for different radioactive point sources (241Am, 133Ba, 137Cs, and 60Co), the mass attenuation coefficient for the samples was measured experimentally. Depending upon the obtained values, the linear attenuation coefficient, half-value layer, tenth value layer, heaviness and relaxation length were estimated. Using the XCOM database, the values of linear attenuation coefficient, mass attenuation coefficient, and other parameters were calculated theoretically for the bulk ZnO blended with high-density polyethylene. The obtained results were compared to the experimental values for nano and bulk ZnO blended with high density polyethylene. The radiation shielding behavior of nano ZnO blended with high density polyethylene was found to be more promising and efficient for radiation protection against gamma ray.

Investigation of Gamma-Ray’s Transmission Geometries for the Measurement of Attenuation Coefficients

Abstract For the measurement of attenuation parameters of any material for gamma (γ)-rays, the narrow-beam transmission geometry is one of the essential requirements. Linear attenuation coefficient (μ, cm−1), half value layer thickness and mean free path are some fundamental parameters used for the analysis of γ-ray attenuation behaviour of any material. The complete experimental setup used to measure these parameters is termed as γ-ray transmission geometry. The geometrical parameters such as the size of collimator aperture, thickness of sample (absorber), source to absorber (SA) distance, absorber to detector distance and source to detector distance (STD) are deciding factors for the nature of γ-ray transmission geometry. A novel geometrical parameter, scattered-to-transmission ratio (STR), has been proposed in this investigation. STR provides qualitative information of various geometrical parameters. It provides influence on the nature of transmission geometry for experimental measurements by various geometrical parameters and buildup factor. To investigate its influence, STR values have been analysed by varying sizes of collimator aperture between 3 and 12 mm and absorber thicknesses between 20 and 280 mm for fixed SA and STD. Six standard building materials (cement black, cement white, clay, red mud, lime stone and plaster of paris) have been used for the investigation. The point isotropic γ-ray sources Cs-137 (3700 M Bq) and Co-60 (370 M Bq) have been used in this study. It has been found that STR provides better information of scattered γ-rays by the material than its buildup factor (B). Additionally, CSTR (the critical value of STR) serves as an extensive parameter to distinguish between narrow-beam (good) and broad-beam (poor) γ-ray transmission geometries.

Preparation and characterization of Bi2O3/XNBR flexible films for attenuating gamma rays

A bismuth oxide (Bi2O3)-dispersed carboxylated nitrile butadiene rubber (XNBR) flexible film was prepared as a flexible lead-free material for gamma ray (γ-ray) attenuation. However, obtaining a uniform and stable dispersion of Bi2O3 in carboxylated nitrile butadiene rubber latex (XNBRL) is a challenge due to sedimentation induced by the remarkable density differences. Here, this challenge was approached by reducing the Bi2O3 particle radius, increasing the viscosity of the latex, and adding a dispersant. The experimental results confirmed that Bi2O3 was well dispersed in the XNBRL in the concentration range of 30–70 wt%. The mechanical properties demonstrated that the Bi2O3/XNBR flexible films had a good resistance to oil, acid, alkali, and hot air. The linear attenuation coefficients of the Bi2O3/XNBR flexible films obtained from the experiments were in good agreement with the calculated values. The attenuation efficiencies of the Bi2O3/XNBR flexible films with different thicknesses and Bi2O3 contents were investigated for a few different γ-ray energies. These results showed that the Bi2O3/XNBR flexible films have wide application prospects for low-energy γ-ray attenuation.