Shielding properties of the ordinary concrete loaded with micro- and nano-particles against neutron and gamma radiations

Investigation of nano MgO loaded polyvinyl chloride polymer in protective clothing as a nonlead materials

Recently, investigation of advanced shielding materials to be used as an alternative to lead apron has become important. In the current study, MgO loaded into PVC matrix as a non-lead modern shielding composite was modeled to evaluate its performance on radiation protective clothing (RPC). Parameters such as mass attenuation coefficient (MAC), mean free path (MFP), flux buildup factor (FBF), transmission factor (TF) and lead equivalent value (LEV) of samples were calculated using MCNPX Code. The simulation of the MCNP code was validated, by comparing the mass attenuation of concrete sample, with standard XCOM data and very good agreement was attended between XCOM and MC Code results. The MAC of nano and micro-sized samples were also compared with pure PVC and it was found that the nano MgO particle exhibits higher attenuation compared to micro MgO particle and pure PVC. The results show that, the MAC of samples increased to 63.13 % in 1.332 MeV with increasing filler concentration of nano MgO to 50 wt% relative to pure PVC. Investigation of LEV shows that nano MgO sample has more effective than Pb in 1.173 and 1.332 MeV gamma ray energy so that it provides 36.46 % and 11.13 % lighter RPC than Pb ones.

Selective detection of fast and thermal neutrons in mixed-radiation fields using tungsten-silica and gold-iodine-silica nanoparticles and their boron-loaded aqueous dispersions

Tungsten-silica and gold-iodine-silica nanoparticles and their boron-loaded aqueous dispersions were used to selectively detect fast and thermal neutrons in mixed-radiation fields generated by a cyclotron on the order of mSv at a neutron flux of 1.0 ×106(neutron/sec∙cm2). The photo-image intensity, fluorescence spectra, absorption spectra, and XRD of their aqueous dispersions were measured immediately and eighteen days after irradiation. The immediate measurements of photo-image intensity and fluorescence spectral area ratios for gold-iodine-silica nanoparticle aqueous dispersions indicated the dose dependence of photo-image intensity and fluorescence spectral area ratios. Measurements of the relative fluorescence and absorption spectral areas of gold-iodine-silica nanoparticle aqueous dispersions 18 days after irradiation also showed similar dose dependences. The precipitates of gold-iodine-silica nanoparticles showed a linear relationship between the XRD peak ratio and the dose with a correlation coefficient of 0.9. The photo-image intensities, fluorescence spectral area, absorption spectral area, and XRD peak ratios were found to be affected by fast and thermal neutrons. Simple methods of fluorescence, absorption, and XRD measurements are proposed for the selective detection of fast and thermal neutrons in mixed-radiation fields.

Investigation on Physico Chemical and X-ray Shielding Performance of Zinc Doped Nano-WO3 Epoxy Composite for Light Weight Lead Free Aprons

This report addresses a way to reduce the usage of highly toxic lead in diagnostic X-ray shielding by developing a cost-effective, eco-friendly nano-tungsten trioxide (WO₃) epoxy composite for low-weight aprons. Zinc (Zn)-doped WO₃ nanoparticles of 20 to 400 nm were synthesized by an inexpensive and scalable chemical acid-precipitation method. The prepared nanoparticles were subjected to X-ray diffraction, Raman spectroscopy, UV-visible spectroscopy, photoluminescence, high-resolution-transmission electron microscope, scanning electron microscope, and the results showed that doping plays a critical role in influencing the physico-chemical properties. The prepared nanoparticles were used as shielding material in this study, which were dispersed in a non-water soluble durable epoxy resin polymer matrix and the dispersed materials were coated over a rexine cloth using the drop-casting method. The X-ray shielding performance was evaluated by estimating the linear attenuation coefficient (μ), mass attenuation coefficient (μ_m), half value layer (HVL), and X-ray percentage of attenuation. Overall, an improvement in X-ray attenuation in the range of 40-100 kVp was observed for the undoped WO₃ nanoparticles and Zn-doped WO₃ nanoparticles, which was nearly equal to lead oxide-based aprons (reference material). At 40 kVp, the percentage of attenuation of 2% Zn doped WO₃ was 97% which was better than that of other prepared aprons. This study proves that 2% Zn doped WO₃ epoxy composite yields a better particle size distribution, μ_m, and lower HVL value and hence it can be a convenient lead free X-ray shielding apron.

Shielding performance of multi-metal nanoparticle composites for diagnostic radiology: an MCNPX and Geant4 study

Lead-free polymer composite shields are used in diagnostic radiology to protect patients from unnecessary radiation exposure. This study aimed to examine and introduce the radiation-shielding properties of single- and multi-metal nanoparticle (NP)-based composites containing Bi, W, and Sn using Geant4, MCNPX, and XCom for radiological applications. The mass attenuation coefficients and effective atomic numbers of single- and multi-metal NP-loaded polymer composites were calculated using the Geant4 and MCNPX simulation codes for X-ray energies of 20-140 keV. The nano-sized fillers inside the polydimethylsiloxane (PDMS:C₂H₆SiO) matrix included W (K = 69.5 keV), Bi (K = 90.5 keV), and Sn (K = 29.20 keV). For single-metal shields, one filler was used, while in multi-metal shields, two fillers were required. The MCNPX and Geant4 simulation results were compared with the XCom results. The multi-metal NP composites exhibited higher attenuation over a larger energy range owing to their attenuation windows. In addition, Bi₂O₃ + WO₃ NPs showed a 39% higher attenuation at 100-140 keV, and that of Bi₂O₃ + SnO₂ NPs was higher at 40-60 keV. Meanwhile, the WO₃ + SnO₂ NPs exhibited lower attenuation. The difference between the results obtained using Geant4 and XCom was less than 2%, because these codes have similar simulation structures. The results show that the shielding performance of the Bi₂O₃ + WO₃ filler is better than that of the other single- and multi-metal fillers. In addition, it was found that the Geant4 code was more accurate for simulating radiation composites.

A Comparative Study on X-ray Shielding and Mechanical Properties of Natural Rubber Latex Nanocomposites Containing Bi2O3 or BaSO4: Experimental and Numerical Determination

This work experimentally determined the X-ray shielding and morphological, density, and tensile properties of sulfur-vulcanized natural rubber latex (SVNRL) nanocomposites containing varying content of nano-Bi₂O₃ or nano-BaSO₄ from 0 to 200 phr in 100 phr increments, with modified procedures in sample preparation to overcome the insufficient strength of the samples found in other reports. The experimental X-ray shielding results, which were numerically verified using a web-based software package (XCOM), indicated that the overall X-ray attenuation abilities of the SVNRL nanocomposites generally increased with increasing filler content, with the 0.25-mm-thick SVNRL films containing 200 phr of the filler providing the highest overall X-ray shielding properties, as evidenced by the highest values of lead equivalence (Pb_eq) of 0.0371 mmPb and 0.0326 mmPb in Bi₂O₃/SVNRL nanocomposites, and 0.0326 mmPb and 0.0257 mmPb in BaSO₄/SVNRL nanocomposites, for 60 kV and 100 kV X-rays, respectively. The results also revealed that the addition of either filler increased the tensile modulus at 300% elongation (M300) and density but decreased the tensile strength and the elongation at break of the Bi₂O₃/SVNRL and BaSO₄/SVNRL nanocomposites. In addition, the modified procedures introduced in this work enabled the developed nanocomposites to acquire sufficient mechanical and X-ray shielding properties for potential use as medical X-ray protective gloves, with the recommended content of Bi₂O₃ and BaSO₄ being in the range of 95–140 phr and 105–120 phr, respectively (in accordance with the requirements outlined in ASTM D3578-19 and the value of Pb_eq being greater than 0.02 mmPb). Consequently, based on the overall outcomes of this work, the developed Bi₂O₃/SVNRL and BaSO₄/SVNRL nanocomposites show great potential for effective application in medical X-ray protective gloves, while the modified procedures could possibly be adopted for large-scale production.

The Advancement of Neutron-Shielding Materials for the Transportation and Storage of Spent Nuclear Fuel

In this paper, the mechanism of neutron absorption and common reinforced particles is introduced, and recent research progress on different types of neutron-shielding materials (borated stainless steels, B/Al Alloy, B4C/Al composites, polymer-based composites, and shielding concrete) for transportation and wet or dry storage of spent fuel is elaborated, and critical performance is summarized and compared. In particular, the most widely studied and used borated stainless steel and B4C/Al composite neutron-absorption materials in the field of spent fuel are discussed at length. The problems and solutions in the preparation and application of different types of neutron-shielding materials for spent fuel transportation and storage are discussed, and their research priorities and development trends are proposed.

Physicomechanical and Antimicrobial Characteristics of Cement Composites with Selected Nano-Sized Oxides and Binary Oxide Systems

In recent years, increasing attention has been paid to the durability of building materials, including those based on cementitious binders. Important aspects of durability include the increase of the strength of the cement matrix and enhancement of material resistance to external factors. The use of nanoadditives may be a way to meet these expectations. In the present study, zinc, titanium and copper oxides, used in single and binary systems (to better the effect of their performance), were applied as additives in cement mortars. In the first part of this work, an extensive physicochemical analysis of oxides was carried out, and in the second, their application ranges in cement mortars were determined. The subsequent analyses were employed in determining the physicochemical properties of pristine oxides: Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray fluorescence (EDXRF), scanning electron microscopy (SEM), measurement of the particle size distribution, as well as zeta potential measurement depending on the pH values. Influence on selected physicomechanical parameters of the cement matrix and resistance to the action of selected Gram-positive and Gram-negative bacteria and fungi were also examined. Our work indicated that all nanoadditives worsened the mechanical parameters of mortars during the first 3 days of hardening, while after 28 days, an improvement was achieved for zinc and titanium(IV) oxides. Binary systems and copper(II) oxide deteriorated in strength parameters throughout the test period. In contrast, copper(II) oxide showed the best antibacterial activity among all the tested oxide systems. Based on the inhibitory effect of the studied compounds, the following order of microbial susceptibility to inhibition of growth on cement mortars was established (from the most susceptible, to the most resistant): E. coli < S. aureus < C. albicans < B. cereus = P. aeruginosa < P. putida.

Understanding the Effect of Introducing Micro- and Nanoparticle Bismuth Oxide (Bi2O3) on the Gamma Ray Shielding Performance of Novel Concrete

The aim of this study is to investigate the radiation shielding properties of novel concrete samples with bulk Bi₂O₃ and Bi₂O₃ nanoparticles (Bi₂O₃ NP) incorporated into its composition. The mass attenuation coefficient of the concrete samples without Bi₂O₃ and with 5 and 7 wt% bulk Bi₂O₃ were experimentally determined and were compared against values obtained using the XCOM and Geant4 simulations. Both methods greatly agree with the experimental values. The linear attenuation coefficients (LAC) of blank concrete (C-0), concrete with 5% bulk Bi₂O₃ (C-B5), and concrete with 5% nanoparticle Bi₂O₃ (C-N5) were determined and compared at a wide energy range. We found that the LAC follows the trend of C-0 < C-B5 < C-N5 at all the tested energies. Since both C-B5 and C-N5 have a greater LAC than C-0, these results indicate that the addition of Bi₂O₃ improves the shielding ability of the concretes. In addition, we investigated the influence of nanoparticle Bi₂O₃ on the LAC of the concretes. The half-value layer (HVL) for the concretes with bulk Bi₂O₃ and Bi₂O₃ nanoparticles is also investigated. At all energies, the C-0 has the greatest HVL, while C-N15 has the least. Thus, C-N15 concrete is the most space efficient, while C-0 is the least space efficient. The radiation protection efficiency (RPE) of the prepared concretes was found to decrease with increasing energy for all five samples. For C-0, the RPE decreased from 63.3% at 0.060 MeV to 13.48% at 1.408 MeV, while for C-N15, the RPE decreased from 87.9 to 15.09% for the same respective energies. Additionally, C-N5 had a greater RPE than C-B5, this result demonstrates that Bi₂O₃ NP are more efficient at shielding radiation than bulk Bi₂O₃.

Novel Cu/Zn Reinforced Polymer Composites: Experimental Characterization for Radiation Protection Efficiency (RPE) and Shielding Properties for Alpha, Proton, Neutron, and Gamma Radiations

In this study, brass (Cu/Zn) reinforced polymer composites with different proportions of brass powders were fabricated. Different types of nuclear shielding parameters such as mass and linear attenuation coefficients, radiation protection efficiency, half and tenth value layers, and effective atomic number values were determined experimentally and theoretically in the energy range of 0.060–1.408 MeV in terms of gamma-ray shielding capabilities of fabricated polymer composites. A high Purity Germanium detector (HPGe) in conjunction with a Multi-Channel Analyzer (MCA) and twenty-two characteristic gamma-ray energies have been used in the experimental phase. In addition, the exposure and energy absorption buildup factors of reinforced Cu/Zn composites were calculated, and relative dose distribution values were computed to verify them. Proton mass stopping power (Ψ_P), proton projected range (Φ_P), alpha mass stopping power (Ψ_A), and alpha projected range (Φ_A) parameters, which indicate the interactions of the produced composites with charged particle radiation, were investigated. Fast neutron removal cross-section (Σ_R) results were determined to give an idea in terms of neutron shielding. According to the obtained results, it is reported that the CuZn20 coded sample’s ability to attenuate gamma-ray and charged particle radiation is more efficient than that of other prepared composites. A CuZn05 coded sample was found to be more suitable for neutron shielding capability.

Appraisal of new density coefficient on integrated-nanoparticles concrete in nuclear protection

The most important material for shielding is concrete in nuclear facilities which performance can be improved by addition some Nanoparticles (NP) at the various concentrations. Nanoparticles, which have a distinctive potential for bio-radiation and shielding of nuclear reactors, are used in many areas due to their special characteristics, which lead to an improvement in the mechanical properties and the pore structure of the concrete shield. The aim of this research was to initiate a novel coefficient (n), experiment to theory density ratio for integrated NP at different nanoparticle concentrations (xnano), established upon purely mathematical viewpoints and some appropriate physical objectives.

Radiation Shielding Concrete with alternate constituents: An approach to address multiple hazards

Radiation Shielding Concrete (RSC) is a superior alternative to many conventional and modern shields against gamma and neutron radiation hazards. The present work is the first comprehensive review on utilization of alternate materials, emphasizing hazardous industrial byproducts, as constituents of RSC. Such usage enhances the performance, sustainability, and affordability of RSC. Added advantages are the immobilization of wastes and the conservation of natural resources for RSC. The review analyses incorporation of ferrous and non-ferrous slags, mines wastes, plastics, red mud, cathode ray tube's glass, metallic wastes, fly ash, silica fume, and miscellaneous residues. Besides, utilization of fibers, nanoparticles, and calcined clay is investigated. The influence on shielding efficiency is adjudged by scrutinizing changes in parameters such as half-value layer and linear attenuation coefficients. Similarly, variations in mechanical and durability properties are investigated and compared. The underlying responsible factors related to the physical, chemical and morphological characteristics of materials and their consequences on RSC's behavior are correlated. In association with alternatives, the advantages, disadvantages, and possible treatment methods are discussed. The country-wise, material-specific, and progressive research trends are revealed to facilitate future work in this upcoming field. Finally, conclusions are drawn with exposition of current bottlenecks and scope of future research.

Gamma / neutron radiation shielding, structural and physical characteristics of iron slag nanopowder

The current study explores the effectiveness of an iron slag nanopowder (ISNP), which prepared from local iron steel industry, against gamma/neutron shielding. The structural and physical characteristics were experimentally determined. The crystal structure, morphology and elemental composition of the ISNP were studied using X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX). On the other hand, a comprehensive experimental and theoretical study on the γ-ray shielding effectiveness of the ISNP was performed. In which, the experimental results have been validated by comparison with theoretical data which obtained by using the WinXcom program. This paper uses the well-known mathematical relationships to derive many shielding and dosimetry parameters such as effective atomic number and, effective electron density, for photon interaction and photon energy absorption as well as the γ-ray kerma coefficient from the mass attenuation coefficient. The exposure and energy absorption buildup factors have been also calculated. Furthermore, the shielding effectiveness against thermal and fast neutrons has been tested in terms of total macroscopic cross-sections. The results have revealed that the produced ISNP, with crystallite size of 24.5 nm, exhibits good shielding characteristics. Finally, based on this preliminary study, we can have concluded that the iron slag nanoparticles can be suitably used as an effective and safe (lead - free) component for radiation shielding.

Shielding characteristics of nanocomposites for protection against X- and gamma rays in medical applications: effect of particle size, photon energy and nano-particle concentration

In recent decades, nanomaterials have been extensively investigated for many applications. Composites doped with different metal nanoparticles have been suggested as effective shielding materials to replace conventional lead-based materials. The use of concretes as structural and radiation protective material has been influenced by the addition of nanomaterials. Several elements with high atomic number and density, such as lead, bismuth, and tungsten, have the potential to form nanoparticles that offer significant enhancements in the shielding ability of composites. Their performance for a range of particle concentrations, particle sizes, and photon energies have been investigated. This review is an attempt to gather the data published in the literature about the application of nanomaterials in radiation shielding, including the use of polymer composites and concretes for protection against X-rays and gamma radiation.

Investigation of fast neutron shielding properties of new polyurethane-based composites loaded with B4C, BeO, WO3, ZnO, and Gd2O3 micro-and nanoparticles

The aim of the current research was to study the radiation shielding properties of polyurethane-based shielding materials filled with B4C, BeO, WO3, ZnO, and Gd2O3 particles against fast neutrons. The macroscopic cross sections of composites containing micro- and nanoparticles with a diameter of 10 µm and 50 nm were calculated using MCNPX (2.6.0) Monte Carlo code. The results showed that adding nano-scaled fillers to polyurethane matrix increases attenuation properties of neutron shields compared to micro-scaled fillers for intermediate and fast neutrons. Among the studied composites, WO3 and Gd2O3 nano-composites presented higher neutron cross section compared to others.

A Monte Carlo Study on the Shielding Properties of a Novel Polyvinyl Alcohol (PVA)/WO3 Composite, Against Gamma Rays, Using the MCNPX Code

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.

Material 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.

Influence of the size of nano- and microparticles and photon energy on mass attenuation coefficients of bismuth-silicon shields in diagnostic radiology

Recent studies have shown that the particle size of the shielding material and photon energy has significant effects on the efficiency of radiation-shielding materials. The purpose of the current study was to investigate the shielding properties of the bismuth-silicon (Bi-Si) composite containing varying percentages of micro- and nano-sized Bi particles for low-energy X-rays. Radiation composite shields composed of nano- and micro-sized Bi particles in Si-based matrix were constructed. The mass attenuation coefficients of the designed shields were experimentally assessed for diagnostic radiology energy range. In addition, the mass attenuation coefficients of the composite were comprehensively investigated using the MCNPX Monte Carlo (MC) code and XCOM. The X-ray attenuation for two different micro-sized Bi composites of radii of 50 µm and 0.50 µm showed enhancement in the range of 37-79% and 5-24%, respectively, for mono-energy photons (60-150 keV). Furthermore, the experimental and MC results indicated that nano-structured composites had higher photon attenuation properties (approximately 11-18%) than those of micro-sized samples for poly-energy X-ray photons. The amount of radiation attenuation for lower energies was more than that of higher energies. Thus, it was found that the shielding properties of composites were considerably strengthened by adding Bi nano-particles for lower energy photons.

Introducing a novel coefficient on mixed-nanoparticles material: relationship between the theoretical and experimental densities

Nanoparticles (NPs) indicating a unique potential in bioradiation and nuclear reactor shielding are employed in many fields due to their particular specifications leading improving the mechanical properties as well as pore structure of the concrete-shield. The aim was to introduce a novel coefficient ( ξ ), namely the experimental to theoretical density ratio for mixed-NPs material at various nanoparticles percent concentrations (ω n a n o ) based on pure mathematical aspects along with the some suitable physical purposes by Monte Carlo method. The change in the mixture density to the change inω n a n o is always proportional to theω n a n o value. The density will become maximum at theω n a n o ∗ in which the physical, morphological and chemical features of NPs along with the amounts of voids in the material have a key role over estimating porosity percentage. The NPs' separation probability as born-cascaded-pairs towards very small radii may be formulated as ξ - ξ - 1 + ω n a n o ∗ + k ' ' | ω n a n o - ω n a n o ∗ | = k ' wherek ' andk ' ' are constant values. In conclusion, the theoretical results may be experimentally used in future work for different applications such as designing shield at a nuclear facility.

MC safe bunker designing for an 18 MV linac with nanoparticles included primary barriers and effect of the nanoparticles on the shielding aspects

Aim

The aim of this study was to design a safe bunker for an 18 MV linac in to configuration; primary barriers made from nanoparticle-containing concrete and pure concrete.

Background

Application of some nanoparticles in the shielding materials has been studied and it was shown that the presence of some nanoparticles improved radiation shielding properties.

Materials and methods

Some percentage of different nanoparticles were modeled by the MCNP5 code of MC in the megavoltage radiotherapy treatment room's primary barriers. Other parts of the designed room, such as secondary barriers and maze door, were modeled as ordinary pure concrete. A safe bunker was designed according to the MC derived spectra at primary and secondary barriers location using a modeled and benchmarked 18 MV linac in free air. Then, the thickness of the required shielding materials for the door and also concrete for the walls and primary barriers were calculated separately.

Results

According to the results, required concrete thickness in primary and secondary barriers was reduced by around 0.8% compared to pure concrete application. Additionally, required lead and BPE decreased by 25% and 15%, respectively, due to primary barriers nanoparticles.

Conclusions

It was concluded that application of some nanoparticles in the shielding materials structures in megavoltage radiotherapy can make the shielding effective.

Enhanced Radiation Shielding with Conformal Light-Weight Nanoparticle-Polymer Composite

This article reports a new property enabled by nanoparticles, where bismuth nanoparticles added in a polymer matrix can block X-ray radiation several times more efficient than microparticles at the same mass ratio. Bismuth nanoparticles are made with cellulose nanofibers and dispersed evenly into a polymer. A four time reduction in the mass of bismuth material is identified at 2% mass ratio when nanoparticles (5 nm in diameter) are used in composite to shield a given flux and energy of radiation, in relative to those of microparticles (5 μm diameter). The enhancement in radiation shielding is primarily attributed to close packing of nanoparticles normal to incoming X-ray direction, which is enabled by strong affinity of nanoparticles to interstitial space of cellulose nanofibers and even distribution of nanoparticles inside polymer. Given its low cost, light weight, and structure conformability, bismuth nanoparticle-polymer composite will find its use in a wide range of fields related to personal radiation protection.