An extensive assessment of the impacts of BaO on the mechanical and gamma-ray attenuation properties of lead borosilicate glass

The current work deals with the synthesis of a new glass series with a chemical formula of 5Al2O3-25PbO-10SiO2-(60-x) B2O3-xBaO; x was represented as 5, 10, 15, and 20 mol%. The FT-IR spectroscopy was used to present the structural modification by rising the BaO concentration within the synthesized glasses. Furthermore, the impacts of BaO substitution for B2O3 on the fabricated borosilicate glasses were investigated using the Makishima-Mackenzie model. Besides, the role of BaO in enhancing the gamma-ray shielding properties of the fabricated boro-silicate glasses was examined utilizing the Monte Carlo simulation. The mechanical properties evaluation depicts a reduction in the mechanical moduli (Young, bulk, shear, and longitudinal) by the rising of the Ba/B ratio in the fabricated glasses. Simultaneously, the micro-hardness boro-silicate glasses was reduced from 4.49 to 4.12 GPa by increasing the Ba2+/B3+ ratio from 0.58 to 3.18, respectively. In contrast, the increase in the Ba/B ratio increases the linear attenuation coefficient, where it is enhanced between 0.409 and 0.448 cm-1 by rising the Ba2+/B3+ ratio from 0.58 to 3.18, respectively. The enhancement in linear attenuation coefficient decreases the half-value thickness from 1.69 to 1.55 cm and the equivalent thickness of lead is also reduced from 3.04 to 2.78 cm, at a gamma-ray energy of 0.662 MeV. The study shows that the increase in the Ba2+/B3+ ratio enhances the radiation shielding capacity of the fabricated glasses however, it slightly degrades the mechanical properties of the fabricated glasses. Therefore, glasses with high ratios of Ba2+/B3+ have high gamma-ray shielding ability to be used in hospitals as a shielding material.

Investigation of scatter radiation intensities in the cardiac catheter laboratory: novel versus traditional shielding solutions

A manufacturer has released a novel shielding solution (NSS): Rampart M1128 and claimed that the personal protective equipment (PPE) can be removed. This study investigates the scatter intensities with the NSS or the traditional shielding solutions (TSS) including the ceiling-suspended screen and the tableside lead drape. Isodose maps were generated by two series of measurements with an anthropomorphic phantom using NSS and TSS. Three survey meters were positioned at different heights to measure the scatter intensities at the eye, chest, and pelvic levels. Additional measurements were made at the primary and secondary operators? locations to evaluate the scatter intensities with different clinical projections. For the main operator positions, the isodose maps showed that NSS could result in a scatter dose that reduced by 80% to 95% compared to the same positions with TSS at the eye and chest levels. The corresponding result at the pelvic level was a reduction of 50%. These reductions should be compared to the additional protection by PPE: up to 80% reduction from lead eyeglasses and up to 95% from protective garments. Considering both operators at clinically relevant LAO projections, NSS resulted in scatter dose that was 80% to 96%, 76% to 96% and 25% to 60% lower than those of the TSS at eye, chest and pelvis levels. The protection of NSS is comparable with that of TSS alongside PPE at the eye but not at the chest and the pelvic levels under the setup of coronary angiography.

Towards sustainable horizons: A comprehensive blueprint for Mars colonization

This paper thoroughly explores the feasibility, challenges, and proposed solutions for establishing a sustainable human colony on Mars. We quantitatively and qualitatively analyze the Martian environment, highlighting key challenges such as radiation exposure, which astronauts could experience at minimum levels of 0.66 sieverts during a round trip, and the complications arising from Mars' thin atmosphere and extreme temperature variations. Technological advancements are examined, including developing Martian concrete, which utilizes sulfur as a binding agent, and innovative life support strategies like aeroponics and algae bioreactors. The human aspect of colonization is addressed, focusing on long-term space habitation's psychological and physiological impacts. We also present a cost-benefit analysis of in-situ resource utilization versus Earth-based supply missions, emphasizing economic viability with the potential reduction in launch costs through reusable rocket technology. A timeline for the colonization process is suggested, spanning preliminary unmanned missions for resource assessment, followed by short-term manned missions leading to sustainable settlements over several decades. The paper concludes with recommendations for future research, particularly in refining resource utilization techniques and advancing health and life support systems, to solidify the foundation for Mars colonization. This comprehensive assessment aims to guide researchers, policymakers, and stakeholders in planning and executing a strategic and informed approach to making Mars colonization a reality.

Valorisation of baryte tailings for radiation shielding in plastics and nuclear waste disposal

Baryte (BaSO4) is a critical raw material with no functional recycling since the used applications are dissipative. Significant quantities of baryte end up in tailings as a side stream from the mining industry. Baryte from a secondary raw material source was used as a filler in plastics for low duty radiation shielding and as an aggregate in radiation shielding geopolymers needed for safely storing low-radioactive waste ash. Mechanical strength in geopolymers remained at a high level with 0-50 % baryte additions. Low-cost plastic composites with baryte additions showed promising attenuation for X-rays and gamma-rays. The results showed improved qualities in the direct use of the secondary baryte material in concrete and plastics in comparison to primary baryte. Baryte from an industrial waste stream was shown to be applicable to be used in radiation shielding in geopolymers for storing low-radioactive waste, and in plastics. Primary baryte can be replaced with secondary baryte to bring environmental, economic, and even functional benefits.

Radiation attenuation of boro-tellurite glasses for efficient shielding applications

The borotellurite glasses whose chemical structure is (29.5-0.4x)CaO + 10CaF2 + (60-0.6x)B2O3 + xTeO2+ 0.5Yb2O3 (where x=10, 16, 22, 31, and 54 % mole. represent TCCBY1-TCCBY5, respectively) are Pb-free, thermally stable, and transparent glasses with attractive optical features for technological applications. The gamma-photons, electrons, protons, neutrons, carbon ions, fast neutrons, and fast neutron interaction parameters of these glasses are presented in this study to better understand the role of TeO2 in influencing their radiation shielding properties and radiation protection applications. The photon mass attenuation coefficient was evaluated by XCOM computation and simulation using the FLUKA code. The FLUKA code was also used to evaluate the mass stopping powers of the charged radiations, while neutrons' cross sections were evaluated using standard expressions. For 0.015 MeV-15 MeV photons, the mass attenuation coefficients of the glasses fell from 17.9499 to 0.0246 cm2/g for TCCBY1, 20.5628 to 0.0263 cm2/g for TCCBY2, 23.2756 to 0.079 cm2/g for TCCBY3, 26.7487 to 0.0298 cm2/g for TCCBY4, and 33.3591 to 0.0335 cm2/g for TCCBY5. The photon half-value layer at 15 keV is reduced by about 19.57%, 32.68%, 48.84%, and 63.89% when the TeO2 content increases from 10 mol to 16, 22, 31, and 54 mol, respectively. TeO2 was found to suppress photon buildup in the glasses. The mass stopping powers of charged radiation increased as glass density decreased. The addition of TeO2 into the glass structure increased the ability of the TCCBY glass to absorb fast neutrons by up to 54 % mole. The gamma radiation and fast neutron moderating ability of TCCBY5 glass compared to common shields and other materials is exceptional. The glass is recommended for the design of Pb-free, transparent, and efficient radiation protection structures.

A novel vanadium pentoxide doped glasses characterization for radiation shielding applications

Glasses are actively used in various fields, from industry to health. Especially, special doped glasses used in radiation areas may vary depending on the type and energy of the radiation. Glasses made of high-density and effective radiation-absorbing materials generally provide adequate protection against X and gamma rays. As an example, in this study, a 42.5P2O5-42.5B2O3-(15-x)Li2O-xV2O5 (x = 0, 2.5, 5, 10 and 15) glass system was produced using the melt quenching technique. The obtained X-ray patterns indicated that lack of crystalline peaks, verifying the glassy nature of all synthesized glass series. The glass transition temperatures and the glass thermal stability were determined using a Differential Thermal Analysis (TGA). The glass transition temperature and thermal stability was found to deteriorate with increasing V2O5 content. The radiation absorption properties of these glass system produced were investigated with 384 keV, 1173 keV and 1333 keV energized gamma using narrow beam transmission geometry. The NaI(Tl) detector system have been used to obtain γ-ray spectra. According to the obtained mass attenuation coefficients (μm) results, it has been determined that as the V2O5 ratio in the glass increases, it provides more effective results in radiation shielding. When the experimental results are compared with the theoretical XCOM results, there are a good match between the values. Finally, the radiation shielding properties of this produced glass system are compared with previously studied standard glasses to refer to the superiority of the installed systems.

Mechanical and radiation shielding characterization of W-based alloys for advanced nuclear unit

The paper aims to investigate the mechanical and radiation shielding properties of two tungsten-based alloys manufactured by powder technology; their features when compared with two standard stainless steel grades for advanced nuclear applications. Multiple measurements were performed to characterize the alloys' structural and mechanical properties. XRD analysis and average surface roughness measurements showed the crystalline and morphological structure of the alloys. Surface microhardness added to the abrasive wear analysis showed the final wear resistance of the selected alloys. In addition, the shielding features against gamma and fast neutrons radiation were calculated. The superior characteristics of W-based alloys manufactured by powder technology make them suitable to be used in advanced nuclear power units.

Measurement on the neutron and gamma radiation shielding performance of boron-doped titanium alloy Ti50Cu30Zr15B5 via arc melting technique

The significance of radiation shielding is on the rise due to the expanding areas exposed to radiation emissions. Consequently, there is a critical need to develop metal alloys and composites that exhibit excellent capabilities in absorbing neutron and gamma rays for effective radiation shielding. Low-density Ti-based alloys with controlled structural properties can be used for radiation protection purposes. The present research investigates boron-doped Ti-based alloy, Ti50Cu30Zr15B5, which is synthesized by arc melting technique, and its structural, mechanical properties, neutron, and gamma-ray transmission rate were investigated. Monte Carlo N-Particle simulation (MCNP6.2) code is used for calculating the Thermal (2.53 × 10-8 MeV) and fast (2 MeV) neutron transmission ratio (I/I0) dependent on the sample thickness. The Phy-x program is employed for calculating the gamma-ray LAC, MAC, HVL, TVL, and MFP values. The calculated neutron shielding performance parameters of Ti50Cu30Zr15B5 alloy were compared with materials in the literature. It was found that Ti50Cu30Zr15B5 alloy demonstrated impressive physical characteristics, suggesting that it can serve as a promising alloy for neutron and gamma-ray shielding applications.

Shielding and dosimetry parameters for aluminum carbon steel

Aluminum is lightweight durable, versatile, non-toxic, and corrosion-resistant surface, which makes aluminum a perfect material for improving the corrosion properties of aluminum-carbon steel which is important in the radiation domain. In this study, six carbon steel alloys doped with different aluminum concentrations were studied and compared with the standard austenite stainless steel AISI316L. Different parameters for shielding and dosimetry such as mass attenuation coefficient, tenth value layer, mean free path, equivalent effective atomic and electronic numbers were calculated using WinXCom, while the exposure absorption buildup factors, thermal and fast neutron removal cross-sections were calculated using MCNPX and the effective conductivity was calculated using Phy-X/PSD program. Regarding the radiation shielding performance, the addition of aluminum to the carbon alloys has a significant influence on the shielding parameters. The results suggest that the addition of aluminum to the carbon steel alloys would improve its shielding properties so that it is a good result to be used in the field of dosimetry and radiation shielding.

Gamma radiation shielding properties for polymer composites reinforced with bismuth tungstate in different proportions

In this study, inorganic compound (Bi2(WO4)3) was added into the composite to improve the radiation shielding properties of polymer composite. A polymer matrix was prepared by combining unsaturated polyester resin with methyl ethyl ketone peroxide and cobalt octoate (6%), and Bi2(WO4)3 was added to this polymer matrix at different ratios as filling material. In order to investigate the gamma radiation attenuation properties of the obtained polymer composites, mass attenuation coefficients, radiation shielding efficiencies, radiation transmission factors, linear attenuation coefficients, half values layer, tenth values layer, mean free path values, effective atomic numbers and effective electron densities parameters were obtained. Experimental studies were carried out with the help of HPGe detector at 22 different energies emitted from 22Na, 54Mn, 57Co, 60Co, 133Ba, 137Cs, 152Eu and 241Am radioactive sources in the photon energy range of 59.5-1408.0 keV. Each obtained experimental result was compared with the theoretical results. It was observed that the sample encoded with BiWO20 is the best radiation shielding material among all studied composites (except 59.5 keV).

Preparation and study of radiation shielding features of ZnO nanoparticle reinforced borate glasses

With the development of technology, the application areas of radiation have expanded and have an important place in our daily life. For this reason, we need more advanced and effective shielding materials to protect lives from the harmful effects of radiation. In this study, a simple combustion method was utilized to synthesize zinc oxide (ZnO) nanoparticles, and obtained nanoparticles' structural and morphological features were examined. The synthesized ZnO particles are used to produce different percentages (0, 2.5, 5, 7.5, 10%) of ZnO-doped glass samples. The structural and radiation shielding parameters of obtained glasses are examined. For this purpose, the Linear attenuation coefficient (LAC) has been measured via ⁶⁵Zn and ⁶⁰Co gamma sources and NaI(Tl) (ORTEC® 905-4) detector system has been used. Using the obtained LAC values, Mass Attenuation Coefficient (MAC), Half-Value Layer (HVL), Tenth-Value Layers (TVL), and Mean-Free Path (MFP) for glass samples have been calculated. According to these radiation shielding parameters, it was concluded that these ZnO doped glass samples provide effective results in radiation shielding and can be used as a shielding material effectively.

Radiation characteristics analysis for spallation products of lead-bismuth target and tungsten-iron-nickel target

The radiation characteristics of spallation products are important references for evaluating the materials used as spallation targets. Therefore, it is necessary to study the radiation characteristics of spallation products. In this study, the spallation products of tungsten-iron-nickel target and lead-bismuth target were calculated and analyzed based on the radionuclide distributions and decay photon shielding of the spallation products. The radionuclide distributions of the spallation products were calculated using FLUKA, and the shielding of decay photons was calculated with OpenMC. In addition, the variance reduction function with an importance card was added to the OpenMC code to allow its use for calculating deep penetration problems.

A comparative neutron and gamma-ray radiation shielding investigation of molybdenum and boron filled polymer composites

This work presents a detailed radiation shielding study for polymer composites filled with Boron and Molybdenum additives. The chosen novel polymer composites were produced at different percentages of the additive materials to provide a proper evaluation of their neutron and gamma-ray attenuation abilities. The effect of additive particle size on the shielding characteristics was further investigated. On the gamma-ray side, simulation, theoretical and experimental evaluations were performed in a wide range of photon energies varying from 59.5 keV to 1332.5 keV with help of MC simulations (GEANT4 and FLUKA), WinXCOM code, a High Purity Germanium Detector, respectively. A remarkable consistency was reported between them. On the neutron shielding side, the prepared samples produced with nano and micron particle size additives were additionally examined by providing fast neutron removal cross-section (Σ_R) and the simulated neutron transmissions through the prepared samples. The samples filled with nano sized particles show better shielding capability than the one filled with micron sized particles. In other words, a new polymer shielding material that does not contain toxic content is introduced: the sample codded N-B0Mo50 exhibits superior radiation attenuation.

Optical and radiation shielding characteristics of tellurite glass doped with different rare-earth oxides

Shielding glass materials doped with heavy metal oxides show an improvement in the effectiveness of the materials used in radiation shielding. In this work, the photon shielding parameters of six tellurite glass systems doped with several metal oxides namely, 70TeO2-10P2O5- 10ZnO- 5.0PbF2- 0.0024Er2O3- 5.0X (where X represents different doped metail oxides namely, Nb2O5, TiO2, WO3, PbO, Bi2O3, and CdO) in a broad energy spectrum, ranging from 0.015 MeV to 15 MeV, were evaluated. The shielding parameters were calculated using the online software Phy-X/PSD. The highest linear and mass attenuation coefficients recorded were obtaibed from the samples containing bismuth oxide (Bi2O3), and the lowest half-value layer and mean free path were recorded among the other samples. Furthermore, the shielding effectiveness of tellurite glass systems was compared with commercial shielding materials (RS-369, RS-253 G18, chromite, ferrite, magnetite, and barite). The optical parameters viz, dispersion energy, single-oscillator energy, molar refraction, electronic polarizability, non-linear refractive indices, n2, and third-order susceptibility were measured and reported at a different wavelength. Bi2O3 has a strong effect on enhancing the optical and shielding properties. The outcome of this study suggests the potential of using the proposed glass samples as radiation-shielding materials for a broad range of imaging and therapeutic applications.

Fabrication and characterization of GdxFe2O3(100-x) /PVA (x=0, 5, 10, 20) composite films for radiation shielding

Purpose of this study is to investigate effect of gadolinium (Gd) content of GdxFe2O3(100-x), (x = 0, 5, 10, 20) composite system on structural, thermal, optical and radiation protection of poly (vinyl alchool) PVA based nanocomposite film. In this study, Gd doped Fe₂O₃ nanopowders (with Gd = 0, 5, 10 and 20) were synthesized by spray pyrolysis method. The characterization of these powders have been obtained by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), and Uv-vis spectrometer. After then, GdxFe₂O₃(100-x)/PVA (x = 0, 5, 10, 20) polymer composite systems were prepared by solution casting technique. The structural, thermal and optical properties of obtained polymer composites have been examined. The irradiation properties of 6 MeV energized X-ray via cLINAC to obtain radiation shielding performance of these different percentage (0, 5, 10, and 20%) Gd doped Fe₂O₃ PVA thin films were also investigated. By using obtained results, the Linear Attenuation Coefficient (LAC), Half Value Layer (HVL), Tenth Value Layer (TVL), Mass Attenuation Coefficient (MAC). Also, theoretically Z_eff value have been calculated. According to all obtained results, it has been seen that the different percentages (0, 5, 10, and 20%) Gd doped Fe₂O₃ PVA thin films can be used as radiation shielding material.

Optimization of the electron beam dump for a GeV-class laser electron accelerator

The advances of laser-driven electron acceleration offer the promise of great reductions in the size of high-energy electron accelerator facilities. Accordingly, it is desirable to design compact radiation shielding for such facilities. A key component of radiation shielding is the high-energy electron beam dump. In an effort to optimize the electron beam dump design, different material combinations have been simulated with the FLUKA Monte Carlo code in the range of 1-40 GeV. The studied beam dump configurations consist of alternating layers of high-Z material (lead or iron) and low-Z material (high-density concrete or borated polyethylene) in either three-layer or five-layer structures. The designs of various beam dump configuration have been compared and it has been found that the iron and concrete stacking in a three-layer structure with a thick iron layer results in the lowest dose at 1, 10, and 40 GeV. The performance of the beam dump exhibits a strong dependence on the selected materials, the stacking method, the beam dump thickness, as well as the electron energy. This parametric study provides general insights that can be used for compact shielding design of future electron accelerator facilities.

A new heavy-mineral doped clay brick for gamma-ray protection purposes

The present work novelty pointed to fabricate new clay bricks doped with heavy minerals to be used in the building materials as a candidate for radiation shielding. The bricks were manufactured as (y)_{Iron mineral}+ (1-y)_clay, where y = 0, 0.1, 0.2 and 0.3 fractional weight. The prepared bricks' chemical composition and density were introduced to the MCNP-5 code to assess the prepared bricks' protection capacity. The simulated linear attenuation coefficient (LAC) was confirmed by comparing the simulated results with those calculated by the Phy-X/PSD program. We found that the simulated and calculated LAC were close together. The diff (%) between the MCNP-5 and Phy-X/PSD is in the range ±2% for all the fabricated bricks. The maximum LAC values occurred at 0.015 MeV, varied between 21.540 and 39.553 cm^-1 for bricks N0 and N30. The lowest LAC achieved at 15 MeV varied between 0.068 and 0.090 cm^-1. Bricks without heavy mineral addition have the lowest LAC values at all energies, ranging from 21.540 cm^-1 to 0.068 cm^-1, while bricks with 30 wt% heavy minerals have the highest LAC. The half-value layer (HVL) values decreased gradually with increasing the mineral ratio in the fabricated bricks. The thinner brick HVL achieved for the sample N 30 with 30 wt % heavy mineral, growing from 0.017 to 7.675 cm. The effective atomic number (Z_eff) was reported, and we found that the minimum Z_eff values equal to 14.006, 14.865, 15.705, and 16.394 for bricks N 0, N 10, N 20, N 30, respectively.

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.

Investigation of gamma-ray attenuation coefficients for solid boronized 304L stainless steel

In this study, mass attenuation coefficient (μ/ρ) and half value layer (HVL) at Eu-152 and Co-60 energies were used in measuring attenuation coefficients of the solid boronized AISI 304L stainless steel at 950 °C for 2, 4, 6 and 8 h. The experimental mass attenuation coefficients, μ/ρ, and HVL for these materials were compared to theoretical values obtained with WinXCOM. At the same time a new boriding agent (Baybora®-1) also developed for solid boriding method was used. The effects of boron layer size on radiation attenuation of boronized composites were evaluated in relation with gamma-ray transmission and the results of the experiments were interpreted. It could be understood that increased of boron layer in AISI 304L causes of increases in the attenuation coefficient values. The measured values agree with the theoretical values. The interaction parameters for selected samples have been computed and provided in the extended energy range 10^-3-10⁴ MeV. The shielding properties prepared stainless steel have also been compared with standard concretes as well as with the standard shielding stainless steel. It is found that the prepared stainless steel is the better shielding substitute to the conventional concretes as well as other standard shielding stainless steel. So, submicron size boron layer used composite materials are more convenient than micron size boron used composite materials as radiation shielding materials for nuclear applications.

Shielding features, to non-ionizing and ionizing photons, of FeCr-based composites

This paper has been focused on the a detail study on non-ionizing and ionizing electromagnetic (EM) shielding features and build-up factors of reinforced with ferrochrome (FeCr) composites. The non-inozing electromagnetic shielding performance quantities of composites have been determined in the frequency range between 12.4 and 18.0 GHz. Also, the experimental mass attenuation coefficients (MAC) have been estimated using gamma spectrometer and various radioactive point, and compared to those of theoretical and simulation (MCNPX) results. With help of the obtained linear attenuation coefficients, several attenuation quantities, i.e., effective atomic number (Z_eff), half value layer (HVL), and mean free path (MFP) have been discussed. In addition, buildup factors (EBF and EABF) values have been estimated utilizing the G-P fitting method. The results showed that composite encoded FeCr(15%) is superior shielding attenuation properties among the investigated samples.

Random model for radiation shielding calculation of particle reinforced metal matrix composites and its application

The work aimed to calculate the radiation biological shielding performance of particle reinforced metal matrix composite (PRMMCs) using more reasonable model instead of conventional Uniform Filling Model, also attempted to provide a basis for the radiation shielding optimal design of such materials. Firstly, RSA (Random Sequential Adsorption) Model and GRM (Grid Random Model) were established based on MATLAB and Monte Carlo Particle transport program MCNP, and then advantages and disadvantages of them were compared. Later, the influences of metal matrix type, particle (B₄C) content, particle shape and particle shape parameters on the biological shielding performance of materials were calculated under different energy neutrons and different thickness shield using random models. Finally, the optimal aspect ratio of regular hexahedral B₄C was calculated by Genetic Algorithm combined with MATLAB and MCNP. It indicated that GRM could be applied to radiation shielding calculation of PRMMCs.

Investigation of the gamma ray shielding properties for polyvinyl chloride reinforced with chalcocite and hematite minerals

Polyvinyl chloride (PVC) is the most widely produced synthetic plastic polymer in the world: it has a variety of applications due to its low cost, elasticity, light weight, good mechanical characteristics and corrosion resistance. In order to protect living beings from harmful radiation such as gamma rays, novel low-cost chalcocite and hematite-based PVCs were fabricated for shielding purposes. The mass attenuation coefficient μ_m for various fabricated hematite and chalcocite-based PVCs was calculated using MCNP-5 code. The results were compared with the values calculated theoretically using XCOM software between 0.015 and 15 MeV. Moreover, the simulated μ_m parameter for chalcocite/PVC and hematite/PVC was used to calculate other shielding factors, such as the half value layer (HVL), the mean free path (MFP) effective atomic number Z_eff, the geometric-progress (G-P) fitting parameters and the exposure buildup factor (EBF). The simulated data of μ_m for all composites is comparable to that obtained from a theoretical calculation. The results showed that the addition of hematite and chalcocite enhance the μ_m of PVC polymers. We also found that the μ_m of chalcocite/PVC is higher than that of hematite/PVC due to the copper content in the former.

Investigation of bismuth borate glass system modified with barium for structural and gamma-ray shielding properties

In the present paper, transparent and non-toxic Bi₂O₃-B₂O₃ glasses doped with BaO have been prepared by the authors which may replace the standard radiation shielding concretes and lead based commercial glasses for gamma ray shielding applications. The effects of BaO on the structural and optical properties of the prepared glass system have been investigated by Raman, FTIR and UV-Visible techniques. It has been observed that barium plays the role of a modifier and it is responsible for conversion of triangular [BO₃] units to tetrahedral [BO₄] units along with formation of non-bridging oxygen and increase in ionic character. It also improves the radiation shielding abilities of the glass system. The mass attenuation coefficients for gamma-ray photons at 662 keV energy by using ¹³⁷Cs radioactive source have been measured by employing narrow beam transmission geometry. This was accompanied by theoretical computation of mass attenuation coefficients in the wide photon energy range varying from 1 keV to 100 GeV. It has been found that values of mean free path and tenth value layer decrease whereas, density and effective atomic number increase with the increase of barium oxide content. As compared with barite concrete and commercial shielding glass RS-360, our prepared Bi₂O₃ - BaO - B₂O₃ glasses have shown better gamma ray shielding properties. This implies that the prepared glass system is a better gamma ray absorber and it has the potential for use in gamma-ray shielding applications.

The Shielding Ability of Novel Tungsten Rubber Against the Electron Beam for Clinical Use in Radiation Therapy

BACKGROUND/AIM

A newly-introduced tungsten containing rubber (TCR) is a potentially useful shielding material in electron radiotherapy because it is lead-free, containing as much as 90% fine tungsten powder by weight. This study aimed to investigate the shielding ability of TCR against electron beams.

MATERIALS AND METHODS

Transmission of TCR was measured for energies of 4, 6, 9 and 12 MeV. Dose profiles were measured to compare the TCR and lead. The electron backscatter factor (EBF) was also compared.

RESULTS

The transmission of equivalent thickness for 4, 6, 9 and 12 MeV with TCR (0.78%, 1.34%, 2.16% and 3.08%, respectively) were lower than that with lead (0.81%, 1.44%, 2.19% and 3.16%, respectively) (p<0.05). The dose profiles were not significantly different for TCR and lead. The EBF with TCR was up to 17% lower than that with lead.

CONCLUSION

TCR has adequate radiation shielding ability for electron beams and could be employed instead of lead.

Radiation and criticality safety analyses for the highly-enriched uranium core removal from a research reactor

Analysis was performed to estimate radiation levels during removal and packaging of the highly-enriched uranium core of the JM-1 SLOWPOKE-2 research reactor. Due to severe limitations of space in and around the reactor pool, the core could not be removed in the conventional manner as was done for previous SLOWPOKE defuelling operations. A transfer shield, with a balance between shielding efficacy, volume and weight was designed. Fuel depletion, Monte Carlo shielding and criticality calculations were performed. Comparisons of measured and calculated dose rates as well as results of the criticality safety assessment are presented. The designed transfer shield reduced the calculated unshielded dose rate from 29Sv/h to 8mSv/h. The maximum calculated effective neutron multiplication factor of approximately 0.89 was below the 0.91 upper subricital limit.

Optimal shielding thickness for galactic cosmic ray environments

Models have been extensively used in the past to evaluate and develop material optimization and shield design strategies for astronauts exposed to galactic cosmic rays (GCR) on long duration missions. A persistent conclusion from many of these studies was that passive shielding strategies are inefficient at reducing astronaut exposure levels and the mass required to significantly reduce the exposure is infeasible, given launch and associated cost constraints. An important assumption of this paradigm is that adding shielding mass does not substantially increase astronaut exposure levels. Recent studies with HZETRN have suggested, however, that dose equivalent values actually increase beyond ∼20g/cm² of aluminum shielding, primarily as a result of neutron build-up in the shielding geometry. In this work, various Monte Carlo (MC) codes and 3DHZETRN are evaluated in slab geometry to verify the existence of a local minimum in the dose equivalent versus aluminum thickness curve near 20g/cm². The same codes are also evaluated in polyethylene shielding, where no local minimum is observed, to provide a comparison between the two materials. Results are presented so that the physical interactions driving build-up in dose equivalent values can be easily observed and explained. Variation of transport model results for light ions (Z ≤ 2) and neutron-induced target fragments, which contribute significantly to dose equivalent for thick shielding, is also highlighted and indicates that significant uncertainties are still present in the models for some particles. The 3DHZETRN code is then further evaluated over a range of related slab geometries to draw closer connection to more realistic scenarios. Future work will examine these related geometries in more detail.

Solar proton exposure of an ICRU sphere within a complex structure Part I: Combinatorial geometry

The 3DHZETRN code, with improved neutron and light ion (Z≤2) transport procedures, was recently developed and compared to Monte Carlo (MC) simulations using simplified spherical geometries. It was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in general combinatorial geometry. A more complex shielding structure with internal parts surrounding a tissue sphere is considered and compared against MC simulations. It is shown that even in the more complex geometry, 3DHZETRN agrees well with the MC codes and maintains a high degree of computational efficiency.

Solar proton exposure of an ICRU sphere within a complex structure part II: Ray-trace geometry

A computationally efficient 3DHZETRN code with enhanced neutron and light ion (Z ≤ 2) propagation was recently developed for complex, inhomogeneous shield geometry described by combinatorial objects. Comparisons were made between 3DHZETRN results and Monte Carlo (MC) simulations at locations within the combinatorial geometry, and it was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in ray-trace geometry. This latest extension enables the code to be used within current engineering design practices utilizing fully detailed vehicle and habitat geometries. Through convergence testing, it is shown that fidelity in an actual shield geometry can be maintained in the discrete ray-trace description by systematically increasing the number of discrete rays used. It is also shown that this fidelity is carried into transport procedures and resulting exposure quantities without sacrificing computational efficiency.

[Radiation protection in interventional radiology]

The application of ionizing radiation in medicine seems to be a safe procedure for patients as well as for occupational exposition to personnel. The developments in interventional radiology with fluoroscopy and dose-intensive interventions require intensified radiation protection. It is recommended that all available tools should be used for this purpose. Besides the options for instruments, x‑ray protection at the intervention table must be intensively practiced with lead aprons and mounted lead glass. A special focus on eye protection to prevent cataracts is also recommended. The development of cataracts might no longer be deterministic, as confirmed by new data; therefore, the International Commission on Radiological Protection (ICRP) has lowered the threshold dose value for eyes from 150 mSv/year to 20 mSv/year. Measurements show that the new values can be achieved by applying all X‑ray protection measures plus lead-containing eyeglasses.

Analysis of the radiation shielding of the bunker of a 230MeV proton cyclotron therapy facility; comparison of analytical and Monte Carlo techniques

The neutron ambient dose equivalent outside the radiation shield of a proton therapy cyclotron vault is estimated using the unshielded dose equivalent rates and the attenuation lengths obtained from the literature and by simulations carried out with the FLUKA Monte Carlo radiation transport code. The source terms derived from the literature and that obtained from the FLUKA calculations differ by a factor of 2-3, while the attenuation lengths obtained from the literature differ by 20-40%. The instantaneous dose equivalent rates outside the shield differ by a few orders of magnitude, not only in comparison with the Monte Carlo simulation results, but also with the results obtained by line of sight attenuation calculations with the different parameters obtained from the literature. The attenuation of neutrons caused by the presence of bulk iron, such as magnet yokes is expected to reduce the dose equivalent by as much as a couple of orders of magnitude outside the shield walls.

3DHZETRN: Neutron leakage in finite objects

The 3DHZETRN formalism was recently developed as an extension to HZETRN with an emphasis on 3D corrections for neutrons and light ions. Comparisons to Monte Carlo (MC) simulations were used to verify the 3DHZETRN methodology in slab and spherical geometry, and it was shown that 3DHZETRN agrees with MC codes to the degree that various MC codes agree among themselves. One limitation of such comparisons is that all of the codes (3DHZETRN and three MC codes) utilize different nuclear models/databases; additionally, using a common nuclear model is impractical due to the complexity of the software. It is therefore difficult to ascertain if observed discrepancies are caused by transport code approximations or nuclear model differences. In particular, an important simplification in the 3DHZETRN formalism assumes that neutron production cross sections can be represented as the sum of forward and isotropic components, where the forward component is subsequently solved within the straight-ahead approximation. In the present report, previous transport model results in specific geometries are combined with additional results in related geometries to study neutron leakage using the Webber 1956 solar particle event as a source boundary condition. A ratio is defined to quantify the fractional neutron leakage at a point in a finite object relative to a semi-infinite slab geometry. Using the leakage ratio removes some of the dependence on the magnitude of the neutron production and clarifies the effects of angular scattering and absorption with regard to differences between the models. Discussion is given regarding observed differences between the MC codes and conclusions drawn about the need for further code development. Although the current version of 3DHZETRN is reasonably accurate compared to MC simulations, this study shows that improved leakage estimates can be obtained by replacing the isotropic/straight-ahead approximation with more detailed descriptions.

Finite and infinite system gamma ray buildup factor calculations with detailed physics

Examination of physical interactions of photons in materials is a significant subject for buildup factor studies. In most of the buildup calculations, by default, coherent (Rayleigh) scattering is ignored and the Compton scattering is modeled by free-electron Klein-Nishina formula with "simple physics" treatment. In this work, photon buildup factors are calculated for many different cases including "detailed physics" by taking into account coherent and bound-electron Compton scatterings with the Monte Carlo code, MCNP5, and the results are compared with the literature values. They are computed for point isotropic photon sources up to depths of 20 mean free paths and at the three photon energies most widely used (0.06, 0.6 and 6MeV). Calculations are made for both finite and infinite homogeneous ordinary water media. It is concluded that Coherent scattering is very dominant at low energies and for deep penetrations and assumed physical approximation (simple/detailed, finite/infinite) is the critical point for determining shielding material dimensions. After all, it can be stated that all parametric assumptions should be clearly given and indicated in the tabulation of photon buildup factors.

3DHZETRN: Shielded ICRU spherical phantom

A computationally efficient 3DHZETRN code capable of simulating High (H) Charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation was recently developed for a simple homogeneous shield object. Monte Carlo benchmarks were used to verify the methodology in slab and spherical geometry, and the 3D corrections were shown to provide significant improvement over the straight-ahead approximation in some cases. In the present report, the new algorithms with well-defined convergence criteria are extended to inhomogeneous media within a shielded tissue slab and a shielded tissue sphere and tested against Monte Carlo simulation to verify the solution methods. The 3D corrections are again found to more accurately describe the neutron and light ion fluence spectra as compared to the straight-ahead approximation. These computationally efficient methods provide a basis for software capable of space shield analysis and optimization.

Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: a spectroscopic study

UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process.

Insulating epoxy/barite and polyester/barite composites for radiation attenuation

A trial has been made to create insulating Epoxy/Barite (EP/Brt) (ρ=2.85 g cm(-3)) and Crosslinked Unsaturated Polyester/Barite (CUP/Brt) (ρ=3.25 g cm(-3)) composites with radiation attenuation and shielding capabilities. Experimental work regarding mechanical and physical properties was performed to study the composites integrity for practical applications. The properties were found to be reasonable. Radiation attenuation properties have been carried out using emitted collimated beam from a fission (252)Cf (100 µg) neutron source, and the neutron-gamma spectrometer with stilbene scintillator. The pulse shape discriminating (P.S.D) technique based on the zero cross-over method was used to discriminate between neutron and gamma-ray pulses. Thermal neutron fluxes, measured using the BF3 detector and thermal neutron detection system, were used to plot the attenuation relations. The fast neutron macroscopic effective removal cross-section ΣR, gamma ray total attenuation coefficient µ and thermal neutron macroscopic cross-section Σ have been evaluated. Theoretical calculations have been achieved using MCNP-4C2 code to calculate ΣR, µ and Σ. Also, MERCSF-N program was used to calculate macroscopic effective removal cross-section ΣR. Measured and calculated results have been compared and were found to be in reasonable agreement.