Half-value Layer Thickness Research Articles

Structural, thermo-mechanical, optical and gamma-ray shielding properties of lead-free BaO–ZnO–B2O3–SiO2 and lead-based PbO–Bi2O3–K2O–SiO2 glasses

Lead-free BaO–ZnO–B2O3–SiO2 glass (BZBS) and lead-based PbO–Bi2O3–K2O–SiO2 glass (LS) were synthesized by melt quench technique. Glass samples were irradiated using 60Co gamma source up to 50 kGy dose to study the changes in structural, thermo-mechanical, optical and gamma ray shielding properties. Measured density values of both the glasses were greater than 4.0 g/cc. X Ray Diffraction (XRD) studies confirmed amorphous nature of prepared glasses before and after gamma irradiation. The structural changes induced by gamma irradiation were also investigated using Raman, Positron annihilation lifetime spectroscopy (PALS) and Electron Paramagnetic Resonance (EPR) spectroscopy. PALS data revealed increase in free volume/voids after irradiation. Defect studies carried using EPR spectroscopy confirmed formation of electron trap centre in BZBS glass, whereas in LS glass in addition to the electron trap centers, non-bridging oxygen hole centers (NBOHC) and peroxy radical defects were also observed. Investigations on thermo-mechanical properties demonstrated higher glass transition temperature (Tg), hardness and modulus of elasticity values for BZBS glass as compared to the LS glass, which were found to be decreased after irradiation because of radiation induced defects. Visible transparency and band gap for BZBS glass were found to be higher than that in LS glass. After irradiation, colour change, reduction in transparency as well as band gap, and red shift in absorption edge were observed due to the formation of defects in both the glasses. The values of radiation induced absorption (α) at three different visible wavelengths have been determined for 50 kGy dose using UV–Vis transmission data. Analysis of refractive index data showed around 12 % reflection losses for both the glasses. Annealing of irradiated samples using UV light source showed significant improvement in transparency. Linear attenuation coefficient (LAC) was calculated using XCOM program and experimentally measured using 60Co 1.33 MeV gamma ray. Linear attenuation coefficient of BZBS glass was around 0.20 cm−1 whereas for LS glass value was 0.24 cm−1. Half value layer thickness of prepared glasses was also compared with available standard materials and it was found that prepared glasses may be suitable for shielding of high energy gamma rays.

Multifiller-based polymer composites for shielding high energy ionising radiation.

Polydimethyl silicone rubber-based polymer composites filled with molybdenum and bismuth were fabricated using simple open mold cast technique. The physical and chemical structure and gamma shielding parameters like attenuation coefficient, half-value layer (HVL) thickness and relaxation length have been investigated for the said novel materials using X-ray diffraction (XRD), Fourier transform Infrared spectroscopy (FTIR) and gamma ray spectrometer. XRD study reveals the crystalline nature of the composites. It is evident from FTIR studies that there is no chemical interaction between the polymer matrix and filler particles. The results of attenuation studies reveal that the linear attenuation coefficient increases with addition of Bi and Mo and is found to be 0.653, 1.341 and 1.017, 1.793 and 0.102, 0.152cm-1 for 1MMB and 2MMB polymer composites at 80, 356 and 662keV gamma rays, respectively. The HVL thickness of the materials is found to be 1.06, 0.51 and 0.68, 0.38 and 6.73, 4.532cm for 1MMB (20Mo+10Bi phr) and 2MMB (40Mo+20Bi phr) at these energies, respectively. The mass attenuation coefficient of the novel composites 1MMB and 2MMB is found to be higher than the conventional materials like lead and barite for 356keV gamma rays. In addition, the material is found to be light weight and flexible enabling to be molded in required forms, thus being a substitute for the material lead that is known to be heavy and toxic by nature.

Radiation shielding properties of shotcrete containing different aggregates

In this study, the physical and mechanical properties of wet mix shotcrete produced using crushed stone aggregate (CS), ferrochrome slag aggregate (FS), and barite (B) aggregate have been investigated. Furthermore, the radiation shielding properties have been determined experimentally, theoretically, and through simulation. A control sample was produced using 50 % CS and 50 % FS. Subsequently, shotcrete groups were produced by substituting B aggregate at replacement rates of 25 %, 50 %, 75 %, and 100 % instead of FS. The mechanical properties such as density, ultrasonic pulse velocity (UPV), compressive strength, flexural strength, and splitting tensile strength of the produced spray concrete groups were investigated. Additionally, experimental radiation shielding measurements were conducted using a high-purity germanium (HPGe) detector system with emissions from four different radioactive sources (133Ba, 137Cs, 60Co, and 22Na) spanning nine different gamma energies ranging from 276.5 to 1332.5 keV. As a result of the experimental measurements, the linear attenuation coefficients (μ) of the shotcrete samples were obtained. A proportional increase in μ was determined with increasing barite content. Using the experimental mass attenuation coefficient (μ/ρ) results, half-value layer (HVL) and tenth-value layer (TVL) thicknesses, as well as mean free path (MFP) values, were calculated. An increasing B aggregate ratio did not have a significant effect on the μ/ρ value, while an increase was observed in the HVL, TVL, and MFP values. Moreover, the WinXCOM interface was employed for theoretical calculations, and the FLUKA Monte Carlo code was utilized for simulation calculations. The obtained data were compared with experimental results, revealing a good agreement between them. Based on the obtained data, it was concluded that increasing the B aggregate ratio resulted in improvement in mechanical properties compared to the control sample, and additionally, it was determined that B aggregate-added shotcrete is an effective gamma radiation shielding material.

A comprehensive study of the shielding ability from ionizing radiation of different mortars using iron filings and bismuth oxide

The current work discusses the radiation attenuation capability and different shielding characteristics of different mortar samples. The samples were prepared by replacing different percentages of fine aggregate with iron filling and replacing different percentages of hydrated lime with Bi2O3 (0–50 wt.%). The prepared mortar samples are coded as CHBFX where X = 0, 10, 30, and 50 wt.%. The mass and linear attenuation coefficient was determined experimentally using a narrow beam technique, where a high purity germanium detector, and different point gamma-ray sources (such as Am-241, Cs-137, and Co-60). The linear attenuation coefficient was also calculated using the Monte-Carlo simulation code and the online Phy-X/PSD software. The comparison of the three methods showed a good agreement in the results. The linear attenuation coefficient drops from 19.821 to 0.053 cm−1 for CHBF0, from 27.496 to 0.057 cm−1 for CHBF10, from 42.351 to 0.064 cm−1 for CHBF30, and from 55.068 to 0.071 cm−1 for CHBF50 at photon energy range from 0.015 to 15 MeV. The half-value layer thickness, tenth-value layer thickness, and mean free path of the prepared mortar composites were also calculated photon energy ranged from 0.015 to 15 MeV. The fast neutron removal cross-section of the prepared CHBFX mortar samples have values of 0.096 cm−1, 0.098 cm−1, 0.103 cm−1, and 0.107 cm−1 for the mortar samples CHBF0, CHBF10, CHBF30, and CHBF50, respectively. The results showed that the mortar sample with the highest iron filing concentration, CHBF50, provides the best protection against gamma rays and fast neutrons which could be used in the nuclear and medical fields.

Radiation shielding properties of some igneous rocks in isparta province at different gamma energies: Experimental and theoretical study

In this study, our aim is to experimentally and theoretically obtain the gamma radiation shielding properties of some igneous rocks extracted in Isparta, Turkey. In the first stage, experimental measurements were performed using a gamma spectroscopy system containing a NaI(Tl) detector at three different gamma energies (511, 835 and 1275 keV) emitted from two different radioactive sources (22Na and 54Mn). As a result of the experiments, linear attenuation coefficients (LACs) of igneous rocks were obtained. The variation of LAC was investigated in relation to the density and the alkali-silica content of the rocks. The results obtained indicated an increase in the LACs with higher rock and an elevated alkali-silica ratio. Using the experimental LAC results, the half and tenth value layer thickness (HVL and TVL), mean free path (MFP), transmission rate, radiation protection efficiency (RPE) and lead equivalent thickness (dPb) values were calculated. In the second stage of this study, LACs were calculated theoretically with the help of XCOM software using the chemical contents of the selected igneous rocks. The comparison of experimentally obtained LACs with those calculated using the XCOM software, revealed a good agreement between the two methods. In addition, the results obtained with the XCOM software gave information about the variation of the attenuation coefficient in different energy regions. Moreover, effective atomic number (Zeff) and electron density (Ne) parameters were calculated using XCOM and experimental results. Based on the data collected, it can be concluded that the trachy-basalt sample taken from the igneous rocks used in this study is more effective than other rocks in terms of gamma radiation shielding.

Effect of colemanite mineral on gamma radiation attenuation properties of vinyl ester resin

In this study, it is aimed to experimentally and theoretically obtain the gamma radiation attenuation properties of vinyl ester resin (VE) containing different rates of colemanite (CO) mineral and to compare these results. In the first stage, experimental measurements were performed using a gamma spectroscopy system containing a NaI(Tl) detector at three different gamma energies (511, 835 and 1275 keV) emitted from two different radioactive sources (22Na and 54Mn). As a result of the experiments, linear attenuation coefficients (LACs) of VE samples were obtained. The variation of LACs according to the density of the samples were investigated. The obtained results showed that LACs increased the density of the VE samples increased. Using the experimental LAC results, the half (HVL) and tenth (TVL) value layer thickness, mean free path (MFP) and transmission rate values were calculated. In the second stage of the study, LACs were calculated theoretically with the help of XCOM code using the chemical contents of VE samples. As a result of the comparison of the LACs obtained experimentally and using the XCOM code, it was observed that they were in good agreement. In addition, the results obtained with the XCOM code gave information about the variation of the attenuation coefficient in different energy regions. Based on all these data, it was concluded that as the amount of colemanite in the vinyl ester resin examined in the study increased, the gamma radiation shielding performance increased.

Unconventional High-Value Utilization of Metallurgical Iron-Bearing Dust as Shielding Composite for Medical X-rays

Iron-bearing dust is one of the main solid wastes in the metallurgical industry, and currently, it is mainly disposed of according to accumulation, which brings great environmental risks. Therefore, this paper proposes a method of preparing X-ray shielding materials by hot pressing using iron-bearing dust as the filler and polyimide resin powder as the matrix. A CT imaging system was used to test the X-ray shielding performance of the materials. The results demonstrated that shielding material I-95 had a shielding percentage of more than 95% at a tube voltage of 55 kVp and a tube current of 2 mA, and the thickness of the half-value layer was less than 0.68 mm. The shielding percentage and mass attenuation coefficient of the composites showed an increasing trend with increased filler addition, tube voltage, and tube current intensity, while the half-value layer thickness showed the opposite trend. Furthermore, the shielding percentage of composites with different fillers was affected by the voltage and hardly affected by the current variation. The dominant part of the shielding material interaction across the tested tube voltage range was photoelectric absorption. The prepared composite is a low-cost material and has high efficiency and is an ideal medical X-ray shielding material.

Translocation of tungsten(vi) oxide/gadolinium(iii) fluoride in tellurite glasses towards improvement of gamma-ray attenuation features in high-density glass shields

Abstract This study investigates the effect of substituting tungsten(vi) oxide/gadolinium(iii) fluoride in tellurite glasses whose densities varies from 5.0879 to 5.3246 g/cm3 on gamma-ray absorption properties. A range of fundamental absorption parameters, including attenuation coefficients, half-value layer thicknesses, effective atom and electron numbers, effective conductivity, exposure, and energy absorption buildup factors, were studied for five different glass samples with varying substitution ratios. The ratio of tungsten(vi) oxide to gadolinium(iii) fluoride varied between 0 and 20 mol%, as well as the TeO2 ratio in the composition was maintained between 90 and 80 mol%. The sample with the composition of 80–20 mol% TeO2/WO3, which attained the maximum density value with 20 mol% WO3 addition, showed the highest gamma-absorption capabilities based on the obtained findings in the range of 0.015–15 MeV. In consideration of the mechanical and physical properties of WO3 in tellurite glasses, it can be concluded that WO3 incorporation is a crucial monotonic process that may be utilized to further improve the properties of glass shields.

On the neutron shielding efficacy of flexible silicone infused with CdO nanoparticles

Shielding material is used for protection against harmful effect of ionizing radiations. This paper is aimed at studying the prospects of silicone elastomer based nanocomposites as neutron shielding material. Cadmium oxide (CdO) nanoparticles and multi-walled carbon nanotubes (MWCNTs) were used as filler medium in the nanocomposites, due to their exceptional neutron attenuation properties. The CdO nanoparticles were synthesized using composite-hydroxide-mediated (CHM) method and their structural purity was confirmed with x-ray diffraction data. Silicone/CdO/MWCNTs nanocomposites were fabricated by room-temperature-vulcanization (RTV) method, with different concentrations of nano-fillers (3, 6 and 9 % wt of CdO; 1 % wt of MWCNTs). The half value layer (HVL) thickness of the nanocomposites were found to be 7.44 cm, 5.90 cm and 5.72 cm, while the neutron removal cross sections were noted as 0.09307, 0.11732, and 0.12107 for the nanocomposites containing 3%, 6% and 9% of CdO, respectively. The Phy-X software was used to calculate the fast neutron removal cross-section and found it consistent with the experimental results. The results revealed that adding nano-fillers (CdO nanoparticles and MWCNTs) into silicone matrix not only enhanced the neutron shielding efficacy of nanocomposites but also have improved their mechanical properties and making it useful for neutron shielding applications.

Polyester‐Based Polymer Composites for Gamma Shielding Applications ‐ A Substitute for Lead

AbstractTungsten oxide (WO3) filled Isophthalic polyester based polymer composites were fabricated by open mould cast technique. The gamma shielding ability of the composites was investigated using gamma ray spectrometer for 80, 127, 356, 662, 1170 & 1332 keV gamma rays in detail and several shielding parameters were estimated to decide the shielding effectiveness of the polymer composites. The results show that, the linear attenuation coefficient increases upon adding tungsten oxide into the matrix and decreases with increase in the energy of gamma photons and is found to be maximum for 80 keV gamma rays. The half value layer thickness, tenth value layer thickness and relaxation length were found to decrease with increase in the filler Wt %, whereas, they were found to increase with increase in energy. XCOM & WinXCOM computer codes were used to estimate the electron density and Zeff of the composites theoretically. ISO+50 Wt % WO3 composite is found to be just 18 % heavy with respect to lead and show better performance than lead at 80 keV and baryte at 127 keV and is almost comparable to steel and concrete in the higher energy range. Thus, lead (Pb) can be replaced by ISO+50 Wt % WO3 composite for low energy gamma shielding applications.

Effect of incorporating hematite on the properties of ultra-high performance concrete including nuclear radiation resistance

Radiation is one of the most important problems for nuclear power plants. To fulfill the urgent need for building materials with high radiation resistance and improved mechanical and durability properties, a novel antiradiation ultra-high-performance concrete (UHPC) was designed. This was accomplished by using hematite powder to partially replace natural river sand at different replacement ratios. A series of tests were conducted, addressing fresh concrete’s fluidity, hardened concrete’s compressive strengths at room and elevated temperatures, impact strength, chloride resistance, radiation resistance, micropore structure, and hydration products. Experimental results show that the addition of hematite slightly decreased the work performance and compressive strength of UHPC, but substantially increased its flexural and impact strength and showed satisfactory high-temperature performance. The gamma-ray shielding performance of hematite UHPC was substantially enhanced by increasing the hematite replacement ratio. Compared with ordinary concrete, the linear attenuation coefficient of the UHPC with a 40% hematite replacement ratio increased by 43%, and the half-value layer thickness was reduced by 30%. The addition of hematite powder did not change the types of cement hydration products, but did improve the internal micropore structure, and cause the UHPC to exhibit excellent chloride ion penetration resistance.

Experimental investigations on the beta attenuation properties of lead monoxide – Polycarbonate composite films

Lead monoxide filled polycarbonate polymer composite films have been prepared with twelve different filler levels, ranging from 0.5 up to 10.0 percent by weight, by using ultrasonic dispersion of lead monoxide in the polycarbonate solution, followed by solution casting. For these composites, beta radiation shielding properties such as mass attenuation coefficient, range of beta particles and half value layer thickness for beta particles from low activity thallium −204 and yttrium – 90 radioactive sources have been found experimentally and computationally, along with the mass density and modified atomic number of the composite material. Two different computational methods, namely, Baltakment’s empirical formula method and Bragg’s mixture rule have been used to calculate the theoretical value of mass attenuation coefficient, whereas Katz and Penfold relationship has been used to calculate the range of the beta particles obtained from these sources in the prepared composite films. The results obtained are discussed.

Evaluation of gamma ray attenuation properties of boron carbide (B4C) doped AISI 316 stainless steel: Experimental, XCOM and Phy-X/PSD database software

This study aimed to investigate the gamma-ray attenuation properties of AISI 316 stainless steel both experimentally and theoretically by doping different ratios of boron carbide. In the experimental measurements, a gamma spectroscopy system with a NaI(Tl) detector was used and 60Co, 137Cs radioactive sources were used as gamma sources. In addition, it was calculated theoretically using XCOM and Phy-X/PSD database software. With the help of both experimental and theoretical results obtained, the effect of adding boron carbide to AISI 316 stainless steel on the change of the linear attenuation coefficients (LAC, µ) of the steel was investigated. Experimental LAC results for 3 different gamma energies of steels have been checked with the calculated theoretical LAC results by XCOM database using the chemical contents and density of the steel samples. It has been observed that the experimental and theoretical results are compatible with each other. Also, by using experimentally obtained LACs, half and tenth value layer thickness, mean free path and radiation protection efficiency parameters were calculated. In addition to these parameters, parameters such as equivalent atomic number (Zeq), effective atomic number (Zeff), exposure accumulation factor (EBF) were theoretically determined in the energy range of 0.015–15 MeV for steel samples produced using the Phy-X / PSD software. From the experimental results obtained, as the ratio of boron carbide in AISI 316 stainless steel increases, LACs and radiation protection efficiency (RPE) values decrease. Other parameters, transmission speed, HVL, TVL and MFP values increased with increasing boron carbide (B4C) ratio. It can be said that different processes are effective in different energy regions for the Zeff, Zeq and EBF results obtained theoretically. From these data, it can be concluded that adding boron carbide to AISI 316 stainless steel reduces the steel's ability to attenuate gamma radiation.

Studies on the effects of Fe3O4-PbO combinations in peroxide vulcanisation of EPDM and shielding 59.54 kev gamma rays

This research work presents the preparation of ethylene-propylene-diene-monomer (EPDM) composites filled with different concentrations of lead oxide (PbO) and magnetite (Fe3O4). The catalytic role of Fe3O4 on peroxide vulcanisation was studied. The morphological studies were done by the FESEM analysis. The evaluation of gamma shielding ability of synthesised composites was done for 59.54 keV gamma rays using a gamma spectrometer. Various shielding parameters, such as percentage attenuation (%Att), linear attenuation coefficient (μ), relaxation length (λ), half value (HVL) and tenth value layer (TVL) thickness, were evaluated for synthesised composites. The obtained results showed that, the shielding ability of the synthesised composites increases with an increase in PbO concentration. Also, the thermal stability of the synthesised composites was studied by TGA and it was found that thermal stability of the synthesised composites decreases with an increase in PbO concentration. Thus by comparing the results of radiation shielding ability and thermal stability, EPDM, with 40 phr PbO and 20 phr Fe3O4, can be considered as an ideal shielding material among the synthesised composites.

Radiation dosimetry of a clinical prototype dedicated cone-beam breast CT system with offset detector.

A clinical-prototype, dedicated, cone-beam breast computed tomography (CBBCT) system with offset detector is undergoing clinical evaluation at our institution. This study is to estimate the normalized glandular dose coefficients ( ) that provide air kerma-to-mean glandular dose conversion factors using Monte Carlo simulations. The clinical prototype CBBCT system uses 49kV x-ray spectrum with 1.39mm 1st half-value layer thickness. Monte Carlo simulations (GATE, version 8) were performed with semi-ellipsoidal, homogeneous breasts of various fibroglandular weight fractions ( , chest wall diameters ( cm), and chest wall to nipple length ( ), aligned with the axis of rotation (AOR) located at 65cm from the focal spot to determine the . Three geometries were considered - -cm detector with no offset that served as reference and corresponds to a clinical CBBCT system, -cm detector with 5cm offset, and a -cm detector with 10cm offset. For 5cm lateral offset, the ranged mGy/mGy and reduction in with respect to reference geometry was observed only for 18cm ( ) and 20cm ( ) diameter breasts. For the 10cm lateral offset, the ranged mGy/mGy and reduction in was observed for all breast diameters. The reduction in was , , , , and for 8, 10, 14, 18, and 20cm diameter breasts, respectively. For a given breast diameter, the reduction in with offset-detector geometries was not dependent on . Numerical fits of were generated for each geometry. The and the numerical fit, would be of benefit for current CBBCT systems using the reference geometry and for future generations using offset-detector geometry. There exists a potential for radiation dose reduction with offset-detector geometry, provided the same technique factors as the reference geometry are used, and the image quality is clinically acceptable.

Characteristics of lead glass for radiation protection purposes: A Monte Carlo study

Background: Lead glass has a wide variety of applications in radiation protection. This study aims to investigate some characteristics of lead glass such as the γ-ray energy-dependent mass and linear attenuation coefficients, the half-value layer thickness, and the absorbed dose distribution for specific energy. Materials and Methods: The attenuation parameters of different lead glass types against high-energy photons (0.2-3 MeV) of gamma rays have been calculated by the Monte Carlo technique and a deterministic method. Besides, the depth dose distribution inside the volume of two cubic lead glass samples was calculated by two Monte Carlo-based computer codes, for gamma rays of 300 keV. In each part of the study, the results of the two methods have been compared. Results: Increasing the Pb concentration (weight in %) by 1% in the lead glass causes a 1.6%-3% increase in the linear attenuation coefficient, depending on the energy. However, the mass attenuation coefficient does not show significant variation for different types of lead glass, especially for the energies higher than 400 keV. Moreover, almost half of the total dose from 300 keV photons will be absorbed in the first 3.5 mm of the sample’s thickness. Conclusion: Results indicate that the Monte Carlo technique is as reliable as the deterministic methods for calculating the attenuation characteristics of the lead glass. The provided data in this investigation can be useful for radiation protection purposes, especially in the case of selecting the lead glass type and dimension based on a specific application.

Investigation of the Radiation Shielding Properties of Black Pine Wood Impregnated with Boric Acid

Aim of study: The present work is to investigate the radiation shielding properties of impregnated black pine (Pinus nigra Arnold subsp. pallasiana) wood material by measuring linear attenuations coefficient, mass attenuations coefficient, half value and tenth value layer thickness for different gamma energies from 5 keV to 1000 keV. Material and methods: The values of linear attenuation coefficient (1/cm), mass attenuation coefficient (cm2/g), half value and tenth value layer thickness of impregnated wood material were calculated in energy range between 5 to 1000 keV using the WinXCOM based Phy-X/PSD software and compared with concrete. Main results: It has been found that the linear attenuation coefficient and the mass attenuation coefficient of impregnated wood decrease as photon energy increases. But, half value layer and tenth value layer of impregnated wood increased as photon energy increased. As a result, it was found that the radiation shielding properties of wood increasing with boric acid impregnation. Highlights: The radiation shielding properties of impregnated wood are higher than pine wood because of its high density and chemical composition, which contains boron elements.

A model for the energy and angular distribution of x rays emitted from an x-ray tube. Part I. Bremsstrahlung production.

To develop an analytical model for bremsstrahlung production in a thick x-ray target (i.e., the x-ray tube anode) that takes into account the intrinsic bremsstrahlung angular distribution. X-ray spectrum models developed from theoretical principles have traditionally treated the angular distribution of the bremsstrahlung production as spherically uniform. This assumption stems from the rationale that electrons promptly attain a diffuse directional distribution in an x-ray target due to multiple scattering, thereby effectively masking the intrinsic bremsstrahlung angular distribution. In this work, a model that explicitly accounts for the angular distribution of the bremsstrahlung production is presented. The model combines Monte Carlo-calculated depth, energy, and angular distributions of electrons penetrating the x-ray target, and incorporates theoretical results for the differential bremsstrahlung cross section. The effects of using different simplified model assumptions for the electron penetration and the intrinsic bremsstrahlung angular distribution are analyzed for tungsten and molybdenum targets in the energy range 20-300keV. Typical assumptions of previous models are shown to introduce errors in calculated spectra. Particularly, it is shown that predictions of fluence and air kerma free-in-air can be overestimated by 15-30% (2-3% in aluminum half-value layer thickness) for clinically relevant beam qualities. The present model is able to reproduce comprehensive Monte Carlo calculations of the bremsstrahlung production generally to within 1%. The bremsstrahlung model developed in this work is an improvement over previous models in that the main features of the electron penetration and the resulting bremsstrahlung are considered in detail. The model can be used for more accurate predictions of the energy and angular distribution of x rays emitted from an x-ray tube.

A model for the energy and angular distribution of x rays emitted from an x-ray tube. Part II. Validation of x-ray spectra from 20 to 300kV.

To present and validate a complete x-ray emission model (bremsstrahlung and characteristic x-ray emission) for the energy range 20-300kV. An analytical x-ray spectrum model that combines the bremsstrahlung emission model developed in Part I with a previously developed characteristic x-ray emission model is validated by comparison with Monte Carlo calculations, published measured spectra, and models developed by other authors. Furthermore, the assumptions and limitations of previous spectrum models are summarized, and their predictions are compared with results obtained by Monte Carlo simulations of x rays emitted from tungsten and molybdenum targets. The model is able to reproduce narrow-beam Monte Carlo calculations to within 0.5% in terms of the first and second aluminum half-value layer thickness (HVL). Compared with measured spectra, the difference in HVL is < 2% for typical diagnostic and therapeutic beam qualities available at primary standard laboratories. Compared with previous spectrum models, the present model performs especially well for low kilovoltage x-ray beams (below 50kV), and is reliable for a wider range of take-off angles, that is, the angle between the target surface and the direction of emission. The difference in model and Monte Carlo predictions of the energy-fluence weighted air kerma (i.e., the photon energy absorption in air) is < 0.5% using the present model, while previous spectrum models can differ by more than 10%. The x-ray emission model developed in this work has been validated against Monte Carlo calculations and measured results. The model provides an efficient alternative to comprehensive Monte Carlo simulations and is an improvement over previous models. The model can be used to predict both central- and off-axis spectra, as well as off-axis effects such as the (anode) heel effect.

An experimental study and WinXCom calculations on X-ray photon characteristics of Bi2O3- and Sb2O3-added waste soda-lime-silica glass

Radiation is used in a variety of different fields, and thus protection from its hazardous effects become a popular subject for researchers. For this purpose, in the present study, waste soda-lime-silica glasses as SiO2–Na2O–CaO–Bi2O3 and SiO2–Na2O–CaO–Sb2O3 were investigated for X-rays photon characteristics in the energies of 0.01–0.1 MeV via WinXCom program, and the results were compared with the experimental findings obtained at 0.04 MeV. Waste packaging glass was evaluated by adding varying amounts (0.005, 0.05, and 0.5 percentages) of Bi2O3 and Sb2O3. Seven different glass batches were prepared by following the procedures of precisely weighing the relevant amounts to obtain 10 g specimen in total, homogeneously mixing the respective contents, and thoroughly melting in an Au–Pt crucible via conventional electrical furnace at 1250 °C for 4 h. The linear attenuation coefficient (LAC) for glass specimens were experienced at 0.04 MeV, and it was found out that increasing contents of both oxides increased the LAC implying that a decrease in X-ray transmission occurred. From the point of WinXCom calculations, the LAC and mass attenuation coefficient (MAC) increased while half value layer (HVL) and mean free path (MFP) thicknesses decreased as the oxide substances increased in the glass specimens. That is, Sb2O3 addition provided higher X-rays attenuation characteristics in comparison to Bi2O3 additive. Further, the experimental data at 0.04 MeV were compared with WinXCom calculations, and it was figured out that the data were parallel for each other, but the correlation coefficient (R2) was found as 0.15 which means that the values were in loose agreement.