Gamma Ray Exposure Buildup Factors Research Articles

Estimation of neutron and gamma-ray attenuation characteristics of some ferrites: Geant4, FLUKA and WinXCom studies

Ferrites are ceramic oxide materials consisting of mainly iron oxide and they have become massively important materials commercially and technologically, having a multitude of uses and applications. The protection against neutron–gamma mixed radiation is crucial in several nuclear applications. From this standpoint, mass attenuation coefficient, radiation protection efficiency and transmission factor of some ferrites namely barium, strontium, manganese, copper and cadmium ferrite has been computed using Geant4 and FLUKA simulations. Based on the simulated mass attenuation coefficient, other significant parameters such as linear attenuation coefficient, effective atomic and electron number, conductivity, half value layer, and mean free path were calculated for the selected ferrite materials. The validation of Monte Carlo geometry has been provided by comparing the mass attenuation coefficient results with standard WinXCom data. Gamma ray exposure buildup factors were computed using geometric progression fitting formula for the chosen ferrites in the energy range 0.015–15 MeV at penetration depths up to 40 mfp. The findings of the present work reveal that among the studied ferrites, barium ferrite and copper ferrite possess superior gamma ray and fast neutron attenuation capability, respectively. The present work provides a comprehensive investigation of the selected iron oxides in the field of neutron and gamma ray.

Effect of Ce-dopant on photon interaction parameters of zirconolite-based borosilicate glass ceramics

In the present investigation, 70 wt% of zirconolite (CaZr1-xCexTi2O7, x = 0, 0.2, 0.4, 0.6, 0.8 and 1) and 30 wt% of sodium borosilicate glass (NaB0.5Al0.5Si2O6) (sample C0 to C10) have been synthesized. The photon interaction parameters viz. mass attenuation coefficient, effective atomic number, effective electron density, mean free path, and half value layer have been investigated for glass-ceramic samples at incident photon energies of 59.58 keV, 81.2 keV, 356 keV, 662 keV, 1173 keV and 1333 keV. Furthermore, effective neutron removal cross-section values, mass stopping power (MSP) and range of alpha particles and proton, were also calculated using SRIM codes. Moreover, gamma-ray energy absorption buildup factor (EABF) and exposure buildup factor (EBF) were also estimated. The experimental results are in agreement with the theoretically calculated values using WinXCOM program. Among the given prepared samples, C10 shows the best shielding properties, and C0 shows the best capability for neutron absorption. The MSP and projected range of α-particles and protons in all the prepared samples show very small variation with the change of Ce content in zirconolite in the energy range upto 15 MeV. The measured values are extensively desirable in fission and fusion reactors, medical applications, shielding researchers, and radiation physics.

Gamma-Ray Attenuation and Exposure Buildup Factor of Novel Polymers in Shielding Using Geant4 Simulation.

Polymers are often used in medical applications, therefore, some novel polymers and their interactions with photons have been studied. The gamma-ray shielding parameters for Polymethylpentene (PMP), Polybutylene terephthalate (PBT), Polyoxymethylene (POM), Polyvinylidenefluoride (PVDF), and Polychlorotrifluoroethylene (PCTFE) polymers were determined using the Geant4 simulation and discussed in the current work. The mass attenuation coefficients (μ/ρ) were simulated at low and high energies between 0.059 and 1.408 MeV using different radionuclides. The accuracy of the Geant4 simulated results were checked with the XCOM software. The two different methods had good agreement with each other. Exposure buildup factor (EBF) was calculated and discussed in terms of polymers under study and photon energy. Effective atomic number (Zeff) and electron density (Neff) were calculated and analyzed at different energies. Additionally, the half-value layer (HVL) of the polymers was evaluated, and the results of this parameter showed that PCTFE had the highest probability of interaction with gamma photons compared to those of the other tested polymers.

Calculation of gamma-ray exposure buildup factor based on backpropagation neural network

In this paper, a method based on a backpropagation neural network (BPNN) is proposed to calculate the exposure buildup factor (BD) of a point isotropic source in an infinite homogeneous medium under arbitrary energy and mean free path (mfp). The results obtained for aluminum, iron, lead, and concrete based on BPNN are compared to ANSI/ANS-6.4.3 standard data, the results calculated by MCNP 5 Monte Carlo code, and a geometric progression (G-P) fitting formula, and show that the BD calculated by the BPNN model is more consistent with the ANS standard data. This method improves the calculation and fitting effect of BD compared to other methods. This paper proposes a systematic process combining a Monte Carlo method and BPNN to calculate and predict the BD of new materials under different energy and mfp, thus replacing the G-P fitting formula and improving calculation accuracy.

Gamma ray exposure buildup factor and shielding features for some binary alloys using MCNP-5 simulation code

Gamma radiation shielding features for three series of binary alloys identified as (Pb–Sn), (Pb–Zn), and (Zn–Sn) have been investigated. The mass attenuation coefficients (μ/ρ) for the selected alloys were simulated using the MCNP-5 code in the energy range between 0.01 and 15 MeV. Moreover, the (μ/ρ) values were computed using WinXCOM database in the same energy range to validate the simulation results. Results reveal a good agreement between the simulated and computed values. The half value layer (HVL), mean free path (MFP), effective atomic number (Zeff) and exposure buildup factor (EBF) were evaluated for the selected binary alloys. Results showed that the PS1, PZ1, and ZS2 alloys have the best shielding parameters and better than the commercially standard and available radiation shielding materials. Therefore, the investigated alloys can be used as effective radiation shielding materials against gamma ray with energies between 0.01 and 15 MeV.

Exposure buildup factor investigation of tungsten gadoliniumborate system

Abstract The gamma ray exposure buildup factors (EBF) of xWO3:(70-x)Gd2O3:30B2O3 system (where x=40, 45, 50, 55 and 60 mol%) have been calculated in the energy region 0.015–15 MeV up to a penetration depth of 40 mfp (mean free path). The five parameter geometric progressions (G-P) fitting method has been used to compute exposure buildup factor values. Variation of exposure buildup factors with incident photon energies and penetration depth have been studied. It was found that EBF values were higher in the intermediate energy region, for all glass system. Moreover, tungsten gadolinium borate glass of 40 mol% WO3, was found to present the lowest EBF values, hence it is excellent gamma ray shielding material. The obtained results in this paper show that these glasses can be used as radiation shielding materials

An improvement to the Kalos’ formula for double layer gamma ray exposure buildup factors for shielding materials of nuclear and radiological facilities

Gamma ray exposure buildup factors (BUFs) are used in point kernel method based shielding codes to estimate the scattered radiation dose rate. BUFs computed by assuming single material for multi-layer shielding configuration either overestimate or underestimate the dose rates. Hence, BUFs computed based on stratified shielding configuration give better estimates of scattered dose rate and provide scope for further optimization of shielding thickness. In nuclear and radiological facilities, shielding materials such as concrete (Con), iron (Fe), lead (Pb), and tungsten (W) are normally used as single or multi-layer shields. For the first time, buildup factors estimated based on Monte Carlo simulations (MCS) for double layer shielding configurations (DBUFs) of W and Fe, W and Con, Pb and Fe, Pb and Con, and Fe and Con are reported. The estimated DBUFs are compared with the values obtained using the empirical formulae published by several authors. A significant variation up to 40% is observed between MCS and empirical formulae. Hence, the correction factor in the empirical formula of Kalos’ is modified and standardized by carrying out further computations for various double layer shielding configurations and energies. Radiation shielding experiments performed to validate the MCS results are presented.

Gamma-Ray Exposure Buildup-Factors Calculations for Some Radiation-Resistant and Radiation-Protective Glasses

In this article, we first calculate gamma-ray exposure buildup-factors of some radiation-resistant glasses and radiation-protective glasses by using the Geometric Progression (G-P) fitting method. And then we analyze variations of the exposure buildup-factor with the incident photon energy and penetration depth. The results show that exposure buildup-factors strongly associate with photon energy and penetration depth. Exposure buildup-factors calculated in this article are useful for the design of a peer window used in nuclear industry.

Bi2O3 effect on physical, optical, structural and radiation safety characteristics of B2O3[sbnd]Na2O-ZnO[sbnd]CaO glass system

Novel transparent glasses with nominal composition of 50B2O3 +15Na2O+15ZnO+(20−x)CaO+xBi2O3; x = 0, 5, 10, 15, and 20 were synthesized using melt quenching method. The molar volume and density of the produced glasses with boosting the substitution ratio of Bi2O3 were measured. X-ray diffraction (XRD) patterns of the glasses were obtained for confirming their amorphous structure. UV–Vis spectra of the prepared samples were detected over the range of 190–1100 nm. By using UV–Vis results, Fermi level energy (Ef), refractive index (n), optical energy gap (Eg), Urbach's energy (Eu), and optical dispersion parameters were estimated. Results exposed that the optical energy gap (Eg) and single-oscillator energy (Eo) were decreased however other parameters increased with increasing Bi2O3 content. Mass attenuation coefficient (μ/ρ), as an essential variable for photon protecting research, was attained at 0.015–15 MeV photon energies for investigated glasses. Other relevant variables that can define the photon protecting features like Mean Free Path (MFP), Half Value Layer (HVL), equivalent atomic number (Zeq), gamma-ray exposure buildup factor (EBF), energy-absorption buildup factor (EABF) were obtained for the prepared glasses. The corollaries revealed that the BCNZB20.0 glass can be a strong shield material against gamma radiation. Finally, the proficiency of proposed glasses to stop fast neutrons charged alpha and proton particles was explored utilizing effective removal cross section (ΣR) and Mass Stopping Power (MSP) parameters. The glass with 20% Bi2O3 (BCNZB20.0) addition is very effective in preventing charged and uncharged particles. The addition of Bi2O3 to the studied glass system not only improved the optical and structural features but also the nuclear radiation shielding properties.

Evaluation of radiation shielding ability of boro-tellurite glasses: TeO2–B2O3–SrCl2–LiF–Bi2O3

This paper focuses on examining the radiation shielding features of seven boro-tellurite glasses in the form of TeO2–B2O3–SrCl2–LiF–Bi2O3. Gamma rays and neutrons shielding features of these glasses have been tested in terms of mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP), effective atomic number (Zeff), and removal cross section (∑R). The μ/ρ values of the present glasses were simulated by Geant4 Monte Carlo simulations over an extended energy range of 0.015 − 20 MeV and then the generated data were verified using the calculated values of WinXCOM software. Additionally, geometric progression (G–P) method was used to estimate gamma ray exposure buildup factor (EBF) for the prepared glasses. It is noted that μ/ρ and Zeff values increase, while MFP and HVL values decrease as TeO2 content increases in the glass sample. The EBF values would be useful to design or develop the present glasses for gamma shielding applications. Results reveal that the present glasses have good capability for gamma rays shielding compared with some commercial radiation shielding materials.

Gamma ray shielding characteristics and exposure buildup factor for some natural rocks using MCNP-5 code

Abstract The mass attenuation coefficient μ m for eight rock samples having different chemical composition was simulated using the MCNP 5 code in energy range ( 0.002 MeV ≤ E ≤ 10 MeV ) . Moreover, the μ m for the studied rock samples was computed theoretically using XCOM database. The comparison between simulated and computed data for all selected rock samples showed a good agreement with differences varied between 0.01 and 8%. The highest μ m was found for basalt rocks M2 and M1 and the lowest one is reported for limestone rocks Dike. The simulated values of the μ m then were used to calculate other important shielding parameters such as the mean free path, effective electron density and effective atomic number. The exposure buildup factor EBF was also computed for the selected rocks with the contribution of G-P fitting parameters and the highest EBF attended by the basalt sample Sill and varied between 1.022 and 744 in the energy range between ( 0.015 ≤ E ≤ 15 MeV ) but the lowest EBF achieved by basalt sample M2 and varied between 1.017 and 491 in the same energy range.

Gamma radiation and neutron shielding properties of transparent alkali borosilicate glass containing lead

In this study, lithium sodium borosilicate glasses with chemical compositions of xPbO-40B2O325Na2O5Li2O-(30 - x)SiO2 (where x = 0, 5, 10, 15, 20, and 25 mol%) were prepared by using the conventional melt-quenching technique. The amorphous nature and the effects of Pb+2 ions in the glass structure were explored by using X-ray diffraction and Fourier transform infrared spectroscopy analyses, respectively. The gamma radiation and neutron shielding properties of the glass system were investigated by determining the mass attenuation coefficients, half value layer, gamma-ray exposure build-up factor (EBF), and fast neutron removal cross section. The EBFs were calculated using the general progressive fitting parameter formula for photon energies of 0.015–15 MeV to penetration depths of 40 mfp. The effective atomic number (Zeff) and electron density (Neff) were determined for all of the prepared glasses. For validation purposes, the experimental values of the mass attenuation coefficient, half value layer, Zeff, and Neff for all of the prepared glasses at 0.239, 0.662, 0.911, and 1.332 MeV were compared with their theoretical values. The fast neutron removal cross sections of the prepared glasses ranged from 0.0890 to 0.1375 cm−1, which corresponded to concentrations of 0–25 PbO mol%. The results confirmed that the glasses prepared with lead concentrations of 5–25 PbO mol% have suitable and comparable gamma attenuation coefficients for use as efficient transparent gamma ray and neutron shielding materials.

A new approach to examine the exposure and dose buildup factors for multi-energy radioisotopic gamma sources with G-P analytical expression

The gamma ray exposure and dose buildup factor for five point isotropic multi-energy sources have been studied up to a depth of 10 mean free paths (mfp) for aluminum, concrete, iron, tin, lead, tungsten and uranium using the Monte Carlo code MCNPX. All secondary particles produced inside the shields were taken into account in the calculations. These findings are adequate for shielding of photon and dosimetry calculations. The obtained values of dose buildup factor were parameterized as a function of mfp based on geometric progression (G-P) analytical expression, and the parameters were obtained for different gamma sources.

Gamma ray buildup factors of lithium borate glasses doped with minerals

Five parameters (G-P) fitting method was used to calculate the gamma ray energy absorption and exposure buildup factor values of barite-doped, limonite-doped, serpentine-doped and undoped lithium borate glass types for incident photon energy, between 0.015 MeV and 15 MeV, and penetration depths, 40 mean free path. It was observed that the buildup factor values vary with not only different incident gamma energy values, but also chemical composition of glass samples. According to our results, the barite and limonite doped glasses (B1, B2 and L2) have the lowest values of energy absorption and exposure buildup factors. Among the selected sample of glasses, the barite and limonite-doped glasses possessed superior gamma-ray shielding effectiveness due to their higher equivalent atomic number values and the lower energy absorption and exposure buildup factor values. In other words, the presence of highly equivalent atomic number minerals improves the gamma ray shielding characteristics of the lithium borate glasses. Moreover, EABF and EBF values were compared and discussed.

Study of gamma ray energy absorption and exposure buildup factors for ferrites by geometric progression fitting method

ABSTRACTThe gamma ray energy absorption and exposure buildup factors (EABF and EBF) were calculated for ferrites such as cobalt ferrite (CoFe2O4), zinc ferrite (ZnFe2O4), nickel ferrite (NiFe2O4) and magnesium ferrite (MgFe2O4) using five parametric geometric progression (G-P fitting) formula in the energy range 0.015–15.00 MeV up to the penetration depth 40 mean free path (mfp). The obtained data of absorption and exposure buildup factors have been studied as a function of incident photon energy and penetration depth. The obtained EABF and EBF data are useful for radiation dosimetry and radiation therapy.

Comprehensive study on estimation of gamma-ray exposure buildup factors for smart polymers as a potent application in nuclear industries

Abstract In the present study, the exposure buildup factors (EBF) have been investigated using geometric progression (G-P) fitting method for different types of smart polymers (DMSO, PDMS, PES, PMA, PVDC, and PVDF) in the energy range of 0.015–15 MeV. From the calculations, the values of the EBF were depended on the incident photon energy, penetration depth as well as chemical composition of the polymers. In the intermediate energy region, the EBF values were reached at maximum point while in low and high energy regions, the EBF values were decreased at minimum point. The obtained results of the selected polymers have been compared in terms of EBF with Al2O3 and other common polymers such as PAN, Teflon and SR. The shielding effectiveness of the selected polymers is found to be comparable to the common polymers. The results of this work should be useful in radiation shielding applications such as in industry, medical and nuclear engineering.

Study of gamma radiation shielding properties of $$\mathbf{ZnO {-}{} \mathbf TeO }_\mathbf{2}$$ ZnO - T eO 2 glasses

Mass attenuation coefficient \((\mu _\mathrm{m})\), half value layer (HVL) and mean free path (MFP) for \(x\hbox {ZnO}{-}\)(100\({-}x)\hbox {TeO}_{2}\), where \(x = 10\), 15, 20, 25, 30, 35 and 40 mol%, have been measured for 0.662, 1.173 and 1.33 MeV photons emitted from \(^{137}\hbox {Cs}\) and \(^{60}\hbox {Co}\) using a \(3\times 3\) inch NaI(Tl) detector. Some relevant parameters such as effective atomic numbers (\(Z_\text {eff})\) and electron densities (\(N_\text {el})\) of glass samples have been also calculated in the photon energy range of 0.015–15 MeV. Moreover, gamma-ray energy absorption buildup factor (EABF) and exposure buildup factor (EBF) were estimated using a five-parameter Geometric Progression (GP) fitting approximation, for penetration depths up to 40 MFP and in the energy range 0.015–15 MeV. The measured mass attenuation coefficients were found to agree satisfactorily with the theoretical values obtained through WinXcom. Effective atomic numbers (\(Z_\text {eff})\) and electron densities (\(N_\text {el})\) were found to be the highest for 40\(\hbox {ZnO}{-}\)60\(\hbox {TeO}_{2}\) glass in the energy range 0.04–0.2 MeV. The \(10\hbox {ZnO}{-}90\hbox {TeO}_{2}\) glass sample has lower values of gamma-ray EBFs in the intermediate energy region. The reported new data on radiation shielding characteristics of zinc tellurite glasses should be beneficial from the point of proper gamma shield designs when intended to be used as radiation shields.

Variation of energy absorption and exposure buildup factors with incident photon energy and penetration depth for boro-tellurite (B2O3-TeO2) glasses

The gamma ray energy absorption (EABF) and exposure buildup factors (EBF) of (100-x)TeO2-xB2O3 glass systems (where x=5, 10, 15, 20, 22.5 and 25mol%) have been calculated in the energy region 0.015–15MeV up to a penetration depth of 40 mfp (mean free path). The five parameters (G-P) fitting method has been used to estimate both EABF and EBF values. Variations of EABF and EBF with incident photon energy and penetration depth have been studied. It was found that EABF and EBF values were higher in the intermediate energy region, for all the glass systems. Furthermore, boro-tellurite glass with 5mol% B2O3, was found to present the lowest EABF and EBF values, hence it is superior gamma-ray shielding material. The results indicate that the boro-tellurite glasses can be used as radiation shielding materials.

Gamma-ray double-layered transmission exposure buildup factors of some engineering materials, a comparative study

Abstract Comparative study on various deterministic methods and formulae of double layered transmission exposure buildup factors (DLEBF) for point isotropic gamma-ray sources has been performed and the results are provided here. This investigation has been performed on some commonly available engineering materials for the purpose of gamma-ray shielding. In reality, the presence of air around the gamma-ray shield motivated to focus this study on exposure buildup factor (EBF). DLEBF have been computed at four energies viz. 0.5, 1.0, 2.0 and 3.0 MeV for various combinations of the chosen five samples taken two at a time with combined optical thickness up to 8 mean free path (mfp). For the necessary computations for DLEBF, a computer program (BUF-toolkit) has been designed. Comparison of Monte Carlo (EGS4-code) and Geometric Progression (G.P.) fitting point kernel methods were done for DLEBF computation. It is concluded that empirical formula given by Lin and Jiang using EBF computed by G.P. fitting formula is the most accurate and easiest method for DLEBF computations. It was observed that DLEBF values at selected energies for two layered slabs with an orientation (low-Z material followed by high-Z material) were lower than the opposite orientation. For optical thickness up to 8 mfp and chosen energy range (0.5–3.0 MeV), Aluminum-Lime Stone shield, appears to provide the best protection against the gamma-rays.

Shielding efficiency of metal hydrides and borohydrides in fusion reactors

Mass attenuation coefficients, mean free paths and exposure buildup factors have been used to characterize the shielding efficiency of metal hydrides and borohydrides, with high density of hydrogen. Gamma ray exposure buildup factors were computed using five-parameter geometric progression fitting at energies 0.015 MeV to15 MeV, and for penetration depths up to 40 mean free paths. Fast-neutron shielding efficiency has been characterized by the effective neutron removal cross-section. It is shown that ZrH2 and VH2 are very good shielding materials for gamma rays and fast neutrons due to their suitable combination of low- and high-Z elements. The present work should be useful for the selection and design of blankets and shielding, and for dose evaluation for components in fusion reactors.