White and some colored marbles as alternative radiation shielding materials for applications

ABSTRACT

In this paper, the radiation shielding parameters such as linear attenuation coefficients (LAC, µ), mass attenuation coefficients (MAC, µ/ρ), effective atomic numbers (Z_eff), effective electron densities (N_eff), half value of layers (HVL), mean free paths (MFP) and buildup factors (exposure (EBF) and energy absorption (EABF)) were investigated for cream (M1), pink (M2), white (M3), maroon (M4) and green (M5) marbles. Attenuation coefficients were measured in the energy region 31.18–661.66 keV photon energies. The values of Z_eff and N_eff were then calculated using these coefficients with logarithmic interpolation method, and HVLs and MFPs were calculated using the values of LAC of marble samples at the same photon energies. The experimental results were compared with the theoretical values obtained from WinXCom program, and good agreements were observed between the experimental and theoretical results. HVLs and MFPs of all marble samples were compared with those of some concretes, glasses and commercial radiation shielding glasses (SCHOTT Co.). The studied marbles were better radiation shielding materials than standard shielding concretes due to lower HVL and MFP values lower than the ordinary concrete. Finally, EBFs and EABFs of the marbles were calculated in the energy region 0.015–1?MeV up to penetration depths of 40 mfps by Geometric Progression method (G-P), and the results were discussed in terms of photon energies and chemical compositions of the marbles.     

Determining the gamma-ray parameters for BaO–ZnO–B2O3 glasses using MCNP5 code: a comparison study

Rapid technological advancement has multiplied people’s exposure to ionizing radiations greatly. Widespread applications of radiation in different fields (such as agriculture, radiation therapy and scientific research fields) require that humans be protected against unnecessary exposure. In this study, mass attenuation coefficient (μ_m), half-value layer, mean-free path, effective atomic number (Z_eff) and exposure buildup factor have been calculated for xBaO–20ZnO–(80???x)B₂O₃ (x?=?5, 10, 15, 20 and 25?mol%) glass systems. The mass attenuation coefficients of the selected glasses were calculated using simulation method of MCNP5 code. The simulation results have been compared with the experimental data and Xcom at the energies 223.02, 252.98, 287.28, 340.83, 398.97, 481.59, 562.68 and 662.00?keV. The agreement amounts of the mass attenuation coefficient values are from 0.2% to 2.8% and from 0.2% to 6.98% for MCNP5 and Xcom relative to experimental results, while the Monte Carlo program values are higher than that obtained by experimental data, using Xcom and MCNP5 code. The glass sample having the highest value of BaO content show high radiation shielding properties. It indicates that the MCNP5 code can be used for estimation of radiation interaction parameters where experimental results are not available.     

Investigation of radiological properties of some shielding materials on charged and uncharged radiation interaction for neutron generator

Radiation interaction parameters such as total stopping power, projected range (longitudinal and lateral) straggling, mass attenuation coefficient, effective atomic number (Z_eff) and electron density (N_eff) of some shielding materials were investigated for photon and heavy charged particle interactions. The ranges, stragglings and mass attenuation coefficients were calculated for the high-density polyethylene(HDPE), borated polyethylene (BPE), brick (common silica), concrete (regular), wood, water, stainless steel (304), aluminum (alloy 6061-O), lead and bismuth using SRIM Monte Carlo software and WinXCom program. In addition, effective atomic numbers (Z_eff) and electron densities (N_eff) of HDPE, BPE, brick (common silica), concrete (regular), wood, water, stainless steel (304) and aluminum (alloy 6061-O) were calculated in the energy region 10?keV–100?MeV using mass stopping powers and mass attenuation coefficients. Two different methods namely direct and interpolation procedures were used to calculate Z_eff for comparison and significant differences were determined between the methods. Variations of the ranges, longitudinal and lateral stragglings of water, concrete and stainless steel (304) were compared with each other in the continuous kinetic energy region and discussed with respect to their Z_effs. Moreover, energy absorption buildup factors (EABF) and exposure buildup factors (EBF) of the materials were determined for gamma rays as well and were compared with each other for different photon energies and different mfps in the photon energy region 0.015–15?MeV.     

Nuclear radiation shielding and mechanical properties of colemanite mineral doped concretes

ABSTRACT

The present research focused on the investigation of photon and fast neutron shielding parameters of colemanite mineral doped and undoped concretes. The fabricated concretes have been exposed to gamma rays at 59.5 and 81?keV energies and the measurements have been carried out with NaI(Tl) detector. The parameters of effective atomic number (Z_eff) and electron density (N_el) have been determined experimentally and theoretically. The exposure buildup factor (EBF) and energy absorption buildup factor (EBF) have been computed utilizing the Geometric progression (G–P) fitting method. In addition to the photon shielding parameters, the macroscopic effective removal cross-section calculations for fast neutron (Σ_R) were performed. As a result, it was observed that the concretes doped with colemanite mineral are not very effective in gamma radiation shielding. On the contrary, it was observed that concretes with colemanite were more effective in shielding fast neutrons and the fast neutron removal cross-section values increased with increasing colemanite concentration in the concrete. Additionally, compressive strength values (MPa) of concretes were tested using ALFA TESTING (B001-PC) 200 tons capacity device.     

Simple parametrization of photon mass energy absorption coefficients of H-, C-, N- and O-based samples of biological interest in the energy range 200–1500 keV

In this paper, we provide polynomial coefficients and a semi-empirical relation using which one can derive photon mass energy absorption coefficient of any H-, C-, N-, O-based sample of biological interest containing any other elements in the atomic number range 2–40 and energy range 200–1500 keV. More interestingly, it has been observed in the present work that in this energy range, both the mass attenuation coefficients and the mass energy absorption coefficients for such samples vary only with respect to energy. Hence it was possible to represent the photon interaction properties of such samples by a mean value of these coefficients. By an independent study of the variation of the mean mass attenuation coefficient as well as mass energy absorption coefficient with energy, two simple semi-empirical relations for the photon mass energy absorption coefficients and one relation for the mass attenuation coefficient have been obtained in the energy range 200–1500 keV. It is felt that these semi-empirical relations can be very handy and convenient in biomedical and other applications. One possible significant conclusion based on the results of the present work is that in the energy region 200–1500 keV, the photon interaction characteristics of any H-, C-, N-, O-based sample of biological interest which may or may not contain any other elements in the atomic number range 2–40 can be represented by a sample-independent (single) but energy-dependent mass attenuation coefficient and mass energy absorption coefficient.      

Investigation of some nuclear engineering materials in terms of gamma ray buildup factors at experimental energies used in nuclear physics experiments

ABSTRACT

In shielding studies, the gamma ray buildup factor is referred to an attenuation correction when the narrow beam transmission geometry conditions are not met. This is the case if there is a beam divergence and a considerably thick material is used as shield. In the present work, a linear logarithmic interpolation based on five parameter geometric progression (G-P) fitting method was used to calculate energy absorption (EABF) and exposure buildup factors (EBF) at discrete energies for some standard nuclear engineering materials (SNEM) such as concrete, Pb glass, brass, bronze and stainless steel, and for some recently developed shielding alloys and glasses. Calculations were made at different penetration depths (1–20?mfp) using photons emitted from the standard radioactive sources such as ¹³³Ba (0.356 MeV), ¹³⁷Cs (0.662 MeV), ⁶⁰Co (1.173, 1.332 MeV) and ²²Na (0.511, 1.275 MeV). Results have been compared with MCNP6.1 Monte Carlo simulation code wherever possible and a reasonable agreement (Relative difference around 10% up to 10?mfp except for Pb glass) has been achieved. Results also showed that the gamma ray buildup correction is necessarily required since buildup factors are greater than unity even at lowest penetration depth, i.e. 1?mfp. The reported data on EABF and EBF for the energy values of radioactive sources may be of practical use in shielding calculations and estimations.     

Energy absorption buildup factors of some potential bioactive compounds in the energy region 0.015–15 MeV

Kinetic energy released per unit mass relative to air and energy absorption buildup factors has been calculated for some potential bioactive compounds in the energy region of 0.015–15?MeV. The bioactive compounds of 1-aryl-3-dibenzylamino-propane-1-on hydrochloride type Mannich bases were used in this work. Aryl part was changed as C₆H₅ (1), 4-CH₃C₆H₄ (2), C₄H₃S-2-yl (3), 4-FC₆H₄ (4), 4-BrC₆H₄ (5), 4-ClC₆H₄ (6), and 4-NO₂C₆H₄ (7). The energy absorption buildup factors have been calculated for penetration depth of 40 mean free paths. It is observed that kinetic energy released per unit mass relative to air depends on the photon energy and chemical content of compounds. The compounds with least mean atomic number possess the maximum value of energy absorption buildup factors. Also, the energy absorption buildup factors are found the highest in intermediate energy, whereas the lowest in low as well as high energies.     

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

The 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.     

Mass attenuation coefficients of composite materials by Geant4, XCOM and experimental data: comparative study

The main goal of this present study is focused on testing the applicability of Geant4 electromagnetic models for studying mass attenuations coefficients for different types of composite materials at 59.5, 80, 356, 661.6, 1173.2 and 1332.5 keV photon energies. The simulated results of mass attenuation coefficients were compared with the experimental and theoretical XCOM data for the same samples and a good agreement has been observed. The results indicate that this process can be followed to determine the data on the attenuation of gamma rays with the several energies in different materials. The modeling for photon interaction parameters was standard for any type of composite samples. The Geant4 code can be utilized for gamma ray attenuation coefficients for the sample at different energies, which may sometimes be impractical by experiment investigation.     

Measurement of photon interaction parameters of high-performance polymers and their composites

In the present study, commercially important high-performance polymers and their composites have been investigated with respect to photon interactions as means of mass attenuation coefficient (μ/ρ), mean free path (MFP), half-value layer (HVL), effective atomic number (Z_eff), effective electron density (N_eff), and energy absorption and exposure buildup factors (EABF and EBF) at different photon energies. For this purpose, sample plates were prepared by extrusion and injection techniques using polyethersulfone, polyetherimide, acrylonitrile butadiene styrene copolymer, polyamide 66, polyphthalamide, and polypropylene copolymers as high-performance polymers and glass and carbon fibers as reinforcement. The (μ/ρ)s of the materials were measured at 81 and 356?keV photon energies to determine MFP, HVL, Z_eff, and N_eff. The theoretical values of these parameters were calculated via ZXCOM, WinXCom and Monte Carlo N-Particle simulation code (MCNP), and a good agreement was obtained between WinXCom–MCNP and MCNP–Exp. Finally, EABFs and EBFs of the samples were calculated up to around 40 MFP in the energy region 0.015–15?MeV and significant variations were observed in the continuous energy and MFP regions.     

Investigations of radiation shielding using Monte Carlo method and elastic properties of PbO-SiO2-B2O3-Na2O glasses

Several physical parameters such as the packing density (PD), oxygen molar volume (OMV), oxygen packing density (OPD) and the elastic moduli of the quaternary glass system xPbO-(30-x)SiO₂-46.67B₂O₃-23.33Na₂O (x = 0, 5, 10 and 15 mol%) have been evaluated. The elastic moduli were computed according to Makishima-Mackenzie model and Rocherulle model. The values of these moduli have been compared to their experimental values. Moreover, different shielding parameters such as mass attenuation coefficients (MAC), half value layer (HVL), mean free path (MFP), effective atomic numbers (EAN), effective electron densities (EED) and buildup factors have been evaluated using the WinXcom program in the energy range 0.015–15 MeV for the quaternary studied glass system. The MAC values have been compared with MCNPX (version 2.6.0) Monte Carlo code. Besides, mass stopping power (MSP) for proton, alpha and electron as well as the removal cross section for fast neutron (∑_R) have been calculated. The results observed that the composition has the highest value of PbO (15 mol %) showed excellent nuclear radiation shielding and elastic properties.     

Comparison study of photon attenuation characteristics of Lead-Boron Polyethylene by MCNP code,XCOM and experimental data

The linear attenuation coefficient, mass attenuation coefficient and mean free path of various Lead-Boron Polyethylene (PbBPE) samples which can be used as the photon shielding materials in marine reactor have been simulated using the Monte Carlo N-Particle (MCNP)-5 code. The MCNP simulation results are in good agreement with the XCOM values and the reported experimental data for source Cesium-137 and Cobalt-60. Thus, this method based on MCNP can be used to simulate the photon attenuation characteristics of various types of PbBPE materials.     

A combined experimental and theoretical approach to determine X‐ray atomic fundamental quantities of tin

The knowledge of atomic fundamental parameters, such as the mass attenuation coefficients or fluorescence yields with low uncertainties, is of decisive importance in elemental quantification involving X‐ray fluorescence analysis techniques. For example, several databases giving the mass attenuation coefficients are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard X‐ray ranges. However, they significantly differ for low photon energies and around the absorption edges of the elements. In the case of the fluorescence yields, some authors made a review of measured values found in the literature. However, reliable measurements are not so many illustrating the inherent difficulties. Mass attenuation coefficients of tin were determined experimentally in the photon energy range from 100 eV to 35 keV by using monochromatized synchrotron radiation at SOLEIL (France). The fluorescence yields of the 3 L‐subshells of tin were also determined using a reflection geometry setup and the X‐ray fluorescence setup of Physikalisch‐Technische Bundesanstalt. The Coster–Kronig factors for the tin L‐shells were also experimentally determined. The application of high‐accuracy experimental techniques resulted in low uncertainty mass attenuation coefficients and L‐subshell fluorescence yields that are directly compared with existing databases and with updated relativistic configuration mixing Dirac–Fock calculations including Quantum electrodynamics (QED) corrections.     

Determination of mass attenuation coefficient of low-Z dosimetric materials

The mass attenuation coefficients of some low-Z dosimetric materials with potential applications in dosimetry, medical and radiation protection have been investigated using the Monte Carlo simulation code Monte Carlo N-Particle (MCNP). Appreciable variations are noted for the mass attenuation coefficient by changing the photon energy. The MCNP-simulated parameters are compared with the experimental data wherever possible and theoretical values through the WinXcom program. The simulated results obtained by MCNP generally agree well with the experiment and WinXcom predictions for various low-Z dosimetric and tissue substitute materials. In addition, the mass attenuation coefficients around the k-edges for low-Z dosimetric materials estimated from the MCNP code agree very well with WinXcom prediction. Finally, the results indicate that this simulation process can be followed to determine the interaction parameters of gamma rays in such low-Z materials for which there are no satisfactory experimental values available.     

Photon interaction studies using 241Am γ-rays

We have carried out some photon interaction measurements using 59.54 keV γ-rays from a ²⁴¹Am source. These include γ attenuation studies as well as photoelectric absorption studies in various samples. The attenuation studies have been made using leaf and wood samples, samples like sand, sugar etc., which contain particles of varying sizes as well as pellets and aqueous solutions of rare earth compounds. In the case of the leaf and wood samples, we have used the γ-ray attenuation technique for the determination of the water content in fresh and dried samples. The variation of the attenuation coefficient with particle size has been investigated for sand and sugar samples. The attenuation studies as well as the photoelectric studies in the case of rare earth elements have been carried out on samples containing such elements whose K-absorption edge energies lie below and close to the γ-energy used. Suitable compounds of the rare earth elements have been chosen as mixture absorbers in these investigations. A narrow beam good geometry set-up was used for the attenuation measurements. A well-shielded scattering geometry was used for the photoelectric measurements. The mixture rule was invoked to extract the values of the mass attenuation coefficients for the elements from those of the corresponding compounds. The results are consistent with theoretical values derived from the XCOM package.     

Advances in the measurements of the mass attenuation coefficients

The knowledge of atomic fundamental parameters, such as mass attenuation coefficients or fluorescence yields with low uncertainties, is of decisive importance in elemental quantification involving X-ray fluorescence analysis techniques. Several databases providing the mass attenuation coefficients are accessible and frequently used within a large community of users. These compilations are most often in good agreement for photon energies in the hard X-ray ranges. However, they significantly differ for low photon energies and around the absorption edges of the elements. Mass attenuation coefficients of several elements were determined experimentally in the photon energy range from 100 eV to 35 keV by using monochromatized radiation at the SOLEIL synchrotron (France). The application of high-accuracy experimental techniques resulted in low uncertainty mass attenuation coefficients. The results are compared with tabulated data.     

Importance of photo atomic cross section for studying physical properties of different types of soil

The objective of this work is focused on development of a classification tool for identifying soil texture based on photon attenuation interaction atomic cross‐section data. The total mass attenuation coefficients (μ/ρ) and the atomic cross sections (σ_a) of soils with different textures have been calculated for total photon interactions in a wide energy range (1 keV to 100 GeV). The values of these parameters have been found to change with soil composition in low energies (1–100 keV), whereas their behavior has been found to be similar at all energies. Slight differences were observed in σ_a in the energy range of 0.01 to 10 MeV and more pronounced ones from 10 MeV to 100 GeV. Regarding μ/ρ, only small differences were observed among soils for all the energy range investigated. Differences between μ/ρ and σ_a considering different proportions of Fe₂O₃ and SiO₂ were also observed. The reported data should be useful for studying soil texture according photo attenuation. The results of this work can stimulate research for all types of soil texture. Copyright © 2016 John Wiley & Sons, Ltd.     

Lifetime measurements of some levels belonging to the 3p <Emphasis Type="Bold">5</Emphasis>nd ( , 5, 6, 7) configuration of ArI

Lifetimes of some 3p^5nd (n = 4, 5, 6, 7) levels of neutral argon have been measured by high frequency deflection technique with a delayed coincidence single photon counting arrangement. The measurements have been performed under conditions where pressure dependent effects are negligible. Lifetimes of some of the levels have been measured for the first time. The results have been compared with other experimental and theoretical values. Received 7 August 2002 / Received in final form 20 December 2002 Published online 24 April 2003     

Photon beam softening coefficients evaluation for a 6 MeV photon beam for an aluminum slab: Monte Carlo study using BEAMnrc Code,DOSXYZnrc Code,and BEAMDP code

Determination and understanding the photon beam attenuation by the photon beam modifier and the radiation beam softening for clinical use is more important part of material study for the beam modifier enhancements and the linac improvements. A Monte Carlo model was used to simulate 6 MeV photon beams from a Varian Clinac 2100 accelerator with the flattening filter and the later was replaced by the aluminum slab with variable thickness. The Monte Carlo geometry was validated by a gamma index acceptance rate of 99% in PDD and 98% in dose profiles, the gamma criteria was 3% for dose difference and 3 mm for distance to agreement. The purpose was to investigate aluminum material attenuation and beam softening coefficients as a function of the inserted aluminum slab thickness and of off-axis distance. The attenuation and beam softening coefficients were not identical for the same off-axis distance and they varied as a function of aluminum slab thickness. The results of our study were shown that the beam softening coefficients were varied with thickness beam modifier material used for beam softening and the off-axis distance inside the irradiation field. Thereafter, the softening coefficient a ₁ have a maximum of 2.5 × 10^–1 cm^–1 for the aluminum slab thickness of 1 mm, 1.4 × 10^–1 cm^–1 for the aluminum slab thickness of 1.5 mm and 4.47 × 10^–2 cm^–1 for the aluminum slab thickness of 2 mm. The maximum of the second softening coefficient a ₂ was 1.02 × 10^–2 cm^–2 for the aluminum slab thickness of 1 mm, was 1.92 × 10^–2 cm^–2 for the aluminum slab thickness of 1.5 mm and was 1.93 × 10^–2 cm^–2 for the aluminum slab thickness of 2 mm. Our study can be a basic investigation of photon beam softening material that will be used in the future linac configuration and also in the photon beam modifiers.     

Charge exchange features of excited sputtered particle production

Abstract

The results are presented which have been obtained by studying the angular dependence of photon and ion emission and the spatial energy distribution of excited silicon ions produced under ion bombardment of monocrystalline and amorphized silicon surface. The experimental data are discussed which have been obtained mostly by the coincidence method. The theoretical concepts making it possible to account for the observed behavioural features are also discussed.