Total Mass Attenuation Coefficients Research Articles

The investigation of vermiculite as an alternating shielding material for gamma rays

In this study, gamma ray shielding properties of vermiculite has been investigated for the first time as a shielding material. The photon total mass attenuation coefficients µm, the half value layer (HVL), the tenth value layer (TVL) and the mean free path (MFP) values have been experimentally determined for the photon energies at 0.244, 0.262, 0.342, 0.600, 0.778, 1.173, 1.332, 1.408 and 1.728MeV. The theoretical data are calculated by using WinXCom computer code. At the end, we obtained good agreement between experimental and theoretical values. As well as the total mass attenuation coefficients, we have also calculated the effective atomic number, Zeff, the effective electron number, Neff, the total atomic cross-section, σt,a, the total electronic cross-section, σt,e, values for vermiculite and some building materials. Consequently, the obtained results showed that vermiculite could be used as a shielding material for gamma radiation.

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 (σa) 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 σa 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 σa 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.

Theoretical Study of the Photon Interaction for Zirconium Alloy at 1 keV to 100 MeV

In this work, the total mass attenuation coefficient and partial interactions of the zirconium alloy have been calculated by WinXCom program at 1 keV-100 MeV gamma ray energies. Zr2(Fe,Ni) alloys was studied for the mass attenuation coefficients, photoelectric absorption, incoherent, coherent and pair production processes. The effective atomic numbers and electron densities were also calculated. The calculated results show that the total mass attenuation coefficient decreased with increasing of gamma rays energy. The value of total mass attenuation coefficient of each material was different, which depend on chemical compositions of alloy. The partials interactions, effective atomic numbers and electron densities were also calculated and discussed.

Luminescence and Scintillation Response of Ce<sup>3+</sup>-Doped Oxide Glasses with High Gd<sub>2</sub>O<sub>3</sub> Content

This report presents the luminescence and scintillation response of Ce3+-doped oxide glasses with high Gd2O3 (30 mol%) content. The characteristic emission of Ce3+ 5d → 4f transition peaking around 380 nm was observed in its luminescence spectra under UV and X-ray excitation. Photoluminescence decay kinetics was governed by a few tens of nanoseconds decay time. The integral scintillation efficiency of about 22% of that of the Bi4Ge3O12 scintillator was obtained under X-ray irradiation. The light yield and its dependence on the integration time were measured and compared with that of the Bi4Ge3O12 crystal. The total mass attenuation coefficient at 662 keV γ-rays was also determined and compared with the theoretical one calculated using the WinXCom program.

Photon Interactions Study of Bi<sub>2</sub>O<sub>3</sub>-Na<sub>2</sub>O-CaO-SiO<sub>2</sub>-B<sub>2</sub>O<sub>3</sub> Glasses

The Bi2O3 doped with soda lime borosilicate glasses in composition xBi2O3 : 15Na2O : 10CaO : 20B2O3 : (55-x)SiO2 at different concentrations (x = 0, 5, 10, 15, 20, 25 mol%) were studied the photon interactions. The total mass attenuation coefficient, coherent, incoherent, photoelectric absorption and pair production of prepared were studies using WinXcom Program at 1keV to 2MeV. The result of total mass attenuation coefficient and photoelectric absorption were decreases but discontinue because of photoelectric absorption edge at low energy. The photoelectric effect shows the main interaction at the low energy and decrease with increasing of photon energy. The higher photon energy the incoherent scattering found to be the main interaction. But at the photon energy 1.022 MeV, the pair production will be occurs and found to be the main interaction at the photon energy higher than 1.022 MeV.

Theoretical Investigation on Radiation Properties of Calcium-Silico-Borate Glasses Doped with Varying Lu<sub>2</sub>O<sub>3</sub> Concentration

In this work, the well-known program WinXCom have been performed over 1 keV to 20 MeV to obtain the radiation properties (in case of theoretical calculation) of calcium-silico-borate glass system containing Lu2O3 in the composition of xLu2O3 : 10.0CaO : 10.0SiO2 : (80.0-x)B2O3 with x are Lu2O3 concentrations varying from 0.0, 5.0, 10.0, 15.0, 20.0, and 25.0 mol%. The total mass attenuation and partial attenuation coefficients have been studied as functions of chemical compositions and incoming photon energies. In addition, the obtained data were then used to compute the effective atomic numbers and effective electron densities. The calculated results show the variation of both parameters with photon energy.

The Experimental Measurements of Total Mass Attenuation Coefficients in Arsenic Oxide

Measurements of K-shell mass attenuation coefficients are reported for the first time in Arsenic oxide (As2O3). Experiments are performed using Arsenic Oxide extended range HPGe detector. To achieve measurements at many small and regular energy intervals, secondary X-ray emission technique using “Seventeen Scatters” is employed. The results are in agreement with the proposed theoretical estimates. No evidence could, however be gained in favor of microscopic theories such as RRS and EXAFS, insofar as there are no energy points within a range of 100eV on either side of the K-edge.

Luminescence and scintillation response of YGd2Al2Ga3O12:Ce and LuGd2Al2Ga3O12:Ce scintillators

The luminescence and scintillation properties of YGd2Al2Ga3O12:Ce and LuGd2Al2Ga3O12:Ce single crystal scintillators were compared. The light yield (LY) and energy resolution were measured using R6231 photomultiplier. At 662 keV γ-rays, high LY value of 37,900 ph/MeV and energy resolution of 7.0% obtained for YGd2Al2Ga3O12:Ce are slightly better than the values of 35,400 ph/MeV and 7.6% obtained for LuGd2Al2Ga3O12:Ce. The ratio of LY values under excitation with α- and γ-rays (α/γ ratio) was also determined. The LY dependence on amplifier shaping time was measured in order to investigate the timing characteristics in the scintillation response. The estimated photofraction in pulse height spectrum of 662 keV γ-rays and the total mass attenuation coefficient at 662 keV γ-rays were also determined and compared with the theoretical ones calculated using the WinXCom program.

Study of absorption parameters around the K edge for selected compounds of Gd

The K shell absorption jump ratios, jump factors, effective atomic numbers, and electron densities were derived from the measured total mass attenuation coefficient using an energy dispersive X‐ray fluorescence spectrometer for Gd2O3, Gd2(CO3)3H2O, Gd2(C2O4)3H2O, and Gd2(SO4)3 compounds. The total mass attenuation coefficients were measured in the X‐ray energy range from 39.52 to 57.14 keV in a transmission geometry utilizing the Kα2, Kα1, Kβ1, and Kβ2 X‐rays from different secondary source targets excited by the 59.54‐keV photons from an Am‐241 annular source and detected by a Si(Li) detector with a resolution of 160 eV at 5.9 keV. The energy gap, ionization energy, electron affinity, and global electrophilicity parameters of oxide, sulfate, oxalate, and carbonate ions were calculated using density functional theory (B3LYP). The experimental results are discussed based on these parameters. Copyright © 2015 John Wiley & Sons, Ltd.

Calculation of gamma-ray attenuation parameters for locally developed shielding material: Polyboron

In the present study, the mass attenuation coefficient (μm) has been calculated analytically for a locally developed shielding material, polyboron, and compared with the values obtained from the WinXCom code, a Windows version of the XCOM database at the photon energy range 0.001 MeV–20 MeV. A good agreement has been observed between these two values. The linear attenuation coefficients (μ) and relaxation lengths (λ) have also been calculated from the obtained μm values and their variations with photon energy have been plotted. For comparison, other four shielding materials- ordinary concrete, pure polyethylene, borated polyethylene and water have also been studied. The obtained result shows that μm, μ and λ strongly depends on the photon energy, chemical composition and density of the shielding materials. The values of μm and μ of polyboron have been found greater than those of pure polyethylene and borated polyethylene but less than those of ordinary concrete and water at low photon energy range; and at the intermediate photon energy range (0.125 MeV–6 MeV), all the sample materials have approximately the same μm values. It has also been noticed that polyboron has the medial relaxation length (λ) over the entire photon energy range. The total mass attenuation coefficient (μm) and linear attenuation coefficient (μ), Half Value Layer (HVL) and Tenth Value Layer (TVL) of the five sample materials for some common gamma sources have been worked out and the transmission curves have been plotted. The curves exhibit that the transmission factor of the sample materials decreases with the increase in shielding thickness. The results of this study can be utilized to comprehend the shielding effectiveness of this locally developed material.

Effect of low-Z absorber׳s thickness on gamma-ray shielding parameters

Gamma ray shielding behaviour of any material can be studied by various interaction parameters such as total mass attenuation coefficient (μm); half value layer (HVL); tenth value layer (TVL); effective atomic number (Zeff), electron density (Nel), effective atomic weight (Aeff) and buildup factor. For gamma rays, the accurate measurements of μm (cm2g−1) theoretically require perfect narrow beam irradiation geometry. However, the practical geometries used for the experimental investigations deviate from perfect-narrowness thereby the multiple scattered photons cause systematic errors in the measured values of μm. Present investigation is an attempt to find the optimum value of absorber thickness (low-Z) for which these errors are insignificant and acceptable. Both experimental and theoretical calculations have been performed to investigate the effect of absorber׳s thickness on μm of six low-Z (10<Zeff<14) construction materials (cement-black; cement-white; clay; red-mud; lime-stone and plaster of paris) at gamma-ray energies 661.66keV, 1173.24keV and 1332.50keV. A computer program (GRIC2-toolkit) was designed for theoretical evaluation of shielding parameters of any material. Good agreement of theoretical and measured values of μm was observed for all absorbers with thickness ≤0.5 mean free paths, thus considered it as optimum thickness for low-Z materials in the selected energy range. White cement was found to possess maximum shielding effectiveness for the selected gamma rays.

Application of solid waste containing lead for gamma ray shielding material

Abstract. The basic strategies to decrease solid waste disposal problems have focused on the reduction of waste production and recovery of usable materials using waste and making raw materials. Generally, various materials have been used for radiation shielding in different areas and situations. In this study, a novel shielding material produced by a metallurgical solid waste containing lead has been analyzed in order to make a shielding material against gamma radiation. The photon total mass attenuation coefficients (µ/ρ) of the samples were measured experimentally and were calculated using WinXCom computer code, then theoretical and experimental values of total mass attenuation coefficient of each studied sample were compared with one another. Consequently, new shielding material made of solid waste containing lead is preferable as a shielding material against gamma radiation for buildings instead of concrete. Another goal of the paper is to obtain the optimum ratio of waste containing lead to achieve a balance between compressive strength and total mass attenuation coefficient. For this purpose an artificial neural network and genetic algorithm were used.

Studies on effective atomic numbers, electron densities from mass attenuation coefficients near the K edge in some samarium compounds

The effective atomic numbers and electron densities of some samarium compounds were determined using the experimental total mass attenuation coefficient values near the K edge in the X-ray energy range from 36.847 up to 57.142keV. The measurements, in the region from 36.847 to 57.142keV, were done in a transmission geometry utilizing the Kα2, Kα1, Kβ1 and Kβ2 X-rays from different secondary source targets excited by the 59.54keV gamma-photons from an Am-241 annular source. This paper presents the first measurement of the effective atomic numbers and electron densities for some samarium compounds near the K edge. The results of the study showed that the measured values were in good agreement with the theoretically calculated ones.

Measurements of K shell absorption jump factors and jump ratios using EDXRF technique

In the present work, the K-shell absorption jump factors and jump ratios for 30 elements between Ti (Z = 22) and Er (Z = 68) were measured by energy dispersive X-ray fluorescence (EDXRF) technique. The jump factors and jump ratios for these elements were determined by measuring the K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using an Am-241 radioactive point source and a Si (Li) detector in direct excitation and transmission experimental geometry. The results for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

A study of K shell X-ray intensity ratios of NixCr1−x alloys in external magnetic field and determination of effective atomic numbers of these alloys

In this study, the effect of external magnetic field on the Kβ/Kα X-ray intensity ratios of various alloy compositions of Ni–Cr transition metal alloys has been investigated. The Kα and Kβ emission spectra of Ni, Cr and NixCr1−x (x=0.40; 0.50; 0.60; 0.80) alloys were measured by using a Si (Li) solid-state detector. Kβ/Kα X-ray intensity ratios of Ni, Cr and NixCr1−x alloys without magnetic field and in 0.5 and 1 T external magnetic field have been measured following excitation by 59.5 keV γ-rays from a 200 mCi241Am radioisotope point source. When the experimental data obtained in external magnetic field have been compared with data without external magnetic field, deviations have been observed in Kβ/Kα X-ray intensity ratios for Ni and Cr in different alloy compositions. Thus, results of these measurements have shown that Kβ/Kα X-ray intensity ratios of Ni and Cr in NixCr1−x alloys are dependent on the external magnetic field. Also the total mass attenuation coefficients for pure 3d transition metals and their alloys at different compositions were measured and theoretically estimated using mixture rule for selected photon energy. Later on, total atomic and electronic cross-sections and effective atomic number for alloys are determined experimentally and theoretically using these mass attenuation coefficients. When these parameters are examined depending on the alloy compositions, thereof have been found to vary with the alloy composition.

A Study on Photon Interaction Cross Sections and Mass Attenuation Coefficients Dependents Chemical Composition of Wood Materials at the Energy Range of 1Kev to 100Mev

This paper reports on evaluation of the partial photon interaction cross sections and total mass attenuation coefficients of different wood materials including soft and hard wood materials. These values are compared with the corresponding values of shielding materials (Pb compounds and Hg). The values of interaction cross sections are computed using X-com computer data base software over the energy levels 1KeV to 100MeV. It is observed that μ total of composite materials (wood materials) decreases sharply in the low energy region which remains constant in the medium energy region, and increases in high energy region. Attenuation coefficients of different partial interaction processes like Photo electric absorption, Coherent Scattering, Pair production are calculated and analyzed. The results suggest that the interaction processes are Z dependent.

Photon atomic parameters of nonessential amino acids for radiotherapy and diagnostics.

The total mass attenuation coefficients (μ t) (cm2/g) and atomic, molecular, and electronic effective cross sections have been calculated for nonessential amino acids that contain H, C, N, and O such as tyrosine, aspartate, glutamine, alanine, asparagine, aspartic acid, cysteine, and glycine in the wide energy region 0.015–15 MeV. The variations with energy of total mass attenuation coefficients and atomic, molecular, and electronic cross sections are shown for all photon interactions.

Determination of K shell absorption jump factors and jump ratios of 3d transition metals by measuring K shell fluorescence parameters

Energy dispersive X-ray fluorescence technique (EDXRF) has been employed for measuring K-shell absorption jump factors and jump ratios for Ti, Cr, Fe, Co, Ni and Cu elements. The jump factors and jump ratios for these elements were determined by measuring K shell fluorescence parameters such as the Kα X-ray production cross-sections, K shell fluorescence yields, Kβ-to-Kα X-rays intensity ratios, total atomic absorption cross sections and mass attenuation coefficients. The measurements were performed using a Cd-109 radioactive point source and an Si(Li) detector in direct excitation and transmission experimental geometry. The measured values for jump factors and jump ratios were compared with theoretically calculated and the ones available in the literature.

ParShield: A computer program for calculating attenuation parameters of the gamma rays and the fast neutrons

This study aims to present a new computer program called ParShield which determines the neutron and gamma-ray shielding parameters. This program can calculate the total mass attenuation coefficients (μt), the effective atomic numbers (Zeff) and the effective electron densities (Neff) for gamma rays and it can also calculate the effective removal cross-sections (ΣR) for fast neutrons for mixtures and compounds. The results obtained for the gamma rays by using ParShield were compared with the results calculated by the WinXcom program and the measured results. The obtained values of (ΣR) were tested by comparing them with the measured results,the manually calculated results and with the results obtained by using MERCSFN program and an excellent agreement was found between them. The ParShield program can be used as a fast and effective tool to choose and compare the shielding materials, especially for the determination of (Zeff) and (Neff), there is no other programs in the literature which can calculate.

Determination of total mass attenuation coefficients, effective atomic numbers and electron densities for different shielding materials

In this paper, the interaction of gamma rays with some shielding materials has been studied. The total mass attenuation coefficient (μt) for eight shielding materials has been calculated by using WinXCOM program in the energy range from 1keV to 100GeV. Also, the effective atomic number (Zeff) and the effective electron density (Neff) were calculated using the values of the total mass attenuation coefficient. The dependence of these parameters on the incident photon energy and the chemical composition has been examined.