Photon Mass Attenuation Coefficients Research Articles

High-accuracy experimental determination of photon mass attenuation coefficients of transition metals and lithium fluoride in the ultra-soft energy range.

In the field of quantitative X-ray analysis techniques, such as electron probe microanalysis, precise knowledge of fundamental parameters is crucial. Especially, the accurate determination of photon mass attenuation coefficients is essential to perform correct elemental quantification. While the widely used databases offer agreement for the hard X-ray range, significant differences arise for lower photon energies. Furthermore, addressing the uncertainties of the tabulated data, which can be of several hundreds of percent, is of urgent need. Driven by recent advances in analytical techniques in the low energy range including investigation of materials containing lithium, the interest in a reliable set of photon mass attenuation coefficients is steadily increasing. In this study, we experimentally determine photon mass attenuation coefficients for lithium fluoride, aluminium, and different transition metals in the extreme low energy range from 40 eV to a several hundreds of eV. This high-precision experimental determination allows a comparison with the existing data tables. We observe differences that turn out to be significant, especially around the absorption edges.

Radiation attenuation of boro-tellurite glasses for efficient shielding applications

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

Study of Gamma-ray Shielding of Two Different Heavy Metals and their Combination for Cs-137 and Co-60 Sources

This article presents data collected by measurements of lead (Pb) and iron (Fe) and their combination as heavy shielding materials. Measurements were performed using gamma photon energies of 662, 1173, and 1332keV for the Cs-137 and Co-60 sources. The theoretical data part was calculated using WinXCom, Phy-X, and Py-MLUBF software packages. Tables and graphs of the photon Mass Attenuation Coefficient (MAC), Linear Attenuation Coefficient (LAC), Half Value Layer (HVL), Tenth Value Layer (TVL) and Mean Free Path (MFP) are presented for both heavy metals and their combination to study the shielding properties experimentally and theoretically. The results will contribute to the ongoing research as a database for future use.

Shielding Properties of Glass Samples Containing Li2O, K2O, Na2O, PbO and B2O3 by Geant4, XCOM and Experimental Data

Abstract: In the present work, glass samples containing 10Li2O, 10K2O, 20Na2O. xPbO, (60-x)B2O3 (where x = 0-60) were prepared by the melt quenching method. The shielding parameters of the prepared samples were measured experimentally and calculated theoretically. The measurements have been performed at energies of 356.5, 662, 1173 and 1333 keV to obtain the total mass attenuation coefficient (μm), using a gamma spectrometer containing a shielded NaI (TI) detector. The results of mass attenuation coefficient (μm), half-value layers (HVLs), mean free path (MFP), radiation protection efficiency (RPE), atomic and electronic electron cross-sections (σa and σe), effective atomic number (Zeff) and effective electron number (Neff) were calculated at energies from 1 keV to 100 GeV using the Monte Carlo simulation code Geant4 and XCOM. The calculated results were compared with each other and with the experimental values. Good agreement has been observed. Keywords: Shielding properties, Glass, Photon mass attenuation coefficient, Atomic and electronic cross-sections, Effective atomic and electron numbers, XCOM, Geant4.

Optical transmission, polarizability, and photon/neutron shielding properties of Bi2O3/MnO/B2O3 glass system

The Bi2O3/MnO/B2O3 glass system was successfully investigated for their optical and radiation protection features. The optical characterization of the glasses was achieved by estimating and analysing important optical parameters such as molar volume, refractive index, and molar refractivity using standard equations. The photon mass attenuation coefficient MAC of the glasses was estimated by FLUKA Monte Carlo simulation and validated by XCOM computation for energies 0.015 – 15 MeV. Further, the fast neutron removal cross section of the glasses was estimated theoretically. The optical and radiation shielding parameters showed strong dependence on the chemical composition. The molar volume of the BMB-Ax glasses decreased from 40.658 to 36.895 cm3/mole as the molar concentration of B2O3 increased relative to Bi2O3 and MnO. In addition, the refractive index of BMB-Ax reduced from 2.60 to 2.34 while the molar refractivity reduced from 26.73 to 22.05 × 10−24 cm3 for BMB-A1 –A3 accordingly. The MAC ranged from 89.629 to 0.039, 76.162–0.037, and 67.414–0.036 cm2g−1 for BMB-A1, and BMB-A2, and BMB-A3. The effective atomic number of the glasses was within the range: 24.62 – 78.05, 18.27 – 76.60, and 15.41 – 75.49 while the fast neutron removal cross section was estimated to be equal to 0.1002, 0.0972, and 0.0967 cm−1 for B2O3 molar concentration of 3, 4, and 6 respectively. The BMB-Ax glasses showed good optical and radiation shielding properties that makes them potentially useful in optical and radiation protection applications such as photonics and shielding respectively.

Gamma-Ray Attenuation Characteristics of Some Essential Amino Acids for 57Co, 192Ir, 18F, and 116mIn Sources

Purpose: In different tissues of the body, proteins are important parts that are made up of building blocks called amino acids. Considering the wide applications of radioactive sources in industry and medicine, the need to study the attenuation characteristics of amino acids is determined.
 Materials and Methods: To study the attenuation characteristics of five types of amino acids, MCNPX Monte Carlo code and XMuDat program were used. Linear and mass attenuation coefficients, half and tenth value layers, mean free path, effective atomic and electronic cross-sections, effective atomic numbers and effective electron densities were calculated. 57Co, 192Ir, 18F, and 116mIn gamma sources were considered for this study. To validate the theoretical results, the obtained values were compared with the available experimental data.
 Results: The difference between the theoretical and experimental results was less than 11%. The results showed that with increasing photon energy, the linear and mass attenuation coefficients and effective atomic and electronic cross-sections decreased, while the half and tenth value layers and mean free path quantities increased. Furthermore, the linear attenuation coefficients, the effective atomic and electronic cross-sections, as well as the effective atomic number values increased with increasing amino acid density, while the effective electron density behaves independently of the amino acid density.
 Conclusion: The presented theoretical methods produced data similar to experimental results with fair accuracy, so by using these methods, attenuation properties of other amino acids can be obtained over a wide range of energies.

A simple software for swift computation of photon and charged particle interaction parameters: PAGEX

PAGEX is a compact and user-friendly cross-platform software developed for swift computation of photon (X-ray and γ-ray) and charged particle interaction parameters for various applications. It is designed based on well-established theoretical formulations and computational techniques integrating various Python packages to effectively calculate parameters such as partial/total photon interaction cross-sections and mass attenuation coefficients, charged particle mass stopping powers and cross-sections, effective atomic number and electron density, mass-energy absorption coefficient, KERMA and build-up factors over a wide energy range. This tool is capable of generating both tabular and graphical outputs which can be saved in any user desired format. PAGEX has been verified against other widely employed software and databases, demonstrating good agreement. This software which facilitates robust computation is freely available from the authors.

Evaluation of photon radiation attenuation and buildup factors for energy absorption and exposure in some soils using EPICS2017 library

In this paper, the EPICS2017 photoatomic database was used to evaluate the photon mass attenuation coefficients and buildup factors of soils collected at different depths in the Philippine islands. The extraction and interpolation of the library was accomplished at the recommended linear-linear scales to obtain the incoherent and total cross section and mass attenuation coefficient. The buildup factors were evaluated using the G-P fitting method in ANSI/ANS-6.4.3. An agreement was achieved between XCOM, MCNP5, and EPICS2017 for the calculated mass attenuation coefficient values. The buildup factors were reported at several penetration depths within the standard energy grid. The highest values of both buildup factor classifications were found in the energy range between 100 and 400 keV where incoherent scattering interaction probabilities are predominant, and least at the region of predominant photoionization events. The buildup factors were examined as a function of different soil silica contents. The soil samples with larger silica concentrations were found to have higher buildup factor values and hence lower shielding characteristics, while conversely, those with the least silica contents have increased shielding characteristics brought by the increased proportions of the abundant heavier oxides.

Measuring Mass Attenuation Coefficient and Elemental Composition for Egbeda Soil Series of Southwestern Nigeria

Information from workers on the profitability of cassava on Iwo and Egbeda soil series in Oyo state, Nigeria have shown the Iwo soil series to be more profitable given the same scale of cassava cultivation. Therefore the need arises to improve on the soil properties of Egbeda soil series which will possibly improve the production efficiency for this category of farmers. In this work, an experimental procedure using gamma attenuation technique to determine the mass attenuation coefficient at different gamma ray energies of 59.5, 661.7, 1173.2 and 1332.5 keV, and at depths of 0 – 15, 15 – 30, 30 – 45, 45 – 60, 60 – 75 and 75 – 90 cm into the Egbeda soil series profile have been studied. Likewise X-ray fluorescence, XRF, method was used to obtain the elemental composition and concentrations at these depths while the XCOM software was applied to obtain the photon mass attenuation coefficients at the different gamma ray energies for the depths. Mass attenuation coefficients, obtained experimentally and that computed theoretically using XCOM varied exponentially with photon energy. The correlation coefficient between the experimentally-obtained and XCOM-obtained μs for the energies considered ranged from 0.89 – 0.96. The variation of with soil depth show that the top soil (0 – 15cm depths) is least attenuating with gamma ray penetrability varying down the profile. Information on the mass attenuation coefficients, elemental composition, and concentrations at varying depths into the soil profile will go a long way in contributing to efforts at improving the soil condition of the Egbeda soil series.

Photon mass attenuation coefficients, effective atomic numbers, CT numbers and density profiles of cured DSF-SPC-based Rhizophora spp. particleboard phantoms coupled with NaOH/IA-PAE at different concentrations

Rhizophora spp. (R. spp.) particleboard phantoms based on defatted soy flour and soy protein concentrate were fabricated using itaconic acid polyamidoamine-epichlorohydrin (IA-PAE) at different concentrations with the incorporation of NaOH. The results showed that the mass attenuation coefficients and effective atomic numbers of the particleboard phantoms at 16.59–25.26 keV photon energies were in good agreement within 0.88% and 0.01% of the XCOM values in water with p-values of 0.072 and 0.075. In addition, DSF-SPC-R. spp. phantom with 15 wt% IA-PAE content shows the nearest CT numbers, electron density, and density profiles to water substitutes at three CT energies. These results indicate the suitability of cured DSF-SPC-R. spp. particleboards as phantom materials for the selected X-ray energies.

Characterizing low-activity waste containers: A case study for Compton Suppression Systems under challenging signal-to-noise ratio

Abstract This work investigates a compact Compton Suppression System (CSS) based on a High-Purity Germanium (HPGe) diode as a primary spectrometer. From a wide range of potential materials for the guard detector, including plastic scintillator, Thallium doped Sodium Iodide (NaI(Tl)), and Lanthanum III bromide (LaBr3), a bismuth germanate crystal (BGO) is selected on account of a high photon mass-attenuation coefficient, thus allowing more compactness. The authors then describe the complete design study of an HPGe/BGO CSS based on the post-processing of Monte Carlo particle track history files (MCNP6.1/PTRAC). The calculation program, simulating the filtering of coincident events on both primary and secondary detectors, is validated through a series of experimental measurements using Am-241, Cs-137, and Co-60 sources in various configurations. On the basis of this empirically validated calculation, an optimization study of the BGO-active shield is performed over two factors of merit: Compton Suppression Factor (CSF) and Full-Energy Peak Efficiency. Optimization steps subsequently involve the scaling of BGO internal and external radii, the thickness of the entrance window, and the diameter of a collimation hole. Eventually, performance figures of the CSS are illustrated in a case study involving the characterization of large waste containers, carrying low levels of uranium activity to seek among natural radiological background. Calculation results show a lowering of minimal detectable activities (MDA) by a factor of 2.5 based on the signature of 1001-keV gamma rays from U-238.

Compositions and photon mass attenuation coefficients of diesel, kerosene, palm and groundnut oils

Diesel, kerosene, palm oil and groundnut oils are important fuels for many household and industrial activities. For optimum benefits and to prevent undesirable effects from their use, the fuels must be in their pure states. Hence, the need to know their compositions in pure states and develop methods for detecting their adulterations. In this study, the compositions and photon mass attenuation coefficients of these fuels were determined. Their chemical compositions were determined using Gas Chromatograph, while attenuation coefficients were determined at photon energies between 60 and 1332 keV using narrow beam geometry. The component with the highest concentrations in Diesel and Kerosene are heptane (62.7%) and pentadecane (45.4%) respectively, Palmitic acid methyl ester (31.5%) and Oleic acid methyl ester (31.5%) are the components with the highest concentrations in palm oil, In groundnut oil, Stearic acid methyl ester (31.4%) had the highest concentration. The attenuation coefficients were essentially the same for all the samples for photon energies greater of equal to 511 keV. It decreased from 0.084 ± 0.002 cm2/g at 662 keV to 0.066 ± 0.006 cm2/g at 1332 keV. At 60 keV, there exist significant differences in the attenuation coefficients of the samples. The total uncertainties in the measured attenuation coefficients ranged from 0.5% to 6.4%. For detection of adulteration photons with energies less than or equal to 60 keV are recommended.

Investigation of the radiological properties of various phantoms for their application in low energy X-rays dosimetry

It has been previously proven that the radiological properties of materials are strongly dependent on the incident radiation energy. Hence, the present study aimed to evaluate the radiological properties and soft tissue equivalency of conventional phantoms at the 1–50 keV photon energy as well as the feasibility study of using a more appropriate material instead of water. The equivalence of water and a number of conventional phantoms with breast and muscle were evaluated in terms of mass density (ρ), effective electron density (Neff), effective atomic number (Zeff), photon mass energy-absorption coefficient (μen/ρ), photon mass attenuation coefficient (μ/ρ), total stopping power of electrons (S/ρ)tot and the absorbed depth dose by using the Auto-Zeff software and XCOM, ESTAR database and Monte Carlo simulation method. The differences of ρ, Neff, Zeff and (S/ρ)tot between investigated materials and breast were 0.5–17%, 0.2–9%, 0.7–26%, and 2–11%, respectively. Additionally, the differences of μen/ρ, μ/ρ, and the absorbed depth dose between the investigated phantom materials and breast tissue were 18–56%, 16–53%, and 5–79% respectively. Also, the differences of ρ, Neff, Zeff, μen/ρ, μ/ρ , (S/ρ)tot, and the absorbed depth dose between the investigated phantom materials and muscle were 1–14%, 2–9%, 1–33%, 4–67%, 6–63%, 1–15% and 3–93%, respectively. Water cannot be considered as breast tissue equivalent phantom in the energy range of 1–50 keV. Moreover, the results of depth dose investigation showed that the GENIPIN gel is the most suitable breast tissue substitute in intraoperative radiotherapy method.

Attenuation Parameters and Effective Atomic Numbers of Concretes Containing Pumice for Some Photon Energies by Experiment, Simulation and Calculation

Photon mass attenuation coefficients ( µ ) and effective atomic numbers ( Z eff ) of three types of concretes containing pumice mineral in different rates (0%, 50% and 100%) were studied by photon transmission experiments and by simulations for 511, 835 and 1275 keV energies. Experimental procedure was realized by using a 3ʺ×3ʺ NaI(Tl) connected to a 16k multichannel analyzer detector system. In simulations, Geant4 Monte Carlo simulation toolkit was used to estimate the total mass attenuation coefficients. For theoretical calculations, web version of XCOM code was used at 1 keV – 100 GeV energy region for comparison. Also, mean free paths and half value layer thicknesses of concretes were calculated at this energies by means of attenuation coefficients obtained by three methods. Results from each method were found to be in a reasonably good agreement.

Water-equivalence of gel dosimeters for radiology medical imaging

International dosimetry protocols are based on determinations of absorbed dose to water. Ideally, the phantom material should be water equivalent; that is, it should have the same absorption and scatter properties as water. This study presents theoretical, experimental and Monte Carlo modeling of water-equivalence of Fricke and polymer (NIPAM, PAGAT and itaconic acid ITABIS) gel dosimeters. Mass and electronic densities along with effective atomic number were calculated by means of theoretical approaches. Samples were scanned by standard computed tomography. Photon mass attenuation coefficients and electron stopping powers were examined. Theoretical, Monte Carlo and experimental results confirmed good water-equivalence for all gel dosimeters. Overall variations with respect to water in the low energy radiology range (up to 130 kVp) were found to be less than 3% in average.

Photon mass attenuation coefficients of a silicon resin loaded with WO3, PbO, and Bi2O3 Micro and Nano-particles for radiation shielding

Novel shielding materials for photons based on silicon resin and WO3, PbO, and Bi2O3 Micro and Nano-particles were designed and their mass attenuation coefficients were calculated using Monte Carlo (MC) method. Using lattice cards in MCNPX code, micro and nanoparticles with sizes of 100 nm and 1 µm was designed inside a silicon resin matrix. Narrow beam geometry was simulated to calculate the attenuation coefficients of samples against mono-energetic beams of Co60 (1.17 and 1.33 MeV), Cs137 (663.8 KeV), and Ba133 (355.9 KeV). The shielding samples made of nanoparticles had higher mass attenuation coefficients, up to 17% relative to those made of microparticles. The superiority of nano-shields relative to micro-shields was dependent on the filler concentration and the energy of photons. PbO, and Bi2O3 nanoparticles showed higher attenuation compared to WO3 nanoparticles in studied energies. Fabrication of novel shielding materials using PbO, and Bi2O3 nanoparticles is recommended for application in radiation protection against photon beams.

A comparison study for mass attenuation coefficients of some amino acids using MCNP code

Abstract In this study, a novel model of MCNP4C code reported recently was used to determine the photon mass attenuation coefficients of some amino acids at energies, 123, 360, 511, 662, 1170, 1280 and 1330 keV. The simulation results were compared with the XCOM data. It was indicated that the results were highly close to the calculated XCOM values. Obtained results were used to calculate the molar extinction coefficient. All the results showed the convenience and usefulness of the model in calculation of mass attenuation coefficients of amino acids.

6 MV X-선 빔의 등가에너지 결정

본 연구의 목적은 실험으로 6 MV X-선 빔의 등가에너지를 결정하는 데 있다. 6 MV X-선 빔에 대한 납의 반가층은 전리함을 사용하여 측정하였다. 선감쇠계수는 측정된 반가층을 사용하여 계산하였다. 그리고 질량감쇠계수는 납의 밀도로 선감쇠계수를 나누어 얻었다. 얻어진 질량감쇠계수의 등가에너지는 미국표준기술연구소에서 주어진 납의 광자에너지 대 질량감쇠계수 자료를 사용하여 결정하였다. 그 결과로서, 6 MV X-선 빔에 대한 등가에너지는 1.61 MeV로 결정되었다. 이 등가에너지는 Reft가 보고한 것 보다 약 30% 낮게 결정되었다. 그 원인은 납 감쇠기 사이의 공기공동의 존재에 기인한 것으로 추정된다. The purpose of this study is to determine the equivalent energy of a 6MV X-ray beam in the experiment. The half-value layer (HVL) of lead for the 6 MV X-ray beam was measured using an ionization chamber. The linear attenuation coefficients were calculated with HVL. And, the mass attenuation coefficient was obtained by dividing the linear attenuation coefficient by the density of lead. The equivalent energy of mass attenuation coefficient was determined using the photon energy versus mass attenuation coefficient data of lead given by National Institute of Standards and Technology (NIST). In conclusion, the equivalent energy of the 6 MV X-ray beam was determined to be 1.61 MeV. This equivalent energy was determined to be about 30% lower than reported by Reft. The reason is presumed to be due to the presence of an air cavity between the lead attenuators.

Towards a quantitative, measurement-based estimate of the uncertainty in photon mass attenuation coefficients at radiation therapy energies

In this study, a quantitative estimate is derived for the uncertainty in the XCOM photon mass attenuation coefficients in the energy range of interest to external beam radiation therapy—i.e. 100 keV (orthovoltage) to 25 MeV—using direct comparisons of experimental data against Monte Carlo models and theoretical XCOM data. Two independent datasets are used. The first dataset is from our recent transmission measurements and the corresponding EGSnrc calculations (Ali et al 2012 Med. Phys. 39 5990–6003) for 10–30 MV photon beams from the research linac at the National Research Council Canada. The attenuators are graphite and lead, with a total of 140 data points and an experimental uncertainty of ∼0.5% (k = 1). An optimum energy-independent cross section scaling factor that minimizes the discrepancies between measurements and calculations is used to deduce cross section uncertainty. The second dataset is from the aggregate of cross section measurements in the literature for graphite and lead (49 experiments, 288 data points). The dataset is compared to the sum of the XCOM data plus the IAEA photonuclear data. Again, an optimum energy-independent cross section scaling factor is used to deduce the cross section uncertainty. Using the average result from the two datasets, the energy-independent cross section uncertainty estimate is 0.5% (68% confidence) and 0.7% (95% confidence). The potential for energy-dependent errors is discussed. Photon cross section uncertainty is shown to be smaller than the current qualitative ‘envelope of uncertainty’ of the order of 1–2%, as given by Hubbell (1999 Phys. Med. Biol 44 R1–22).

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.