Determination Of Effective Atomic Number Research Articles

Determination of effective atomic number, electron density and Kerma of some ferroelectric materials using mass attenuation coefficients in the energy range 1 keV -100 GeV

The effective atomic number Zeff and the corresponding effective electron density Nel of ferroelectric materials (BaCoF4, LiNbO3, KNbO3, BaTiO3, PbZrO3, PbTiO3, KNbO3, Bi4Ti3O12, KHPO4, PbBi2Nb2O9, SrBi2Ta2O9, Ba0.73Sr0.27TiO3 and Mg3B7O13Cl) has been calculated in the extended energy region from 1 keV – 100 GeV using WinXCom program. The total photon interaction with coherent and incoherent one can distinguish three energy regions are approximately E<1 keV, 10 keV<E<1 GeV and E>10 GeV. The main photon interaction processes in these regions are photoelectric absorption, incoherent (Compton) scattering and pair production. Zeff and Nel values also have been obtained for different processes such as coherent and incoherent scattering pair production in nuclear and electric field, photoelectric absorption and the variations are shown graphically. The variations are due to the presence of different elements in a compound. The behaviour of the energy dependence of electron density is similar to the energy dependence of effective atomic number. The photoelectric absorption is dominant for total coherent process for Kinetic energy released per unit mass (Kerma). Direct method is one of the method helpful to calculate effective atomic number for all types of materials, for all energies greater than 1 keV.

Determination of Effective Atomic Number and Radiation Mass Attenuation Coefficient of the Bolus from Alginate Impression Material

Alginate impression material is a material that is commonly used to print dentures. This material is made from alginate. The properties of this material are rubbery, elastic, and not easily deformed so it can be applied as a bolus. This study aims to determine the tissue equivalence of this material by looking at aspects of the effective atomic number and radiation mass attenuation coefficient. To determine the effective atomic number, we used the EDX results from the SEM machine and input the concentration data of each element from alginate gel with 20% water content into the Autozeff software. The radiation mass attenuation coefficient is simulated by calculations involving each element’s concentration, then confirmed by CT-Number obtained from CT-Scan images. We obtained an effective atomic number and mass attenuation coefficient from the calculation results, which are described as a function of photon energy. Based on the results obtained, it can be concluded that the bolus made from alginate impression material is equivalent to soft tissue and breast tissue.

Dual-energy CT plaque characteristics of post mortem thin-cap fibroatheroma in comparison to infarct-related culprit lesions.

Improvement of non-invasive identification of high-risk plaque may increase the preventive options of acute coronary syndrome. To describe the characteristics of thin-cap fibroatheroma (TCFA) in a post mortem model in comparison to characteristics of culprit lesions in patients with non-ST-elevation-myocardial-infarction (NSTEMI) using the dual energy computed tomography (DECT). Three post mortem hearts were prepared with iodine-contrast, inserted in a Kyoto phantom and scanned by DECT. Six TCFA were identified using histopathological analysis (cap thickness < 65μm and necrotic core > 10% of the plaque area). In the NSTEMI group, 29 patients were scheduled to DECT prior to coronary angiography and invasive treatment. Culprit lesions were identified blinded for the patient history by two independent invasive cardiologists using the coronary angiography. The DECT analysis of TCFA and culprit lesions was performed retrospectively with determination of effective atomic number (Effective-Z), Hounsfield Unit (HU), plaque type (non-calcified, predominantly non-calcified, predominantly calcified or calcified), spotty calcification,, plaque length, plaque volume and plaque burden and the remodeling index. The Effective-Z, HU and plaqueburden were significantly different between TCFA and culprit lesions (P < 0.05).The TCFA plaques were more calcified in comparison to culprit lesions (P < 0.05). No significant difference in the other plaque characteristics was observed. The use of DECT demonstrated different Effective-Z values and different characteristics of post mortem TCFA in comparison to in vivo culprit lesions. This finding may highlight, that not all TCFA should be considered as vulnerable.

Practical simulation method for determination of effective atomic number from Rayleigh to Compton scattering ratio by MCNP

Monte Carlo simulation of the Rayleigh/Compton scattering method for effective atomic number determination with MCNP (version 6.2) was proposed. As known, effective atomic numbers can be used for evaluating shielding behavior, in non-destructive analysis and medical imaging, especially for binary compounds with high precision. Various methods for the determination of effective atomic number are present in the literature, and they depend on different mathematical manipulations. For the first time, a simulation method was developed for the determination of effective atomic numbers of some compounds. Rayleigh to Compton scattering intensity ratios (R/C) of seven different pure elements (from Indium to Gadolinium) were determined with simulations. A straight line equation is fitted using R/C scattering intensity ratios of these seven elements. R/C values of five different compounds were also simulated. Thus, effective atomic numbers of these compounds were determined using the equation. The results of the simulation were compared with available experimental and theoretical results. The studied simulation method showed acceptable agreement with ZXCOM calculation results and acceptable results with the experimental study. This method is suitable to be used for almost every material type and quite insensitive to experimental details, such as material phase, thickness, etc. The simulation results are really encouraging and can be used to guide various experiments.

Effective atomic number for Compton scattering: a benchmark tool to characterize materials

Compton scattering is a very useful tool to probe the material properties. Traditional techniques such as energy dispersive spectroscopy (EDS) lead to (i) a choice of small size (amount) of the sample resulting in altering the pristine form of the sample, (ii) an ambiguity while marking the closely lying K-shell and L-shell peaks of different elements. It is felt that this can be overcome through the determination of effective atomic number ($$Z_{\text {eff}}$$) which can yield a fair idea of the content of the material supplementing the EDS information. In the present work, we have made an attempt to determine $$Z_{\text {eff}}$$ from Compton scattering with the angles beyond $${90^\circ }$$ which has an advantage of placing both the radiation source and the detector on the same side of the medium making it possible to analyze the samples such as those of archaeological importance which are usually accessible only from one side. A goniometer assembly using $${59.54}\,{\hbox {keV}}$$ gamma rays emitted by a $${7.4}\,{\hbox {GBq}}$$$$^{241}$$Am isotope and a high purity germanium detector were employed. The values of the $$Z_{\text {eff}}$$ have been verified with that of the Auto-$$Z_{\text {eff}}$$ program values obtained by making use of the composition information from the EDS data. The present work points to the fact that $$Z_{\text {eff}}$$ of archaeological samples is a handy, confirmatory onsite tool for their non-destructive evaluation.

Determination of effective atomic number of multifunctional materials using backscattered beta particles – a novel method

The effective atomic number of multifunctional composite materials has been determined experimentally by adopting backscattering of beta particles technique. A 2.2 MeV beta particles emitted from a weak radioactive beta source were allowed to backscatter at an angle of 150 degrees from the elemental and composite targets. The backscattered beta particles were detected with the end window Geiger–Mueller gas detector. Experimentally, it is observed that the yield of the backscattered beta particle increases with increasing the target thickness for pure elements. Then, the yield of backscattering beta particle saturates after a certain thickness. The linear fit between the saturated thickness and the atomic number of the elemental target has been used to determine the effective atomic number of composite materials. The determined Zeff values of multifunctional composite targets have been compared with the values obtained by Monte Carlo method and computational codes.

Determination of effective atomic numbers and electron densities for some synthesized triazoles from the measured total mass attenuation coefficients at different energies

The effective atomic numbers and electron densities of some synthesized triazoles were determined using the experimental values of total mass attenuation coefficients at 13.93, 17.77, 26.34, and 59.54 keV photon energies. The measurements were performed in a transmission geometry that consists of a Si(Li) detector, an 241Am point source and a target. The measured results were compared with two different theoretical results. The measured results are generally consistent with the theoretical results. It is observed that the measured parameters depend on the photon energy, weighted contributions of the individual atoms within the triazoles, atom number in the triazoles, and chemical composition of triazoles. Also, the effective electron density increases linearly with increasing effective atomic number.

Determination of effective atomic number of composite materials using backscattered gamma photons – A novel method

The effective atomic number (Zeff) of composite materials has been determined by measuring the backscattered gamma photons at 180°. A 661.6 keV gamma photons from 137Cs radioactive source are allowed to scatter at an angle of 180° from the sample. The backscattered photons at 180° from the sample are detected with “2 × 2″ NaI(Tl) scintillation gamma ray spectrometer coupled to 16 K Multi Channel Analyzer (MCA). It is observed experimentally that the intensity of backscattered photons increases initially with increasing the thickness of the target and then it becomes saturated above a certain thickness. By knowing the saturated thickness values for known atomic number of the elemental targets, the Zeff of composite materials has been determined. The experimentally measured Zeff values have been compared with theoretical values predicted by direct method, power law method and AutoZeff code.

Thermoluminescence studies of calcium metaborate (CaB2O4) nanocrystals synthesized by solution combustion method

This study reports the thermoluminescence properties of calcium metaborate (CaB2O4) nanocrystals prepared by solution combustion method. The characterization by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) analysis was presented here. The XRD patterns showed the orthorhombic structure with the crystallite size at about 27 nm and the FESEM micrograph revealed the formation of irregular spherical shape nanoparticles. Weight fraction obtained from EDX analysis consequently lead to determination of effective atomic number. It was found that the effective atomic number of CaB2O4, Zeff= 14.13 was equivalent to the effective atomic number of the bone, Zeff= 13.23 with percent error 6.83 %. The samples were annealed using the TLD oven type LAB-01/400 and exposed to cobalt-60 source (Gammacell 220 Excel). TL glow curves were recorded using a Harshaw model 3500 TLD reader. The TL glow curve of this material showed a simple, single, peak located at around 150 °C. The most striking dosimetric feature of this nanomaterial was the excellence linearity response of a dose range from 1 Gy up to 100 Gy with R2= 0.9827 compared to the TLD-100 powder with R2= 0.9276. The high linear correlation between dose and TL response to gamma radiation suggest that calcium metaborate nanocrystals can be considered as a promising material to be used in thermoluminescence dosimetry.

Determination of effective atomic numbers and electron densities from mass attenuation coefficients for some selected complexes containing lanthanides

The effective atomic numbers and electron densities for the pure elemental forms of gadolinium (Gd), dysprosium (Dy), erbium (Er), and ytterbium (Yb), and some of their selected complexes, were obtained from the measured total mass attenuation coefficients at 13.92, 17.75, 20.78, 26.34, and 59.54 keV photon energies using a high-resolution Si(Li) detector by adopting transmission geometry. The measured results were compared with two different theoretical results. Within experimental deviations, our data are in good agreement with the theoretical values. The obtained parameters were also interpreted with some selected chemical parameters.

Determination of effective atomic numbers and mass attenuation coefficients of samples using in‐situ energy‐dispersive X‐ray fluorescence analysis

The matrix effect has a major impact on energy‐dispersive X‐ray fluorescence analysis (EDXRFA) and is difficult to be evaluated due to that the contents of some low‐atomic‐number elements cannot be identified by in‐situ EDXRFA. Up to today, the fundamental parameter algorithm proposed by Rousseau has been widely applied to correct the matrix effect. Accordingly, determining the matrix and mass attenuation coefficient (μ/ρ) of sample is a key issue for the fundamental parameter algorithm. In present work, the method to deduce μ/ρ by effective atomic number (Zeff) was studied. First, the relationship between Zeff and coherence to Compton scatting ratio (R) of the incident X‐ray was determined by standard samples. Then, we deduce Zeff and their μ/ρ. The value of μ/ρ deduced by our method is in good agreement with that calculated by WinXCOM, and the relative change (Δ) is less than 7%. We also deduced Zeff and their μ/ρ of Chinese national standard soil samples employing our method and good agreement with the calculated values were also obtained. We found that the agreement between experimental values of μ/ρ with theoretical values by WinXCOM still exists when the energy of the incident X‐ray is greater than 4 keV, and the Δ is less than 10%. The result indicates that our method may be applied directly to in‐situ EDXRFA.

Determination of effective atomic numbers from mass attenuation coefficients of tissue-equivalent materials in the energy range 60 keV-1.33 MeV

The main aim of this study was to establish a cost-effective tissue-equivalent material for phantom fabrication. Effective atomic numbers (Zeff) and effective electron densities (Neff) were calculated based on mass attenuation coefficient values. The linear and mass attenuation coefficients of two samples of paraffin wax and NaCl compositions were measured using Si detector for NaI (Tl) detector of 1.5” resources. Radioactive source was placed in front of detector and the sample was placed between the source and the photomultiplier tube (PMT) of the detector. The real time was set for 6000 seconds. The photopeak, full width at half maximum (FWHM) and net area of photopeak were measured using Meastro software. The attenuation coefficient values obtained from this study were used to calculate Zeff and Neff of paraffin wax and NaCl compositions. The measured results were compared with the theoretical values from XCOM and ICRU Report 44. The relative percentage difference of mass attenuation coefficients between experimental and human tissue for both paraffin wax and NaCl mixture are below 5%, whereas the relative percentage difference of Zeff and Neff are above 5%. The measured values of Zeff and Neff of paraffin wax and NaCl help us to establish the optimal mixtures to fabricate a cost-effective tissue-equivalent material.

Determination of effective atomic numbers, effective electrons numbers, total atomic cross-sections and buildup factor of some compounds for different radiation sources

The photon interaction parameters such as mass attenuation coefficient, effective atomic number, effective electron density, buildup factor have been measured for Fe(NO3)3, V4O2, NaCO3·H2O, C6H5FeO7·H2O and CuCI compounds using 137Ba, 157Gd and 241Am γ-rays sources in stable geometry. The mass attenuation coefficients have been determined experimentally via Energy Dispersive X-ray Fluorescence Spectroscopy (EDXRF) system and theoretically by using WinXCom computer program. Then, effective atomic numbers, Zeff, and electron densities, Neff, have been calculated by using the mass attenuation coefficients. The obtained values of effective atomic numbers have been compared with the ones calculated according to a different approach proposed by Hine and the calculated ones from theory. Also, photon buildup factors were obtained by changing collimator diameters in the different photon energies. We observed that the buildup factor increased as the collimator diameter increased for all sources used.

Determination of effective atomic number and electron density of heavy metal oxide glasses

ABSTRACTThe effective atomic number (Zeff) and effective electron density (Neff) of eight heavy metal oxide (HMO) glasses have been determined using the Monte Carlo simulation code MCNP for the energy range of 10 keV–10 MeV. The interpolation method was employed to extract Zeff and Neff values from the simulation and that calculated with the help of XCOM program. Comparisons are also made with predictions from the Auto-Zeff software in the same energy region. Wherever possible, the simulated values of Zeff and Neff are compared with experimental data. In general, a very good agreement was noticed. It was found that the Zeff and Neff vary with photon energy and do not have extended intermediate regions where Compton scattering is truly dominating; only dips slightly above ∼1.5 MeV were recorded. Zeff and Neff are found to increase with PbO and Bi2O3 contents. It was found that the Zeff value rather than the Neff value is a better indicator for PbO and/or Bi2O3 contents.

Determination of Effective Atomic Number for Different Brands of Diclofenac Sodium Drug at 8 keV to 32 keV X-Ray Energy

Determination of Effective Atomic Number for Different Brands of Diclofenac Sodium Drug at 8 keV to 32 keV X-Ray Energy

Determination of Effective Atomic Number and Electron Density of Wrought Aluminum Alloy 7010 for Multi-Energetic Photons

Determination of Effective Atomic Number and Electron Density of Wrought Aluminum Alloy 7010 for Multi-Energetic Photons

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 simple method to determine effective atomic numbers of some compounds for multi-energetic photons

A simple method has been presented for determination of effective atomic numbers (Zeff) in some compounds for multi-energetic photons such as Bremsstrahlung X-rays. Effective attenuation coefficient measurements were performed using a linear accelerator (Siemens Primus) which allows a good transmission geometry. Since the X-rays used are heterogeneous in energy, effective photon energies (Eeff) of the given compounds have been estimated first for 6MV and 18MV photons. Effective atomic cross-sections obtained from total mass attenuation coefficients have been used to estimate Eeff values. These Eeff values were then used to obtain Zeff values of the compounds for 6MV and 18MV photons. Finally, with the help of the present simple method it is possible to assign an effective atomic number of a multi-element material for multi-energetic Bremsstrahlung X-rays using the effective photon energies.

Determination of effective atomic numbers for 3d transition metal alloys with a new semi-empirical approach

A new, reliable and practical semi-empirical equation based on the total interaction cross sections ( σ t ) is presented to determine the values of the effective atomic numbers ( Z eff ) of 3d transition metal alloys. With this goal, the total interaction cross sections measured at 22.1, 25.0, 59.5 and 88.0 keV incident photon energies for Ti, Cr, Fe, Co, Ni and Cu metals have been used. The effective electron numbers ( N eff ) is also obtained by using the semi-empirical equations. Both the effective atomic numbers and the effective electron numbers produced by means of semi-empirical approach have been compared with the experimental and calculated values based on WINXCOM data. A good correspondence has been observed among the present results and the other results.

Determination of effective atomic number and electron density of chitin by gamma-ray attenuation

The effective atomic numbers (Zeff) and effective electron density (Ne) of chitin have been calculated using the mass attenuation coefficients (m/r) obtained via XCOM (COMpilation of X-ray Cross Sections) in the photon energy range between 1 keV and 1 GeV. The results were compared with the measured values at the photon energy of 662, 1173 and 1332 keV. Both measured and calculated results were in good agreement. Key words: Effective atomic number, chitin, effective electron number, COMpilation of X-ray Cross Sections (XCOM).