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X-Ray Spectrometry

Current research reports and chronological list of recent articles..




The international scientifc journal X-Ray Spectrometry is devoted to the rapid publication of papers dealing with the theory and application of x-ray spectrometry using electron, x-ray photon, proton, gamma and gamma-x sources. Covering advances in techniques, methods and equipment, this established journal provides the ideal platform for the discussion of more sophisticated X-ray analytical methods.

The publisher is Wiley. The copyright and publishing rights of specialized products listed below are in this publishing house. This is also responsible for the content shown.

To search this web page for specific words type "Ctrl" + "F" on your keyboard (Command + "F" on a Mac). Then: type the word you are searching for in the window that pops up!

Additional research articles see Current Chemistry Research Articles. Magazines with similar content (spectroscopy):

 - Analytical Chemistry.

 - Journal of Analytical Atomic Spectrometry.



X-Ray Spectrometry - Abstracts



Distinction and quantification of inorganic sulfur species including thiosulfate by X-ray fluorescence (WD-XRF)

Sulfur occurs in a variety of inorganic and organic compounds with oxidation states from −II up to +VI. Differentiation of these species in solid geochemical samples can be challenging because of oxidation processes during sample preparation by acidic digestion. Applying pressed powder pellets and an analysis by wavelength-dispersive X-ray fluorescence minimises reactions with oxidants and water. Main subjects of this work were five inorganic sulfur species, sulfide −II, elemental sulfur 0, thiosulfate +II, sulfite +IV, and sulfate +VI, and the determination of their fluorescence energies in the sulfur X-ray spectra. S Kα1,2 and S Kβ1 can be observed for all species, S Kβ′ satellites only for species with coordinated oxygen. The results are in good agreement with previously published data. Yet none of the 38 investigated papers from the past 90 years reported S Kα1,2 of thiosulfate, which was determined as E = 2,309.12 eV in this work apparently for the first time. Binary mixtures of sulfur species are strongly differing in their ability of being quantitatively differentiated, as a reliable quantification requires a sufficient difference of the respective fluorescence energies. Regression equations for each mixture can be used to calculate the ratio of mass fractions of the investigated species from the evaluated fluorescence energy. If boundary conditions are considered, the presented approaches can be applied for analyses of geochemical samples or quality control of technical products. The main advantage of the described methods is the option of implementation to everyday X-ray fluorescence lab routine without substantial additional effort.
Datum: 11.01.2018


Investigation of cadmium accumulation mechanism in hepatopancreas of Patinopecten yessoensis by synchrotron radiation X-ray absorption fine structure and synchrotron radiation X-ray fluorescence analyses

Chemical state of cadmium in a hepatopancreas of a scallop (Patinopecten yessoensis) was studied by means of synchrotron radiation-based X-ray analytical techniques. X-ray absorption fine structure (XAFS) and X-ray fluorescence (XRF) imaging were used to identify the chemical state and the distribution of cadmium in the hepatopancreas, respectively. The results of in vivo Cd K-edge XAFS suggested that the neighboring atoms of the cadmium in the hepatopancreas are of sulfur. Therefore, we propose that cadmium was accumulated by a metalloprotein with sulfur. Micro XRF imaging of thin sections of the hepatopancreas showed that cadmium is distributed on the surface of intestinal epithelia and concentrated in the internal tissue of the hepatopancreas. These results indicated that scallops accumulate cadmium inside the hepatopancreas through the intestinal epithelium.
Datum: 05.01.2018


The elemental composition of Stradivari's musical instruments: new results through non-invasive EDXRF analysis

During recent decades, many researchers have tried to understand the main influences on the extraordinary sound and beauty of the masterpieces made by the ancient violin makers. This is still a challenge for many others today. Mainly because of a lack of written historical documents, the rediscovery of some of the ancient violin-making processes was made possible thanks to scientific analyses performed on their materials by means of diagnostic techniques. However, understanding which substances were adopted is a very hard task, because the analyses are influenced by many factors: for example, alterations, wear, retouches, and the heterogeneity of materials. This paper presents some new EDXRF results collected on eight-stringed musical instruments made by Antonio Stradivari between 1669 and 1734 (“Clisbee” 1669, “Hellier” 1679, “Ford-Rougemont” 1703, “Joachim-Ma” 1714, “Russian Federation” viola 1715, “Cremonese” 1715, “Vesuvius” 1727, and “Scotland” 1734) and now preserved at the Museo del Violino in Cremona. A brief comparison with a modern violin made by Simone Ferdinando Sacconi (“Hellier copy” 1941), one of the most eminent violin makers of the 20th century and one of the greatest experts on Stradivari's work, is also provided. This represents the first comparative analysis of a wide number of ancient musical instruments made by the same violin maker over an extended period. A non-destructive and non-invasive approach was followed to (a) understand the elemental composition differences between the best conserved and most worn-out surfaces; (b) check if there are elemental similarities among the finishing materials of violins made in different years by the same violin maker; (c) give new suggestions about the materials used. To distinguish the best conserved areas from the worn-out ones, a preliminary investigation by UV-induced fluorescence photography was performed. In addition, stereomicroscopic observations and Fourier transform infrared spectroscopy (FTIR) analyses were performed on selected areas to validate the hypotheses. The results, in some cases comparable with previous research on Stradivari instruments, have increased the pool of information about materials and treatments adopted in the Stradivari workshop.
Datum: 28.12.2017


Quantitative analysis of Mo–Si–B alloy phases with wavelength dispersive spectroscopy (WDS–SEM)

Mo–Si–B alloys show great potential as high temperature materials. Due to peak overlapping of B-Kα and Mo-Mζ, analyzing these alloys with microanalysis presents a real challenge. This paper describes the analytical methodology used to qualify and quantify the boron content in these alloys without stoichiometric reference samples by the use of a single parallel-beam wavelength dispersive spectrometer. Characterization of boron is performed by using a coupled energy dispersive X-ray spectroscopy—wavelength dispersive spectroscopy system in a scanning electron microscope. Self-made pure element samples are used for calibration and quantification of the boron content.
Datum: 22.12.2017


Scientific investigations of the Imperial Gates from the Petrindu wooden church, Salaj County, Romania

In order to preserve and restore the Imperial Gates from the Petrindu wooden church, Salaj County, Romania, (map location—latitude, longitude: 46.97, 23.19), the scientific investigation of the wooden support and painting materials (ground and pigments) was performed, employing Fourier-transform infrared spectroscopy (FTIR), X-ray fluorescence spectroscopy, and 3D scanning. FTIR spectroscopy offered information about the wooden degradation stage, whereas X-ray fluorescence and FTIR spectroscopic methods were employed for structural painting materials characterization. The structural data can be correlated with the artistic, theological, and historical analysis of this religious patrimony object. After obtaining information about the wooden support and painting materials, the Imperial Gates were 3D digitized using state of the art laser scanning technology. The digital 3D model obtained was restored in a virtual environment and converted into an interactive 3D model that can be used for Romanian cultural heritage digital dissemination.
Datum: 19.12.2017


Application of XANES spectroscopy to investigate Sb species in corroded bullets crust material oriented to evaluate the potential toxic effects in the environment

Lead, antimony, and other toxic metals from pellets alloy are dispersed in the soil of the shooting fields. As long as the corroding bullets are present in soil, secondary Pb and Sb phases appear in the weathering crusts being an important source of bioavailable Pb and Sb. Knowledge about the corrosion mechanism of Sb from the bullet is limited, and reports on Sb speciation in crust and soils are still scarce. Considering that Sb species have different toxicological properties in the environment, this work has focused attention in X-ray Absorption Near Edge Structure measurements at the Sb L-edges in order to identify its chemical speciation in crust (Sb(0), Sb(III), and Sb(V)). X-ray Absorption Near Edge Structure measurements were carried out at the D04A Soft X-ray Spectroscopy beamline at the LNLS. Samples consisted of dust crust taken from physically deformed and strongly corroded metallic bullets retained in soil samples sieving from shooting fields of the North and East region of Córdoba, Argentina. The results showed that the main species found in all samples were Sb(V)(Sb2O5) followed by Sb(0) (metallic). Sb(III) was not observed, and it is known that Sb(III) is more toxic than Sb(V). The results suggested that in these environmental conditions, pentavalent Sb was the predominant species after weathering of metallic Sb from corroding bullets.
Datum: 14.12.2017


A study of KαL1 X-ray satellite spectrum of the elements 27 ≤ Z ≤ 31 by photon excitation

Kα X-ray satellite spectra of Co, Ni, Cu, Zn, and Ga generated by photon excitation are analyzed using a wavelength dispersion spectrometer. Spectra of Ni, Cu, Zn, and Ga are studied for the first time using a LiF420 crystal. Spectrum of Co was studied with LiF200 crystal in second order. KαL1 X-ray satellite energies and relative intensities are measured. The energy shifts relative to diagram line are computed and are compared with theoretical and semi-empirical values. Dependence of energy shifts and relative intensities on Z and mode of excitation is analyzed.
Datum: 11.12.2017


Issue Information

No abstract is available for this article.
Datum: 05.12.2017


Study of chemical shift in Ll and Lƞ X-ray emission lines in different chemical forms of 48Cd and 50Sn compounds using WDXRF technique

Chemical shift in Ll and Lƞ X-ray emission lines of 48Cd and 50Sn elements in various chemical compounds was determined with high resolution wavelength dispersive X-ray fluorescence (WDXRF) spectrometer. The positive and negative shifts were measured in 48Cd compounds viz, CdS, CdB4O7, CdCl2, Cd3(PO4)2, CdCO3, CdI2 and CdO with reference to pure Cd foil and 50Sn compounds viz, Sn(CrO4)2, SnO, SnO2, SnCl2, SnF2, SnF4 with reference to pure Sn foil. The measured energy shifts in Ll X-ray emission lines range from −0.47 to 1.82 eV and Lƞ emission lines range from −2.67 to 1 eV for both compounds. The effective charges (q, q/, q//, and q///) were calculated from four models (Pauling method, Suchet method, Levine method and Batsonav method) and found to be linear dependence with chemical shift. The measured chemical shifts were correlated with effective charge, number of ligands and electronegativity of the central metal atom in the given compounds.
Datum: 28.11.2017


Comparison of standard-based and standardless methods of quantification used in X-ray fluorescence analysis: Application to the exoskeleton of clams

In this work, we aim at achieving the most accurate quantitative determination of the composition of exoskeletons of bivalves from Tagus estuary with Energy Dispersive X-ray Fluorescence. Samples from the shells of clams ranging from the Bronze Ages to the 16th century A.D. belonging to the Museu Arqueológico de Almada, and also from the shells of clams collected recently in the same region, were analyzed for comparison of the trace element composition and detection of heavy metals. The analysis was performed with 2 Energy Dispersive X-ray Fluorescence setups, one with triaxial geometry and another with a conventional geometry and vacuum capabilities. Samples were pressed as pellets, and the spectra collected with both setups were evaluated using standardless fundamental parameter based software's implemented in each setup, and by comparing with standard reference materials of similar matrix. The comparison of the results obtained with different methods lead to the conclusion that the most realistic results were obtained with calibration curves obtained with external standards and correction the fluorescent intensities with the Compton scattering peak. When comparing the obtained concentrations for all the analyzed periods, results showed a decrease of Fe in the 12th Century. Regarding the environmental current state of the Tagus estuary, there were no heavy metals detected above the safety regulations.
Datum: 07.11.2017


Prototype GaAs X-ray detector and preamplifier electronics for a deep seabed mineral XRF spectrometer

Work towards developing a prototype GaAs based X-ray fluorescence spectrometer focusing on the detector-preamplifier system for in situ characterisation of deep seabed minerals is presented. Such an instrument could be useful for marine geology and provide insight into hydrothermal processes. It would also be beneficial for deep sea mining applications. The GaAs photodiode was electrically characterised at 4 °C (ambient seawater temperature) and 33 °C. A system energy resolution (full width at half maximum) at 5.9 keV of 580 eV at 4°C, limited by the dielectric noise, broadening to 680 eV at 33°C, was recorded. The spectral performance of the system was characterised across the energy range 4.95 keV to 21.17 keV, at 33°C, using high-purity X-ray fluorescence calibration samples excited by a Mo target X-ray tube. The charge output from the system was found to be linear with incident photon energy. The energy resolution was found to broaden from 695 eV at 4.95 keV to 735 eV at 21.17 keV, attributed to the increasing Fano noise with energy. The same X-ray tube was used to fluoresce an unprepared manganese nodule (revealing the presence of Mn, Fe, Ni, Cu, Zn, Pb, Sr, and Mo) and a black smoker hydrothermal vent sample (containing Fe, Co, Ni, Cu, Zn, Pb, and Mo). Such a spectrometer may also find use in future space missions to study the hydrothermal vents that are believed to exist in the oceans of Jupiter's moon Europa.
Datum: 03.11.2017


XRF characterization and source apportionment of PM10 samples collected in a coastal city

In the current study, a yearlong measurement campaign was conducted during the year 2012 in a medium sized coastal Greek city, Patras. PM10 samples were collected once every 3 days, and a number of those samples were analyzed by the use of a commercial X-ray fluorescence system, Epsilon 5 by PANalytical, The Netherlands. PMF model was used for source identification. Because the uncertainty of the measurements is used as input in the model, special emphasis was given in its accurate estimation. Seven PM10 emission sources were identified using PMF 5.0 and were, namely, mineral dust (15%), road dust (4.6%), shipping emissions (3.8%), sea salt (11.9%), biomass burning (6.9%), traffic (46.2%), and sulfates (11.6%). The concentration weighted approach was used to investigate if the contributions of the sources identified in the area are affected by long range transportation events. A methodology of estimating the uncertainty of the day to day source contributions is proposed in this study. A comparison between the 24-hr contribution for the mineral dust factor provided by the model and the calculated contributions for the same factor deduced from appropriate equations (chemical reconstruction) can be used for this purpose. The analysis showed that when the concentrations of the elements associated with the mineral dust source are close to their lowest value, the model assigns zero contribution to the mineral dust source. Following this methodology in the current study, 6 points were identified as bad fitting points, a number that represents less than 10% of the total measurements.
Datum: 02.11.2017


Archaeometric study of possible Ninevite-5 pottery from upper Tigris region using SEM-EDS, PEDXRF, and OM

This study aims to reveal the production technology of some representative samples of possible Ninevite-5 potsherds which are generally dated between the Early Jezirah I to EJ-II/EJ-III periods (roughly 3000–2500 bc) and accepted as the typical ceramics reflecting the northern Mesopotamian culture in the first half of the 3rd millennium BC. The samples were selected from the archeological excavation area of Kuriki (upper Tigris region, Turkey) and exposed to multiple analytical techniques including scanning electron microscopy with an energy dispersive spectrometer, optical microscopy, and polarized energy dispersive X-ray fluorescence spectrometry. The results showed that all the samples have high amounts of CaO (up to 29.83 wt.%) indicating use of calcareous clay deposits and they have an analogous chemical compositions in terms of both major oxides and trace elements which implied the use of the same raw materials. The vitrification degrees of the samples, examined by back scattered electron images, suggested that the firing temperature of the potsherds did not exceed the range of 800–900°C. It was also revealed that the firing atmosphere was oxidative which would be attributed to use of kiln firing rather than a bonfire or pit firing. Both the chemical and petrographic results suggested that the investigated samples presumably belong to a regional (upper Tigris) production rather than a local one.
Datum: 30.10.2017


Role of the mass attenuation coefficient database in standardization of a silicon drift X-ray detector for PIXE analysis

A simple, inexpensive procedure is described for calibrating a silicon drift detector-based PIXE system for the analysis of geological and other “thick-target” materials. It rests on the use of single element, chemical compound, and National Institute for Standards and Technology multielement standards. Much less effort has been focussed on the impact of mass attenuation coefficients on PIXE's analytical accuracy than on ionization cross sections and fluorescence yields. The calibrated system enables us to investigate the effects of inserting different mass attenuation coefficient datasets into the GUPIX database. For the K X-rays of light elements, accuracy is significantly improved by replacing the formerly used XCOM self-attenuation coefficients by the corresponding FFAST values; this effect decreases rapidly with increasing atomic number. Similar improvement was found for L X-rays of medium-Z, but not for high-Z atoms.
Datum: 27.09.2017


Utilization of nondestructive techniques for analysis of the Martian meteorite NWA 6963 and its implications for astrobiology

Martian meteorites are excellent study materials for understanding the present and past of Mars, as they are important historical astrophysical artifacts because they possess information about Martian geological evolution and physical and chemical characteristics. In our case, we analyzed the NWA 6963 Martian meteorite classified as basaltic shergottite because of its chemical structure. A computerized microtomography (μCT) study in the NWA 6963 Martian meteorite provided us with 2D and 3D images that were extremely useful for ascertaining the internal structure of the analyzed sample and gave us the opportunity to find a crumpled material with a very peculiar structural format. In addition, it was possible to observe through the μCT that this encrusted material also has a completely different density of the meteorite. Calcium, strontium, and potassium were detected qualitatively, among others through the technique of X-ray fluorescence.
Datum: 25.09.2017


Size-resolved analysis of fine and ultrafine fractions of indoor particulate matter using energy dispersive X-ray fluorescence and electron microscopy

We used a multistage PIXE inertial impactor with nine different aerodynamic diameter ranges (between 16 and 0.06 μm) to sample indoor particulate matter (PM). X-ray fluorescence (XRF) measurements performed at cutoff diameters (CoDs) of 0.25, 0.5, 1, 2, 4, and 8 μm were used to identify elements in various size fractions. Anthropogenic sources were the dominant sources for fine and ultrafine particle sizes. The XRF results show that natural sources also contribute to the fine and ultrafine fractions of pollutants. Scanning electron microscopy and energy-dispersive system analysis were performed on membranes having PM CoDs of 4, 2, 1, 0.5, and 0.25 μm. Elemental mappings show the membranes with PM of CoDs 0.25 and 0.5 μm having S as a dominant element, confirming the results obtained with XRF. Strong correlation among maps of S, N, and O show that ammonium sulfate is the major constituent at these size fractions. Other elements such as Si, Ca, Fe, Al, and Mg show up in smaller amounts at these size fractions but increase for membranes with larger particles. For size fractions larger than 0.5 μm, there is a good correlation between the elemental maps of these elements and oxygen, indicating that these elements exist mostly in oxide forms. The absence of clear N signals and the correlation between the Ca and S maps indicate that S in these size fractions is not due to ammonium sulfate. The presence of Mg, K, Cl, and Na at these CoDs shows that these elements are due to salts originating from sea breeze.
Datum: 22.09.2017


An upgraded external beam PIXE setup for multielemental analysis of atmospheric aerosol samples

The external beam particle-induced X-ray emission (PIXE) setup has been upgraded by introducing a new silicon drift detector with the aim of obtaining better minimum detection limits (MDLs) at the 2 × 1.7 MV Tandetron accelerator of the Beijing Normal University in China. The upgraded external beam PIXE setup is equipped with two silicon drift detectors for PIXE analysis of low and high Z elements. A surface barrier detector for Rutherford backscattering spectrometry monitors beam and helium flow. Two kinds of aerosol filter samples (quartz fiber filters and Teflon filters) were studied. A 200-μm thick Mylar absorber in front of the medium-high energy X-rays detector was adopted, and it got the best MDLs for atmospheric aerosol samples analysis. Multielemental analysis of quartz fiber filter aerosol samples was achieved. For more accurate and better MDLs of low Z elements in PIXE analysis, it is necessary to keep sufficient helium flow behind the thin samples.
Datum: 15.09.2017


Study of gamma/X-ray interaction in Kondo insulators

We have studied the gamma/X-ray interaction parameters such as mass attenuation coefficient, mean free path (λ), half value layer, 10th value layer, energy-absorption buildup factors, and variation of electrical conductivity with the energy of gamma/X-ray between 1 keV and 100 GeV for Kondo insulators such as FeSi, Ce3Bi4Pt3, SmB6, YbB12, CeNiSn, CeRhSb, CeRuSn, and CeFeP. The variation of photon interaction parameters with incident energy of gamma/X-ray is graphically represented. We have also identified the X-ray absorption edges for the Kondo insulators. This identified X-ray absorption edges are useful in the characterizing of Kondo insulators such as FeSi, Ce3Bi4Pt3, SmB6, YbB12, CeNiSn, CeRhSb, CeRuSn, and CeFeP. Hence, these data are also useful in the material science. This type of data for Kondo insulators is not available in literature. Hence, this work is first of its kind, and it is useful in various fields of nuclear physics.
Datum: 15.09.2017


High concentration measurements of U and Pu with nondestructive and standardless K-edge densitometer device

In nuclear activities such as reprocessing plants, safeguard laboratories, or research centers, U and Pu are regularly analyzed. Fast and accurate analytical devices are favored such as K-edge densitometer. This paper presents the results obtained by this device from assay samples with high U and Pu concentrations. Two processing methods without calibration (except energy calibration) are compared and discussed. Despite literature advising against the use of estimated mass attenuation coefficients for near edge energy, this study shows that these values can contribute to very good results for uranium and plutonium concentration estimations, with a bias less than 1%.
Datum: 14.09.2017


Pigments characterization of polychrome vases production at Lipára: New insights by noninvasive spectroscopic methods

One of the most impressive Sicilian pottery production is attributed to the so-called Lipari Painter and his followers, whose vessels—found in the archeological site of Lipari (Aeolian Island, Sicily)—are decorated with characteristic blue, red, and white figures. From the archeological point of view, these artworks keep open many questions concerning dating, production technique, and cultural background. In this context, new data on the manufacture procedures and on the raw materials used for the pigments may contribute to a deeper comprehension of this early Hellenistic vase tradition. The preciousness of the vessels, exhibited at the Archeological Museum of Lipari, imposed the use of in situ nondestructive methods to address new insights on the nature of the colored layers. Thus, analyses by Raman and X-ray fluorescence spectroscopy have been performed with portable instruments on a selection of vessels certainly attributed to Lipari Painter and to some others of his followers. The results of this study testify the use of different pigments: kaolin and gypsum, probably supplied locally, for white layers; Egyptian blue for blue hues; red ochre for brown-reddish hues; and cinnabar for pink and red-purple nuances. The identification of both Egyptian blue and cinnabar opens an interesting discussion about dating and circulation of the raw materials.
Datum: 11.09.2017


A sample carrier for measuring discrete powdered samples with an ITRAX XRF core scanner

The elemental composition of discrete powdered sediment samples can be measured by the energy-dispersive X-ray fluorescence (XRF) system that is installed in XRF core scanners. Because an appropriate sample carrier for powdered samples is currently not available, for example, for the ITRAX XRF core scanner, such a carrier is presented in this technical note. The designed sample carrier can hold 30 sample cups with a volume of 0.88 cm3 each. A maximum of 5 sample carriers, that is, 150 samples, can be measured in one run. The sample cups and carriers are optimized for a measurement procedure with a step size of 5 mm and variable count times up to 100 s per sample. With this setting, data are collected from an area of 100 mm2 in the center of the sample thereby ensuring a good representativeness of the signal because potential sample inhomogeneity is accounted for. Because the described sample carrier system allows rapid element analyses of discrete powdered environmental samples with an XRF core scanner, it may in some cases represent a time- and cost-efficient alternative to conventional XRF analyses.
Datum: 11.09.2017


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.
Datum: 24.08.2017


Synchrotron radiation induced X-ray production cross sections of 66Dy at energies across its Li (i = 1–3) subshell absorption edges

The X-ray production (XRP) cross sections for the 66Dy Lk (k = l, α, η, β2,6,7,15, β1,6, β1,3,4,6, β2,7,15, γ1,5, γ2,3) emission lines have been measured by tuning the incident synchrotron radiation at energies over the range 7.8–9.2 keV and ~10–370 eV above the respective Li (i = 1–3) absorption edges. These measurements aim to check the reliability of the independent particle approximation models used to generate the theoretical data sets of different physical parameters required to calculate the XRP cross sections and also investigate the influence of many body effects on the photoionization process. The measured values have been compared with 4 sets of XRP cross sections calculated using the Dirac–Fock model-based X-ray emission rates, 2 sets of the Li (i = 1–3) subshell photoionization cross sections deduced from the self-consistent Dirac–Hartree–Fock model-based values and the nonrelativistic Hartree–Fock–Slater model-based values, and 2 sets of the fluorescence (ωi) and Coster–Kronig (fij) yields. The present measured Lγ2,3 (originating from decay of the L1 subshell vacancies) XRP cross sections are found to be significantly higher than different sets of theoretical values, whereas a good agreement is generally observed for the various other XRP cross sections and relative intensities.
Datum: 04.08.2017


 


Category: Current Chemistry Research

Last update: 04.01.2018.






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