An accurate determination of the K-shell X-ray fluorescence yield of silicon

A measurement of the K-shell fluorescence yield of silicon is undertaken in which identified sources of systematic errors in previous measurements are reduced or eliminated. This enables a stringent test of the only two sets of theoretical predictions available for atomic numbers less than 18. Our result ?K?=?0.0495?±?0.0015 is very slightly lower than the non-relativistic Hartree-Fock-Slater (HFS) prediction of 0.0514. This stringent test of the HFS predictions helps to refine the fundamental parameter database of the X-ray fluorescence analysis technique, whose importance for light elements is increasing. Our work indicates the need for new theoretical calculations of K-shell fluorescence yields for these elements. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 9 February 2012 | 4:13 pm

Undersized (12.5?mm diameter) glass beads with minimal amount (11?mg) of geochemical and archeological silicic samples for X-ray fluorescence determination of major oxides

The small glass bead technique was developed to assay precious silicic samples for geochemical and archeological analyses. Undersized (12.5?mm diameter) glass beads were prepared for wavelength dispersive X-ray fluorescence determination of major oxides (Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, and total Fe2O3). Synthetic calibration standards were prepared by compounding chemical reagents (oxides, carbonates, and diphosphate). For reliable calibration, recipe compositions of standard specimens were constructed on the basis of the evenness of plot intervals on a calibration curve. Calibration curves showed good linearity (correlation coefficient: r?>?0.998). Analytical results of major oxides in granitic and basaltic rocks, obsidian, and ancient pottery were obtained with good precision (relative standard deviations were the following: <3% for more than 10.0 mass% of analyte, <5% for 1.0–10.0 mass% of analyte, and <15% for 0.1–1.0 mass% of analyte). Lower limits of detection were roughly a sub-percentage of analyte in an unprepared sample: 0.3 mass% for Na2O, 1.0 mass% for SiO2, 0.01 mass% for MnO, and so on. The present preparation reduced the following analytical scales: (1) amount of sample from 400?mg to 11?mg (97% cutting out), (2) amount of Li2B4O7 as an alkali flux from 4000?mg to 396?mg (90% cutting out), and (3) weight of platinum crucible from 80?g to 12.5?g (84% cutting out). This small-scale preparation might enable us to conduct destructive pretreatment of valuable and limited silicic samples such as archeological ceramics and stone tools, geochemical minerals in rock, and sediments and sand. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 9 February 2012 | 4:13 pm

Measurement of proton beam fluence by PIXE analysis of residual gas

Knowledge of beam fluence has a crucial role in quantitative particle-induced X-ray emission analysis. In some situations, a direct measurement of the beam charge on the target is either impossible or impractical. In such cases, indirect determination of the beam fluence can utilise the characteristic X-ray of argon or other gases, which was being kept at a stable low partial pressure in the vicinity of the analysed sample. As the X-ray signal of argon depends on the total charge, it can be used to quantify the charge. This paper describes the experimental design, the hardware and software modules that we created, the validation of the method, the application of the method during elemental analyses of fragile philatelic samples with overprints, and the lessons learned. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 9 February 2012 | 4:11 pm

Role of polarization Bremsstrahlung in the formation of thick target Bremsstrahlung spectra in the energy range of 5–10?keV

Role of polarization Bremsstrahlung in the formation of total Bremsstrahlung (BS) spectra in thick targets of Al, Ti, Sn and Pb, produced by complete absorption of 90Sr beta particles having an energy range of 0–546?keV, are studied in the photon energy region of 5 to 10?keV. The theoretical BS spectral photon distributions, obtained from Elwert corrected (nonrelativistic) Bethe–Heitler theory, a modified Elwert factor (relativistic) Bethe–Heitler theory that describe ordinary Bremsstrahlung (OB) and a modified Elwert factor (relativistic) Bethe–Heitler theory for BS spectra that includes the polarization Bremsstrahlung (PB) into OB in stripped atom approximation, were compared with the experimentally measured BS spectral photon distributions. It has been observed that the experimental results are in agreement with the modified Elwert factor (relativistic) Bethe–Heitler theory at photon energy from 5 to 10?keV. It has been also observed that the contribution of PB into OB decreases with increase in end-point energy of beta emitter and the energy of the emitted photon. Further, it has been found that the contribution of PB into OB increases with increase in atomic number of the target atom. This indicates the importance of PB in the formation of BS produced by continuous beta particle. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:46 am

Chemical analysis of very small-sized samples by wavelength-dispersive X-ray fluorescence

The chemical characterisation of very small-sized samples is often of major interest in forensic analysis, studies of artworks, particulate matter on filters, raw materials impurities, and so on, although it generally poses considerable problems owing to the difficulty of obtaining precise and accurate results. This study was undertaken to develop a set of methods for the chemical characterisation of very small-sized samples by wavelength-dispersive X-ray fluorescence.To conduct the study, sample preparation (as beads and pellets) and measurement conditions were optimised to reach the necessary detection and quantification limits and to obtain the appropriate measurement uncertainty for characterising the types of materials involved. The measurements were validated by using reference materials.Three test methods were developed. In two methods, the samples were prepared in the form of beads (one method being for geological materials and the other for the analysis of nongeological materials such as particulate matter on filters, glasses, frits, and ceramic glazes and pigments). In the third method, the samples were prepared in the form of pellets for the analysis of volatile elements in geological materials. In the three methods, detection limits, quantification limits and measurement uncertainties were obtained similar to those found when a bead or pellet is prepared by the usual methods from 0.5?g sample. However, in this study, sample size was between 30 and 40 times smaller in the case of beads and 100 times smaller in the case of pellets, thus broadening the range of possible wavelength-dispersive X-ray fluorescence applications in the chemical characterisation of materials. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:45 am

Levels and sources of heavy metal contamination in road dust in selected major highways of Accra, Ghana

Environmental studies have revealed significant contributions of vehicular exhaust emissions to high pollution levels in urban dwellings. The levels and sources of heavy metal contaminations of some major roads in Accra have been investigated in this work. Street dust samples collected from four major roads in Accra (Mallam Junction-Weija road, John Teye-Pokuase road, Tema Motorway and Tetteh Quarshie Interchange in Accra) were analysed for their elemental concentrations using energy-dispersive X-ray fluorescence. Twenty elements were identified: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr and Pb. Significant concentration levels were obtained for K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr, Y, Zr and Pb in all the samples and were used for the source identification. Enrichment factors and principal component analysis were used to verify the anthropogenic contribution to road dust. Results obtained for the enrichment factors showed moderate enrichment for V, Cr and Cu, while Zn, Br, Zr and Pb were significantly enriched. Principal component analysis identified four sources and their contributions to the elemental contents in the road dust. Natural crust, brake wear, tyre wear and vehicle exhaust emission were the four sources identified. The contribution of vehicular non-exhaust emissions to heavy metal contamination in the road dust was found to be greater than that of exhaust emissions. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:33 am

Depth profiling of dopants implanted in Si using the synchrotron radiation based high-resolution grazing emission technique

We report on the surface-sensitive grazing emission X-ray fluorescence technique combined with synchrotron radiation excitation and high-resolution detection to realize depth-profile measurements of Al-implanted Si wafers. The principles of grazing emission measurements as well as the benefits offered by synchrotron sources and wavelength-dispersive detection setups are presented. It is shown that the depth distribution of implanted ions can be extracted from the dependence of the X-ray fluorescence intensity on the grazing emission angle with nanometer-scale precision provided that an analytical function describing the shape of the depth distribution is assumed beforehand. If no a priori assumption is made, except a bell shaped form for the dopant distribution, the profile derived from the measured angular distribution is found to reproduce quite satisfactorily the depth distribution of the implanted ions. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:33 am

Application of energy dispersive X-ray fluorescence spectrometry for the characterization of plastic materials in synthetic polymer conservation work

Plastic artifacts archived in museums deteriorate with time and require proper care by conservators to prevent their degradation and to maintain the objects in good condition. Degradation processes depend on the type of plastic and conditions of storage. Knowledge of the chemical composition of plastic artifacts is thus very important and facilitates conservation work. The capabilities of energy dispersive X-ray fluorescence spectrometry with monochromatic excitation were investigated for possible characterization of the plastic materials used in artifacts from museum collections. For this purpose, a simple and suitable nondestructive analytical protocol was developed on the basis of the intensity of the coherent and the incoherent scattered excitation radiation from artifacts, compared with scattering from typical plastic materials such as polyethylene, polyvinyl chloride, and polypropylene. Fifteen plastic artifacts, such as souvenirs, household wares, and toys, were characterized in this way according to their chemical composition. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:32 am

Determination of Pb, Zr, Ti, Sr, Cr, Nb and La in lead zirconate titanate ceramics by particle-induced X-ray emission

A particle-induced X-ray emission (PIXE) technique has been used in the determination of the principal components Pb, Zr and Ti and the substituting elements Sr, Cr, Nb and La in lead zirconate titanate ceramics. In general, precision of analysis was concentration dependent from each element under study. For Pb, precision varied between 0.13% and 0.16%, at higher concentration of 59.32–64.5%. It was around 6–9% for Sr, Cr and Nb at concentrations of 1% or lower. Particular attention was devoted to the estimation of the analysis trueness. With this purpose, three methods were applied: (1) comparison of PIXE and inductively coupled plasma optical emission spectrometry concentrations, (2) recovery study and (3) comparison with a laboratory standard. Trueness of analysis was around 100?±?10% for the evaluated elements Pb, Zr, Ti, Sr and Cr. The expected stoichiometry and elemental composition homogeneity of a wide group of produced ceramics were confirmed by the PIXE technique. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:32 am

Estimation of trace elements in some medicinal plants used in anti-cancer drugs by PIXE

A trace elemental analysis was carried out in various parts of 12 anticancer medicinal plants, using the PIXE (particle-induced X-ray emission) technique. A 3-MeV proton beam was used to excite the samples, and spectra were recorded using a Si (Li) detector. Data analysis was done using the GUPIX software. The elements Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified, and their concentrations estimated. The results of the present study provide justification for the usage of these medicinal plants in the development of anticancer drugs. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:30 am

Performances of a metallic magnetic calorimeter for the measurement of hard X-ray emission intensities

The energy spectrum analysis of X-ray intensities with semiconductor detectors is often difficult because their energy resolution is usually not good enough to separate the different X-ray lines. Metallic magnetic calorimeters (MMCs) can be an alternative; they can offer both high energy resolution and high intrinsic detection efficiency from 0 to 100?keV. MMCs are thermal detectors; that is to say, the energy of each absorbed photon is measured as a temperature elevation. At very low temperature, typically few tens of mK, a very large pulse height-to-noise ratio can be obtained that is an essential condition for high energy resolution.We are involved in the development of MMCs for metrology applications such as the determination of hard X-ray emission intensities. For that purpose, we conceived an MMC with an energy resolution of 57?eV around 30?keV. The absorber is made of gold providing high intrinsic detection efficiency even for a small volume, greater than 90% below 60?keV. We will describe the physical principle and the practical realisation of this detector and discuss its performances by analysing the energy spectrum obtained from a 133Ba source. Preliminary outcomes of relative emission intensities of the K X-ray of cesium are presented and compared with other experimental data and theoretical calculations. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 25 January 2012 | 10:27 am

Determination of Pb, As, Cd and trace elements in polluted soils near a lead–zinc mine using polarized X-ray fluorescence spectrometry and the characteristics of the elemental distribution in the area

Polarization energy dispersive X-ray fluorescence spectrometry was used in the determination of Pb, As and Cd, as well as Cr, Cu, Zn, Ni and other minor and trace elements in the soil samples taken from a polluted area by lead mine exploitation. Two difficulties have to be overcome. One is strong overlap of Pb L? over As K? and another is lack of suitable certified reference materials. The different excitation conditions and analytical lines were tried to reduce the impact of overlap of Pb L? over As K?. When KBr was used as the second target, compared with Zr, the proportion from Pb L? was reduced about six times. Even so, however, the overlap was not reduced enough to be ignored. The inductively coupled plasma atomic emission spectrometry and mass spectrometry methods were used to analyze parts of soil samples and provide data for compensating lack of reference materials. By this method, the analytical concentration range of Pb, As and Cd were significantly extended. The analytical range of Pb, As and Cd were 1.4?µg/g~4.2%, 0.6?µg/g~9.3% and 0.5?µg/g~1500?µg/g, respectively. The high concentrations of Pb, As and Cd were found in the samples in the vicinity of the Pb-Zn mine. The concentrations of Pb, As, Cd, Zn and Cu were higher than the Class III in the Chinese environmental quality standard for soils. The highest concentrations of Pb, As, Cd and Zn in the soil samples were 14?960, 2726, 65 and 9439?µg/g, respectively. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 23 January 2012 | 12:36 pm

Inter-elemental correlations in liver and lung tissue of rats with alimentary adiposity (SRXRF)

The distribution of adiposity steadily grows all over the world. The reasons of the adiposity increase, especially in the developed countries, are not well understood. In particular, the role of lungs in the development of adiposity is not clear. There are many enzymes in the lungs (as well as in the liver), providing the metabolic processes on a high level. Additionally, lung is the first organ which lipids are delivered to with blood after the food intake. The data on the inter-elemental correlations in the lungs (concerning the alimentary adiposity) are not found in the literature. Thus, the investigation of trace element status of lungs and liver after the fatty food intake is expedient. The experiments were carried out on the adult nonlinear Wistar rats. Two series of the experiments were conducted with control (normal weigh) and animals with adiposity. Each of these series was subdivided into two groups: animals not having food (before the sacrifice) and receiving lard. The results obtained show that the metabolic changes under the alimentary adiposity of experimental rats are accompanied by the redistribution of inter-elemental correlations in the liver and in the lungs either. The greatest number of strong correlations is observed in case of starving animals of control group. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 23 January 2012 | 12:34 pm

Nondestructive method for the calculation of bulk material composition by X-ray fluorescence, using surface analysis on corroded bronze objects

The formation of patina on the surface of archeological bronze objects is a complex phenomenon, being influenced by various parameters induced by the environment and the alloy composition. Over several years, many attempts have been made to analyze the bulk composition of the alloys by nondestructive surface measurements. In this paper, we propose an analytical approach to evaluate the composition of bronze alloys using neural network analysis and X-ray fluorescence spectrometry. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 23 January 2012 | 12:34 pm

A critical analysis of the experimental L-shell Coster–Kronig and fluorescence yields data

A critical analysis of the methods used to determine the L-shell Coster–Kronig and fluorescence yield data are given. The collected data sets have a large scatter, indicating methodological issues. The K?-L coincidence technique and the synchrotron ionization methods are analyzed in detail, and it is demonstrated that both methods have unrecognized systematic errors. It is emphasized that the synchrotron measurements clearly show deviations from the exclusively used exponential form of the energy dependence of the photoionization cross-section. Thus, the far-range extrapolation introduces an error, which magnitude is difficult to assess. Comment on the use of polarization-sensitive devices to detect polarized X-ray is offered. New strategies are recommended for the measurement of these parameters. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 23 January 2012 | 12:34 pm

PIXE–RBS survey of a Meissen porcelain snuff box: first version or not?

Non-destructive materials analysis provided essential knowledge for deciding on the complete authenticity of a unique work of art made from porcelain, rich of delicate painting. The combination of ion-beam based methods proton-induced X-ray emission (PIXE) and Rutherford-backscattering spectrometry (RBS) was able to make simultaneously available both bulk composition and surface characterization. Potential differences in glazing and painting materials were verified when examining the base body and the lid of the box. In particular, RBS from Pb atoms in the near-surface depth region could identify lead-glazing for the shaded porcelain of the bottom. The chemical composition of the brilliant glaze of the lid was proved by PIXE to conform to the typical Meissen recipe. Consequently, a later completed or restored object was deduced. Copyright © 2012 John Wiley & Sons, Ltd.

Posted on 18 January 2012 | 10:30 pm

L?2 satellites in the X-ray emission spectra of elements 72Hf, 73Ta, 74W, 81Tl, 83Bi and 92U

The satellite spectra arising due to the L3Mx–MxN4,5 (x?=?1–5) transition array in the X-ray emission spectra of 72Hf, 73Ta, 74W, 81Tl, 83Bi and 92U have been calculated using available HFS data on K–LM and L–MN Auger transition energies. The agreement between the calculated and measured energies, that between calculated and measured separations in energies and the consideration of the relative probabilities of all the L3Mx–MxN4,5 transitions have been used as the basis for deciding the origin of the satellites. It has been established that two satellites observed in the L?2 region of the X-ray spectra of various elements, named ?2I and ?2II in the order of increasing energy, are mainly emitted by the L3M4,5–M4,5N4,5 transitions. It is observed that satellite ?2I in the spectra of elements with 72Hf to 74W has been assigned to the superposition of the 3F4–3G5 and 3F4–3D3 transitions and must be the most intense one among all these satellites. The same transition has been proved to be the main origin of satellite ?2II, reported in the element with 81Tl, 83Bi and 92U. Further, satellite ?2I, reported in the spectra of elements with 81Tl and 92U, has been associated with the transitions 3D3–3F4 and 1D2–1F3. Finally, line ?2II, reported in the spectra of elements with Z?=?72–74, has been assigned to the 1F3–1G4 and 3P0–3D1 transitions. The possible contributions of other transitions of the L3Mx–MxN4,5 (x?=?1–5) array having intensities comparable with those of the above transitions, as well as the corresponding lines that have not yet been observed, have also been discussed. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

Glass-bead/X-ray fluorescence analysis of earthenware body – sampling from heterogeneous earthenware

Samples of ancient earthenware were prepared in 1?:?10 glass beads for the X-ray fluorescence quantitation of 10 major elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, and Fe). Calibration standards of the glass beads were used with a mixture of reagents in an arbitrary ratio instead of rock standards. The calibration curves were constructed using the reported values of Japanese wares and clay materials. The adequacy of conventional sampling methods was statistically evaluated by examining the homogeneities of two shards (112?g of Jomon ware and 92?g of Yayoi ware) with respect to their crystalline phases and 10 major constituents. Both shards were found to be heterogeneous. An important finding is that in the sampling from a shard, unless at least half of the shard is homogenized, small sampling cannot represent the whole shard. The sampling was found to be only marginally reliable because the K/Ca scatter diagram for determination of provenance showed regional characteristics, and the measured analytical values showed normal (or Gaussian) distributions. Furthermore, taking eight samples or above from a shard enhances the reliability of small sampling. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

Bone-nanohydroxyapatite spheres interface evaluation by synchrotron radiation X-ray microfluorescence

Hydroxyapatite (HA) is largely used as bone graft; it seems to be the most promising synthetic implant material, mainly because of its excellent biocompatibility. The crystallinity, particle and pore size of HA are important characteristics and can be modified by decreasing basic structural form below 100?nm and have evoked a great amount of attention for improving prevention, diagnosis, and disease treatment, besides improving bone repair through the biodegradation of the material. The aim of this study was to investigate bone mineral content in bone samples with nanohydroxyapatite and HA spheres, specially its spatial distribution on bone microarchitecture. Circular bone defects were made in both tibiae of 12 White New Zeland adult rabbits (Oryctolagus cuniculus) and were divided randomly into five groups – blood clot (control group), sintered HA, non-sintered HA, sintered nanoHA and non-sintered nanoHA – all materials in spherical shape, to smooth handling and accommodation of the surgical bed, and to minimize inflammatory response. The rabbits were euthanatized according to the experimental period of 1 and 4?weeks after surgery. The samples were evaluated by polarized microscopy as well as X-ray microfluorescence in order to account the bone mineral content bone-implant interfaces, through synchrotron radiation. Our results revealed greater newly formed bone area in the non-sintered materials and control groups, and the used technique showed that the amount of calcium of new bone was consistent with both mature bone and HA spheres. In conclusion, the present findings suggest that HA-based biomaterials are biocompatible, promote osteoconduction and favored bone repair. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

PXRF and multivariate statistics analysis of pre-colonial pottery from northeast of Brazil

Portable system of energy dispersive X-ray fluorescence was used to determine the elemental composition of 68 pottery fragments from ‘Sambaqui do Bacanga’, an archeological site in São Luis, Maranhão, Brazil. This site was occupied from 6600 BP until 900 BP. By determining the element chemical composition of those fragments, it was possible to verify the existence of engobe in 43 pottery fragments. Obtained from two-dimensional graphs and hierarchical cluster analysis performed in fragments of stratigraphies from surface and 113-cm level, and 10 to 20, 132 and 144-cm level, it was possible to group these fragments in five distinct groups, according to their stratigraphies. The results of data grouping (two-dimensional graphics) are in agreement with hierarchical cluster analysis by Ward method. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

Glass bead with minimized amount (11?mg) of sample for X-ray fluorescence determination of archaeological ceramics

By using very small amount – 11-mg – of sample powder, major oxides (Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, MnO, and total Fe2O3) in ancient pottery (and igneous rocks) were determined with X-ray fluorescence spectrometry. This minimized amount of sample was used to prepare a fused glass bead with 300 times the weight of lithium tetraborate as an alkali flux. Calibration standards were obtained by compounding chemical reagents (Na2CO3, MgO, Al2O3, SiO2, Na4P2O7, K2CO3, CaCO3, TiO2, MnO2, and Fe2O3) and the flux. Fewer 11?mg of reagents as oxides were able to give reliable calibration curves with good linearity (correlation coefficient: r?>?0.995). Fewer 11?mg of sample was able to give reliable analytical results with good precision (relative standard deviation: <3% for more than 10.0?mass% of analyte, <10% for 1.0–10.0?mass% of analyte, and <20% for 0.1–1.0?mass% of analyte). Lower limits of detection were roughly a sub-percentage of analyte in an unprepared sample (e.g. 0.3?mass% for Na2O, 0.5?mass% for MgO, 1.0?mass% for Al2O3, and 0.01?mass% for MnO). Composition of major oxides in artificial and natural aluminosilicate materials (including rock, stone, sand, sediment, and clay; and their products) should be fundamental information to be considered in detail. The present X-ray determination based on very small amount of sample might be made readily accessible for destructive analysis of precious samples for archaeology (and geochemistry). Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

Calendar

Posted on 1 January 2012 | 6:00 am

In situ energy dispersive X-ray fluorescence analysis of rock art pigments from the ‘Abrigo dos Gaivões’ and ‘Igreja dos Mouros’ caves (Portugal)

A portable energy dispersive X-ray fluorescence spectrometer was used to obtain the elemental composition of Neolithic rock art paintings of the ‘Abrigo dos Gaivões’ and ‘Igreja dos Mouros’ caves. These caves, located in the Esperança parish, Arronches' county, in the San Mamede's mountains (Portugal), belong to a group of spread shelters just next to the western Spanish border. Results show the strong presence of iron in bare rock, and this element can be clearly detected as the main component of the red paintings. No evidence of manganese was detected in either the brownish or the black paintings, contrary to other Neolithic paintings in the Mediterranean area. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

Dimensional characterization of selected elements in airborne PM10 samples using ?-SRXRF

Micro synchrotron radiation X-ray fluorescence (?-SRXRF) is a powerful spectroscopy technique that uses synchrotron radiation to induce X-ray fluorescence in samples and provides exhaustive information on the micron and submicron scale. Among the major advantages of ?-SRXRF spectroscopy are its nondestructive nature and that samples can usually be analyzed without pretreatment. At the ESRF (Grenoble, France) ID-21 beamline, we examined PM10 samples collected at two sites in the Province of Trieste, Italy, in order to determine possible correlations among some low- to mid-Z elements (S, Cl, K, Ca, Ti, V, Cr, Mn, and Fe), as well as investigated the possibility of using synchrotron radiation imaging techniques as a way to examine the granulometry of PM10 particles containing the various chemical elements. A consistent significant correlation between Ca and S has been found, which, coupled with the data obtained in a related study, indicates that a major part of the sulfate is present as CaSO4. Granulometry measurement via imaging techniques has shown that some elements such as Fe, Ca, and S are more amenable to this type of analysis than others. Additionally, the spatial homogeneity of a PM2.5 certified reference material (NIST SRM-2783) has been investigated by analyzing four adjacent areas on the certified sample (total area 1?mm2). The certified reference material has shown a percentage relative standard deviation less than 7% for Al, Si, P, S, Cl, K, Ca, V, Cr, and Fe, and close to 17% for Ti and Mn. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 1 January 2012 | 6:00 am

News

Posted on 1 January 2012 | 6:00 am

Background estimation based on Fourier Transform in the energy-dispersive X-ray fluorescence analysis

This paper discusses a new method of background estimation in the energy-dispersive X-ray fluorescence (EDXRF) analysis, which is based on Fourier Transform (in this paper, we call it Fourier Transform background estimation method). Compared with the Sensitive Nonlinear Iterative Peak method, the new method has the feature of FWHM independence. It has been proved that a background can be estimated automatically and accurately by the new method in the synthesized spectrum and the spectra from measurement. Fourier Transform background estimation method can estimate the background accurately in the EDXRF spectrum using an X-ray tube source. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 30 December 2011 | 3:27 pm

Lead concentration in feces and urine of exposed rats by x-ray fluorescence and electrothermal atomic absorption spectrometry

Measurements made in feces and urine of Wistar rats exposed to lead acetate (n?=?20) in drinking water since the fetal period were compared with those obtained from a control group (n?=?20) in order to assess the age influence on Pb excretion. The measurements were made in different collections of rats aging between 1 and 11?months. To determine the Pb content of the samples, total reflection X-ray fluorescence (TXRF) and electrothermal atomic absorption spectrometry (ETAAS) were used for the urine samples and energy dispersive X-ray fluorescence (EDXRF) was used for the feces.The results show high concentrations of Pb being eliminated from the organism by urine and feces in contaminated rats. Values vary from (600?±?140)?µg?l?1 to (5 460?±?115)?µg?l?1 in urine and from (4 500?±?300)?µg?g?1 to (11 400?±?3 300)?µg?g?1 in dry feces. The control rats show, in general, low lead concentrations or below detection limits. The fecal/urinary ratio was studied. It was shown to be about three to four orders of magnitude and positively correlated with time. It was verified in feces and urine that excretion decreases with the animal age and that this decrease is made by different levels of excretion. The excretions of Pb in urine and in feces are positively correlated.A good agreement was found between the results obtained with TXRF and ETAAS for urine samples. This work also stresses the suitability of these techniques in the study of Pb intoxication. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 21 December 2011 | 9:31 am

X-ray compositional microanalysis and diffraction studies of Haltern 70 amphorae sherds

Haltern 70 amphorae sherds from excavations at Castro do Vieito, north of Portugal, and amphora sherds found inside kilns from Baetican and Lusitanian provinces of the Roman Empire are studied by X-ray diffraction and X-ray fluorescence (scanning electron microscopy/energy-dispersive X-ray spectroscopy). The comparison of these results is also made. The chosen methods give the possibility to determine element composition of the pottery, which is already fired, and thus try to single out the match of the two series of amphorae sherds. From the chemical analysis, the Castro do Vieito sherds are very homogeneous, but this is not the case of the sherds collected in the overall kilns. Vieito sherds have nearly no Na content, and Al content is about 9?wt% as well as samples from kilns from Medium Guadalquivir, Cadiz Bay and Guadiana estuary. Ca content in Vieito sherds are about 1?wt% and in amphorae kilns sherds except in the case of samples from Puerto Real and Arva, where Ca concentration is about 5?wt% and Lebrija and Pinguele where Ca concentration is about 10?wt%. The main conclusion drawn is that the provenance of Castro do Vieito sherds seems to be confirmed as being from Baetica (actual Andaluzia) because of the aforementioned reasons together with the fact that the elements found in the sherds are the same as the ones known to belong to raw materials from Baetica. Copyright © 2011 John Wiley & Sons, Ltd.

Posted on 21 December 2011 | 9:27 am