Particle Induced X-ray Emission Analysis Research Articles

Elemental composition (Si, Fe, Ti) of atmospheric dust over the last 220 kyr from the EPICA ice core (Dome C, Antarctica)

AbstractIn this work, we present the records of insoluble silicon (Si), iron (Fe) and titanium (Ti) from continental mineral particles (dust) archived in the first 2200m of the EPICA Dome C (EDC) ice core. More than 200 samples covering the last 220 kyr, back to marine isotopic stage 7.4, were analyzed using the particle-induced X-ray emission (PIXE) technique, applied here for the first time to the investigation of the mineral content of an Antarctic ice core. The measurements were made exclusively on the insoluble fraction, obtained from filtration of the melted ice samples. The mineral fraction of the particle mass determined from the PIXE measurements is highly correlated to the total dust mass determined by particle counting using a Coulter©Counter. The principal variations during the different climatic periods are very coherent between the PIXE analysis results and the total dust mass determined by counting. Both sets of results show increasing concentration values during glacial stages 2, 4 and 6 and very low particle content during interglacials (Holocene and stage 5e). The large increase in atmospheric dustiness during cold stages is assumed to be caused by several factors, among which are the enhanced vigour of atmospheric transport. However, the PIXE results from this work highlight some slight differences in Si, Fe and Ti concentrations with respect to the total dust mass during the different climatic periods. As a hypothesis, such variations could reflect either different atmospheric processes affecting particles during transport, or changes that occurred in the dust source regions.

Co-doping of sulfur and boron in CVD-diamond

Diamond films had been grown by microwave plasma-assisted CVD using acetone diluted in hydrogen. Sulfur incorporation in diamond was achieved by co-doping method using dimethyl disulfide and boron dioxide. Structural and compositional characterization of the as-grown films was carried out by scanning electron microscopy (SEM), Raman spectrum, auger electron spectrometer (AES) and particle-induced X-ray emission (PIXE). AES and PIXE analyses confirmed that the sulfur was successfully introduced into diamond films. N-type conduction of the films was confirmed by Seebeck-effect measurements. The donor activity of the sulfur decreased from 0.52 to 0.39 eV with increasing of S incorporation into diamond. Results indicated that boron facilitated the sulfur into diamond via co-doping method.

Sources of optically active aerosol particles over the Amazon forest

Abstract Size-fractionated ambient aerosol samples were collected at a pasture site and a primary rainforest site in the Brazilian Amazon Basin during two field campaigns (April–May and September–October 1999), as part of the European contribution to the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA-EUSTACH). The samples were analyzed for up to 19 trace elements by particle-induced X-ray emission analysis (PIXE), for equivalent black carbon (BC e ) by a light reflectance technique and for mass concentration by gravimetric analysis. Additionally, we made continuous measurements of absorption and light scattering by aerosol particles. The vertical chemical composition gradients at the forest site have been discussed in a companion article (Journal of Geophysical Research-Atmospheres 108 (D18), 4591 (doi:4510.1029/2003JD003465)). In this article, we present the results of a source identification and quantitative apportionment study of the wet and dry season aerosols, including an apportionment of the measured scattering and absorption properties of the total aerosol in terms of the identified aerosol sources. Source apportionments (obtained from absolute principal component analysis) revealed that the wet and dry season aerosols contained the same three main components, but in different (absolute and relative) amounts: the wet season aerosol consisted mainly of a natural biogenic component, whereas pyrogenic aerosols dominated the dry season aerosol mass. The third component identified was soil dust, which was often internally mixed with the biomass-burning aerosol. All three components contributed significantly to light extinction during both seasons. At the pasture site, up to 47% of the light absorption was attributed to biogenic particles during the wet season, and up to 35% at the tower site during the wet-to-dry transition period. The results from the present study suggest that, in addition to pyrogenic particles, biogenic and soil dust aerosols must be taken into account when modeling the physical and optical properties of aerosols in forested regions such the Amazon Basin.

Chemie der Kunst - Zerstörungsfreie Analyse von Kunst- und Kulturgütern

tural heritage objects. Scientific analysis, especially the chemical composition, of artistic and cultural heritage objects reveals information, which cannot be gained from art historical investigations alone. The improvement of X-ray analytical method, like X-ray fluorescence (XRF) analysis and Particle-Induced X-ray Emission (PIXE) analysis, makes it possible to investigate even fragile and very precious objects non-destructively. In principle, two strategies are generally embarked: First, very sophisticated set-ups using particle accelerators or synchrotron-radiation sources for very sensitive or highly spatially-resolved and depth-sensitive analysis. Second, portable instrumentation for in-situ measurements at archaeological excavations, museums and collections. Highlights of investigated objects are limoges school enamels, manuscripts of Goethe and Schiller, the sceptre of Charlemagne, medieval metal objects, silverpoint drawings from the Renaissance, and Indian Mughal paintings.

Focusing of MeV ion beams by means of tapered glass capillary optics

We present evidence of the focusing effects of fine glass capillary optics for MeV He ion beams. The glass capillary optics are formed by a puller as to have inlet diameters of about 1 mm and outlet diameters of submicrons. The total length of the optics is about 50 mm. Impingent MeV ions to such optics are reflected by the inner wall several times, in a very similar process to the so-called surface channeling. The majority of incident ions are lost by the dechanneling, or large-angle scattering process, however, a part of them, actually about 1% more or less, is emitted through the outlet without significant energy loss. Compared with the conventional micro-ion beam facilities, the present method is certainly simple and lowcost, thus providing an easy method of submicron Rutherford backscattering spectrometry or particle induced x-ray emission analyses. In addition, if the ion species are extended to heavier elements, the present method provides versatile maskless ion implantation techniques.

Determination of elemental and ionic compositions for diesel exhaust particles by particle induced X-ray emission and ion chromatography analysis.

The purpose of this study is to clarify the chemical characterization of PM2.5 and PM10 in diesel exhaust particles (DEP). Sampling of PM2.5 and PM10 in DEP was carried out in November 1999 using an automobile exhaust testing system at the National Traffic Safety and Environment Laboratory, with a diesel truck (engine type: direct injection, displacement: 7,961 cc, carrying weight: 2,020 kg, equivalent inertia weight: 5,600 kg) placed on a chassis dynamometer. Sampling conditions included idling, constant speed of 40 km/h, M-15 test pattern and 60%-revolution/40%-load of maximum power. Samples were collected on a polycarbonate membrane filter (Nuclepore, pore size: 0.8 microm) using a MiniVol Portable Air Sampler (Airmetrics Co., Inc.). The concentrations of several elemental and ionic species in the PM2.5 and PM10 samples were determined by particle induced X-ray emission (PIXE) and ion chromatography analysis. PIXE analysis of the PM2.5 and PM10 samples revealed 15 elements, of which Na, Mg, Si, S, Cl, Ca, Fe and Zn were found to be the major components. Ionic species were Cl-, NO2-, NO3-, SO4(2-), Na+, NH4+, K+ and Ca2+. Concentrations of elements and ionic species under the sampling condition of 60%-revolution/40%-load were highest in comparison with those of the other sampling conditions. The elemental and ionic species data were compared for PM2.5 and PM10; PM2.5 concentrations were 70% or more of PM10 concentrations for the majority of elements, and concentrations of ionic species in PM2.5 and PM10 were almost identical.

The scanning microbeam PIXE analysis facility at NIRS

In March 1999, a HVEE Tandetron was installed in the Electrostatic Accelerator Building of National Institute of Radiological Sciences (NIRS) for particle induced X-ray emission (PIXE) analysis. The specifications of the Tandetron accelerator system operating at NIRS are as follows: the accelerating voltage is 0.4–1.7 MV, and the maximum beam current is 500 nA at 3.4 MeV. The accelerator facility incorporates three beam lines for conventional, in-air and microbeam PIXE analysis. The scanning microbeam PIXE analysis line is based around an Oxford Microbeams OM2000 nuclear microscope end stage. This system provides the ability of multi-elemental mapping over sample areas up to 2 × 2 mm area with spatial resolutions routinely at 1 × 1 μm. The scheduled operation of this facility started in April 2000 and is controlled by the Division of Technical Service and Development. The result of beam resolution tests carried out in 2001 are as follows: for scanning transmission ion microscopy, the estimated beam size is 100 × 200 nm, measured using a 2.6 MeV proton beam scanned over a 12.7 μm repeat distance copper grid. For PIXE operation at 50 pA beam current the estimated best spot size is 0.4 × 0.6 μm. The microbeam facility is being used for research into the elemental distribution of small biological samples such as biological cells and tissue.

Quality assurance in elemental analysis of airborne particles

Instrumental neutron activation analysis (INAA) and particle induced X-ray emission (PIXE) are commonly used to yield multielemental data in atmospheric studies. In this work the quality assurance of the analytical data is discussed based on two studies. The first is a precision study, involving sampling and analysis of air particulate matter in the size ranges of the aerodynamic diameter (AD) <2.5 μm and 2.5 μm < AD < 10 μm, using two Gent collectors, operating side-by-side, on a daily basis. Mass concentrations obtained by gravimetry, for the two collectors, were compared showing a very good reproducibility. Elemental analysis was carried out in different parts of the same filter, testing both the homogeneity of the aerosol sample and the precision of the techniques. A relation between the elemental concentration and the differences obtained for different parts of the same filter was observed. Results suggest that, for the elements studied, data are reproducible to within 5–15%. In the second INAA and PIXE analysis of different sections of the same filter are discussed. Results indicate a good agreement for the determination of K, Fe and Zn by the two techniques.

Fixation and chemical analysis of single fog and rain droplets

Last decade, the importance of global environmental problems has been recognized worldwide. Acid rain is one of the most important global environmental problems as well as the global warming. The grasp of physical and chemical properties of fog and rain droplets is essential to make clear the physical and chemical processes of acid rain and also their effects on forests, materials and ecosystems. We examined the physical and chemical properties of single fog and raindrops by applying fixation technique. The sampling method and treatment procedure to fix the liquid droplets as a solid particle were investigated. Small liquid particles like fog droplet could be easily fixed within few minutes by exposure to cyanoacrylate vapor. The large liquid particles like raindrops were also fixed successively, but some of them were not perfect. Freezing method was applied to fix the large raindrops. Frozen liquid particles existed stably by exposure to cyanoacrylate vapor after freezing. The particle size measurement and the elemental analysis of the fixed particle were performed in individual base using microscope, and SEX-EDX, particle-induced X-ray emission (PIXE) and micro-PIXE analyses, respectively. The concentration in raindrops was dependent upon the droplet size and the elapsed time from the beginning of rainfall.

Analysis of Trace Level Thorium and Uranium in Drainage from a Radioisotope Laboratory by Particle-Induced X-ray Emission

A procedure has been developed and tested for particle induced X-ray emission (PIXE) analysis for thorium and uranium in drainage from the radioisotope laboratory at Tohoku University. Two kinds of targets were prepared and analyzed by PIXE under the condition of 3-6 μC irradiation of 3 MeV protons. Concentrations higher than 40 ppb, regardless of the chemical forms of thorium and uranium ions in a sample solution, were determined for targets prepared by deposition of 0.15 ml solution containing Ga-internal standard on a thin polycarbonate film. Uranium was analyzed quantitatively down to 5 ppb with good precision by a pre-concentration method of dibenzyl-dithiocarbamate complexation combined with subsequent condensation into dibenzylidene-D-sorbitol gels. The PIXE analysis for these two kinds of targets can be applied to routine work for contamination control of drainage from a radioisotope laboratory using extremely long-lived actinides such as thorium and natural uranium in various experiments.

On the Chemical Purity of Marine Microfossils

As a paleontologist, I was pleased to see the 35-million-year-old shell of the planktonic foraminiferan Cribrohantkenina inflata grace the cover of Physics Today ( Physics Today 0031-9228 54 12 2001 16 https://doi.org/10.1063/1.1445530. December 2001; story on page 16 ). Calcium carbonate–secreting microfossils are a powerful proxy for estimating sea-surface temperature change through time using stable oxygen isotopes. Another challenge that biogeochemists and geoscientists face is the alteration of in vivo isotopic values by mineral and chemical changes after an organism’s death. Implicit in any isotopic analysis using calcite shells, or fossil mammal teeth, or even dinosaur bones, is the assumption that the original stable isotopes survived the passage of millions of years.A hemisphere away from the late Cretaceous marine localities of Paul Pearson’s work, 1 1. P. Pearson, et al. , Nature 413, 481 (2001). https://doi.org/10.1038/35097000 dinosaur bones lie buried in late Cretaceous clays above the Arctic Circle on the North Slope of Alaska. 2 2. W. A. Clemens, L. G. Nelms, Geology 21, 503 (1993). https://doi.org/10.1130/0091-7613(1993)021<0503:PIOATV>2.3.CO;2 They are so well preserved that an oil geologist in the 1960s originally identified them as the fossil remains of Ice Age mammals. A collection of those bones is cataloged in the University of California Museum of Paleontology. Under high magnification, the Alaska fossils reveal a beautifully preserved system of bone cells that are identical to the micron-scale architecture of a modern vertebrate bone. Similar to the Pearson group’s foraminifera, the dinosaur bones are entombed in clay sediments and do not appear altered by secondary remineralization or recrystallization. Microbeam particle-induced x-ray emission analysis revealed, however, that the bones showed significant postmortem enrichment by metals, primarily iron and manganese, more than 104 times greater than in the bones of modern crocodilians and birds (a dinosaur’s closest living relatives). 3 3. M. B. Goodwin, G. S. Bench, J. Vertebr. Paleontol. 20(3), 45A (2000). Clay surrounding the Alaska dinosaurs was also markedly enriched in these metals from the burial environment.Understandably, such factors are site specific and most likely vary by sediment layer and location. Their range and potential influence on a paleobiological isotopic signature remains largely unknown. Until that situation changes, the potential alteration of stable isotope values in fossil shells, bones, and teeth prevents the rejection of the null hypothesis that all fossil material is altered.Beauty is in the eye of the beholder, and exceptional fossil preservation, even at the micron level, does not guarantee pristine chemistry.REFERENCESSection:ChooseTop of pageREFERENCES <<CITING ARTICLES1. P. Pearson, et al. , Nature 413, 481 (2001). https://doi.org/10.1038/35097000 , Google ScholarCrossref2. W. A. Clemens, L. G. Nelms, Geology 21, 503 (1993). https://doi.org/10.1130/0091-7613(1993)021<0503:PIOATV>2.3.CO;2 , Google ScholarCrossref3. M. B. Goodwin, G. S. Bench, J. Vertebr. Paleontol. 20(3), 45A (2000). Google Scholar© 2002 American Institute of Physics.

Fly Ash Penetration through Electrostatic Precipitator and Flue Gas Condenser in a 6 MW Biomass Fired Boiler

The effects of an electrostatic precipitator and a flue gas condenser on size resolved fly ash particle concentration and composition were studied in a 6 MW biomass combustion unit, fired with moist forest residue. The boiler was of moving grate type. The fly ash particles were sampled upstream and downstream of the electrostatic precipitator and flue gas condenser, respectively. Fine particle number size distributions were measured using an electric mobility spectrometer (SMPS) and coarse particle number size distributions were measured using a time-of-flight instrument (APS). The mass size distributions were measured using a multi-jet low pressure cascade impactor (DLPI). For chemical analyses of the impactor substrates particle induced X-ray emission analysis (PIXE) was used. After the flue gas passed the electrostatic precipitator (ESP), the fly ash particle concentration was reduced by approximately 96% by number and 83% by mass. After the particles passed the flue gas condenser, particle number concentration was only marginally altered, whereas the mass concentration was reduced by half. Both the ESP and the condenser showed, size dependent particle separation efficiency. The main elements (Z > 12) in the fine fly ash fraction were K, S, and Cl, whereas the main elements in the coarse fraction were Ca, K, S, and Cl. After passing the ESP the mass ratio of Ca decreased in the coarse fraction, while the ratios of K, S, and Cl increased, indicating transference of fly ash material from the fine to the coarse particle fraction. There was no significant difference in the elemental composition for any particle size fraction sampled upstream or downstream of the condenser.

The GCM domain is a Zn-coordinating DNA-binding domain

Glial cells missing (GCM) proteins form a small family of transcriptional regulators involved in different developmental processes. They contain a DNA-binding domain that is highly conserved from flies to mice and humans and consists of approximately 150 residues. The GCM domain of the mouse GCM homolog a was expressed in bacteria. Extended X-ray absorption fine structure and particle-induced X-ray emission analysis techniques showed the presence of two Zn atoms with four-fold coordination and cysteine/histidine residues as ligands. Zn atoms can be removed from the GCM domain by the Zn chelator phenanthroline only under denaturating conditions. This suggests that the Zn ions are buried in the interior of the GCM domain and that their removal abolishes DNA-binding because it impairs the structure of the GCM domain. Our results define the GCM domain as a new type of Zn-coordinating, sequence-specific DNA-binding domain.

Thick-Target PIXE Analysis of Trace Elements in Wood Incoming to a Pulp Mill

Summary Trunk-wood samples of wood raw material incoming to a pulp mill were analysed by thick-target particle induced X-ray emission (PIXE). The tree species studied were pine and spruce from Finland, birch from Finland and Poland and eucalyptus from Uruguay. The wood samples were dry ashed to 550 °C prior to the analysis in order to increase the sensitivity of the method. The method was calibrated and validated using some wood based certified reference materials. The elements determined with the method were P, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Pb, Sr, Rb, Ba and F. The concentrations of the main elements P, S, K, Ca and Mn exceeded 50 ppm in most wood samples. The concentrations of heavy metal ions like Cu, Ni and Pb in the samples studied were below or close to 1 ppm. The ash content of birch, pine and spruce wood were in the range 0.2–0.4% and that of eucalyptus ca 0.5%.

Analysis of individual fluid inclusions using synchrotron X-ray fluorescence microprobe: progress toward calibration for trace elements

A critical problem for conducting quantitative analysis of individual fluid inclusions using Synchrotron X-Ray Fluorescence (SXRF) technique relates to the standardization and the calibration of the X-ray spectra. In this study, different approaches have been tested for calibration purposes: (a) the use of chlorine when Cl content can be estimated either from melting point depressions of undersaturated fluid inclusions or from saturation limits for halite-bearing fluid inclusions, (b) the use of calcium from synthetic fluid inclusions of known CaCl2 content as an external standard. SXRF analysis was performed on individual fluid inclusions from the Chivor and Guali emerald deposits, Columbia. These well-known samples contain a single fluid inclusion population for which detailed crush-leach analyses are available, thus providing a relevant compositional reference frame. Concentration estimates were also compared to Particle Induced X-ray Emission (PIXE) analysis carried out independently on the same fluid inclusions.Results of the calibration tests indicate that major (Cl, K, Ca, Fe, Mn) and trace element (Cu, Zn, As, Br, Rb, Sr, Ba, Pb) concentration estimates can be performed without precise knowledge of the analytical volume and the inclusion’s 3D geometry. Although the standard deviation of the SXRF results can be relatively high depending on the calibration mode used, mean concentration estimates for most elements are in good agreement with PIXE and crush-leach analysis. Elemental distributions within single fluid inclusions were also established. Associated correlation diagrams argue for the homogeneous distribution of most elements in the fluid inclusion. In contrast, Br shows a bimodal distribution interpreted to reflect a significant enrichment of the vapor portion of the inclusion fluid.

Intercomparison of electron probe micro-analyses and particle induced X-ray emission analyses of Pt–Pd–Ni–S matrices

Divergencies in the compositions of phases from the Pt–Pd–Ni–S system, derived from electron probe micro-analysis and micro-PIXE analysis of thick samples have been investigated. Discrepancies stem from the different penetration and excitation processes of the two techniques. A specially prepared set of targets, of varying element ratios of Pt, Pd, Ni and S, were studied in a round robin analysis using three independent experimental facilities and analytical procedures. The results allow identification of the different phases, but the observed deviations can only partly be explained by software deficiencies.

PIXE analysis to estimate the elemental composition of ectomycorrhizal rhizomorphs grown in contact with different minerals in forest soil

The aim of this study was to investigate possible interactions between minerals and ectomycorrhizal (EM) mycelia. Fungal rhizomorphs growing in association with apatite and/or biotite were sampled both from a laboratory experimental system ( Rhizopogon sp. and Pinus muricata) and from mesh bags buried in forest soil in the field. The elemental composition of the samples was analyzed with particle-induced X-ray emission (PIXE). Many EM rhizomorphs associated with apatite in laboratory systems and in mesh bags contained larger amounts of Ca (mean ranges between 12 and 31 mg Ca g −1) than similar rhizomorphs connected to acid-washed sand (range 0.3–3.5 mg Ca g −1). Ca originating from apatite was deposited as calcium oxalate crystals on the surface of the rhizomorphs. EM mycelium produced in mesh bags had a capacity to mobilize 0.6 mg P kg −1 year −1 from apatite-amended sand (which is 0.04% of the added apatite). A high concentration of K in some rhizomorphs (up to 11 mg K g −1) suggests that these fungi are good accumulators of K and may have a significant role in transporting K to trees.

PIXE analysis to estimate the elemental composition of ectomycorrhizal rhizomorphs grown in contact with different minerals in forest soil

The aim of this study was to investigate possible interactions between minerals and ectomycorrhizal (EM) mycelia. Fungal rhizomorphs growing in association with apatite and/or biotite were sampled both from a laboratory experimental system (Rhizopogon sp. and Pinus muricata) and from mesh bags buried in forest soil in the field. The elemental composition of the samples was analyzed with particle-induced X-ray emission (PIXE). Many EM rhizomorphs associated with apatite in laboratory systems and in mesh bags contained larger amounts of Ca (mean ranges between 12 and 31 mg Ca g(-1)) than similar rhizomorphs connected to acid-washed sand (range 0.3-3.5 mg Ca g(-1)). Ca originating from apatite was deposited as calcium oxalate crystals on the surface of the rhizomorphs. EM mycelium produced in mesh bags had a capacity to mobilize 0.6 mg P kg(-1) year(-1) from apatite-amended sand (which is 0.04% of the added apatite). A high concentration of K in some rhizomorphs (up to 11 mg K g(-1)) suggests that these fungi are good accumulators of K and may have a significant role in transporting K to trees.

Source Apportionment in the Town of La Spezia (Italy) by Continuous Aerosol Sampling and PIXE Analysis

We describe the results of an aerosol sampling campaign performedin 1999 in the medium-size industrial town of La Spezia, in theNorthwest of Italy. We used two-stage continuous streakersamplers in three different sites and periods of the year. This kind of samplers allows the separation of the PM10 andPM2.2 fractions of the particulate matter. Moreover, the hourly resolution in the aerosol collection is particularly useful inan urban environment where, typically, many pollution sourceswith fast variations are present. Up to 1700 samples have beenanalysed by Particle Induced X-ray Emission (PIXE) at the INFNaccelerator facility in Florence, obtaining hourly concentrationfor about 20 elements from Na to Pb, with a sensitivity rangingfrom below 1 to about 10 ng m-3. The total hourly aerosolmass has been estimated with an optical analysis of the samesamples performed (before the PIXE analysis) by an equipment designed and mounted in Genoa. An extensive statistical analysisof the data included standard and Absolute Principal ComponentFactor Analysis (PCFA and APCFA) to deduce the compositionand the weight of the major aerosol sources in both fractions.Thorough different statistical approaches, we generally resolvedcontributions from vehicle emission, fossil fuel combustion,soil-road dust and sea salt aerosol.

Sediment varve counting with PIXE

The feasibility of the particle induced X-ray emission (PIXE) technique for varve counting of vertically taken marine and lacustrine sediments was studied aiming at its possible use as a dating procedure by observing the yearly variation of the constituent elements. The samples were impregnated with a low viscosity epoxy resin to obtain slabs with preserved layered structure suitable for the PIXE analyses. PIXE-spectra were taken as a function of depth distance and the normalized X-ray peak area variations were determined. Especially, concentration changes of silicon and iron were found to be clear. Due to the employed sample preparation technique the observed chlorine concentration corresponds to the amount of water in the initial sample. Maximum chlorine concentration appeared at positions where the Si and Fe concentrations were near minimum. By plotting the Si/Cl or Fe/Cl peak area ratios, an even more distinct position dependent variation was noted.