PIXE Analysis Research Articles

Comparison of trace elements in freshwater pearls cultured in Japan, China, and USA

In this paper, we performed PIXE analysis of trace elements in freshwater pearls cultured in four different areas: Lake Biwa (Japan), Lake Kasumigaura (Japan), an unidentified lake in China, and Kentucky Lake (USA). We investigated the difference of trace elements contained in the four pearls from different aquaculture environments. The observed trace elements are Mn, Fe, Cu, Zn, and Sr. The major trace elements are Mn, Sr for all the samples. From comparison of the proportions of elements contained, we found the following features: (1) The Kasumigaura pearl has a nucleus with a high Mn/Sr ratio, (2) The Biwako pearl is low in iron content, and (3) The American pearl has high in Fe/Sr, Cu/Sr, and Zn/Sr ratios.

The application of stereo scanning transmission ion microscopy (stereo-STIM) imaging in biological specimen

The quantitative two-dimensional areal density can be revealed from the scanning transmission ion microscopy (STIM) image of the sample owing to the relationship between the beam energy loss and the sample areal density. The obtained areal density map can provide fine spatial resolution to identify microstructures. Furthermore, this information can be used to achieve more precise quantification on X-ray absorption if simultaneously performing PIXE analysis. The development of STIM tomography enables to access the inner structure of the sample, especially in studying biological specimens. However, STIM tomography requires a large number of projections while stereo-STIM pair projections provide a quick tool for imaging the shape of the sample and determining the relative position, orientation and shape of the internal and external structures. Stereo-STIM experiments using 2 MeV proton microbeam were carried out on an insect and transmitted energies data were simultaneously collected by two surface barrier detectors mounted on 30° and -30° with respect to the beam direction. The defined disparity value resolved the features of different parts of the body of an insect not seen in individual STIM data.

The first year operation experience with Ion Beam Analysis at the new STU Ion Beam Laboratory

Ion Beam Analysis is an important part of the new Ion Beam Laboratory at the Slovak University of Technology in Bratislava based on a HVEE 6 MV Tandetron® accelerator. The system is equipped with an end station for Rutherford Backscattering Spectrometry - RBS, Particle Inded X-ray Emission - PIXE and Elastic Recoil Detection Analysis - ERDA. Following commissioning in December 2015, the IBA system was extended with Nuclear reaction analysis - NRA and a thin sample holder for PIXE aerosol filter measurements.

L-shell X-ray production cross sections in metal oxide thin films due to 12C, 16O and 28Si ion beams at MeV SIMS energies

Successful co-implementation of different heavy ion beam nuclear analytical techniques such as heavy ion PIXE, ERDA, MeV SIMS and RBS hinges on the availability of accurate databases of fundamental ion beam-matter interaction parameters. We report on measurements carried out to determine L-shell X-ray production cross sections in 101Ru and 181Ta due to 12C, 16O and 28Si projectile ions in the 0.2 MeV/u–1.0 MeV/u energy range. Experimental data is compared to calculations by one of the most widely implemented X-ray ionisation theories in PIXE analyses – the ECPSSR theory in its modified United Atom (UA) version. Results show fairly good agreement between experiment and theory for the 181Ta target atoms, with the level of agreement improving as the Zion/Ztarget ratio decreases and as beam energy increases. For 101Ru target atoms theoretical predictions tend to underestimate experimental data and the discrepancies increase with projectile mass and decreasing energy. The contribution of projectile electron capture (EC) to the measured X-ray production cross sections is also considered in the data analysis and discussion.

PIXE contribution for a database of Phoenician pottery in Lebanon

The study the ancient Phoenician cult place of Kharayeb, in the rural hinterland of Tyre, southern of Lebanon, dated to the Iron Age and Hellenistic periods is particularly helpful in evaluating the complexity and variability of the so called “Hellenism” and of “Greek cultural influences” in the Phoenician world. The PIXE analytical technique was used to characterize the elemental composition of several artefacts from this archaeological site, mainly figurines and some artisanal objects, with an attempt to analyze geological samples that could be potential clay sources in the area. Furthermore, the PIXE information about the composition of the studied objects helped to understand if the figurines were locally produced or imported from the coast and how was the process of production connected to the sanctuary. Hence, particle induced X-ray emission technique PIXE was used to determine the elemental composition of about 57 excavated fragments of figurines and pottery from Kharayeb site, as well as from two another archaeological sites, Jemjim and Tyre which is the prestigious city of antiquity, located on the eastern Mediterranean coast. Then, PIXE analyses with multivariate statistical methods were used to compare and to reveal characteristic groups. Finally, PIXE technique contributed to establish a first database of chemical composition of Phoenician pottery, which will broaden the existing database currently related only to archaeological pottery from coastal sites in Lebanon. Therefore, this work will probably be used for any future archaeological study on Phoenician pottery in the Phoenician colonies in the Mediterranean basin.

PIXE and XRF elemental analysis of breakfast cereals consumed in Mexico

Elemental concentrations in breakfast cereals consumed in Mexico were measured using Particle induced X-ray emission with 1.7 MeV protons and X-ray fluorescence with a Rh X-ray tube operating at 35 kV. The specimens, obtained from packages purchased in markets, were freeze dried, ground and pelletized. Standardization was done with tomato, spinach, peach, and orchid leaves NIST standard reference materials, and analytical accuracy verified with NIST 3233 standard reference material (fortified cereal). The concentrations of nine elements did not agree with values quoted in the packages. Therefore, there may be inaccurate official estimations of Mexican population nutrient intakes.

Transversal dose distribution optimization for laser-accelerated proton beam medical applications by means of Geant4

The main purpose of this paper is to quantitatively study the possibility of delivering dose distributions of clinical relevance with laser-driven proton beams. A Monte Carlo application has been developed with the Geant4 toolkit, simulating the ELIMED (MEDical and multidisciplinary application at ELI-Beamlines) transport and dosimetry beam line which is being currently installed at the ELI-Beamlines in Prague (CZ). The beam line will be used to perform irradiations for multidisciplinary studies, with the purpose of demonstrating the possible use of optically accelerated ion beams for therapeutic purposes. The ELIMED Geant4-based application, already validated against reference transport codes, accurately simulates each single element of the beam line, necessary to collect the accelerated beams and to select them in energy. Transversal dose distributions at the irradiation point have been studied and optimized to try to quantitatively answer the question if such kind of beam lines, and specifically the systems developed for ELIMED in Prague, will be actually able to transport ion beams not only for multidisciplinary applications, such as pitcher-catcher nuclear reactions (e.g. neutrons), PIXE analysis for cultural heritage and space radiation, but also for delivering dose patterns of clinical relevance in a future perspective of possible medical applications.

Multiple ionization X-ray satellites of magnesium, aluminum and silicon in alpha particle PIXE

Abstract Wavelength-dispersive spectroscopy was used to study the multiple ionization satellites in the K X-ray spectra of magnesium, aluminum and silicon bombarded by alpha particles having energies of 3, 4 and 5 MeV. The measured energy shifts and intensities relative to the diagram lines of the groups with one, two and three L-shell vacancies were extracted from the spectra. These results compare well with the values in an interim database which was recently assembled from the limited existing literature. The present work is the first step in refining this database so that it may be used to improve the accuracy of PIXE analysis using alpha particle beams, including the PIXE mode of the Mars alpha particle X-ray spectrometers. The effects of oxide bonding are also determined and compared to those observed when excitation is effected by photons and by electrons.

Computed Radiography, PIXE and XRF analysis of pre-colonial pottery from Maranhão, Brazil

This work concerns the archaeometric analysis of ceramic fragments from archaeological excavations carried out in “Sambaqui do Bacanga”, “Sambaqui do Panaquatira” and “Rabo de Porco”, located in the São Luiz city area, at Brazilian northeast. Ancient civilizations that inhabited that territory were characterized as fishing, catchers, hunters and ceramist populations. Dates obtained by thermoluminescence ranged from 6600 to 127 BP. The studied samples were sixty three representative pottery fragments selected of stratigraphic levels from the surface up to 170 cm deep for Sambaquis do Bacanga and Panaquatira and from surface up to 105 cm depth for Rabo de Porco. The three analytical methods employed were Computed Radiography, PIXE and XRF. Sixteen elements were measured with good statistics in the different ceramic samples through EDXRF and PIXE analysis: Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, Sr, Y and Zr. Multivariate statistical analysis, Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA), of the fragments elemental composition were performed to separate and correlate the groups of the samples. Fragments of the three archaeological sites grouped into two clusters, the first is composed of samples from “Sambaquis do Bacanga and Panaquatira”, and the second consists of the “Rabo de Porco” samples. This result indicates that each cluster of fragments was manufactured with different clays, and “Sambaquis do Bacanga and Panaquatira” fragments are derived from the same source or same kind of clay. The internal structure of the ceramic fragments observed by Computed Radiography revealed the presence of various sizes and types of anti-plastics in the sherds.

Acid Washed, Steam Activated, Coconut Shell Derived Carbon for High Power Supercapacitor Applications

The suitability of steam activated, coconut shell derived carbon (CSC) and its three variants obtained by acid washing of the CSC is investigated in detail for high power super capacitor applications using in depth electrochemical characterization. The CHNS and PIXE analysis is used to verify the purity of the samples. The structural and surface studies using Raman spectroscopy and BET techniques reveal that, after washing with acids, the structural features of the activated carbon get improved to a significant extent. Out of the three acid washing procedures, washing with HF is found to yield the activated carbon sample AC4 with maximum purity, structural order and surface morphology with optimum ratio of micropores to mesopores, suitable to facilitate fast electrolyte ion diffusion and transport. The two electrode measurements with organic electrolyte using symmetric AC4 electrode based supercapacitor test cells give an electrode capacitance of 162 F g−1 and an energy density of 35.2 Wh kg−1 at a current density of 1 A g−1, and a power density of 3967 W kg−1 at 10 A g−1 along with good cycling stability. It is also observed that 96% of the initial capacitance is retained after 5000 cycles at a current density of 10 A g−1.

Enhanced identification of trace element fingerprint of prehistoric pigments by PIXE mapping

Abstract The elemental composition of Fe rich rocks used as pigment during prehistoric periods can provide valuable information about the type of material used and their geological origin. However, these materials present several analytical constraints since their patrimonial value involve using non-invasive techniques maintaining a high sensitivity of the detection and the quantification of trace elements. Micro-beam techniques also require to take into account the heterogeneity of these geomaterials from the macroscopic to microscopic scales. Several previous studies have demonstrated that PIXE analysis satisfies these analytical conditions. However, application of micro-PIXE analysis is still complex when thin and discontinuous layer of pigment is deposed on the surface of other materials such as rocks or bones. In such case, PIXE imaging could improve the ability to take into account the high heterogeneity of such archaeological objects. In study, we used PIXE imaging system developed at the NewAGLAE facility in order to visualize distribution of elements associated with iron-rich pigment phase. The results obtained show that PIXE maps can improve the identification of the main trace elements specific to the iron mineral phase. By grouping pixels of iron-rich areas and performing quantitative treatment, it was possible to reveal additional trace elements associated to pigment. This study highlights the contribution of PIXE imaging to the identification of elements associated with mineral phases of interest and to use them as proxies to discriminate different geological materials used in archaeological context.

Separation of detector non-linearity issues and multiple ionization satellites in alpha-particle PIXE

Abstract Multiple ionization satellites are prominent features in X-ray spectra induced by MeV energy alpha particles. It follows that the accuracy of PIXE analysis using alpha particles can be improved if these features are explicitly incorporated in the peak model description when fitting the spectra with GUPIX or other codes for least-squares fitting PIXE spectra and extracting element concentrations. A method for this incorporation is described and is tested using spectra recorded on Mars by the Curiosity rover’s alpha particle X-ray spectrometer. These spectra are induced by both PIXE and X-ray fluorescence, resulting in a spectral energy range from ∼1 to ∼25 keV. This range is valuable in determining the energy-channel calibration, which departs from linearity at low X-ray energies. It makes it possible to separate the effects of the satellites from an instrumental non-linearity component. The quality of least-squares spectrum fits is significantly improved, raising the level of confidence in analytical results from alpha-induced PIXE.

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.

Characterization of Byzantine pottery from Oltina (Constanţa County), Romania, using PIXE and Optical Microscopy

Abstract An assemblage of 58 ceramic shards discovered in archaeological excavations at Oltina, Romania, dated to the 10th-11th century CE, was subjected to archaeometric investigations in order to reveal the raw materials and manufacturing techniques employed by the potters from the Lower Danube zone during the Byzantine ruling. The initial grouping of the shards according to stylistic criteria was refined by the subsequent petrographic study. Optical Microscopy (OM) detailed the general mineralogy and the pottery fabric, i.e. the textural characteristics, porosity and microstructure, surface treatments and firing. The PIXE analyses of potteries performed at AN2000 accelerator of LNL, INFN, Italy led to the identification of the chemical composition of the ceramic shards. The Hierarchical Cluster Analysis of the PIXE data evidenced several categories of shards with distinct compositional signatures, the main division being the one separating the ceramic fragments made of kaolinitic clays from the rest of the Oltina potteries.

Preliminary Results of PIXE Analysis of Mosses for Air Pollution Monitoring in Hanoi Using Pelletron Accelerator

Abstract: Air pollution is a major problem in many cities in Vietnam. The existence of heavy metals in dust particles in the air impacts negatively on human health. There are many different methods to collect dust in the air and analyse the heavy metals concentration. The method using mosses as a biological indicator for monitoring air pollution has been using widely around the world. This paper presents the preliminary results of using moss for analysis of heavy metals in the air in Hanoi by PIXE technique on Pelletron electrostatic accelerator of the VNU, University of Science (HUS).

An Investigation of Glassmaking Industry at Tal-i Malyan Based on PIXE Analysis

An Investigation of Glassmaking Industry at Tal-i Malyan Based on PIXE Analysis

Ion beam modification of zinc white pigment characterized by ex situ and in situ µ-Raman and XPS

Zinc oxide, known as zinc white, is one of the principal white pigments developed in the 18th century and was used by the Impressionist painters. ZnO as artists’ pigment has occasionally been characterized by X-ray and ion beam techniques, but these studies are limited by the potential for visible radiation effect. Ion beam modifications of zinc oxide have extensively been investigated, but mainly for electronic and industrial applications. In this paper, we focus our investigation on ion beam modification of ZnO used as pigment. Two irradiation conditions have been used: an external 3MeV proton micro-beam representative of PIXE analysis and 2MeV H+ and 1.2MeV Au+beams in vacuum to investigate irradiation modifications in electronic and nuclear energy loss regimes. Ion beam modification was characterized by ex situ and in situ micro-Raman spectrometry and XPS. The results shows that IBA of zinc white can be carried out safely in historical paintings with low current and dose.

Trace element mapping of two Pyrenean chert deposits (SW Europe) by PIXE

The geochemical character of two chert formations from the Pyrenean mountain range (SW Europe) was established by PIXE analyses. While it was not possible to distinguish the formations through reference to major and minor elements, some variations were revealed at the trace elemental level. In order to determine if these elements are associated with the Si matrix or to the contents of a specific inclusion, elemental maps were acquired and the elemental composition of the identified inclusions were also determined. As a result, Sr, Ni and Zn are better represented in Montgaillard samples while Y, Hf, W and Zr are typical of Montsaunès cherts. Thanks to elemental maps it has been possible to determine that most of these characteristic elements are usually related to a specific inclusion content.

New parallel beam wavelength dispersive X-ray emission spectrometer at Ljubljana microprobe

A new parallel beam wavelength dispersive X-ray emission spectrometer for high energy resolution PIXE analysis using focused proton microbeam has been constructed and installed at the microprobe of the J. Stefan Institute. Polycapillary X-ray optics is used to enhance the solid angle of X-ray collection and to transform collected proton-induced X-rays into quasi parallel beam which is analyzed using diffraction on a flat crystal. The spectrometer is installed in a vacuum chamber and operates in the 2–10keV energy range. The main characteristics and operational properties are presented together with the results of first characterization measurements. Finally, two selected experimental examples are given illustrating the capabilities of the spectrometer in PIXE analysis and fundamental research in atomic physics.

PIXE analysis of stream water following the Mt. Hakone eruption on 30 June 2015 — temporal changes in elemental concentrations over two years

After the 2011 Off the Pacific Coast of Tohoku Earthquake on 11 March, 2011, volcanic activity in Japan was observed to increase. In this study, we use the PIXE method to analyze elemental concentrations in stream water flowing directly from the fumarolic area on Mount Hakone, which erupted on 30 June 2015. Throughout a two-year monitoring period following the eruption, concentrations of 12 dissolved elements were measured. We found that the stream water was strongly acidic. For one year after the eruption, the concentrations of magma-derived elements (S, Cl) and rock-derived elements (Al, Ca, Fe, K, Mg, Mn, and Na), except for Si, showed a clear decreasing trend. These measurements suggest that magmatic activity and fumarolic activity reduced gradually over one year. After this year-long period, elemental concentrations stopped decreasing and instead showed broadly flat levels with sporadic increases and decreases. However, throughout the year immediately following the eruption, the number of volcanic earthquakes was consistently at zero or close to zero. These different indications of volcanic activity suggest that the elemental concentrations in stream water may be more sensitive indicators of small changes in subterranean behavior than of the number of volcanic earthquakes.