Ion Beam Analysis Research Articles

3D deposition patterns of deuterium retention and impurities in the COMPASS divertor: a data-driven root cause analysis and prediction approach

Divertor tiles from the COMPASS tokamak have been examined with ion beam analysis for the determination of deuterium retention and co-deposits. A novel approach was used to draw 2D deuterium retention maps at different depths and correlated to the concentrations of other elements: boron, carbon, oxygen and metals. This approach, which employs all three spatial dimensions, revealed that the deuterium retention pattern is not toroidally symmetric at different depths while the overall deuterium pattern is toroidally symmetric. Analysis of visible-light camera records disclosed that parts of the divertor were not wetted by plasma. The radial profile of deuterium in both wetted and non-wetted (“shadowed”) divertor regions was compared to strike point positions, angle of incidence, electron temperature Te, parallel heat flux Qpar and ion saturation current Isat in order to find the influence of these parameters on deuterium retention. There are certain series of consecutive shots for which correlations between deuterium retention and separate plasma parameters (Te, Isat, Qpar) are high. Combining the three parameters in a linear model or a power law model enabled reconstruction of the radial deuterium retention pattern. After fitting the model to one third of the data points, the deuterium retention for shadowed tiles was reproduced at the other two thirds of the data points within 20% deviation. This study shows the need for detailed tile analysis in three dimensions, the great benefits of broad statistical analysis in solving challenges in fusion, and motivates the investigation of COMPASS tiles after dismantling.

Reverse trajectory analysis of the hydrogen negative ion beam in a prototype accelerator for ITER

Reverse calculation of negative ion trajectory based on the measured beam emittance has been performed for the first time in multi-stage accelerator in order to reconstruct negative ion profile near meniscus, which has been a long-term issue for negative ion sources. According to reverse calculation, negative ions are mainly extracted from the periphery of extraction area, and the particles extracted from the aperture edge is lost on acceleration grids. By taking into account the lost component with reconstructed negative ion profile, the negative ion trajectory became consistent with observed beam traces on the acceleration grids. This result can be applied directly to the design of ITER accelerator as well as the other Cs-seeded negative ion sources.

A forensic procedure based on GC–MS, HPLC-HRMS and IBA to analyse products containing sildenafil or the doping agent oxandrolone

The market of falsified or sub-standard medical products is a global scale phenomenon. This issue affects a wide range of medications, including life-saving medical products. In high-income countries the most falsified products are those defined “lifestyle”, which include foremost anabolic steroids and phosphodiesterase 5 inhibitors. The spread of these products in the last years has been possible also because of their online purchase, since they can be bought anonymously and without any medical supervision or prescription. Their use can pose a serious threat for public health, especially because often are manufactured without adherence to quality standards. This leads to final products containing active ingredients different from those declared, at the wrong or unknown dose and contaminated with metals, synthesis by-products and other chemical substances. In this work, we present results on characterisation of illegal pharmaceutical products and doping agents by combining different techniques: chromatography coupled to mass spectrometry for organic analysis and accelerator-based nuclear analytical techniques, such as ion beam analysis (IBA), for elemental analysis. Three IBA techniques, namely PIXE (particle induced X-ray emission), PIGE (particle induced gamma-ray emission) and EBS (elastic backscattering spectrometry) were used in external beam mode to provide an elemental characterisation of the as-is material, placed simply in front of the proton beam, thus avoiding the need of preparing them with pre-analytical steps and greatly enhancing the measurement throughput. Several elements (F, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Br and Sr) were identified in the analysed products. External beam IBA measurements provided the quantitative elemental characterisation of the illegal pharmaceutical products and doping agents under study, complementary to the organic analysis results by chromatography and mass spectrometry thus allowing a rapid (a few minutes) and non-destructive direct assessment of the material for forensic purposes. For the first time IBA results from doping products are reported and further analysis by IBA involving two different accelerator laboratories (one in Italy and one in Brazil) allowed the comparison of results obtained on the same pharmaceutical product. Starting from the results obtained in our study, the actualisation of new research plans should be evaluated, which could lay the foundation for a classification system of illegal pharmaceutical products, doping products. and other substances, based on chromatography, mass spectrometry and IBA measurements; this could allow drawing inferences about the common characteristics of these substances, e.g. provenience of bulk materials, site of production etc. With this purpose, results obtained from two samples of the same pharmaceutical product by IBA in two different accelerator laboratories (one in Italy and one in Brazil) are compared.

Inter-diffusion and stability studies in W/Cr and W/Fe films using ion beam analysis

Plasma facing components in fusion reactors are exposed to intense plasma and the accompanying thermal loads and undergo surface modification due to sputtering and thermal diffusion. In order to get insight into the thermal diffusion in reduced-activation ferritic/martensitic (RAFM) steel, a prominent W containing plasma facing material, the compositional, structural and morphological changes occurring in W/Cr and W/Fe bi-layered films on vacuum annealing in 373–873 K temperature range were investigated. Compositional analysis by ion beam techniques established the out-diffusion of Cr and Fe through the W layer to the top surface. The diffusion coefficients of Cr and Fe in W were determined to be 8.0 × 10-19 (at 873 K) and 9.75 × 10-18 m2/s (at 773 K) respectively. The out-diffusion of Cr and Fe was substantiated by diffraction studies; however, no inter-metallic phases were formed. Annealing, besides promoting grain growth also introduced roughness in films.

Liquid lithium wetting and percolation in a porous tungsten/liquid Li plasma facing component (PFC)

This work explores the concept of a hybrid material system designed to protect the plasma from high-Z material emission while also protecting an underlying high-Z wall material from erosion by integrating a low-Z component in the liquid phase. Plasma-surface interaction properties of a porous tungsten (W)-liquid metal hybrid system, having the favorable bulk thermomechanical properties of W while serving as a scaffold for a liquid metal with self-healing and radiative vapor shielding characteristics, are examined. W-substrates with 70% density of bulk W and 1–5 μm sized pores have been fabricated with 50-nm W powders using spark plasma sintering. Enhanced lithium (Li) wettability, driven by percolation through the porous W architecture, is demonstrated with in-situ liquid Li drop measurements. Results show complete wetting of liquid Li at 250 °C in the porous W, 100 °C lower temperature than what has been observed on traditional W surfaces. In operando ion beam analysis of Li films deposited on porous W substrates provides microscopic evidence of Li percolation into the substrate and a first look at D retention up to a depth of 100 nm after plasma exposure at a flux of 1020 m−2s−1, 250 eV/amu D+ plasma to a fluence of 1.16 × 1023 m−2 at a temperature of 200 °C.

An innovative kinetic model allowing insight in the moderate temperature chemical vapor deposition of silicon oxynitride films from tris(dimethylsilyl)amine

An apparent kinetic model is developed for a novel chemical vapor deposition (CVD) process of silicon oxynitride (SiOxNy) films from tris(dimethylsilyl)amine (TDMSA) and O2, operating at moderate temperature (600–650 °C) and at atmospheric pressure. The definition of reaction pathways and the extraction of kinetic information is based on recently reported results of the gas phase composition, complemented by solid phase characteristics obtained by spectroscopic ellipsometry (SE) and ion beam analyses (IBA). Incorporation of carbon (up to 20 at.%) is considered alongside nitrogen (up to 25 at.%) for variable O2 flow rates (0.3–1.2 sccm). This combined gas- and solid-phase analysis is utilized to identify the main gaseous species and provide insight into the deposition mechanism. A silicon- and a nitrogen-centered radical intermediates are considered as the primary species of the mechanism, based on evidence from gas phase characterizations. A third, fictitious, nitrogen- and carbon-containing molecule is also conceptualized to account for carbon incorporation. Eight chemical reactions are defined alongside their respective kinetic parameters and are implemented in the ANSYS® FLUENT® computational fluid dynamics (CFD) code. Upon validation, the model allows for the successful prediction of local deposition rates and SiOxNy film composition containing non-negligible carbon, marking it as the first kinetic model able to represent the main chemical mechanisms involved in the CVD of a four-component material. The reported combined approach could be applied to other existing or new CVD chemistries forming multi-component thin films, favoring their implementation in original applications.

Improved quantitation of SIMS depth profile measurements of niobium via sample holder design improvements and characterization of grain orientation effects

The importance of SIMS analyses for “N-doped” impurity alloyed niobium and other surface-alloyed materials continues to increase. A major hurdle is the uncertainty of instrument calibration due to changes in sample height either from sample surface topography or from the sample holder itself. The CAMECA sample holder design allows for many types of samples to be analyzed. However, a drawback is that the holder faceplate can bend, contributing an uncertainty in the relative sensitivity factor (RSF) used to quantify the SIMS results. Here, we describe an improved sample holder having a reinforced faceplate, which prevents deflection and reduces uncertainty. Simulations show that the new design significantly reduces deflection from 10 μm to 5 nm. Sample measurements show a reduction of RSF uncertainty from this source from 4.1% to 0.95%. Grain orientation has long been suspected to affect RSF measurement as well. A bicrystal implant standard, consisting of randomly oriented and [001] grains, was successively rotated 15° between analyses. It was observed that 20% of the analyses performed on the randomly oriented grain exhibited anomalously high RSF values as well as slow sputter rates. These features were associated with the changing grain normal orientation with respect to the primary Cs+ beam. The grain orientation associated with the rise in RSF was simulated and determined to be the [101] crystallographic plane, thus indicating that ion channeling was responsible for the significantly increased RSF. Focused ion beam analysis confirmed slower sputter rates for the cardinal crystallographic orientations, indicating that ion channeling occurred for each.

Visualizing Grain Statistics in MOCVD WSe2 through Four-Dimensional Scanning Transmission Electron Microscopy.

Using four-dimensional scanning transmission electron microscopy, we demonstrate a method to visualize grains and grain boundaries in WSe2 grown by metal organic chemical vapor deposition (MOCVD) directly onto silicon dioxide. Despite the chemical purity and uniform thickness and texture of the MOCVD-grown WSe2, we observe a high density of small grains that corresponds with the overall selenium deficiency we measure through ion beam analysis. Moreover, reconstruction of grain information permits the creation of orientation maps that demonstrate the nucleation mechanism for new layers-triangular domains with the same orientation as the layer underneath induces a tensile strain increasing the lattice parameter at these sites.

Promotion of pitting corrosion at hydrogen-enriched α/γ phase boundaries in austenitic stainless steel weld joints

Weld joints can experience numerous defects, which may become enriched in hydrogen and form pits after an attack. However, few in situ studies have been conducted on the relationship between hydrogen enrichment and pitting initiation sites. Moreover, the mechanism by which hydrogen enrichment promotes the initiation and propagation of pitting is unknown. In this study, the pitting susceptibility of austenitic stainless steel weld joints that had been used for 6 years in a hydrocracking unit was investigated. Scanning Kelvin probe force microscopy (SKPFM) was performed to characterize the Volta potential before and after hydrogen removal. The α/γ phase boundaries of the as-received samples were mostly enriched in hydrogen. Furthermore, the α/γ phase boundaries were the preferential locations for the initiation and propagation of pits, which were located at sites of hydrogen enrichment. The results of focused ion beam analysis revealed that the pits deepened along the α/γ phase boundaries and achieved stability. Hydrogen enrichment promotes the transformation of metastable pits to stable pits, which may be the mechanism underlying the promotion of pitting propagation by hydrogen enrichment.

Inter-laboratory workflow for forensic applications: Classification of car glass fragments

The International Atomic Energy Agency (IAEA) has coordinated a research project titled ”Enhancing Nuclear Analytical Techniques to Meet the Needs of Forensics Sciences” (CRP F11021) with the aim of empowering accelerator and reactor based techniques for applications in forensic sciences. One of the key topics of this project was the analysis and classification of forensic glass specimens using Ion Beam Analysis (IBA) techniques and in particular, Particle Induced X-ray Emission (PIXE).To this end, glass fragments from car windows from different car models and manufacturers provided by the Israeli police force were subjected to PIXE measurements at three laboratories to determine their elemental compositions and possible glass corrosion. Major and trace elements were measured and given as an input to machine learning (ML) algorithms in order to develop classification models to determine the origin of the glass samples.First, we have developed ML models based on the results obtained at each lab. These models successfully classified glass fragments into different car models with an accuracy> 80% on external test sets. Next, we demonstrated that following an appropriate pre-processing step, results from different labs could be combined into a single unified database for the derivation of a classification model. This model demonstrates good performances that matches or surpasses the performances of models derived from the individual labs. This finding paves the way towards establishing an international database that is composed of measurements from various PIXE labs. We believe that using this methodology of combining various sources of measurements will improve models’ performances and generality and will make the models accessible to law enforcement agencies around the world.

Spontaneous moisture-driven formation of Cs2Pb1-xMxCl2I2 single crystals with M = Bi, In, Ga and Cr

Micrometer to millimeter platelets-like single crystals of the 2D-derivated perovskite structure Cs2PbCl2I2 were synthesized by a very simple route using the humid ambient environment surrounding a DMSO solution containing the salt precursors. Cs2Pb1-xMxCl2I2 formation was also evidenced by single crystal X-ray diffraction, with M = Bi, Ga, In and Cr. X-ray photoelectron spectroscopy (XPS) confirmed the presence of each dopant, with an amount of x ∼ 5 ato.% for the last three materials. For the Bi-doped sample, XPS showed a larger quantity of dopant that can be due to XPS difficulty to discriminate too close elements for a few nanometers of analysis or higher concentrations in some crystals due to the affinity of both elements to integrate this structure on the same crystallographic site. A decrease of Bi concentration was determined by ion-beam and XPS simultaneous analysis. Finally, a photoluminescence (PL) peak was observed at ∼420 nm for all samples. Peak widening and blue-shift can be ascribed to the doping, and attributed to photon recycling and radiative self-trapped states. These results show the great versatility of ionic substitution and adaptive optoelectronic properties of the 2D phase that is stable in temperature.

Quantitative Lithiation Depth Profiling in Silicon Containing Anodes Investigated by Ion Beam Analysis

The localisation and quantitative analysis of lithium (Li) in battery materials, components, and full cells are scientifically highly relevant, yet challenging tasks. The methodical developments of MeV ion beam analysis (IBA) presented here open up new possibilities for simultaneous elemental quantification and localisation of light and heavy elements in Li and other batteries. It describes the technical prerequisites and limitations of using IBA to analyse and solve current challenges with the example of Li-ion and solid-state battery-related research and development. Here, nuclear reaction analysis and Rutherford backscattering spectrometry can provide spatial resolutions down to 70 nm and 1% accuracy. To demonstrate the new insights to be gained by IBA, SiOx-containing graphite anodes are lithiated to six states-of-charge (SoC) between 0–50%. The quantitative Li depth profiling of the anodes shows a linear increase of the Li concentration with SoC and a match of injected and detected Li-ions. This unambiguously proofs the electrochemical activity of Si. Already at 50% SoC, we derive C/Li = 5.4 (< LiC6) when neglecting Si, proving a relevant uptake of Li by the 8 atom % Si (C/Si ≈ 9) in the anode with Li/Si ≤ 1.8 in this case. Extrapolations to full lithiation show a maximum of Li/Si = 1.04 ± 0.05. The analysis reveals all element concentrations are constant over the anode thickness of 44 µm, except for a ~6-µm-thick separator-side surface layer. Here, the Li and Si concentrations are a factor 1.23 higher compared to the bulk for all SoC, indicating preferential Li binding to SiOx. These insights are so far not accessible with conventional analysis methods and are a first important step towards in-depth knowledge of quantitative Li distributions on the component level and a further application of IBA in the battery community.

Multivariate Regression Analysis of the NiTi Alloys’ Surface Corrosion Depending on the Measured Oxygen Value: Tests in Three Different Marine Environments

Actual corrosion experiments are based mainly on methodologies that measure the corrosion rate of alloys as a function of the parameters that characterise different external influences and the specific environment in which the alloys are placed. Corrosive processes are viewed as complex stochastic processes described by linear and nonlinear probabilistic models. In contrast to these common ways of analysing corrosive processes, this paper investigates the corrosion process in terms of chemical changes in the alloys’ surface compositions. For this purpose, two NiTi Shape Memory Alloys obtained by different technological production processes were tested, followed by an analysis of the empirical data obtained in a real experiment that included monitoring the corrosion behaviour. Both the analysed alloys were exposed to three different types of marine environment: air, tide, and sea. Data were collected continuously after 6, 12 and 18 months of samples’ exposure to the marine environmental influences. A total of six empirical databases were formed, one for each of the observed NiTi alloys in each of the three observed environments. The empirical databases systematised the data related to the measurements of the surface chemical composition obtained using Energy Dispersive X-ray (EDX) and Focused Ion Beam (FIB) analyses. Statistical analysis was performed to determine the correlation between the corrosion depth and the percentage of oxygen in the sample surfaces as well as to determine the similarities and differences in the corrosive behaviour of the two observed alloys in different marine environments.

Application of Ion Beam Analysis in Studies of First Wall Materials in Controlled Fusion Devices

The paper provides a concise overview of ion beam analysis methods and procedures in studies of materials exposed to fusion plasmas in controlled fusion devices with magnetic confinement. An impact of erosion–deposition processes on the morphology of wall materials is presented. In particular, results for deuterium analyses are discussed. Underlying physics, advantages and limitations of methods are addressed. The role of wall diagnostics in studies of material migration and fuel retention is explained. A brief note on research and handling of radioactive and beryllium-contaminated materials is also given.

Metallurgical Tests in Endodontics: A Narrative Review.

Since there are no reviews of the literature on this theme, the aim of this narrative review is to summarize the metallurgical tests used in endodontics, pointing out their functional use and their pros and cons and giving readers a user-friendly guide to serve as an orientation aid in the plethora of metallurgical tests. With this purpose, a literature search for articles published between January 2001 and December 2021 was conducted, using the electronic database PubMed to collect all published articles regarding the metallurgical tests used in endodontics for the evaluation of NiTi rotary instruments. The search was conducted using the following keywords: “metallurgy”, “differential scanning calorimetry” (DSC), “X-ray diffraction” (XRD), “atomic force microscopy” (AFM), “energy-dispersive X-ray spectroscopy” (EDS), “focused ion beam analysis” (FIB) and “Auger electron spectroscopy” (AES) combined with the term “endodontics” or “NiTi rotary instruments”. Considering the inclusion and exclusion criteria, of the 248 articles found, only 81 were included in the narrative review. According to the results, more than 50% of the selected articles were published in one of the two most relevant journals in endodontics: International Endodontic Journal (22.2%) and Journal of Endodontics (29.6%). The most popular metallurgical test was DSC, with 43 related articles, followed by EDS (33 articles), AFM (22 articles) and XRD (21 articles). Few studies were conducted using other tests such as FIB (2 articles), micro-Raman spectroscopy (4 articles), metallographic analysis (7 articles) and Auger electron spectroscopy (2 articles).

Proton beam irradiation induces invisible modifications under the surface of painted parchment

Ion beam analysis plays an important role in cultural heritage (CH) studies as it offers a combination of simultaneous and complementary analytical techniques (PIXE/PIGE/RBS) and spatially resolved mapping functions. Despite being considered non-destructive, the potential risk of beam-induced modifications during analysis is increasingly discussed. This work focuses on the impact of proton beams on parchment, present in our CH in form of unique historical manuscripts. Parchment is one of the organic, protein-based CH materials believed to be the most susceptible to radiation-induced changes. Various modification patterns, observed on parchment cross-sections by optical and electron microscopy are reported: discoloration (yellowing), formation of cavities and denaturation of collagen fibers. Considerable modifications were detected up to 100 µm deep into the sample for beam fluences of 4 µC/cm2 and higher. The presence of ultramarine paint on the parchment surface appears to increase the harmful effects of proton radiation. Based on our results, a maximum radiation dose of 0.5 µC/cm2 can be considered as ‘safe boundary’ for 2.3 MeV PIXE analysis of parchment under the applied conditions.

Tracking the role of nitrogen in the improvement of the high temperature oxidation resistance of titanium by mechanical treatments

We report the role of ultrasonic shot-peening (SP) and laser-shock peening (LSP) on the insertion of atmospheric nitrogen during high temperature oxidation of pure titanium and the improvement of its oxidation resistance. Ion Beam analysis showed that for short oxidation durations, a layer of Ti2N is formed at the oxide-metal interface. However, only the LSP treatment leads to the formation of a long-term stable nitrogen-rich layer which acts as a barrier for the diffusion of oxygen. This explains the efficiency of the LSP treatment to reduce the oxidation of Ti and prevent embrittlement.

Comparative study of the MeV ion channeling implantation induced damage in 6H-SiC by the iterative procedure and phenomenological CSIM computer code

Due to its unique material properties, such as extreme hardness and radiation resistance, silicon carbide has been used as an important construction material for environments with extreme conditions, like those present in nuclear reactors. As such, it is constantly exposed to energetic particles (e.g., neutrons) and consequently subjected to gradual crystal lattice degradation. In this article, the 6H-SiC crystal damage has been simulated by the implantation of 4 MeV C3+ ions in the (0001) axial direction of a single 6H-SiC crystal to the ion fluences of 1.359 1015 cm-2, 6.740 1015 cm-2, and 2.02 1016 cm-2. These implanted samples were subsequently analyzed by Rutherford and elastic backscattering spectrometry in the channeling orientation (RBS/C & EBS/C) by the usage of 1 MeV protons. Obtained spectra were analyzed by channeling simulation phenomenological computer code (CSIM) to obtain quantitative crystal damage depth profiles. The difference between the positions of damage profile maxima obtained by CSIM code and one simulated with stopping and range of ions in matter (SRIM), a Monte Carlo based computer code focused on ion implantation simulation in random crystal direction only, is about 10%. Therefore, due to small profile depth shifts, the usage of the iterative procedure for calculating crystal damage depth profiles is proposed. It was shown that profiles obtained by iterative procedure show very good agreement with the ones obtained with CSIM code. Additionally, with the introduction of channeling to random energy loss ratio the energy to depth profile scale conversion, the agreement with CSIM profiles becomes excellent.

Recent developments in IBA analysis at CENTA, Bratislava

An experimental setup used at the CENTA (Centre for Nuclear and Accelerator Technologies) laboratory to carry out IBA (Ion Beam Analysis) techniques is described. PIXE (Particle Induced X-ray Emission) technique offers a unique way of non-destructive elemental analysis using accelerated ion beams. The calibration of instrumental constants (H-values) of SDD and BEGe detectors, used in the setup, is described in detail. The H-value was determined as a function of X-ray energy by using thin MicroMatter standards of chosen elements. The calibrated H-values were then used in GUPIXWIN for the determination of elemental concentrations in two IAEA reference materials, which were compared with reference values. A reasonable agreement was achieved between the measured and reference values, while the calibrated H-values will be used for further analyses.

Boron in Ni-Rich NCM811 Cathode Material: Impact on Atomic and Microscale Properties

Doping of Ni-rich cathode active materials with boron is a promising way to improve their cycling stability and mitigate their degradation, but it is still not understood how this effect is achieved and where the boron is located. To receive deeper insights into the impact of doping on atomic and microscale properties, B-doped Li[Ni0.8Co0.1Mn0.1]O2 (NCM811) cathode materials were synthesized by a hydroxide coprecipitation as a model compound to verify the presence and location of boron in B-doped, Ni-rich NCM, as well as its impact on the microstructure and electrochemical properties, by a combined experimental and theoretical approach. Besides X-ray diffraction and Rietveld refinement, DFT calculation was used to find the preferred site of boron absorption and its effect on the NCM lattice parameters. It is found that boron shows a trigonal planar and tetrahedral coordination to oxygen in the Ni layers, leading to a slight increase in lattice parameter c through an electrostatic interaction with Li ions. Therefore, B-doping of NCM811 affects the crystal structure and cation disorder and leads to a change in primary particle size and shape. To experimentally prove that the observations are caused by boron incorporated into the NCM lattice, we detected, quantified, and localized boron in 2 mol % B-doped NCM811 by ion beam analysis and TOF-SIMS. It was possible to quantify boron by NRA with a depth resolution of 2 μm. We found a boron enrichment on the agglomerate surface but also, more importantly, a significant high and constant boron concentration in the interior of the primary particles near the surface, which experimentally verifies that boron is incorporated into the NCM811 lattice.