Ion Beam Analytical Methods Research Articles

Surface morphology and mechanical properties changes induced in Ti3InC2 (M3AX2) thin nanocrystalline films by irradiation of 100 keV Ne+ ions

We report on the structure of the Ti3InC2 (M3AX2) thin nanocrystalline films (TNCFs) produced by ion beam sputtering of the Ti, In, and C targets with subsequent thermal annealing, and irradiation by 100 keV Ne+ ions with two different fluences of 1 · 1014 cm−2 and 1 · 1016 cm−2. The Ti3InC2 TNCFs were characterized by a set of microscopic techniques (AFM, STEM/EDS, and HRTEM) as well ion beam analytical methods RBS and NRA. The STEM/EDS analysis revealed that the structure and chemical composition of the Ti3InC2 TNCF remained intact after irradiation with the lower fluence of 1 · 1014 cm−2 Ne+. However, a significant morphological instability was observed after irradiation with the higher fluence of 1 · 1016 cm−2 Ne+. The simulation of the nanobeam electron diffraction (NBED) patterns by using CrystalMaker code has pointed at the existence of new ε-Ti2C0.06 (MXene) structures and separation of Indium (In) from the Ti3InC2 matrix. The analysis by nanoindentation showed that the irradiated Ti3InC2 TNCFs exhibited promising mechanical properties considering Young's modulus and hardness even for the locally disordered structure. M3AX2 TNCFs are a new type of 2D materials designed for applications in extreme environments, such as nuclear facilities with intensive radiation fields. However, the research is still in its infancy and requires further study on the synthesis of high-quality, dense, and homogeneous M3AX2 TNCFs. This work is an initial study related to the radiation resistance of Ti3InC2 TNCFs.

Small accelerators and their applications in the CANAM research infrastructure at the NPI CAS

The Nuclear Physics Institute (NPI) of the Czech Academy of Sciences (CAS) operates, among other facilities, a Tandetron linear accelerator, TR-24 and U-120M cyclotrons, and an MT25 microtron. A new accelerator mass spectrometry (AMS) instrument, MILEA, has recently been acquired. Except for the MT25, all facilities are synergic parts of the Centre of Accelerators and Nuclear Analytical Methods Research Infrastructure (CANAM RI) ( http://canam.ujf.cas.cz ). This paper demonstrates the instrumental, scientific and application capabilities of the devices for many fundamental nuclear physics experiments and a wide spectrum of applications. The Tandetron Laboratory has a full arsenal of ion-beam analytical methods, ion-beam nano- and microstructuring techniques, as well as tools for the doping and synthesis of new progressive materials using energetic ion beams. It uniquely utilises ion beams for 3D elemental mapping; it studies internal morphology using ion-microprobe methods applicable in many scientific branches. The TR-24 and U-120M cyclotrons provide the primary beams of accelerated ions as well as the generated secondary fast neutrons, including the necessary instrumentation and the target technology, and enable fundamental experiments in nuclear physics, astrophysics, dosimetry, etc. The microtron MT25 is a source of relativistic electrons (the primary electron beam), the secondary photon beam (bremsstrahlung) and neutrons from photonuclear reactions which are used, e.g. for analysis and preservation of cultural heritage. The MILEA AMS system offers a highly sensitive isotopic ratio measurement of very long-lived radionuclides at levels up to 10–15.

Investigation of chemical changes in PMMA induced by 1.6 MeV He+ irradiation by ion beam analytical methods (RBS-ERDA) and infrared spectroscopy (ATR-FTIR)

Generally, organic materials are rather sensitive against ionizing radiations. Polymers have exact and known chemical structure, so they are ideal model materials to study ion beam irradiation induced chemical processes. The type and degree of the degradation strongly depend on the chemical groups attached to the main chain of the polymer. However, how these reactions are affected by the characteristics of the irradiation source such as the type of the particle, its energy and the linear energy transfer is not fully understood yet.The aim of this study was the investigation of the chemical effects of He+ ion irradiation on poly(methyl methacrylate) (PMMA) polymer. In-situ Rutherford Backscattering Spectrometry (RBS) and elastic recoil detection analysis measurements (ERDA) were performed simultaneously. In this way, the material loss occurring during irradiation could be followed. Infrared spectroscopy (ATR-FTIR) was applied to monitor chemical changes. With the in situ RBS-ERDA measurements, completed with FT-IR method, a comprehensive radiation chemical analysis could be achieved on the widely used PMMA polymer. Our results concerning the evolution of the hydrogen, carbon and oxygen contents and the changes in chemical groups indicate that a somewhat different radiation chemical mechanism takes place during 1.6 MeV He+ irradiation compared to proton irradiation.

Laser modification of graphene oxide layers

The effect of linearly polarized laser irradiation with various energy densities was successfully used for reduction of graphene oxide (GO). The ion beam analytical methods (RBS, ERDA) were used to follow the elemental composition which is expected as the consequence of GO reduction. The chemical composition analysis was accompanied by structural study showing changed functionalities in the irradiated GO foils using spectroscopy techniques including XPS, FTIR and Raman spectroscopy. The AFM was employed to identify the surface morphology and electric properties evolution were subsequently studied using standard two point method measurement. The used analytical methods report on reduction of irradiated graphene oxide on the surface and the decrease of surface resistivity as a growing function of the laser beam energy density.

Multi-energy ion implantation from high-intensity laser

Abstract The laser-matter interaction using nominal laser intensity above 1015 W/cm2 generates in vacuum non-equilibrium plasmas accelerating ions at energies from tens keV up to hundreds MeV. From thin targets, using the TNSA regime, plasma is generated in the forward direction accelerating ions above 1 MeV per charge state and inducing high-ionization states. Generally, the ion energies follow a Boltzmann-like distribution characterized by a cutoff at high energy and by a Coulomb-shift towards high energy increasing the ion charge state. The accelerated ions are emitted with the high directivity, depending on the ion charge state and ion mass, along the normal to the target surface. The ion fluencies depend on the ablated mass by laser, indeed it is low for thin targets. Ions accelerated from plasma can be implanted on different substrates such as Si crystals, glassy-carbon and polymers at different fluences. The ion dose increment of implanted substrates is obtainable with repetitive laser shots and with repetitive plasma emissions. Ion beam analytical methods (IBA), such as Rutherford backscattering spectroscopy (RBS), elastic recoil detection analysis (ERDA) and proton-induced X-ray emission (PIXE) can be employed to analyse the implanted species in the substrates. Such analyses represent ‘off-line’ methods to extrapolate and to character the plasma ion stream emission as well as to investigate the chemical and physical modifications of the implanted surface. The multi-energy and species ion implantation from plasma, at high fluency, changes the physical and chemical properties of the implanted substrates, in fact, many parameters, such as morphology, hardness, optical and mechanical properties, wetting ability and nanostructure generation may be modified through the thermal-assisted implantation by multi-energy ions from laser-generated plasma.

Evaluation of cryoanalysis as a tool for analyzing elemental distribution in “live” tardigrades using micro-PIXE

Although heavy on labor and equipment, thus not often applied, cryoanalysis of frozen hydrated biological specimens can provide information that better reflects the living state of the organism, compared with analysis in the freeze-dried state. In this paper we report a study where the cryoanalysis facility with cryosectioning capabilities at Materials Research Department, iThemba LABS, South Africa was employed to evaluate the usefulness of combining three ion beam analytical methods (μPIXE, RBS and STIM) to analyze a biological target where a better elemental compositional description is needed – the tardigrade. Imaging as well as quantification results are of interest.In a previous study, the element composition and redistribution of elements in the desiccated and active states of two tardigrade species was investigated. This study included analysis of both whole and sectioned tardigrades, and the aim was to analyze each specimen twice; first frozen hydrated and later freeze-dried. The combination of the three analytical techniques proved useful: elements from C to Rb in the tardigrades could be determined and certain differences in distribution of elements between the frozen hydrated and the freeze-dried states were observed. RBS on frozen hydrated specimens provided knowledge of matrix elements.

Micro-fluidic target chamber machined by proton beam writing for the in situ analysis of gas absorption in synthetic crystals

Many synthetic crystals used for chemical and industrial applications have special internal structures, e.g. nano-pores, which allow separating different gases and fluids. Ion beam analytical methods can be used to study the gas diffusion and absorption in these materials in situ and to visualize their inner surfaces which affect these processes. For this purpose, a small target chamber was constructed in PMMA (polymethyl methacrylate) using proton beam writing (PBW). This micro-fluidic structure enables the establishment of a defined atmosphere around a crystal and allows the simultaneous ion beam analysis. In order to confine the gas from the high vacuum in the measurement chamber Si3N4-windows of 200nm thickness were thermally bonded to the structured PMMA block yielding a closed target chamber with the possibility to accomplish PIXE and RBS measurements. In addition, two capillaries were connected to the chamber for gas inlet and evacuation. First tests showed that the construction is leak-proof and allows to establish a defined atmosphere. After that, the Argon gas diffusion into Zn(tbip)-crystals was studied. These measurements have shown unexpectedly high nickel concentrations in the host crystal which reduces the Argon density in these areas after absorption, because the Ni atoms decrease the pore size by replacing Zn-atoms in the Zn(tbip)-lattice. It could be demonstrated that gas diffusion and absorption in organic crystals can be studied in situ with high lateral resolution using ion beam analysis in a dedicated target chamber machined by PBW.

Study of Cl-containing urban aerosol particles by ion beam analytical methods

Fine (aerodynamic diameter < 2.5 μm) and coarse (10 μm ⩾ aerodynamic diameter ⩾ 2.5 μm) mode urban aerosol samples were collected with 2-h time resolution in the frame of several sampling campaigns between 2007 and 2009 in downtown Debrecen, East-Hungary. The elemental composition (for Z ⩾ 13) of the samples was measured by particle induced X-ray emission (PIXE). On this basis sources of urban aerosol were determined by factor analysis. For both size fractions a source characterized by high chlorine content were found. However, the origin of the Cl-containing aerosol could not be ascertained. Further investigation of samples characterized with high Cl content were done on the ATOMKI Scanning Nuclear Microprobe Facility in order to determine the possible chemical composition of these particles and thus the potential sources. Morphology, size and elemental composition for Z ⩾ 6 of around 1000 coarse mode particles were determined by using STIM (Scanning Transmission Ion Microscopy), light-element PIXE and PIXE analytical methods. Hierarchical cluster analysis was performed on the obtained dataset in order to group the particles; correlations between different elements were also calculated. Five possible sources of Cl were identified, from which four were anthropogenic: winter salting of streets, agriculture through fertilizers, buildings and industry; the natural group was sea-salt.

Quantitative micro-analysis of metal ions in subcellular compartments of cultured dopaminergic cells by combination of three ion beam techniques

Quantification of the trace element content of subcellular compartments is a challenging task because of the lack of analytical quantitative techniques with adequate spatial resolution and sensitivity. Ion beam micro-analysis, using MeV protons or alpha particles, offers a unique combination of analytical methods that can be used with micrometric resolution for the determination of chemical element distributions. This work illustrates how the association of three ion beam analytical methods, PIXE (particle induced X-ray emission), BS (backscattering spectrometry), and STIM (scanning transmission ion spectrometry), allows quantitative determination of the trace element content of single cells. PIXE is used for trace element detection while BS enables beam-current normalization, and STIM local mass determination. These methods were applied to freeze-dried cells, following a specific cryogenic protocol for sample preparation which preserves biological structures and chemical distributions in the cells. We investigated how iron accumulates into dopaminergic cells cultured in vitro. We found that the iron content increases in dopaminergic cells exposed to an excess iron, with marked accumulation within distal ends, suggesting interaction between iron and dopamine within neurotransmitter vesicles. Increased iron content of dopaminergic neurons is suspected to promote neurodegeneration in Parkinson's disease.

RBS, PIXE and NDP study of erbium incorporation into glass surface for photonics applications

This paper reports on the fabrication and the characterisation of successful erbium in-diffusion into silicate glass surface for potential use in photonics active structures through ion beam analytical methods. The erbium doping occurred by ion exchange of erbium ions from a molten source for lithium ions from the specially designed glass substrates. Composition of the optical layers was studied by ion beam analytical techniques: RBS (Rutherford backscattering spectroscopy) characterized depth distribution of the incorporated Er3+ ions and PIXE (particle induced X-ray emission spectroscopy) gave information on the total amount of erbium incorporated in the samples. The NDP (neutron depth profiling) method was used to evaluate changes in distribution of Li+ ions in the surfaces of the fabricated samples. We observed shallow Er profiles that were accompanied by more mobile Cs+, Rb+ ions incorporated in the much deeper layer as compared to the Er. The Li concentration in the glass substrate occurs as the most important parameter for Er diffusion into the glass substrate.

High-Sensitivity Ion Beam Analytical Method for Studying Ion-Implanted SiC

Abstract. The combination of Backscattering Spectrometry and channeling with the 12 C(,) 12 C nuclear resonance at 4.26 MeV to study radiation damage in the carbon sublattice of 6H-SiC was applied. 6H SiC samples were implanted with 200 keV Al ions in a dose range of 410 14 cm -2 - 110 16 cm -2 with different current densities at room temperatures. The implanted samples were annealed at 1200oC in argon for 1 hour. In the case of low dose, low current density implantation damage recovery seems to be complete. Introduction Silicon carbide is a wide bandgap semiconductor material with many advantages for high temperature, high power and high frequency applications. Its local doping can only be performed by ion implantation, due to the very low diffusivity of the dopants in SiC, even at high temperatures. However, an equivalent ion beam irradiation creates more damage in the crystal lattice of SiC than it would be in Si. Moreover in the case of SiC the damage creation depends not only the dose of implanted atoms, but on the ion current during implantation [1]. The damage process and the structural recovery after a further high temperature annealing are not yet fully understood. Ion beam analytical methods are suitable for observing ion implantation damage. Widely used Rutherford Backscattering method with channeling (BS/C) provides information on the damage only in the silicon sublattice since the small signals from carbon are situated on the high background of silicon. In our present work the 4.26 MeV

Ion Bombardment Induced Damage in Silicon Carbide Studied by Ion Beam Analytical Methods

Ion Bombardment Induced Damage in Silicon Carbide Studied by Ion Beam Analytical Methods

The production of the new cubic FeN phase by reactive magnetron sputtering

FeN y films with a nitrogen content of nearly 50 at.% ( y≈1) were prepared by reactive magnetron sputtering. Their properties were studied as a function of several sputtering parameters (gas-flow rates, substrate temperature and bias voltage), using ion-beam analytical methods, Mössbauer spectroscopy as well as transmission electron microscopy (TEM) and X-ray diffraction (XRD). In order to highlight the role of light contaminant elements (H,C,O) in the production of single-phase cubic FeN films, the concentration profiles of all the elements of the films were measured by Time of Flight Elastic Recoil Detection Analysis (TOF-ERDA).

Pore structure investigations in porous silicon by ion beam analytical methods

Ion beam analytical methods (e.g. Rutherford Backscattering, RBS, Elastic Recoil Detection, ERD, or Nuclear Reaction Analysis, NRA) are widely used for quantitative determination of the depth distribution of elements. In porous samples however, where the diameter of the pores is a few tens of nm (i.e. unresolvable even by the most sophisticated microbeam), the measured depth distribution differs from the real one and this difference strongly depends on the pore structure.

Channeling experiments on porous silicon before and after implantation

Porous silicon films with sponge like structure were implanted with phosphorus ions in order to lower their resistivity. The effects of ion implantation and various heat treatments were investigated using ion beam analytical methods. Depending on the layer thickness as well as the energy and dose of the bombarding ions a highly damaged layer could be formed inside or underneath the porous layer. We found that there are two main effects of ion implantation, the amounts of the contaminants can be decreased and the porous layer may be densified. If the dose was high enough to deplete almost all of the contaminants, the resistivity decreased by three orders of magnitude after the subsequent heat treatment.

Ion beam analytical methods for attempts to establish the provenance of archaeological objects in the absence of reference artefacts

The methods of prompt photon excitation, whether X-rays (PIXE and XSQR) or γ-rays (PIGME), the equipment used and the methodology for the nondestructive analysis of art objects and archaeological samples are described. The multivariable statistical method of correspondence analysis is used to discover similarities between objects on the basis of their multielemental analytical data. These techniques are applied to the analysis of pottery, glass, porcelains, gold objects and postage stamps.