In this work the influence of surface roughness on the sputter yield of Mo under keV D ion bombardment was investigated for different impact angles. For this purpose, thin films of Mo (~ 120 nm) were ...deposited by pulsed laser deposition onto graphite substrates with varying surface roughness (Ra ranging from 5 nm to 2–3 µm). The as-deposited samples were irradiated at room temperature by 3 keV D3+ ions originating from an electron-cyclotron-resonance ion gun. Samples were exposed to D ions at angles between 0° and 70° and fluences in range of 1023 D/m2. The areal densities of the Mo marker layers were determined with Rutherford backscattering spectroscopy. For all the surfaces we observed a strong angular dependence of the sputter yield. For smooth and intermediate surface roughnesses, up to Ra ~ 280 nm, we obtained an increase of the sputter yield with the angle up to a factor of five compared to 0°. In contrast, at the highest surface roughness in the 2–3 µm range the sputtering yield decreases with increasing impact angle. The obtained data were compared to SDTrimSP-3D simulations. We obtained good agreement between the simulated and experimental sputter yield for surfaces for which we could provide high resolution atomic force microscopy (AFM) surface representations. As high-resolution surface mapping was not possible for surface roughness of 2–3 μm, we found large deviation between the calculation and the measured data. The combination of measured and simulated data represent important input for predicting the erosion rates of surfaces at inner walls of thermonuclear fusion devices, which are expected to change surface roughness over time by sustained plasma exposure.
We discuss how different accelerator-based techniques can be employed synergistically as a powerful analytical tool for forensic studies of foodstuff. Brazilian and Jamaican coffees were chosen as a ...showcase due to its popularity and potential risk of adulteration and/or falsification. Comprehensive characterization of major and trace elements, age since production and compound contents were achieved using different techniques, including PIXE (Particle-Induced X-ray Emission), FTIR (Fourier Transform Infrared), and AMS-14C (Accelerator Mass Spectrometry – Radiocarbon Analysis). While PIXE provides information on the elements present in the samples, FTIR probes the types of compounds through their vibrational spectra. Finally, AMS-14C is capable of dating organic samples regarding their harvesting time. Five different laboratories from research institutions around the world took part in the experiments. The integration of the results obtained with different techniques provided multifaceted perspectives on the coffee under study, thus allowing a direct assessment of the material for forensic purposes such as authentication, determination of provenance, and combat counterfeiting.
•Accelerator-based techniques helping forensic studies of coffee.•PIXE: provides information on the elemental profile of coffee.•AMS-14C: provides information on the date of production.•ATR-FTIR: provides information on the molecular profile of coffee.•Overall results show a synergetic integration of these techniques.
•Determination of the differential cross-sections for the measured 3He+3H nuclear reaction, which has three decaying channels.•First cross-section measurements with 3He beam energy up to 3.3 MeV for ...two decay channels 3H(3He,d)4He and 3H(3He,p)5He.•Measured angular dependence for the two decay channels.•Utilization of special ΔE–E telescope detector to distinguish between the different decay channels.•Establishment of 3He nuclear reaction ion beam technique for non-destructive tritium depth profiling in solids.
The differential cross-section for the 3He+3H nuclear reaction was measured in a thin tritiated PdTi film that was deposited on a Si wafer. The sample was loaded with 3H2 gas at a temperature of 300 °C and at a pressure of 1.8 bar. The total activity of the sample, measured by the liquid scintillation technique, was found to be 395 MBq. Two peaks were observed in the spectrum of the thick Si detector, corresponding to the 3H(3He,d)4He and 3H(3He,p)5He reaction channels. The differential cross-section was determined for the energy range of the 3He beam from 0.6 to 3.4 MeV, at three scattering angles of 125, 135 and 155°. The differential cross-section for the first channel remained almost constant within the measured energy range, while the cross-section for the second channel increased with energy. In both cases, the cross-sections reached their maximum value at the lowest scattering angle measured. The differential cross-sections were verified using a thick solid tritiated tungsten target. For assessing the tritium depth profile, only the reaction channel 3H(3He,d)4He can be utilized.
Recently we completed a construction of a cryostat at Jožef Stefan Institute (JSI) nuclear microprobe enabling us to analyze various types of biological samples in frozen hydrated state using ...micro-PIXE/STIM/RBS. Sample load-lock system was added to our existing setup to enable us to quickly insert a sample holder with frozen hydrated tissue samples onto a cold goniometer head cooled with liquid nitrogen inside the measuring chamber.
Cryotome-cut slices of frozen hydrated plant samples were mounted between two thin silicon nitride foils and then attached to the sample holder. Sufficient thermal contact between silicon nitride foils and sample holder must be achieved, as well as between the sample holder and the cold goniometer head inside the measuring chamber to prevent melting of the samples. Matrix composition of frozen hydrated tissue is consisted mostly of ice. Thinning of the sample as well as water evaporation during high vacuum and proton beam exposure was inspected by the measurements with RBS and STIM method simultaneously with micro-PIXE.
For first measuring attempts a standard micro-PIXE configuration for tissue mapping was used with proton beam cross section of 1.2×1.2μm2 and a beam current of 100pA. The temperature of the cold goniometer head was kept below 130K throughout the entire proton beam exposure. First measurements of thin plant tissue samples in frozen hydrated state show minute sample degradation during the 10h period of micro-PIXE measurements.
The analysis of biological samples in frozen-hydrated state with micro-PIXE technique at Jozef Stefan Institute (JSI) nuclear microprobe has matured to a point that enables us to measure and examine ...frozen tissue samples routinely as a standard research method. Cryotome-cut slice of frozen-hydrated biological sample is mounted between two thin foils and positioned on the sample holder. The temperature of the cold stage in the measuring chamber is kept below 130K throughout the insertion of the samples and the proton beam exposure. Matrix composition of frozen-hydrated tissue is consisted mostly of ice. Sample deterioration during proton beam exposure is monitored during the experiment, as both Elastic Backscattering Spectrometry (EBS) and Scanning Transmission Ion Microscopy (STIM) in on-off axis geometry are recorded together with the events in two PIXE detectors and backscattered ions from the chopper in a single list-mode file. The aim of this experiment was to determine differences and similarities between two kinds of biological sample preparation techniques for micro-PIXE analysis, namely freeze-drying and frozen-hydrated sample preparation in order to evaluate the improvements in the elemental localisation of the latter technique if any. In the presented work, a standard micro-PIXE configuration for tissue mapping at JSI was used with five detection systems operating in parallel, with proton beam cross section of 1.01.0 mu m2 and a beam current of 100pA. The comparison of the resulting elemental distributions measured at the biological tissue prepared in the frozen-hydrated and in the freeze-dried state revealed differences in elemental distribution of particular elements at the cellular level due to the morphology alteration in particular tissue compartments induced either by water removal in the lyophilisation process or by unsatisfactory preparation of samples for cutting and mounting during the shock-freezing phase of sample preparation.
•Deuterium retention measured for the first time in tungsten samples simultaneously damaged by high energy W ions and loaded by D atoms.•Synergistic effects between damage creation and presence of ...hydrogen were observed.•Increased D retention obtained for simultaneous damaging and D exposure as compared to sequential damaging at high temperatures.•Competition between defect annihilation and defect stabilization with D was observed.•Thermal D de-trapping is the dominant process at high temperatures.
Deuterium retention was for the first time measured in tungsten samples simultaneously irradiated by W ions and exposed to D atoms at five different temperatures from 450K to 1000K. In order to obtain information on the defect concentration, samples were afterwards exposed to D atoms at 600K to populate the created defects. The results were compared to different sequential damaging/exposure experiments. Synergistic effects were observed, namely, higher D concentrations were found in the case of simultaneous damaging and D-atom loading as compared to sequential damaging at elevated temperatures and populating the defects afterwards. However, the deuterium retention is still lower as compared to sequential damaging at room temperature and post-damaging annealing. The observations are explained by stabilization of defects by the presence of solute hydrogen in the bulk that would annihilate at high temperatures without the presence of hydrogen. Results of simultaneous W-ion damaging and D exposure at elevated temperatures were also compared to a sequential experiment of W-ion damaging at room temperature and then D-atom loading at high temperatures showing that thermal D de-trapping dominates deuterium retention at high temperatures.
•Production of stable tritiated sample.•Detection of reaction products from nuclear reaction between tritium and 3-helium.•Establishment of a new nuclear reaction analyzing method for tritium ...detection via 3-helium beam.•Review of the existing literature on the nuclear reaction between 3He and 3H.
A solid thick tritiated W sample was produced in order to probe the efficiency of detecting tritium via 3He ion beam using nuclear reactions analysis (NRA). Extensive literature search showed that there were only a few measurements done more than sixty years ago using the reaction with 3He. Their aim was mainly to measure the absolute cross section of the reaction. In order to use this reaction as an analysing tool for low level radioactive waste we need the differential cross section at certain angles. Using a thick tritiated W sample we measured the NRA signal in the 3He energy range from 0.7 MeV to 5.1 MeV and we have detected reaction products with energies between 6.5 MeV and 9.75 MeV that were not present on a deuterated W sample prepared in the same manner. This NRA signal proved to be due to deuterium and protons coming from the nuclear reaction between tritium and 3He. The detection signal increased with 3He energy up to 3.4 MeV and decreased with energy at the highest beam energies. At higher energies particles from W and target impurities start to disturb the measurement. Their origin might be due to other nuclear reactions, for example between 3He and W or 3He with 13C or 14N.
► Different multilayer (Ni/Ti) structures were modified by picoseconds Nd:YAG laser. ► Laser-induced alloying was achieved within the heat affected zone (HAZ) of the sample. ► Surface segregation of ...titanium was followed by formation of thin TiO2 film. ► Ripple structures on the surfaces of the 5- and 10-bilayered samples were recorded.
Laser-induced alloying effects on the composition and structure of different Ni/Ti multilayer structures were studied. Thin films composed of one, five, and ten (Ni/Ti) bilayers were deposited by DC ion sputtering on (100) Si wafers. Laser irradiations were performed by 150ps pulses of a Nd:YAG laser operating at 1064nm. The samples were characterized by Rutherford backscattering spectrometry (RBS), Auger electron spectroscopy (AES), X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). At a laser fluence of 0.9Jcm−2, interaction between Ni and Ti layers was initiated, and NiTi alloy formed in 5- and 10-bilayered samples. Progressed alloying was achieved at a laser fluence of 1.2Jcm−2. The alloy was formed mostly within the heat affected zone (HAZ) of the sample. Surface segregation of titanium was followed by formation of a 25nm thin TiO2 film on the surface of the multilayered structures. In addition, parallel periodic surface structures on the surfaces of the 5- and 10-bilayered samples were clearly recorded. Their period in the case of the 5-bilayered system (0.77μm) agrees very well with the predictions of the common theory, whereas, in the case of the 10-bilayered system, two periods of such structures are observed (1.43μm and 0.4μm), and none of them coincides with the prediction.
This paper presents an analysis of the carbon–deuterium circulation and the resulting balance in Tore Supra over the period 2002–2007. Carbon balance combines the estimation of carbon gross erosion ...from spectroscopy, net erosion and deposition using confocal microscopy, lock-in thermography and SEM, and a measure of the amount of deposits collected in the vacuum chamber. Fuel retention is determined from post-mortem (PM) analyses and gas balance (GB) measurements. Special attention was paid to the deuterium outgassed during the nights and weekends of the experimental campaign (vessel under vacuum, Plasma Facing Components at 120°C) and during vents (vessel at atmospheric pressure, PFCs at room temperature). It is shown that this outgassing is the main process reconciling the PM and GB estimations of fuel retention, closing the coupled carbon–deuterium balance. In particular, it explains why the deuterium concentration in deposits decreases with increasing depth.
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