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Boudreault, Ghislain. "Accurate ion beam analysis". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/844001/.
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This thesis primarily deals with accuracy obtainable when using IBA (Ion Beam Analysis) techniques to characterize materials. RBS (Rutherford Backscattering Spectrometry) is the main technique used, together with EBS (Elastic Backscattering Spectrometry), ERDA (Elastic Recoil Detection Analysis) and NRA (Nuclear Reaction Analysis). An exhaustive literature review on these analytical methods is made in connection with accuracy issues such as stopping powers and multiple scattering. The experimental set-ups and procedures are described, with emphasis laid on critical aspects of work where the highest accuracy is required. The instrumentation for dosimetry on ion implanters is first estabhshed at the 1% level for high-dose heavy implants in silicon. A new parameterisation of He stopping power in Si is used, and this latter material, via the surface yield, is used as a calibration standard. A precision (standard uncertainty) in the determination of implantation doses by RBS is conclusively demonstrated at 1.5%. The IBA DataFurnace code is validated for such accurate analysis, which can now be made routinely and rapidly. The certified Sb sample IRMM-302/BAM-L001, which has a certification of 0.6% traceable to the international standard of weight in Paris, is measured, and more importantly this measurement demonstrates the reliability of the stopping power parameterisation at 1.4%. Using conventional ERDA, the H dose of an amorphised Si wafer, implanted with 6-keV H+ ions, is found to be 57.8(1.0)x1015 at/cm2, which is a 1.8% standard uncertainty. The estimated combined uncertainty of this measurement is ~6%, and this mainly comes from the determination of the ERDA solid angle by using standard Kapton. The Kapton composition is carefully determined using RBS. The RBS solid angle is obtained using the amorphised silicon surface yield as a calibration standard as in the dosimetry analysis mentioned above. The ERDA H absolute dose obtained is compared with the results from other participants from all over the world in a Round Robin exercise, which includes measurements by using both He-ERDA and HI-ERDA (Heavy Ion-ERDA) together using various detectors. The results from each participant are given and compared. The overall absolute dose obtained of the implant is 57.0(1.2)x1015 H/cm2, and this represents an inter-lab reproducibility of 2.2% (standard uncertainty). Unstable surface hydrogen contamination was observed, and this surface peak was resolved by some of the methods. This implant can now be used as a standard for quantitative analysis of hydrogen. Low-fluorine content SiO2:F films are analysed by RBS for absolute fluorine concentration determination. Prior to the RBS analysis, the uniformity of the films and stability of F under beam irradiation is investigated. Because the RBS is not very sensitive to F and the F signal has a large matrix background, an internally consistent method of data handling, which enables the relative collected charge to be determined very precisely for the spectra from different samples, is developed. This method has as a parameter the F content, which is then extracted iteratively. A F concentration of 10 at% is determined with an estimated uncertainty of 10% (one percentage point, i.e. 10 +/- 1%). The O stopping powers are found to be the main factor governing the accuracy of the absolute determination of the F content. All the other uncertainties add up to only ~1%. The elemental composition of residual deposits from an ion implanter is thoroughly investigated using several complementary analytical methods, namely, RBS, BBS and NRA. Preliminary SEM/EDAX results are used as a guide. Depth profiles of such non-homogeneous, non-fiat and brittle samples are obtained, which give an indication of the concentration of each element present. From this complete IBA elemental study, some unprecedented light is brought on both the history of the implanter and the way in which these deposits are formed. Such an investigation is essential for a better understanding and the development/miniaturisation of semiconductors as it impressively pushes the boundaries of accuracy obtainable in IBA material characterisation.
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Müggenburg, Jan. "Ion beam analysis of metallic vanadium superlattices : Ion beam analysis of metallic vanadium superlattices". Thesis, Uppsala universitet, Tillämpad kärnfysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328067.
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Messerly, Michael Joseph. "Ion-beam analysis of optical coatings". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184273.
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Rutherford backscattering spectrometry (RBS) is shown to be an elegant, powerful tool for the chemical characterization of optical coatings. RBS studies of several thin film materials are presented to illustrate the technique's unique abilities, and to show how RBS is best exploited in investigations of thin film stoichiometry and diffusion. The text begins with an introduction to optical coatings and the practical problems encountered in their implementation. The basic principles of RBS are discussed, and the technique is compared to other popular surface analysis tools. The introductory material concludes with a chapter devoted to specific techniques for RBS data and error analysis, including the derivation of a simple formula for determining the optimum thickness of multi-element samples. The accurate stoichiometric measurements provided by RBS give new insights into the chemical structure of ion-bombarded MgF₂ coatings. The analysis shows that lightly-bombarded coatings contain a small oxygen fraction (< 6%), and the absence of this oxygen in opaque, heavily-bombarded samples implies the oxygen compensates for fluorine deficiencies and is therefore an essential ingredient for transparent films. This beneficial oxygen appears to diffuse into the coatings along columnar voids, and the implied compromise between packing density and transparency is discussed. The final chapter takes advantage of the nondestructive depth-profiles provided by RBS. We present the first direct experimental verification of the interfacial oxide layer responsible for the superior adhesion of aluminum to glass, and show that contrary to popular belief, the layer is not an artifact of oxygen adsorbed during the aluminum's evaporation. We then discuss the diffusion of copper through silver films, and show that the migration is enhanced by exposure to the RBS probe beam. Finally, we consider the diffusion of carbon, from graphite substrates, into the voids of porous coatings during the RBS measurements. This effect, like the enhanced copper diffusion, is consistent with a low temperature, measurement-induced anneal; however, we show that the migrant carbon does not alter the chemical structure of the coatings, but instead serves as a convenient, non-intrusive indicator of film porosity.
4
Gauntlett, F. E. "Novel applications of ion beam analysis techniques". Thesis, University of Surrey, 2009. http://epubs.surrey.ac.uk/842938/.
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Ion beam analysis (IBA) has been used as a powerful tool for studying materials for many years. Depending on the specific experimental design, IBA techniques can provide a non-destructive means of analysing samples to obtain such information as the elements or isotopes present and diffusion or depth profiles. Ion beam analysis has the ability to keep up with the rapid progress in new materials both as technology improves and as scientists have the creativity to develop existing and new techniques. Many different types of IBA exist. The experiments reported in this thesis were carried out using backscattering of the beam ions, ion induced X-ray emission, and ion induced nuclear reactions. The two experimental projects involved the use of modem cadmium-telluride detectors, including a unique array of CdZnTe detectors. The subsidiary project investigated using nuclear reaction measurements to study moisture diffusing into epoxy resin bonded with aluminium. Current standard techniques cannot measure diffusion profiles directly, resulting predictions rely on assumptions as to the particular mode of moisture migration. I have shown that the ion beam analysis technique can be applied to directly study moisture diffusion profiles parallel and perpendicular to the interfacial region whilst the bond remains intact. Further use of the technique would be of importance in studying the effect of moisture on bond integrity in automotive and aerospace industries - this would result in better predictions of the longevity of adhesive joints. For the main experiment, novel ion beam methods were developed to characterise, for the first time non-destructively, gold flecks dispersed within low density foam cylinders. The techniques allow the measurement of both the mass of gold in the cylinders and the average size of the individual gold flecks. Several different problems not previously encountered in ion beam analyses have been addressed and understood.
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Shearmur, Thomas E. "Ion beam analysis of diffusion in polymers". Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/844449/.
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With the rapid spread in use of polymers the study of diffusion in them is becoming increasingly important. For a number of industrial processes diffusion coefficients and elemental distributions need to be quantified precisely. From a more scientific approach accurate models need to be devised to describe the various diffusion mechanisms involved as well as the concentration and temperature dependencies of the diffusion coefficients. Using ion beam analysis techniques (Rutherford Backscattering and Nuclear Reaction Analysis) three systems were studied. The first was an industrially relevant system of relatively small dye molecules diffusing into a number of different polymer matrices. For fixed diffusion settings, diffusion coefficients were measured and found to correlate with the matrix glass transition temperatures. Surface dye concentrations, on the other hand, were independent of matrix properties. The other two systems studied involved polymer interdiffusion. Based on different assumptions, two contradictory theories have been developed to describe the concentration dependence of the mutual diffusion coefficient; the 'slow' and 'fast' theories. In one system, blends of low molecular weight (unentangled) polystyrene and poly(methyl methacrylate) our data followed the 'slow' theory at low temperatures and the 'fast' theory at high temperatures. An equation describing the concentration dependence of the mutual diffusion coefficient at all intermediate annealing temperatures (hence linking the 'slow' and 'fast' theories) was developed and found to describe the data accurately. In the second system, blends of entangled poly(methyl methacrylate) of several molecular weights, the mutual diffusion coefficient was found to follow the 'fast' theory at all studied temperatures. In all three systems the temperature dependence of the tracer diffusion coefficients of the various components were accurately described by the semi-empirical equations of the Free Volume theory.
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Healy, M. J. F. "The development of MeV ion beam analysis techniques". Thesis, Cranfield University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403621.
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Jenneson, P. M. "Ion beam analysis of molecular diffusion in heterogeneous materials". Thesis, University of Surrey, 1998. http://epubs.surrey.ac.uk/844259/.
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Scanning ion micro-beam analysis has been used to determine the diffusion of molecules in materials with a combination of high spatial resolution and concentration sensitivity not possible with other analytical techniques. The ion beam analysis apparatus and techniques available at the University of Surrey are described. Methodologies have been devised to determine the scanning micro-beam line scan size and the diameter of the beam spot. Adaptations to the micro-beam line hardware have been proposed with the design of a novel form of none interrupting beam current monitor utilising a transmission Faraday cup and charge collection from the object aperture. Micro-Nuclear Reaction Analysis (NRA) has been used for the first time to resolve the location and concentration of a hydrocarbon molecule in a biological matrix. Deuterated molecules (a surfactant and a hair conditioning agent) were imaged in perm damaged and undamaged hair fibres. Natural deuterium levels were ascertained with reference to a virgin hair fibre. Profiles of chlorine diffusing into cement paste blends have been determined using micro-Particle Induced X-ray Emission (PIXE). The profiles were fitted with a semi-infinite model of Fickian diffusion. The analysis was combined with micro-NRA to simultaneously profile the aqueous carrier (deuterium oxide) with the diffusing chlorine. A combination of micro-PIXE and micro-NRA has been used for the first time to image the ingress of water (deuterium oxide) and subsequent redistribution of drug in a polymeric drug release system. The two dimensional distributions of water, drug, and polymeric matrix are statistically correlated.
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Chaffee, Kevin Paul. "Ion beam analysis of diffusion in diamondlike carbon films". Case Western Reserve University School of Graduate Studies / OhioLINK, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=case1055777288.
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Tucker, Thomas Marshall. "Three dimensional measurement data analysis in stereolithography rapid prototyping". Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17082.
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Smith, Richard W. "A study of small molecule ingress into planar and cylindrical materials using ion beam analysis". Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390579.
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Murphy, Peter. "Ion beam analysis : a novel study of diffusion in ionic polymers". Thesis, University of Surrey, 1990. http://epubs.surrey.ac.uk/844203/.
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An ion-beam technique based on the nuclear reaction d(3He,p) 4He has been applied to measurements of polymer interdiffusion. A diffused bilayer of deuterated polystyrene and unmodified polystyrene is analysed by a beam of 3He ions and a concentration-profile of deuterium is extracted by analysis of the energy-spectrum of the emitted energetic protons. This technique can be used to measure diffusion over several microns with a depth-resolution of 20 nm. Reptation has been confirmed as the mechanism governing polymer self-diffusion over the molecular weight range 90,000 to 1,800,000. The 3He-d method has also been used to study mechanisms of diffusion in ionomers, a class of polymers containing pendant ionic groups. The effect of ionic concentration on diffusion shows that the critical concentration for the formation of diffusion-inhibiting ionic aggregates lies in the range 2.8 - 5 weight % of ionic material. Ionomers with concentrations below this range diffuse by reptation at an effective temperature equal to the difference between the annealing temperature and the glass-transition temperature.
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Barapatre, Nirav. "Application of Ion Beam Methods in Biomedical Research". Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-126262.
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The methods of analysis with a focused ion beam, commonly termed as nuclear microscopy, include quantitative physical processes like PIXE and RBS. The element concentrations in a sample can be quantitatively mapped with a sub-micron spatial resolution and a sub-ppm sensitivity. Its fully quantitative and non-destructive nature makes it particularly suitable for analysing biological samples. The applications in biomedical research are manifold.
The iron overload hypothesis in Parkinson\\\'s disease is investigated by a differential analysis of human substantia nigra. The trace element content is quantified in neuromelanin, in microglia cells, and in extraneuronal environment. A comparison of six Parkinsonian cases with six control cases revealed no significant elevation in iron level bound to neuromelanin. In fact, a decrease in the Fe/S ratio of Parkinsonian neuromelanin was measured, suggesting a modification in its iron binding properties.
Drosophila melanogaster, or the fruit fly, is a widely used model organism in neurobiological experiments. The electrolyte elements are quantified in various organs associated with the olfactory signalling, namely the brain, the antenna and its sensilla hairs, the mouth parts, and the compound eye. The determination of spatially resolved element concentrations is useful in preparing the organ specific Ringer\\\'s solution, an artificial lymph that is used in disruptive neurobiological experiments.
The role of trace elements in the progression of atherosclerosis is examined in a pilot study. A differential quantification of the element content in an induced murine atherosclerotic lesion reveals elevated S and Ca levels in the artery wall adjacent to the lesion and an increase in iron in the lesion. The 3D quantitative distribution of elements is reconstructed by means of stacking the 2D quantitative maps of consecutive sections of an artery.
The feasibility of generating a quantitative elemental rodent brain atlas by Large Area Mapping is investigated by measuring at high beam currents. A whole coronal section of the rat brain was measured in segments in 14 h. Individual quantitative maps of the segments are pieced together to reconstruct a high-definition element distribution map of the whole section with a subcellular spatial resolution. The use of immunohistochemical staining enhanced with single elements helps in determining the cell specific element content. Its concurrent use with Large Area Mapping can give cellular element distribution maps.
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Zorman, Christian Aaron. "Annealing of diamond and diamondlike carbon films: An ion beam analysis study". Case Western Reserve University School of Graduate Studies / OhioLINK, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1057697009.
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Christopher, Matthew E. "Development of ion beam analysis methods for the characterisation of gunshot residue". Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.581802.
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This thesis investigates the feasibility of using ion beam analysis (IBA) techniques for the characterisation of gunshot residue (GSR) in forensic casework. GSR-is an important type of trace evidence used to link suspects to shooting incidents. The current forensic procedure for GSR analysis utilises scanning electron microscopy with energy dispersive X -ray spectroscopy (SEM-EDS), but this lacks sensitivity to important trace elements when compared with IBA. In this thesis, the development of a new protocol for GSR analysis by IBA is described, including a robust particle relocation method, an efficient spectral fitting process and the implementation of a background subtraction procedure. Canonical discriminant function analysis (CDP A) is employed to demonstrate the ability of IBA to discriminate between different brands of ammunition in a way not currently possible using existing GSR casework methodologies. A database of results for GSR particles collected from cartridge cases and hands is presented along with a discussion as to how it would be best utilised in a casework scenario. An investigation into how IBA can be applied to lead-free ammunitions is also presented. These ammunitions are known to produce particles that are problematic for forensic examiners to positively identify as being GSR. IBA is shown to increase the evidential value of such particles due to the higher sensitivity of IBA when compared with SEM-EDS. IBA is shown to offer improved discrimination between all types of ammunition using methods that would not require any alteration to well- established sample collection and preparation procedures.
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Franich, Rick, i rick franich@rmit edu au. "Monte Carlo Simulation of Large Angle Scattering Effects in Heavy Ion Elastic Recoil Detection Analysis and Ion Transmission Through Nanoapertures". RMIT University. Applied Sciences, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080212.121837.
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Heavy Ion Elastic Recoil Detection Analysis (HIERDA) is a versatile Ion Beam Analysis technique well suited to multi-elemental depth profiling of thin layered structures and near-surface regions of materials. An existing limitation is the inability to accurately account for the pronounced broadening and tailing effects of multiple scattering typically seen in HIERDA spectra. This thesis investigates the role of multiple large angle scattering in heavy ion applications such as HIERDA, and seeks to quantify its contribution to experimental output. This is achieved primarily by the development of a computer simulation capable of predicting these contributions and using it to classify and quantify the interactions that cause them. Monte Carlo ion transport simulation is used to generate simulated HIERDA spectra and the results are compared to experimental data acquired using the Time of Flight HIERDA facility at the Australian Nuclear Science and Technology Organisat ion. A Monte Carlo simulation code was adapted to the simulation of HIERDA spectra with considerable attention on improving the modelling efficiency to reduce processing time. Efficiency enhancements have achieved simulation time reductions of two to three orders of magnitude. The simulation is shown to satisfactorily reproduce the complex shape of HIERDA spectra. Some limitations are identified in the ability to accurately predict peak widths and the absolute magnitude of low energy tailing in some cases. The code is used to identify the plural scattering contribution to the spectral features under investigation, and the complexity of plurally scattered ion and recoil paths is demonstrated. The program is also shown to be useful in the interpretation of overlapped energy spectra of elements of similar mass whose signals cannot be reliably separated experimentally. The effect of large angle scattering on the transmission of heavy ions through a nano-scale aperture mask, used to collimate an ion beam to a very small beam spot, is modelled using a version of the program adapted to handle the more complex geometry of the aperture mask. The effectiveness of nano-aperture collimation was studied for a variety of ion-energy combinations. Intensity, energy, and angular distributions of transmitted ions were calculated to quantify the degree to which scattering within the mask limits the spatial resolution achievable. The simulation successfully predicted the effect of misaligning the aperture and the beam, and the result has subsequently been observed experimentally. Transmitted ion distributions showed that the higher energy heavier ions studied are more effectively collimated than are lower energy lighter ions. However, there is still a significant probability of transmission of heavy ions with substantial residual energy beyond the perimeter of the aperture. For the intended application, ion beam lithography, these ions are likely to be problematic. The results indicate that medium energy He ions are the more attractive option, as the residual energy of scattered transmitted ions can be more readily managed by customising the etching process. Continuing research by experimentalists working in this area is proceeding in this direction as a result of the conclusions from this work.
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Kerckhove, Diane G. de. "The design, implementation and applications of a beam rocking system for a nuclear microprobe". Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326002.
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Manuel, Jack Elliot. "Design, Construction, and Application of an Electrostatic Quadrupole Doublet for Heavy Ion Nuclear Microprobe Research". Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1062819/.
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A nuclear microprobe, typically consisting of 2 - 4 quadrupole magnetic lenses and apertures serving as objective and a collimating divergence slits, focuses MeV ions to approximately 1 x 1 μm for modification and analysis of materials. Although far less utilized, electrostatic quadrupole fields similarly afford strong focusing of ions and have the added benefit of doing so independent of ion mass. Instead, electrostatic quadrupole focusing exhibits energy dependence on focusing ions. A heavy ion microprobe could extend the spatial resolution of conventional microprobe techniques to masses untenable by quadrupole magnetic fields. An electrostatic quadrupole doublet focusing system has been designed and constructed using several non-conventional methods and materials for a wide range of microprobe applications. The system was modeled using the software package "Propagate Rays and Aberrations by Matrices" which quantifies system specific parameters such as demagnification and intrinsic aberrations. Direct experimental verification was obtained for several of the parameters associated with the system. Details of the project and with specific applications of the system are presented.
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Young, Joshua Michael. "Synthesis, Modification, and Analysis of Silicate Cosmic Dust Analogues Using Ion-Beam Techniques". Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707354/.
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Silicates analogous to cosmic dust were synthesized, modified, and analyzed utilizing ion-beam techniques with Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD). Silicate dust is a common constituent in interstellar space, with an estimated 50% of dust produced in the stellar winds of M class Asymptotic Giant Branch (AGB) stars. Silicate dust acts as a surface upon which other chemicals may form (water ice for example), increasing significance in the cosmochemistry field, as well as laboratory astrophysics. Silicate formation in the stellar winds of AGB stars was simulated in the laboratory environment. Three sequential ion implantations of Fe-, MgH2-, and O- with thermal annealing were used to synthesize a mixture appropriate to silicate dust in the surface layers of a p-type Si substrate. Post implantation He+ irradiation was shown to preferentially induce crystalline formation in the analogue prior to thermal annealing. This effect is believed to originate in the ion-electron interaction in the Si substrate. The effects of ionization and ion energy loss due to electronic stopping forces is believed to precipitate nucleation in the amorphous media. For annealing temperatures of 1273 K, predominant quartz formation was found in the substrate, whereas lower annealing temperatures of 1000 K formed enstatite without post-implantation He+ irradiation, and olivine with He+ irradiation. Post annealed crystalline phase modification was investigated via x-ray diffraction and elemental compositions were investigated utilizing RBS. Finally, the interdiffusion of Fe and Mg at temperatures of 900-1100 K was investigated with RBS, and activation energies for interdiffusion were extracted for the transition from amorphous to crystalline phase in the silicate analogues. Fe had an interdiffusion energy of 1.8 eV and Mg 1.5eV. The produced analogues have similar properties to those inferred from infrared spectroscopy of the stellar winds of M-class AGB stars with an oxygen-rich outflow. This work established a method of silicate production using ion beam modifications, explored He+ irradiation effects in the annealed structures, and derived interdiffusion activation energies for Fe and Mg in the amorphous structure. Grain sizes were <100 nm with the observed formation of quartz, enstatite, and olivine.
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Petersson, Per. "Ion Beam Analysis of First Wall Materials Exposed to Plasma in Fusion Devices". Doctoral thesis, Uppsala universitet, Jonfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-128875.
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One major step needed for fusion to become a reliable energy source is the development of materials for the extreme conditions (high temperature, radioactivity and erosion) caused by hot plasmas. The main goal of the present study is to use and optimise ion beam methods (lateral resolution and sensitivity) to characterise the distribution of hydrogen isotopes that act as fuel. Materials from the test reactors JET (Joint European Torus), TEXTOR (Tokamak Experiment for Technology Oriented Research) and Tore Supra have been investigated. Deuterium, beryllium and carbon were measured by elastic recoil detection analysis (ERDA) and nuclear reaction analysis (NRA). To ensure high 3D spatial resolution a nuclear microbeam (spot size <10 µm) was used with 3He and 28Si beams. The release of hydrogen caused by the primary ion beam was monitored and accounted for. Large variations in surface (top 10 µm) deuterium concentrations in carbon fibre composites (CFC) from Tore Supra and TEXTOR was found, pointing out the importance of small pits and local fibre structure in understanding fuel retention. At deeper depths into the CFC limiter tiles from Tore Supra, deuterium rich bands were observed confirming the correlation between the internal material structure and fuel storage in the bulk. Sample cross sections from thick deposits on the JET divertor showed elemental distributions that were dominantly laminar although more complex structures also were observed. Depth profiles of this kind elucidate the plasma-wall interaction and material erosion/deposition processes in the reactor vessel. The information gained in this thesis will improve the knowledge of first wall material for the next generation fusion reactors, concerning the fuel retention and the lifetime of the plasma facing materials which is important for safety as well as economical reasons.
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Padayachee, Jayanethie. "The application of Bayesian statistics and maximum entropy to Ion beam analysis techniques". Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/16143.
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Bibliography: pages 128-129.The elimination of some blurring property, such as the detector response function, from spectra has received a considerable amount of attention. The problem is usually complicated by the presence of noise in the data, and in general, there exists an infinite set of possible solutions which are consistent with the data within the bounds imposed by the noise. Such a problem is known, generally, as an ill-defined inverse problem. Many techniques have been developed in an attempt to solve inverse problems, for example the problem of deconvolution, but these techniques employ ad hoc modifications to solve different problems. Bayesian Statistics has been proved to be the only consistent method for solving inverse problems of the type where the information is expressed in terms of probability distributions. This dissertation presents results of applying the Bayesian formalism, together with the concepts of maximum information entropy and multiresolution pixons, to various inverse problems in ion beam analysis; The results of this method of deconvoluting Rutherford Backscattering Spectrometry (RBS) and Proton Induced X-ray Emission (PIXE) spectra are compared to the results from other deconvolution techniques, namely Fourier Transforms, Jansson's method and maximum entropy (MaxEnt) without pixons. All the deconvolution techniques show an improvement in the resolution of the RBS spectra but only the MaxEnt techniques show a significant improvement in the resolution of the PIXE spectra. The MaxEnt methods also produce physically acceptable results. The MaxEnt formalism was applied to the extraction of depth profiles from RBS and PIXE spectra and yielded good results. The technique was also used to deconvolute the beam profile from one-dimensional nuclear microprobe scans.
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Yuan, Hui. "3D morphological and crystallographic analysis of materials with a Focused Ion Beam (FIB)". Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0134/document.
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L’objectif principal de ce travail est d’optimise la tomographie par coupe sériée dans un microscope ‘FIB’, en utilisant soit l’imagerie électronique du microscope à balayage (tomographie FIB-MEB), soit la diffraction des électrons rétrodiffusés (tomographie dite EBSD 3D). Dans les 2 cas, des couches successives de l’objet d’étude sont abrasées à l’aide du faisceau ionique, et les images MEB ou EBSD ainsi acquises séquentiellement sont utilisées pour reconstruire le volume du matériau. A cause de différentes sources de perturbation incontrôlées, des dérives sont généralement présentes durant l'acquisition en tomographie FIB-MEB. Nous avons ainsi développé une procédure in situ de correction des dérives afin de garder automatiquement la zone d'intérêt (ROI) dans le champ de vue. Afin de reconstruction le volume exploré, un alignement post-mortem aussi précis que possible est requis. Les méthodes actuelles utilisant la corrélation-croisée, pour robuste que soit cette technique numérique, présente de sévères limitations car il est difficile, sinon parfois impossible de se fier à une référence absolue. Ceci a été démontré par des expériences spécifiques ; nous proposons ainsi 2 méthodes alternatives qui permettent un bon alignement. Concernant la tomographie EBSD 3D, les difficultés techniques liées au pilotage de la sonde ionique pour l'abrasion précise et au repositionnement géométrique correct de l’échantillon entre les positions d'abrasion et d’EBSD conduisent à une limitation importante de la résolution spatiale avec les systèmes commerciaux (environ 50 nm)3. L’EBSD 3D souffre par ailleurs de limites théoriques (grand volume d'interaction électrons-solide et effets d'abrasion. Une nouvelle approche, qui couple l'imagerie MEB de bonne résolution en basse tension, et la cartographie d'orientation cristalline en EBSD avec des tensions élevées de MEB est proposée. Elle a nécessité le développement de scripts informatiques permettant de piloter à la fois les opérations d’abrasion par FIB et l’acquisition des images MEB et des cartes EBSD. L’intérêt et la faisabilité de notre approche est démontrée sur un cas concret (superalliage de nickel). En dernier lieu, s’agissant de cartographie d’orientation cristalline, une méthode alternative à l’EBSD a été testée, qui repose sur l’influence des effets de canalisation (ions ou électrons) sur les contrastes en imagerie d’électrons secondaires. Cette méthode corrèle à des simulations la variation d’intensité de chaque grain dans une série d’images expérimentales obtenues en inclinant et/ou tournant l’échantillon sous le faisceau primaire. Là encore, la méthode est testée sur un cas réel (polycritsal de TiN) et montre, par comparaison avec une cartographie EBSD, une désorientation maximale d'environ 4° pour les angles d’Euler. Les perspectives d’application de cette approche, potentiellement beaucoup plus rapide que l’EBSD, sont évoquéesThe aim of current work is to optimize the serial-sectioning based tomography in a dual-beam focused ion beam (FIB) microscope, either by imaging in scanning electron microscopy (so-called FIB-SEM tomography), or by electron backscatter diffraction (so-called 3D-EBSD tomography). In both two cases, successive layers of studying object are eroded with the help of ion beam, and sequentially acquired SEM or EBSD images are utilized to reconstruct material volume. Because of different uncontrolled disruptions, drifts are generally presented during the acquisition of FIB-SEM tomography. We have developed thus a live drift correction procedure to keep automatically the region of interest (ROI) in the field of view. For the reconstruction of investigated volume, a highly precise post-mortem alignment is desired. Current methods using the cross-correlation, expected to be robust as this digital technique, show severe limitations as it is difficult, even impossible sometimes to trust an absolute reference. This has been demonstrated by specially-prepared experiments; we suggest therefore two alternative methods, which allow good-quality alignment and lie respectively on obtaining the surface topography by a stereoscopic approach, independent of the acquisition of FIB-SEM tomography, and realisation of a crossed ‘hole’ thanks to the ion beam. As for 3D-EBSD tomography, technical problems, linked to the driving the ion beam for accurate machining and correct geometrical repositioning of the sample between milling and EBSD position, lead to an important limitation of spatial resolution in commercial softwares (~ 50 nm)3. Moreover, 3D EBSD suffers from theoretical limits (large electron-solid interaction volume for EBSD and FIB milling effects), and seems so fastidious because of very long time to implement. A new approach, coupling SEM imaging of good resolution (a few nanometres for X and Y directions) at low SEM voltage and crystal orientation mapping with EBSD at high SEM voltage, is proposed. This method requested the development of computer scripts, which allow to drive the milling of FIB, the acquisition of SEM images and EBSD maps. The interest and feasibility of our approaches are demonstrated by a concrete case (nickel super-alloy). Finally, as regards crystal orientation mapping, an alternative way to EBSD has been tested; which works on the influence of channelling effects (ions or electrons) on the imaging contrast of secondary electrons. This new method correlates the simulations with the intensity variation of each grain within an experimental image series obtained by tilting and/or rotating the sample under the primary beam. This routine is applied again on a real case (polycrystal TiN), and shows a max misorientation of about 4° for Euler angles, compared to an EBSD map. The application perspectives of this approach, potentially faster than EBSD, are also evoked
22
King, Stanley W. "Mass transfer analysis of polyether sulfone and polyamide membranes modified by ion beam irradiation /". See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1083875419.
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Thesis (M.S.C.)--University of Toledo, 2004.Typescript. "A thesis [submitted] as partial fulfillment of the requirements of the Master of Science degree in Chemical Engineering." Bibliography: leaves 109-113.
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Kobayashi, Hajime. "Lattice location of impurities in ZnSe and GaN as studied by ion beam analysis". 京都大学 (Kyoto University), 2000. http://hdl.handle.net/2433/181171.
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King, Stanley Wayne. "Mass Transfer Analysis of Polyether Sulfone and Polyamide Membranes Modified by Ion Beam Irradiation". University of Toledo / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1083875419.
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Chowdhury, Alimul Islam. "Applications of nuclear magnetic resonance and ion beam analysis for the investigation of cement-mortar". Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368420.
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Rasera, Roy L. (Roy Louis). "Laser linking of metal interconnect : process considerations and failure analysis using focused ion beam milling". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/32180.
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Lin, Zhongtian. "A study of ion beam analysis techniques using non-Rutherford scattering, nuclear reactions and channeling". Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186711.
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Rutherford Backscattering Spectrometry (RBS) is a very popular, fast, and non-destructive technique that has been used extensively for Ion Beam Analysis (IBA). However, RBS with ⁴He⁺ ion beams, in many cases, is ineffective for light element analysis due to overlapping signals. This project is an attempt to develop special techniques using non-Rutherford elastic scattering, nuclear reactions and elastic scattering under channeling conditions for light element analysis in cases where regular RBS is ineffective. The ⁴He-N elastic scattering cross sections for He⁺ ion energies from 1750 KeV to 5000 KeV at a lab angle of 170.5° were measured. Non-Rutherford elastic backscattering of He⁺ from nitrogen near an energy of 3500 KeV was applied to improve mass resolution; an example is described resolving the signals from nitrogen and oxygen in a target. A narrow resonance at He energy of 3575 KeV (Γ = 4 ± 1 KeV) was used for nitrogen depth profiling. The (ɑ,p) nuclear reaction for nitrogen, boron and silicon analysis in thin films was investigated. The excitation functions for the reactions at a lab angle of 135° were measured. The ¹⁴N(ɑ,p₀) ¹⁷O and ¹⁰B(ɑ,p) ¹³C reactions were used for nitrogen and boron content determination in thin films in cases where regular RBS is ineffective because of signal interference. The resonance in the ²⁸Si(ɑ,p)³¹ reaction near He ion energy of 3875 KeV was used to determine the thickness of silicon backed films. The (p,ɑ) nuclear reactions for boron and fluorine analysis in thick targets was investigated. The ¹¹B(p,ɑ₀) ⁸Be and ¹⁹F(p,ɑ₀) ¹⁶O reactions were applied to quantify boron and fluorine in thick targets. A technique of non-Rutherford backscattering combined with channeling was used for quantifying carbon and silicon in a SiₓC overlayer on a single crystalline Si substrate. The He-C non-Rutherford scattering enhanced the backscattering from carbon and the channeling condition improved the signal-to-background ratio. An example of use of this technique for determination of a small dose of carbon implanted in a single Si crystal is also presented to show the sensitivity of the measurement.
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Kuzema, P. O., M. Ya Dovzhyk i O. S. Kuzema. "Main Stages of Development and Recent Advances of Mass Spectrometry". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42625.
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It has been presented the review and analysis of the main evolution stages of one of the most efficient methods for investigation of composition and properties of substances – mass spectrometry. The advantages and application area of the method were described, as well as physical and technical peculiarities of the devices for its realization were considered.
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Giordani, Andrew J. "A Fundamental Study on the Relocation, Uptake, and Distribution of the Cs⁺ Primary Ion Beam During the Secondary Ion Mass Spectrometry Analysis". Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/64998.
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Combining cesium (Cs) bombardment with positive secondary molecular ion detection (MCs+) can extend the analysis capability of Secondary Ion Mass Spectrometry (SIMS) from the dilute limit (<1%) to matrix elements. The MCs+ technique has had great success in quantifying the sample composition of III-V semiconductors as well as dopants and/or impurities; however, it has been less effective at reducing the matrix effect for IV compounds, particularly Si-containing compounds, due to Cs overloading at the surface during the analysis from the Cs primary ion beam. The Cs overloading issue is attributable to the mobility and relocation of the implanted Cs to the surface; this effect happens almost instantaneously. Once the surface is overloaded with Cs, the excess Cs begins to reneutralize the ionization Cs and, as a result, the MCs+ technique is ineffective at reducing the matrix effect.
This research provides new insights for improving the MCs+ technique and elucidating the Cs mobility. A combination of multiple experimental techniques and theoretical modeling was implemented to assess the Cs retention, up-take, and distribution differences between group III-V and IV materials. Early experiments revealed a temperature-dependent component of the Cs mobility, prompting an investigation of this phenomenon. Therefore, we designed, built, and installed a variable temperature stage for our SIMS with temperatures ranging from -150 to 300 C. This enabled us to study the temperature-dependent component of the Cs mobility and the effect it has on the secondary ion emission processes. Additionally, a method was devised to quantify the amount of neutralization and ionization due to the relocated Cs. The results allow for a more thorough understanding of the material dependence on the Cs+-sample interaction and the temperature component of the Cs mobility.Ph. D.
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Rihawy, Mohammed Salah. "In-vacuum and in-air ion beam analysis techniques for the investigation of diffusion in materials". Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/843215/.
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In-vacuo and in-air ion beam analysis techniques have been developed to investigate diffusion in materials at the University of Surrey 2MV Tandem accelerator. Following Energy calibration of the accelerator, two main systems were studied using these techniques. Lithium intercalation into thin films of vanadium pentoxide was investigated using both nuclear reaction analysis and backscattering spectrometry in-vacuo. Energy loss techniques were used for both proton backscattering and the reaction 7Li(p,alpha)4He. Simulated annealing software enabled both data sets to be analysed simultaneously to give the Li profile. An in-air scanning micro-PIXE technique was developed to investigate diffusion into cementitious materials. Internal and external normalisation methods for elemental diffusion studies have been developed, applied and compared. Both Chloride and Sulphate ingress in cement, mortars and concrete have been studied. Results were obtained both from samples prepared in the lab and from large core samples taken from concrete blocks exposed to a saline environment for 30 years. Additional studies were performed both to compare results from scanning micro-PIXE and micro-XRF techniques and to compare results from an abraded small core. Another application of the technique is the study of chloride and heavy element distributions in paste, mortar and brick samples before and after electrochemical extraction methodologies. A CdTe detector was used for the first time with an external beam, to detect Kalpha X-rays induced from the heavy elements.
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Seki, Toshio. "Nanoscale Observation and Analysis of Damage Formation and Annealing Processes in Ion Beam Interactions with Surfaces". Kyoto University, 2000. http://hdl.handle.net/2433/8950.
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学位授与年月日: 2000-03-23 ; 学位の種類: 新制・課程博士 ; 学位記番号: 1890For controlling ion beam processes at an atomic level, it is necessary to study the interaction between energetic ions and solid surfaces. This thesis aims to reveal the ion bombardment effects on surfaces and the process of annealing the damage caused by ion impacts. The formation, structure and extinction of surface defects created at high temperature were observed with a Variable Temperature Scanning Tunneling Microscope (VT-STM). A Si(111) 7x7 surface was irradiated with Xe ions and single ion impact traces of about 20 Å diameter were clearly observed with atomic resolution. In the range from 1 to 5 keV, the average size of the trace did not depend on the impact energy. When the sample was annealed at 400℃, the vacancies created in the subsurface by the impact started to diffuse toward the surface and appear on the surface, but the interstitial atoms generated together with the vacancies remained in the bulk. At 600℃, vacancy clusters were formed, whose size corresponded to the number of vacancies created near the surfaces. At 650℃, the interstitial atoms diffused and recombined with surface vacancies and the size of the vacancy cluster decreased with annealing time. When a Si(111) surface was irradiated with Ar cluster ions at 8 keV, the traces of a cluster ion impact showed a crater shape, with a diameter of about 80 Å. This indicates that cluster impact processes are quite different from a summation of separate monomer impacts. When the surface was annealed at 600℃ after irradiation, the outer rim of the crater has disappeared and the hemispherical damage in the target was removed, but the hole at the center of crater remained. On Highly Oriented Pyrolitic Graphite (HOPG) surfaces irradiated with carbon cluster of up to 70 atoms, large hills were observed. The impact site diameters were found to be proportional to cluster size for clusters of up to 10 atoms and increase discontinuously for cluster sizes above 10 atoms. This can be explained by considering that small affected areas overlap. This indicates that non-linear multiple collision effects occur only when a local area is instantaneously bombarded by more than 10 atoms. In order to reveal the role of ion bombardment during film formation, ion bombardment effects at each stage of film formation were investigated. After annealing of a Si(111) sample at 400℃, with Ge atoms deposited to a few A, the formation of many islands of Ge on that surface was observed. In order to physically change the shape of Ge islands by ion impacts, it is necessary to irradiate the surface so that the ratio of ions to deposited atoms is above 1/10. At this ion dose, the total number of defects is higher than that of deposited Ge atoms. When Ge islands on the Si(111) surface after Xe ion irradiation were annealed at 400℃, many small islands, vacancy clusters, and complicated steps were created. After annealing at 600℃, the islands either combined with the steps or became larger. The complex surface structure observed after Xe ion irradiation and thermal annealing can be caused by the appearance and surface migration of vacancies that were formed by Xe ion impacts. The Xe ion impacts can have a large effect on the film formation if samples are annealed. When the Si(111) surface was irradiated with Ar cluster ion after Ge islands formation, the large craters were found. This result indicates that Ar cluster ion impacts can physically change the shape of Ge islands with low ion dose. The cluster ion impacts can also have a large effect on the film formation even if samples are not annealed. Thus, the damage formation and annealing processes in ion beam interactions with surfaces can be analyzed with a VT-STM. The ion bombardment effects on surfaces and annealing process of surface defects are revealed at an atomic level.
Kyoto University (京都大学)
新制・課程博士
博士(工学)
甲第8325号
工博第1890号
新制||工||1165(附属図書館)
UT51-2000-F229
京都大学大学院工学研究科電子物性工学専攻
(主査)教授 山田 公, 教授 木村 健二, 助教授 高岡 義寛
学位規則第4条第1項該当
32
Liu, Bing. "Characterisation of Dust Particles Trapped in Silica Aerogels". Thesis, KTH, Fusionsplasmafysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-38828.
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This thesis involves the study of dust particles trapped in silica aerogel for fusion dust diagnostics purpose. The low velocity impact experiments are done by implanting predefined dust particles into silica aerogel by using a springpiston air gun. The impact experiment results show that the hypervelocity impact model may not suitable for describing the fusion characteristic dust particles. The samples made by impact experiment are analyzed by ion microbeam analysis methods: Rutherford backscattering spectrometry (RBS) and Particle-induced X-ray Emission spectrometry (PIXE). The elements of dust particles are well identified by the X-ray spectra. The X-ray maps clearly show the dust shape. RBS and NRA spectra of an individual particle or a specific region show the depth information of the trapped particles, which is useful for determining the dust velocities. For the interpretation of ion beam analysis result, simulation of dust particles for RBS and NRA are done. The accessible depth for ion beam analysis in silica aerogel can be several hundred micrometers, which is adequate for dust diagnostics.
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Agostinetti, Piero. "Methods for the Thermo-mechanical Analysis and Design of High Power Ion Sources". Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425025.
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The present doctorate thesis regards the major issues related to the thermo-mechanical analysis and design of high power ion sources. The activities were carried out in the following three areas:
1. Experimental activities on the existing ion sources.
2. Evaluation of the main operating parameters (plasma density, heat loads etc.) of the ITER Neutral Beam Injector (NBI) ion source.
3. Optimization of the thermo-mechanical design of the ITER NBI ion source, considering both the point of views of a good operating behaviour (in terms of ion current density and electrons-to-ions ratio) and a good reliability of the machine (in terms of structural verifications, low deformations and ability to control the operating parameters).
The main original contributions in the three fields have been respectively:
1. A new method for the post-processing of the calorimetric measurement on an ion source, able to precisely evaluate the heating power loads deposed on the various components of the ion source.
2. A new method for the evaluation of the damages given by sputtering inside an ion source.
3. A new Finite Element Method (FEM) technique especially developed for high performance cooling systems, that integrates non-linear CFD, thermal and structural analysis.
Moreover, the following themes, related to the analysis and design of a generic mechanical component, have been investigated and applied to the ion sources:
* The Decision Making methods, with a comparison between the main approaches and an application on the accelerator cooling system design.
* The Computational Fluid Dynamics analyses, with a comparison between the most sophisticated approaches, analytical formulas and experimental data, and an application to the ITER Neutral Beam Injector design.
* The Buckling analyses, with a comparison between different analytical and numerical approaches for the calculation of the buckling modes of a structure subjected to external pressure, and an application to the vacuum vessel of the ELISE facility.
The methods described on this doctorate thesis were developed during the design activities for the ITER Neutral Beam Test Facility at Consorzio RFX (Padova, Italy) and for the ELISE Facility at the Max-Planck-Institut für Plasmaphysik (Garching, Germany), supported by the European Communities under contracts of Association between EURATOM and ENEA, and carried out within the framework of the European Fusion Development Agreement.
Most of these methods can be used also for the analysis and design of a generic high heat flux component. In particular, they are suitable for the analysis and design of many components for the ITER experiment, for the demonstrative reactor DEMO and for the future commercial fusion reactors.
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Klingner, Nico. "Ionenstrahlanalytik im Helium-Ionen-Mikroskop". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-220036.
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Die vorliegende Arbeit beschreibt die Implementierung ionenstrahlanalytischer Methoden zur Charakterisierung der Probenzusammensetzung in einem Helium-Ionen-Mikroskop mit einem auf unter einen Nanometer fokussierten Ionenstrahl. Zur Bildgebung wird dieser im Mikroskop über Probenoberflächen gerastert und die lokale Ausbeute an Sekundärelektronen gemessen. Obwohl sich damit ein hoher topografischer Kontrast erzeugen lässt, lassen sich weder aus der Ausbeute noch aus der Energieverteilung der Sekundärelektronen verlässliche Aussagen zur chemischen Zusammensetzung der Probe treffen. Daher wurden in dieser Arbeit verschiedene ionenstrahlinduzierte Sekundärteilchen hinsichtlich ihrer Eignung für die Elementanalytik im Helium-Ionen-Mikroskop verglichen. Zur Evaluation standen der Informationsgehalt der Teilchen, deren Analysierbarkeit sowie deren verwertbare Ausbeute. Die Spektrometrie rückgestreuter Teilchen sowie die Sekundärionen-Massenspektrometrie wurden dabei als die geeignetsten Methoden identifiziert und im Detail untersucht. Gegenstand der Untersuchung waren physikalische Limitierungen und Nachweisgrenzen der Methoden sowie deren Eignung zum Einbau in ein Helium-Ionen-Mikroskop. Dazu wurden verschiedene Konzepte von Spektrometern evaluiert, erprobt und hinsichtlich ihrer Effizienz, Energieauflösung und Umsetzbarkeit im Mikroskop bewertet. Die Flugzeitspektrometrie durch Pulsen des primären Ionenstrahls konnte als die geeignetste Technik identifiziert werden und wurde erfolgreich in einem Helium-Ionen-Mikroskop implementiert. Der Messaufbau, die Signal- und Datenverarbeitung sowie vergleichende Simulationen werden detailliert beschrieben. Das Spektrometer wurde weiterhin ausführlich hinsichtlich Zeit-, Energie- und Massenauflösung charakterisiert. Es werden ortsaufgelöste Rückstreuspektren vorgestellt und damit erstmalig die Möglichkeit zur Ionenstrahlanalytik im Helium-Ionen-Mikroskop auf einer Größenskala von ≤ 60 nm aufgezeigt. Das Pulsen des primären Ionenstrahls erlaubt es zudem, die Technik der Sekundärionen-Massenspektrometrie anzuwenden. Diese Methode bietet Informationen zur molekularen Probenzusammensetzung und erreicht für einige Elemente niedrigere Nachweisgrenzen als die Rückstreuspektrometrie. Damit konnten erstmalig im Helium-Ionen-Mikroskop gemessene Sekundärionen-Massenspektren sowie die ortsaufgelöste Elementanalyse durch spektrometrierte Sekundärionen demonstriert werden. Die Ergebnisse dieser Arbeit sind in der Fachzeitschrift Ultramicroscopy Band 162 (2016) S. 91–97 veröffentlicht. Ab Oktober 2016 werden diese auch in Form eines Buchkapitels in dem Buch „Helium Ion Microscopy“, Springer Verlag Heidelberg zur Verfügung stehenThe present work describes the implementation of ion beam analysis methods in a helium-ion-microscope for the determination of sample compositions with a focused ion beam of < 1 nm size. Imaging in the microscope is realized by scanning the focused ion beam over the sample surface while measuring the local secondary electron yield. Although this procedure leads to a high topographical contrast, neither the yield nor the energy distribution of the secondary electrons deliver reliable information on the chemical composition of the sample. For this purpose, in this work different ion beam induced secondary particles were compared with respect to their suitability for the analysis of the chemical composition in the helium-ion-microscope. In particular the information content of the particles, their analysability and their yield were evaluated. As a result, the spectrometry of backscattered particles and the mass spectrometry of sputtered secondary ions were identified as the most promising methods and regarded in detail. The investigation focused on physical limitations and detection limits of the methods as well as their implementability into a helium-ion-microscope. Therefor various concepts of spectrometers were evaluated, tested and validated in terms of their efficiency, energy resolution and practicability in the microscope. Time-of-flight spectrometry by pulsing the primary ion beam could be identified as the most suitable technique and has been successfully implemented in a helium-ion-microscope. The measurement setup, signal processing and data handling as well as comparative simulations are described in detail. Further the spectrometer was characterized explicitly in terms of time, energy and mass resolution. Spatially resolved backscattering spectra will be shown demonstrating the feasibility of performing ion beam analysis in a helium-ion-microscope for the first time on a size scale of ≤ 60 nm. By pulsing the primary ion beam the technique of secondary ion mass spectrometry becomes automatically accessible. This method provides information on the molecular composition of samples and can reach higher detection limits than those from backscattering spectrometry. For the first time, in a helium-ion-microscope measured secondary ion mass spectra and spatially resolved elemental analysis by spectrometry of secondary ions, could be demonstrated. The results of this work are published 2016 in the scientific journal Ultramicroscopy, volume 162 on pages 91 to 971. In October 2016 there will be another publication as a book chapter in „Helium Ion Microscopy“ (publisher: Springer Verlag Heidelberg)
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Carter, Jesse James. "Analysis of a direct energy conversion system using medium energy helium ions". Texas A&M University, 2005. http://hdl.handle.net/1969.1/3790.
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A scaled direct energy conversion device was built to convert kinetic energy of
singly ionized helium ions into an electric potential by the process of direct conversion.
The experiments in this paper aimed to achieve higher potentials and higher efficiencies
than ever before. The predicted maximum potential that could be produced by the 150 kV
accelerator at the Texas A&M Ion Beam Lab was 150 kV, which was achieved with 92%
collection efficiency. Also, an investigation into factors affecting collection efficiency
was made. It was concluded that charge was being lost due to charge exchange occurring
near the surface of the target which caused positive target atoms to be ejected from the
face and accelerated away. Introducing a wire mesh near the face of the target with an
electric potential, positive or negative, which aimed to control secondary ion emissions,
did not have an effect on the collection efficiency of the system. Also, it was found that
the gas pressure inside the chamber did not have an effect on the collection efficiency.
The goal of achieving higher electric potentials and higher efficiencies than previous
direct conversion work was met.
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ITO, Toshimasa, Keisuke TANAKA, Yoshiaki AKINIWA, Takahiro ISHII i Yasuhiro MIKI. "X-Ray Study of Mechanical Properties of TiN Thin Films Coated on Steel by Ion Beam Mixing Method". The Japan Society of Mechanical Engineers, 2003. http://hdl.handle.net/2237/9182.
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Katrík, Peter [Verfasser], Dieter [Akademischer Betreuer] Hoffmann i Christina [Akademischer Betreuer] Trautmann. "Activation analysis of heavy ion accelerator constructing materials and validation of beam-loss criteria / Peter Katrík ; Dieter Hoffmann, Christina Trautmann". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1140586688/34.
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Back, Markus. "Investigation of the properties of thin films grown via sputtering and resistive thermal evaporation : an Ion Beam Analysis (IBA) study". Thesis, Uppsala universitet, Tillämpad kärnfysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-257506.
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In this project, thin films are being manufactured by different methods in a thin film deposition set-up and subsequently characterized. This is done in order to determine if the set-up is capable of producing films of sufficient quality to be used for research purposes in the ion physics group of the division of applied nuclear physics at Uppsala University. Both copper and silver films are manufactured by magnetron sputtering deposition. Copper films are also manufactured by evaporation deposition. Deposition is made on Si(001) substrates. The films are analyzed with Rutherford Backscattering Spectrometry (RBS) and Time of Flight- Elastic Recoil Detection Analysis (ToF-ERDA). Results show that the deposition rate of the set-up is much faster compared to the one provided by the manufacturer of the set-up. The purity of the films i.e. the concentrations of the contaminants are found to be in an acceptable range for research applications with an average oxygen contamination of I det här projektet produceras tunnfilmer med olika metoder i en uppställning för tunnfilmsdeposition och karaktäriseras sedan för att bedöma om maskinen är kapabel att producera filmer av tillräckligt bra kvalitet för att kunna användas i forskningssyften inom jonfysikgruppen på avdelningen för tillämpad kärnfysik på Uppsala Universitet. Både koppar och silverfilmer produceras med magnetronsputtring. Kopparfilmer produceras också med resistiv förångning. Deposition sker på Si(001)-substrat. Filmerna analyseras med Rutherford Backscattering Spectrometry (RBS) och Time of Flight- Elastic Recoil Detection Analysis (ToF-ERDA). Resultaten visar att depositionshastigheten för maskinen är snabbare än det som angetts av företaget som producerar maskinen. Renheten hos filmerna, dvs. koncentrationen av föroreningar, finnes vara inom en acceptabel nivå för forskningstillämpningar med en genomsnittlig syrekontamination på
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Barnard, Harold Salvadore. "Development of accelerator based spatially resolved ion beam analysis techniques for the study of plasma materials interactions in magnetic fusion devices". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87495.
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Thesis: Sc. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 214-218).
Plasma-material interactions (PMI) in magnetic fusion devices pose significant scientific and engineering challenges for the development of steady-state fusion power reactors. Understanding PMI is crucial for the develpment of magnetic fusion devices because fusion plasmas can significantly modify plasma facing components (PFC) which can be severely detrimental to material longevity and plasma impurity control. In addition, the retention of tritium (T) fuel in PFCs or plasma co-deposited material can disrupt the fuel cycle of the reactor while contributing to radiological and regulatory issues. The current state of the art for PMI research involves using accelerator based ion beam analysis (IBA) techniques in order to provide quantitative measurement of the modification to plasma-facing surfaces. Accelerated ~MeV ion beams are used to induce nuclear reactions or scattering, and by spectroscopic analysis of the resulting high energy particles (s', p, n, a, etc.), the material composition can be determined. PFCs can be analyzed to observe erosion and deposition patterns along their surfaces which can be measured with spatial resolution down to the -1 mm scale on depth scales of 10 - 100 pim. These techniques however are inherently ex-situ and can only be performed on PFCs that have been removed from tokamaks, thus limiting analysis to the cumulative PMI effects of months or years of plasma experiments. While ex-situ analysis is a powerful tool for studying the net effects of PMI, ex-situ analysis cannot address the fundamental challenge of correlating the plasma conditions of each experiment to the material surface evolution. This therefore motivates the development of the in-situ diagnostics to study surfaces with comparable diagnostic quality to IBA in order resolve the time evolution of these surface conditions. To address this fundamental diagnostic need, the Accelerator-Based In-Situ Materials Surveillance (AIMS) diagnostic [22] was developed to, for the first time, provide in-situ, spatially resolved IBA measurements inside of the Alcator C-Mod tokamak. The work presented in this thesis provided major technical and scientific contributions to the development and first demonstration AIMS. This included accelerator development, advanced simulation methods, and in-situ measurement of PFC surface properties and their evolution. The AIMS diagnostic was successfully implemented on Alcator C-Mod yielding the first spatially resolved and quantitative in-situ measurements of surface properties in a tokamak, with thin boron films on molybdenum PFCs being the analyzed surface in C-Mod. By combining AIMS neutron and gamma measurements, time resolved and spatially resolved measurements of boron were made, spanning the entire AIMS run campaign which included lower single null plasma discharges, inboard limited plasma discharges, a disruption, and C-Mod wall conditioning procedures. These measurements demonstrated the capability to perform inter shot measurements at a single location, and spatially resolved measurements over longer timescales. This demonstration showed the first in-situ measurements of surfaces in a magnetic fusion device with spatial and temporal resolution which constitutes a major step forward in fusion PMI science. In addition, an external ion beam system was implemented to perform ex-situ ion beam analysis (IBA) for components from Alcator C-Mod Tokamak. This project involved the refurbishment of a 1.7 MV tandem linear accelerator and the creation of a linear accelerator facility to provide IBA capabilities for MIT Plasma Science and Fusion Center. The external beam system was used to perform particle induced gamma emission (PIGE) analysis on tile modules removed after the AIMS measurement campaign in order to validate the AIMS using the well established PIGE technique. From these external PIGE measurements, a spatially resolved map of boron areal density was constructed for a section of C-Mod inner wall tiles that overlapped with the AIMS measurement locations. These measurements showed the complexity of the poloidal and toroidal variation of boron areal density between PFC tiles on the inner wall ranging from 0 to 3pm of boron. Using these well characterized ex-situ measurements to corroborate the in-situ measurements, AIMS showed reasonable agreement with PIGE, thus validating the quantitative surface analysis capability of the AIMS technique.
by Harold Salvadore Barnard.
Sc. D.
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Salamat, Cabanos Cerrone. "Molecular and Structural Analysis of Peanut Allergens and Development of a Peanut Variety Lacking Major Allergens by Heavy-ion Beam Irradiation". Kyoto University, 2011. http://hdl.handle.net/2433/142321.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第16123号
農博第1859号
新制||農||989(附属図書館)
学位論文||H23||N4593(農学部図書室)
28702
京都大学大学院農学研究科農学専攻
(主査)教授 裏出 令子, 教授 松村 康生, 教授 奥本 裕
学位規則第4条第1項該当
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Nigam, Mohit. "The Stopping of Energetic Si, P and S Ions in Ni, Cu, Ge and GaAs Targets". Thesis, University of North Texas, 2001. https://digital.library.unt.edu/ark:/67531/metadc3004/.
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Accurate knowledge of stopping powers is essential for these for quantitative analysis and surface characterization of thin films using ion beam analysis (IBA). These values are also of interest in radiobiology and radiotherapy, and in ion- implantation technology where shrinking feature sizes puts high demands on the accuracy of range calculations. A theory that predicts stopping powers and ranges for all projectile-target combinations is needed. The most important database used to report the stopping powers is the SRIM/TRIM program developed by Ziegler and coworkers. However, other researchers report that at times, these values differ significantly from experimental values. In this study the stopping powers of Si, P and S ions have been measured in Ni, Cu, Ge and GaAs absorbers in the energy range ~ 2-10 MeV. For elemental films of Ni, Cu and Ge, the stopping of heavy ions was measured using a novel ERD (Elastic Recoil Detection) based technique. In which an elastically recoiled lighter atom is used to indirectly measure the energy of the incoming heavy ion using a surface barrier detector. In this way it was possible to reduce the damage and to improve the FWHM of the detector. The results were compared to SRIM-2000 predictions and other experimental measurements. A new technique derived from Molecular Beam Epitaxy (MBE) was developed to prepare stoichiometric GaAs films on thin carbon films for use in transmission ion beam experiments. The GaAs films were characterized using X-ray Photoelectron Spectroscopy (XPS) and Particle Induced X-ray Emission (PIXE). These films were used to investigate the stopping powers of energetic heavy ions in GaAs and to provide data for the calculation of Bethe-Bloch parameters in the framework of the Modified Bethe-Bloch theory. As a result of this study, stopping power data are available for the first time for Si and P ions in the energy range 2-10 MeV stopping in GaAs absorbers.
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Holeňák, Radek. "Komplexní iontová analýza složení antikorozních vrstev". Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402577.
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Předložená diplomová práce se zabývá implementací metody rentgenové emisne indukované částicemi do experimentálního uspořádání za účelem doplnění rodiny metod založených na iontových technikách, tj. Rutherfordovy zpětné rozptylové spektrometrie, spektrometrie elastického zpětného rozptylu a analýzy detekce doby letu/energie elastického odrazu. Výhoda více-metodického přístupu je demonstrována na vrstvách ze slitin přechodných kovů obsahujících lehké prvky, kde samo-konzistentní analýza poskytuje výrazně zlepšené a přesné informace o stechiometrii, hloubkovém rozložení a tloušťce slitiny. Hmotnostní spektrometrie sekundárních iontů je použita pro porovnání a doplnění získaných výsledků.
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Aðalsteinsson, Sigurbjörn Már. "Study of rare-earth oxy-hydrides as candidates for photochromic materials". Thesis, Uppsala universitet, Tillämpad kärnfysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-396533.
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Kesler, Leigh A. (Leigh Ann). "Development and testing of an in situ method of ion beam analysis for measuring high-Z erosion inside a tokamak using an AIMS diagnostic". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121707.
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This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2019
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 157-163).
While many ex situ measurements exist to measure plasma-facing component (PFC) surfaces of materials extracted from tokamaks, developing a deeper understanding of the dynamics of erosion, redeposition, and fuel retention in these surfaces will require in situ measurements. A first-of-a-kind technique, Accelerator-Based In-Situ Materials Surveillance (AIMS), was developed for this purpose and first demonstrated on Alcator C-Mod to study divertor surfaces with shot-by-shot resolution [1]. However, the original AIMS methods are not applicable to studying the erosion of bulk, high-Z PFCs like molybdenum and tungsten. Thus, a new method of ion beam analysis (IBA) has been developed to expand the capabilities of AIMS to directly measure this high-Z bulk erosion. This new method, called DEA (Depth markers for Evaluating high-Z materials with AIMS), combines the traditional IBA technique of particle-induced gamma emission (PIGE) with implanted depth markers.
The implanted markers enable the study of bulk material by providing a reference to the surface that can be monitored for erosion and redeposition. Implanting the marker eliminates the need for specially-manufactured "marker tiles" formed by deposited layers that can delaminate and otherwise fail under operational conditions. Two variations of this method were developed: ex situ DEA (eDEA) and in situ DEA (iDEA). Both use PIGE spectroscopy with implanted markers, but they take advantage of different features in gamma production cross sections to analyze data. eDEA, which has shown promising results in ex situ analysis of materials exposed in a tokamak, can also be used to validate the use of depth markers. iDEA provides AIMS with the ability to measure in situ high-Z bulk erosion. As part of this thesis, the following ex situ experiments have been carried out to assess the viability of these techniques.
eDEA samples with implanted depth markers have been studied after plasma exposure on the Material and Plasma Evaluation System (MAPES) in the Experimental Advanced Superconducting Tokamak (EAST). Stability of the marker to temperature excursions was studied by exposing samples to temperatures from 200 to 1000C for times from 1 to 24 hours. iDEA samples were implanted at different depths to determine the sensitivity of the technique to depth. Two simulations were developed to allow interpretation of the experimental data and to test the sensitivity, with initial studies showing a match between predicted and experimental results. eDEA measured erosion of 42.0 23.5 nm on one sample exposed in EAST, and iDEA depth markers were located with 40 nm of accuracy. These results show that DEA, as a part of an AIMS experiment, has the appropriate resolution to monitor surfaces inside a tokamak for time-resolved bulk erosion.
by Leigh A. Kesler.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Nuclear Science and Engineering
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Castro, Olivier de. "Development of a Versatile High-Brightness Electron Impact Ion Source for Nano-Machining, Nano-Imaging and Nano-Analysis". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS468/document.
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Les nano-applications utilisant des faisceaux d'ions focalisés nécessitent des sources d'ions à haute brillance avec une faible dispersion en énergie (ΔE) ce qui permet une excellente résolution latérale et un courant d'ions suffisamment élevé pour induire des vitesses d'érosion raisonnables et des rendements élevés d'émission électronique et ionique. Les objectifs de cette thèse sont le développement d'une source d'ions basée sur l'impact électronique ayant une brillance réduite Br de 10³ – 10⁴ A m⁻² sr ⁻ ¹ V⁻ ¹, une dispersion en énergie ΔE ≲ 1 eV et un choix polyvalent d'ions. Le premier concept évalué consiste à focaliser un faisceau d'électrons à une énergie de 1 keV entre deux électrodes parallèles distant de moins d'un millimètre. Le volume d'ionisation « micrométrique » est formé au-dessus d'une ouverture d'extraction de quelques dizaines de µm. En utilisant un émetteur d'électrons LaB₆ et une pression de 0.1 mbar dans la région d'ionisation, Br est proche de 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ avec des tailles de source de quelques µm, des courants de quelques nA pour Ar⁺/Xe⁺/O₂ ⁺ et une dispersion en énergie ΔE < 0.5 eV. La brillance réduite Br est encore en dessous de la valeur minimum de notre objectif et la pression de fonctionnement très faible nécessaire pour l'émetteur LaB₆ ne peut être obtenue avec une colonne d'électrons compacte, donc ce prototype n'a pas été construit.Le deuxième concept de source d'ions évalué est basé sur l’idée d’obtenir un faisceau ionique à fort courant avec une taille de source et un demi-angle d’ouverture similaire aux résultats du premier concept de source, mais en changeant l’interaction électron-gaz et la collection des ions. Des études théoriques et expérimentales sont utilisées pour l’évaluation de la performance de ce deuxième concept et de son utilité pour les nano-applications basées sur des faisceaux d'ions focalisésHigh brightness low energy spread (ΔE) ion sources are needed for focused ion beam nano-applications in order to get a high lateral resolution while having sufficiently high ion beam currents to obtain reasonable erosion rates and large secondary electron/ion yields. The objectives of this thesis are: the design of an electron impact ion source, a reduced brightness Br of 10³ – 10⁴ A m⁻² sr⁻ ¹ V⁻ ¹ with an energy distribution spread ΔE ≲ 1 eV and a versatile ion species choice. In a first evaluated concept an electron beam is focussed in between two parallel plates spaced by ≲1 mm. A micron sized ionisation volume is created above an extraction aperture of a few tens of µm. By using a LaB₆ electron emitter and the ionisation region with a pressure around 0.1 mbar, Br is close to 2.10² A m⁻² sr ⁻ ¹ V ⁻ ¹ with source sizes of a few µm, ionic currents of a few nA for Ar⁺/Xe⁺/O₂ ⁺ and the energy spread being ΔE < 0.5 eV. The determined Br value is still below the minimum targeted value and furthermore the main difficulty is that the needed operation pressure for the LaB₆ emitter cannot be achieved across the compact electron column and therefore a prototype has not been constructed. The second evaluated source concept is based on the idea to obtain a high current ion beam having a source size and half-opening beam angle similar to the first concept, but changing the electron gas interaction and the ion collection. Theoretical and experimental studies are used to evaluate the performance of this second source concept and its usefulness for focused ion beam nano-applications
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Curtis, Matthew Earl. "Investigation and characterization of the Direct Analysis in Real Time helium metastable beam open-air ion source: Mechanism of ionization, fluid dynamic visualization, and applications". Scholarly Commons, 2013. https://scholarlycommons.pacific.edu/uop_etds/146.
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The DART ion source was introduced in 2005 at the ASMS Sanibel Conference and immediately afterward Professor Sparkman was contemplating of a way to get our lab this revolutionary mass spectrometry ionization technique. It did not take long because it was delivered to the Pacific Mass Spectrometry Facility in August 2006 and I was able to being using and learning the technique. The ion source creates excited state helium metastables (2 3 S) with an ionization potential of 19.8 eV are created by a glow discharge at atmospheric pressure. The metastables are sent through an optional heater, to aid in desorption, enter the open-air to directly ionize your sample or ionize reagent species to react with the analyte molecules. The most observed ionization mechanism is the formation of protonated molecules from a proton-transfer reaction between the analyte and protonated water clusters. The limited to no sample preparation with the "soft" ionization provide very quick identification of intact organic ions in or on various types of matrices. When the DART is coupled to a high resolving power instrument, such as the JEOL AccuTOF, accurate masses and accurate isotope ratios are assigned to aid in the determination of unknown elemental compositions. This research discusses the formation of the metastable species and how they are used to produce analyte and reagent ions within the open-air sample gap of the DART-mass spectrometer interface. A description of the fundamentals on the operation including real time visualization of the fluid dynamics and confirmation of the formation of a hydroxyl radical in the proposed formation of the protonated water clusters, along with applications developed in the Pacific Mass Spectrometry Facility will also be discussed. These include cleavage, desorption, and ionization of solid-phase peptides, desorption of aqueous metal ions using a heated wire filament and the increased ion transmission with the Vapur interface using metal coated glass tube for the transfer tube.
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Bykov, Igor. "Experimental studies of materials migration in magnetic confinement fusion devices : Novel methods for measurement of macro particle migration, transport of atomic impurities and characterization of exposed surfaces". Doctoral thesis, KTH, Fusionsplasmafysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145045.
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During several decades of research and development in the field of Magnetically Confined Fusion (MCF) the preferred selection of materials for Plasma Facing Components (PFC) has changed repeatedly. Without doubt, endurance of the first wall will decide research availability and lifespan of the first International Thermonuclear Research Reactor (ITER). Materials erosion, redeposition and mixing in the reactor are the critical processes responsible for modification of materials properties under plasma impact. This thesis presents several diagnostic techniques and their applications for studies of materials transport in fusion devices. The measurements were made at the EXTRAP T2R Reversed Field Pinch operated in Alfvén laboratory at KTH (Sweden), the TEXTOR tokamak, recently shut down at Forschungszentrum Jülich (Germany) and in the JET tokamak at CCFE (UK). The main outcomes of the work are: Development and application of a method for non-destructive capture and characterization of fast dust particles moving in the edge plasma of fusion devices, as well as particles generated upon laser-assisted cleaning of plasma exposed surfaces. Advancement of conventional broad beam and micro ion beam techniques to include measurement of tritium in the surfaces exposed in future D-T experiments. Adaption of the micro ion beam method for precision mapping of non uniform elements concentrations on irregular surfaces. Implementation of an isotopic marker to study the large scale materials migration in a tokamak and development of a method for fast non destructive sampling of the marker on surfaces of PFCs.QC 20140508
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Alarcón, Díez Víctor. "Development of charged particle detection systems for materials analysis with rapid ion beams : large solid angle detectors and numerical nuclear pulse processing". Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066489/document.
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Cette thèse présente de nouveaux développements en détection de particules chargées et traitement tout-numérique d'impulsions pour application à l'analyse avec des faisceaux d'ions rapides (IBA). Un ensemble de 16 détecteurs gravés sur une puce de Si est mis en œuvre, ce qui fournit un angle solide de détection environ 100 fois plus grande que celle des détecteurs utilisés auparavant pour l'IBA. Seize chaines d'acquisition sont également mises en œuvre avec une approche 'tout-numérique' pour le traitement des signaux issus des détecteurs. Dans son ensemble, le système ainsi développé a une résolution en énergie équivalent à celle des détecteurs standards. La considérable quantité d'information ainsi générée est traitée de manière cohérente en ajustant des spectres en énergie simulé aux spectres mesurés grâce à un algorithme de recuit simulé, avec le NDF DataFurnace. Les grandes angles solides disponibles sont exploitées pour des études par rétrodiffusion de Rutherford (RBS) et canalisation d'ions de l'isolant topologique Bi2Se3 enrichi en fer en vue d'études de l'effet thermoélectrique, de spintronique ou encore la computation quantique, ainsi que pour des études par RBS et analyse par réactions nucléaires (NRA) de matériaux pour la photovoltaïque organique, basés sur tetraphenyldibenzoperiflanthene (DBP) comme photo-absorbant avec oxydes de métaux de transition pour injection de chargeThis thesis presents new developments in charged particle detection and digital pulse processing for application in analysis with fast ion beams - Ion Beam Analysis (IBA). In particular a charged particle detector array, consisting of 16 independent charged particle detectors on a single silicon chip is implemented giving an overall solid angle of detection around two orders of magnitude greater than the standard charged particle detectors used in IBA. Sixteen parallel data acquisition channels are implemented using a fully digital approach for nuclear pulse processing. The overall system has an energy resolution equivalent to that of standard detectors. The large amount of data generated is handled in a self-consistent way by spectrum fitting with a simulated annealing algorithm via the NDF DataFurnace. The large solid angles thus achieved are exploited in Rutherford Backscattering Spectrometry (RBS) and ion channelling studies of the topological insulator Bi2Se3 enriched in Fe, in view of studies of the thermo-electric effect, spintronics and quantum computing, and in RBS and Nuclear Reaction Analysis (NRA) studies of organic photovoltaic materials based on tetraphenyldibenzoperiflanthene (DBP) as the photo-absorber and transition metal oxide charge injectors
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Alarcón, Díez Víctor. "Development of charged particle detection systems for materials analysis with rapid ion beams : large solid angle detectors and numerical nuclear pulse processing". Electronic Thesis or Diss., Paris 6, 2016. http://www.theses.fr/2016PA066489.
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Cette thèse présente de nouveaux développements en détection de particules chargées et traitement tout-numérique d'impulsions pour application à l'analyse avec des faisceaux d'ions rapides (IBA). Un ensemble de 16 détecteurs gravés sur une puce de Si est mis en œuvre, ce qui fournit un angle solide de détection environ 100 fois plus grande que celle des détecteurs utilisés auparavant pour l'IBA. Seize chaines d'acquisition sont également mises en œuvre avec une approche 'tout-numérique' pour le traitement des signaux issus des détecteurs. Dans son ensemble, le système ainsi développé a une résolution en énergie équivalent à celle des détecteurs standards. La considérable quantité d'information ainsi générée est traitée de manière cohérente en ajustant des spectres en énergie simulé aux spectres mesurés grâce à un algorithme de recuit simulé, avec le NDF DataFurnace. Les grandes angles solides disponibles sont exploitées pour des études par rétrodiffusion de Rutherford (RBS) et canalisation d'ions de l'isolant topologique Bi2Se3 enrichi en fer en vue d'études de l'effet thermoélectrique, de spintronique ou encore la computation quantique, ainsi que pour des études par RBS et analyse par réactions nucléaires (NRA) de matériaux pour la photovoltaïque organique, basés sur tetraphenyldibenzoperiflanthene (DBP) comme photo-absorbant avec oxydes de métaux de transition pour injection de chargeThis thesis presents new developments in charged particle detection and digital pulse processing for application in analysis with fast ion beams - Ion Beam Analysis (IBA). In particular a charged particle detector array, consisting of 16 independent charged particle detectors on a single silicon chip is implemented giving an overall solid angle of detection around two orders of magnitude greater than the standard charged particle detectors used in IBA. Sixteen parallel data acquisition channels are implemented using a fully digital approach for nuclear pulse processing. The overall system has an energy resolution equivalent to that of standard detectors. The large amount of data generated is handled in a self-consistent way by spectrum fitting with a simulated annealing algorithm via the NDF DataFurnace. The large solid angles thus achieved are exploited in Rutherford Backscattering Spectrometry (RBS) and ion channelling studies of the topological insulator Bi2Se3 enriched in Fe, in view of studies of the thermo-electric effect, spintronics and quantum computing, and in RBS and Nuclear Reaction Analysis (NRA) studies of organic photovoltaic materials based on tetraphenyldibenzoperiflanthene (DBP) as the photo-absorber and transition metal oxide charge injectors
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Dahlström, Christina. "Quantitative microscopy of coating uniformity". Doctoral thesis, Mittuniversitetet, Institutionen för tillämpad naturvetenskap och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-16454.
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Print quality demands for coated papers are steadily growing, and achieving coating uniformity is crucial for high image sharpness, colour fidelity, and print uniformity. Coating uniformity may be divided into two scales: coating thickness uniformity and coating microstructure uniformity, the latter of which includes pigment, pore and binder distributions within the coating layer. This thesis concerns the investigation of both types of coating uniformity by using an approach of quantitative microscopy.First, coating thickness uniformity was analysed by using scanning electron microscope (SEM) images of paper cross sections, and the relationships between local coating thickness variations and the variations of underlying base sheet structures were determined. Special attention was given to the effect of length scales on the coating thickness vs. base sheet structure relationships.The experimental results showed that coating thickness had a strong correlation with surface height (profile) of base sheet at a small length scale. However, at a large length scale, it was mass density of base sheet (formation) that had the strongest correlation with coating thickness. This result explains well the discrepancies found in the literature for the relationship between coating thickness variation and base sheet structure variations. The total variance of coating thickness, however, was dominated by the surface height variation in the small scale, which explained around 50% of the variation. Autocorrelation analyses were further performed for the same data set. The autocorrelation functions showed a close resemblance of the one for a random shot process with a correlation length in the order of fibre width. All these results suggest that coating thickness variations are the result of random deposition of particles with the correlation length determined by the base sheet surface textures, such as fibre width.In order to obtain fundamental understandings of the random deposition processes on a rough surface, such as in paper, a generic particle deposition model was developed, and systematic analyses were performed for the effects of particle size, coat weight (average number of particles), levelling, and system size on coating thickness variation. The results showed that coating thickness variation3grows with coat weight, but beyond a certain coat weight, it reaches a plateau value. A scaling analysis yielded a universal relationship between coating thickness variation and the above mentioned variables. The correlation length of coating thickness was found to be determined by average coat weight and the state of underlying surfaces. For a rough surface at relatively low coat weight, the correlation length was typically in the range of fibre width, as was also observed experimentally.Non-uniformities within the coating layer, such as porosity variations and binder distributions, are investigated by using a newly developed method: field emission scanning electron microscopy (FESEM) in combination with argon ion beam milling technique. The combination of these two techniques produced extremely high quality images with very few artefacts, which are particularly suited for quantitative analyses of coating structures. A new evaluation method was also developed by using marker-controlled watershed segmentation (MCWS) of the secondary electron images (SEI).The high resolution imaging revealed that binder enrichment, a long disputed subject in the area, is present in a thin layer of a 500 nm thickness both at the coating surface and at the base sheet/coating interface. It was also found that the binders almost exclusively fill up the small pores, whereas the larger pores are mainly empty or depleted of binder.