Ion Beam Analysis Research Papers (original) (raw)

2025, AIP Conference Proceedings

In typical algorithms for optimally filtering transition-edge-sensor-microcalorimeter pulses, the average value of a filtered pulse is set to zero. The achieved energy resolution of the detector then depends strongly on the chosen length of the pulse record. We report experimental confirmation of this effect. We derive expressions for the dependence of energy resolution on record length, and apply them to a pair of detector models for the X-ray Microcalorimeter Spectrometer instrument on NAS A/ES A/JAXA's proposed International X-ray Observatory. Although the two models have identical pulse time-constants, they differ by a factor of two in the record length required to achieve a given energy resolution. Finally, we derive an expression for the maximum output count rate at high energy resolution of a TES pixel.

2025, NATO Science for Peace and Security Series A: Chemistry and Biology

2025, European Physical Journal Plus

2025, Bulletin of Materials Science

Refurbishment of hot components of gas turbines damaged in the harsh working environments is necessary to increase their lifetime. Scanning proton microscopy was employed to evaluate the quality of refurbishment process of gas turbine blades. Distribution patterns of different elements were observed in the polished cross-sections of turbine blade samples by proton microbeam. In the cross-sections of refurbished and used samples, distinct regions were identified corresponding to the base superalloy, original protection layer and applied coating for refurbishment. The elemental composition of each of these regions was measured by Micro-PIXE analysis. Inhomogeneous and high content of Si as well as undesired light elements were observed in the cross-sections of refurbished samples, indicating imperfections in the refurbishment process.

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

A novel vacuum chamber for ion beam analysis of large-size industrial samples -whose analysis are not feasible in conventional ion beam analysis reaction chambers -has been designed, fabricated and successfully tested. Using the newly developed chamber, both PIXE and RBS analyses could be carried out at the same time and on the same point of the samples. Ion beam analysis using this novel chamber lacks the disadvantages of external beam analysis and benefits the advantages of in-vacuum analysis. This has been achieved by designing a tiny open port in the wall of the reaction chamber to be sealed with a small flat area of sample body where its analysis is of interest. As a case study, two samples of gas turbine blades, a corroded one at highly corrosive environment and a refurbished one after application of certain coatings are analysed using the novel chamber. Experimental results confirm the performance and capability of the reaction chamber.

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

This work describes the ability of ion beam analysis techniques IBA to simultaneously determine the concentration and the possible depth profile of some light elements, such as carbon, oxygen and nitrogen, in matrices of high atomic number Z, such as stainless steel materials. In fact, the nitriding process of some materials has the potential to improve their tribological and mechanical properties and to offer various advantages as compared with other methods used in the modification of surfaces. Gas and Plasma nitriding were applied to certain types of steel, such as AISI-304 and H-13 which are commonly used in the industry, in order to improve their hardness and their surface corrosion resistance. The improvement was correlated with the depth profile of N and the consequent structure variations. More specifically, non-Rutherford elastic backscattering (alpha, alpha) at 5 MeV was performed on different samples, before and after nitriding, in order to determine the stoichiometry and the thickness of the newly formed surface nitrided layers.

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Ion Beam Analysis techniques were developed and utilized for applications in the domain of archeology at the accelerator laboratory of the Lebanese Atomic Energy Commission. The characterization of Beirut kiln materials, mainly amphorae ceramics from the Roman period, was done using PIXE technique. In two runs with 1 and 3 MeV protons, we measured 20 major and trace elements. Consequently, a classification based on the elemental composition and on multivariate statistical techniques of some 70 ceramic objects was obtained providing the first step of a Lebanese database for future studies. Furthermore, the analysis of carrot amphorae found in Gaul (south of France) showed that some of them were of Beirut products and hence emphasized the role of Beirut city in the Mediterranean trade in the Roman period.

2025

The thesis reviews two pyrolysis techniques -ultrasonic spray pyrolysis (USP) and laser pyrolysis (LP). The two techniques -USP at the Physics LP at the National Laser Centre, CSIR in Pretoria, South Africa -were designed and assembled by the candidate for the purpose of producing two related materials -VO2 and WO3. The two smart materials find applications in energy regulation for air conditioning alternatives, gas sensing for pollution control purposes, recording industry and computer memory. The thesis shows the pursuit for small particles of these materials in order to see the change in their properties at nano-scale. Novel structures that were not expected were foundnanowires and nanotips of WO3 and nanobelts and nano-ribbons of VO2. The Haddad of the School of Physics at the University of the Witwatersrand and also for supporting the ultrasonic spray pyrolysis assembly that the candidate set up. Dr. Andrew Forbes of the CSIR National Laser Centre for allowing the candidate to introduce, design and implement the laser pyrolysis technique at CSIR and Dr.

2025, Synthetic data generation from a fine particulate matter PM2.5 experimental data seed and its use in PMF and APCA

Synthetic databases produced using the Gaussian Copula Model, among others, represent a great aid to analysing experimental databases. Particularly, when the experimental databases have limited data density, synthetic databases can boost the data density without significantly altering the experimental data interpretation. In this work, experimental data of two years and 10 months of fine airborne particulate matter (PM 2.5), analysed by PIXE, ditto the total concentration and concentrations of 15 elements, were used as seed to feed the model and obtain synthetic data. An analytical study of both databases was conducted using Positive Matrix Factorisation (PMF) and Absolute Principal Component Analysis (APCA), which are the most common algorithms used by the community, some differences, acceptable limitations, and advantages are discussed in this document.

2025

This report introduces new features in the OmniTrak support utilities Mapper and GenDist. The capabilities are illustrated with an example, a twisted electrostatic quadrupole channel for low-energy ion beam transport. A standard quadrupole array consists of individual lenses rotated by 90 degrees. The difference is that the rotation in a twisted quadrupole occurs continuously. A potential application of the configuration is a differential pumping region between an ion source and an accelerator.

2025, Physica Scripta

Future fusion reactors use a D-T plasma mixture as fuel. A fraction of hydrogen species can escape the plasma confinement and hit the first wall. Hydrogen isotope exchange, a process in which trapped T atoms are replaced with lighter hydrogen isotopes D or H, is a potential method to minimize radioactive T retention in the wall materials. The present work extends our systematic research on isotope exchange by reversing the process, i.e., by implanting H ions into tungsten followed by subsequent annealing at different constant temperatures in D 2 atmosphere. Elastic Recoil Detection Analysis was used to determine the H and D concentrations. The results show that the isotope exchange process takes place regardless of the mass of the active hydrogen isotope. This indicates that the isotope exchange is a statistical phenomenon in which the abundance of the neighboring hydrogen near the trapped hydrogen isotope defines the efficiency of the process.

2025, Physica Scripta

2025, Nuclear instruments and methods in physics research

Frequently samples are presented in powdered form, or have for reasons of inhomogeneity to be powdered and thoroughly mixed in order to get a representative sample. In other situations while solid samples may be available, in the case of precious minerals such as diamond, they may be very small so that accurate results can inherently not be obtained. Since these problems frequently present themselves with our interests in nuclear geology, solutions to the problem which does not arise in most other analytical techniques have been sought and now established. Two basic approaches will be described together with the instrumentation developed.

2025, Bulletin of the American Physical Society

2025

Le travail de cette thèse a été effectué à l'Institut de Physique Nucléaire d'Orsay au sein du groupe NESTER. Je remercie tout d'abord la directrice de l'IPN Mme. Dominique Guillemaud-Mueller ainsi que le directeur de la division de recherche M. Bernard Berthier de m'avoir accueillie dans leur laboratoire et permis de mener ma thèse dans les meilleures conditions. J'exprime chaleureusement ma reconnaissance la plus sincère à François Le Blanc pour avoir accepté de m'accueillir au sein de son groupe et de m'avoir proposé un sujet de thèse aussi passionnant et riche. Je le remercie pour sa patience et sa gentillesse tout au long de cette thèse. Il a su me guider pas à pas dans toutes les étapes particulièrement pour m'initier à la pratique des lasers et à la préparation des différentes expériences ainsi que lors du dépouillement des résultats. Ses conseils ont toujours été très précieux. Merci de m'avoir encouragée et soutenue et surtout de m'avoir supportée malgré mes nombreuses baisses de moral durant les 6 mois de rédaction. Je remercie Pierre Desesquelles d'avoir accepté de présider le jury de cette thèse. Je remercie vivement mes deux rapporteurs Fazia Hannachi et Gerda Neyens d'avoir accepté d'en examiner les travaux malgré leurs emplois du temps trés chargés. J'adresse aussi mes remerciements à Marek Lewitowicz et Klaus Wendt pour avoir fait le déplacement pour faire partie du jury de soutenance. L'expérience COMPLIS ne peut aboutir sans la contribution de nombreux collaborateurs. Je remercie Jacques Pinard pour sa passion inaltérée aux lasers grâce à laquelle on a pu bénéficier de son expérience et de son doigté qui ont toujours assuré un très bon fonctionnement du système laser tout au long de ma thèse et tout au long des années précédant celle-ci, sans oublier le savoir faire de Louis Cabaret à qui j'exprime mes sincères remerciements. Le contrôle informatique de l'expérience et le bon déroulement de l'acquisition ne serait mené à bien sans la présence indispensable de Nathalie Barré. Qu'elle trouve ici l'expression de mes profonds remerciements. Je remercie également Jeannine Genevey, John Crawford et Jonathan K.P. Lee pour leur disponibilité et leur participation aux longues nuits de manip, sans oublier Henri Stroke. Merci pour ta gentillesse Henri et pour ta bonne humeur communicative, merci de m'avoir éclairée par ton immense expérience pour analyser les spectres si compliqués des tellure. J'adresse mes profonds remerciements à Gerhard Huber qui veille toujours (de près ou de loin) au bon déroulement de la collaboration COMPLIS et à l'intérêt qu'il a porté à mon travail. Merci à mon Professeur M. Slimane Barhoumi de m'avoir fait bénéficier de son expérience et de ses contacts, grâce à lui j'ai pu explorer d'autres horizons et faire la rencontre de tout ce beau monde cité précédemment. Toutes ces personnes me font aimer la physique de plus en plus. Cette thèse n'aurait pu voir le jour sans le soutien et les encouragements de ma famille, grâce à eux j'ai pu avancer malgré les épreuves difficiles endurées durant les 3 dernières années. Merci à mon défunt père de m'avoir poussée à faire cette thèse, je ne regrette rien car elle m'a tellement enrichie et j'ai tellement appris. Je te dédie ce mémoire car tu n'as pas pu voir l'aboutissement de ce travail. Merci également à tous mes amis, que je ne peux citer ici car la liste est longue, qui ont toujours cru en moi et soutenu. Un petit clin d'oeil également au gardien de l'IPN qui s'est assuré à plusieurs reprises que j'étais toujours en vie pendant les longues nuits passées à rédiger dans mon bureau. Table des matières INTRODUCTION ……………………………………….…………………….1 I-RIS : Spectroscopie par ionisation résonante 1-Principe de l'ionisation résonante ………………………………………………...3 a-Ionisation résonante en deux étapes .……………………………………..4 b-Les caractéristiques des faisceaux laser ………………………………….7 i-Le choix du schéma d'ionisation ……………………………………..7 ii-L'énergie des faisceaux laser ………………………………….

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

The indium profile of MBE-grown InXGal_,As/GaAs single quantum well structures and In,%Ga, _,As layers on InAlAs buffer layers have been measured with heavy ion Rutherford backscattering using a time-of-flight detector. The depth resolution of the 0 method is better than 30 A at the sample surface using 15 MeV 35C1 ions. The results for the average indium molar fraction are compared with phonoto reflectance me~urements. The alu~num molar fraction in the InAlAs buffer layer has been profiled by nuclear reaction analysis.

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

The accelerator mass spectrometry (AMS) radiocarbon dating facility at the University of Lecce, Italy is now fully operational and in the first year of operation more than 500 samples both organic and inorganic have been measured for applications in archaeology, history of art, geology and environmental sciences. The experimental capabilities of the facility have been recently significantly improved by the installation of an in vacuum and in air ion beam analysis (IBA) beam line. Investigations are routinely carried out in material science and cultural heritage diagnostics.

2025, Applied Physics A

Applied Physics A g. quarta u m. d'elia k. butalag l. maruccio g. demortier l. calcagnile

2025

We consider the thermodynamic and kinetic properties of Nickel as an example of transition metal in two-temperature state (T e T i , ) produced by femtosecond laser heating. Our physical model includes essential processes induced in metals by ultrafast laser energy absorption. Specifically, the electron-ion collision frequency was obtained from recent high-temperature measurements of electrical conductivity and electron-electron screened Coulomb scattering was calculated by taking into account s-s and s-d collisions. In addition, chemical potential, energy, heat capacity, and pressure were obtained from first-principles density functional theory calculations. This model was implemented in two-temperature hydrodynamic code (2T-HD) and combined with molecular dynamics (MD) to determine strength of molten Ni at high strain rates ∼ 10 8 -10 9 s -1 under conditions of femtosecond laser ablation experiments. The simulated ablation threshold, which depends on material strength, was found to be in good agreement with our experimental measurements reported here. The combined 2T-HD/MD modeling explains the surprisingly high experimental energy density necessary to initiate ablation in Ni (the experimental crater depth in Ni is several times smaller than in Al and Au, while ablation threshold energies are similar).

2025

This manuscript explores the tailoring of structural, optical, and transport properties of ion induced amorphous and subsequent recrystallized indium-tin oxide (ITO) films. Amorphization of ITO thin films, induced by various energetic projectile ions (10 keV Ar + , O + , N + , and C + at normal incidence), introduces vacancies and defects at various depth and thereby alters their physical, chemical, optical, and electrical properties. Through a comprehensive array of analytical techniques, including X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy, UV-VIS-IR spectroscopy, and transport property assessments, this manuscript elucidates the transition of ion-induced amorphized ITO surfaces into polycrystalline films upon annealing at 350°C. Chemical transformations, including the formation of indium oxide in post anneal scenario, occur through the bonding of indium with the available oxygen produced from tin oxide during sputtering. Additionally, the investigation reveals a shift in absorption edge and increased photon absorbance in the UV-VIS-IR wavelength range on post-annealing scenario, while transmittance remains relatively constant. A wide range of variation in resistivity, mobility and carrier concentration is achieved due to amorphization and subsequent recrystallization of ITO films. The tailoring of structural, morphological, optical and electrical properties is elaborated using chemical composition and Monte Carlo simulations using SRIM based on binary collision approximation (BCA) calculations. Additionally, dynamic Monte Carlo simulations are carried out to support the negligible amount of concentration of implanted projectile ions. This comprehensive analysis elucidates the post-annealing recrystallization behaviour of ITO films, highlighting the tailored physico-chemical properties induced by atomic diffusion resulting from ion-induced sputtering and mass redistribution.

2025

We report the formation of a buried ultra-thin layer of Ag clusters in a Si substrate through 6 keV Ag⁺ ion beam implantation, which exhibits a significant
enhancement of the Raman signal. This suggests the development of a reliable and reusable chip for Surface Enhanced Raman Spectroscopy (SERS). The presence of a
clustered Ag layer in Si also leads to pronounced UV absorption, thus expanding the material’s potential in safeguarding from photo-degradation and optoelectronic
devices. Physicochemical analysis conducted using X-ray photoelectron spectroscopy (XPS), Atomic Force Microscopy, and cross-sectional Transmission Electron
Microscopy (TEM) confirms the formation of a 9 nm buried layer of Ag clusters within the amorphous Si layer. This method of Ag ion implantation in Si offers a
simple approach to engineering surfaces with enhanced optical and spectroscopic characteristics.

2025

At the GSI heavy ion LINAC, the properties of scintillating screens irradiated by the ion beam were studied. Different ion beams from H + to U 28+ in the energy range from 4.8 to 11.4 MeV/u were used with currents up to some mA. The investigations were focused on ceramic materials. Their properties (light yield, beam width and higher statistical moments) were compared with different quartz glasses. The image of each ion beam pulse was recorded by a digital CCD camera and individually evaluated. The recorded beam width shows dependence on the used scintillator material. Additionally, the light yield and beam width depend significantly on the screen temperature. For ZrO 2 the influence of the screen temperature on the statistical moments was investigated. Furthermore, the spectra of the scintillation screens were studied in the UV-VIS region with different ion species.

2025, Surface and Coatings Technology

In the perspective of long term geological storage, high level nuclear wastes will be overpacked in low carbon steel containers. In that context, we have studied the influence of oxygen dissolved in water on iron corrosion. Therefore, leaching experiments were performed in desaerated D 2 O and in aerated H 2 O and a kinetic study of iron corrosion under proton irradiation was lead in aqueous media with two different dissolved oxygen concentrations. The leaching experiments underline the major role of dissolved oxygen in oxydoreduction reactions which take place as far as iron is in contact with water. But the kinetic study of iron corrosion under irradiation put in evidence the balance between the oxydoreduction reactions and the corrosion rate induced by radicals species generated by water radiolysis. In addition, to check if, in the atomic % concentration range, hydrogen diffuse from the air/Fe interface through the foil an irradiation experiment was performed in argon. It proved that no hydrogen permeation occurs at a concentration level of the atomic percent.

2025, J. Comp. Phys.

This paper describes a new method for numerical modeling of extraction of high-current ion beams from a plasma source. The challenge in the application is to satisfy simultaneously requirements for space-charge-limited flow and uniform ion flux. The plasma surface must assume a special shape that is not known in advance. The method involves the use of finite-element techniques coupled with a dynamic conformal mesh. Starting from an initial estimate, the flexible mesh is shifted to achieve uniform flux over the emission surface. The approach achieves high accuracy and has the versatility to handle complex emission surfaces in gridded guns. In contrast to trial-and-error approaches, the method proceeds directly to the optimum solution. The technique can also be applied to determine cathode shapes for uniformflux electron guns. Benchmark calculations using the Trak two-dimensional ray-tracing code are described. The program automatically carries out the surface search.

2025, Physical Review B

The magnetic rare earth element gadolinium (Gd) was doped into thin films of amorphous carbon (hydrogenated a-C:H, or hydrogen-free a-C) using magnetron co-sputtering. The Gd acted as a magnetic as well as an electrical dopant, resulting in an enormous negative magnetoresistance below a temperature (T ′ ). Hydrogen was introduced to control the amorphous carbon bonding structure. High-resolution electron microscopy, ion-beam analysis and Raman spectroscopy were used to characterize the influence of Gd doping on the a-Gd x C 1-x (:H y ) film morphology, composition, density and bonding. The films were largely amorphous and homogeneous up to x=22.0 at.%. As the Gd doping increased, the sp 2 -bonded carbon atoms evolved from carbon chains to 6-member graphitic rings. Incorporation of H opened up the graphitic rings and stabilized a sp 2 -rich carbonchain random network. The transport properties not only depended on Gd doping, but were also very sensitive to the sp 2 ordering. Magnetic properties, such as the spin-glass freezing temperature and susceptibility, scaled with the Gd concentration.

2025

DOE Scientific and Technical Information. DOE Scientific and Technical Information. ...

2025

Armelle Charrié-Duhaut ( a ), Margaux Fresnais( a ), Pascale Richardin( b ), Thomas Calligaro ( b,c ), Quentin Lemasson ( b ), Emmanuelle Leize-Wagner( a ) (a)

2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

measuring the diffusion coefficient of a deuterated polystyrene in a hydrogenated polystyrene, we demonstrate the use of the D(3He,p)4He reaction to profile deuterium in polymers. Evaluation of the technique shows that with a 3He beam energy of 2 MeV, the beam at normal incidence to the sample and a detector angle of 160 O, depths of 8 pm can be profiled, with a resolution of 390 nm at the surface and 420 nm at 8 pm. At the other extreme with a beam energy of 0.7 MeV and a glancing angle of incidence of 15 o a resolution of 30 nm can be achieved at depths of up to 0.2 pm. The capability of the technique is compared with the ion beam technique more commonly used for profiling deuterium: elastic recoil detection analysis.

2025, arXiv (Cornell University)

LAMFI is a laboratory dedicated to the development and application of ion beam techniques for the analysis of bulk materials and thin films. Its main facilities comprise an 1.7MV Pelletron tandem accelerator and two analytical setups, one mainly for Rutherford Backscattering Spectrometry (RBS), and channeling, and another, for Particle Induced X-ray Emission (PIXE) analysis. Since its beginning in March 1992, over 10 institutions involving about 68 researchers, 42 graduate and 9 undergraduate students have been direct or indirectly users at LAMFI.

2025, Atti dell'Istituto Italiano di Preistoria e Protostoria

Nel Sulcis e nell'Iglesiente (Sardegna Sud-occidentale) la produzione litica scheggiata di numerosi siti neolitici sfrutta litotipi differenti; la distribuzione delle materie permette di tracciare specifiche forme di interazione in una tra le aree più densamente insediate fin dal primo Neolitico. A prescindere dalle tipologie dei siti, l'ossidiana del Monte Arci, distante ca. 80 km in linea d'aria, è largamente dominante tra le materie prime rispetto alla selce ed altre rocce ben caratterizzate come il diaspro. Quest'ultimo, pur in quantità ridotte, rivela una distribuzione spaziale relativamente ampia fin dal Neolitico antico (VI mill. cal BC) (Vacca 2002, p. 3; Melis e Vacca 2000, p. 18; Alba e Canino 2004), anche a maggiore distanza in siti del Terralbese (Lugliè cds). Per l'analisi dei sistemi di circolazione delle materie prime è di particolare interesse la localizzazione esclusiva degli affioramenti del diaspro lungo la costa occidentale dell'Isola di San Pietro (51 kmq), nella località denominata Il Becco: i banconi di diaspro affiorano intercalati a rioliti ed ignimbriti a chimismo da riolitico a quarzolatitico, risalenti al vulcanismo calco-alcalino oligo-miocenico (17-11 ma.: Garbarino et alii 1990). Campionamenti sistematici delle varietà, intrapresi su un fronte esteso oltre 400 m, hanno individuato in situ elementi di débitage e percussori litici, pur nel disturbo creato da massive alterazioni moderne, corroborando l'ipotesi di una coltivazione preistorica della risorsa anche con attività localizzate in cava. Al Becco le formazioni del diaspro appaiono in filoni oriz

2025, Http Www Theses Fr

Préparer une thèse dans un laboratoire en pleine expansion comme SUBATECH, aujourd'hui dirigé par Hans GUTBROD, est une expérience enrichissante. Si j'ai pu entrer dans ce qui était encore le Laboratoire de Physique Nucléaire il y a trois ans, c'est à Daniel ARDOUIN, précédent directeur, que je le dois. Cette page me donne l'occasion de le remercier. Ces trois années passées aux côtés de Barbara ERAZMUS, ma directrice de thèse, m'ont été riches d'enseignements. J'ai pu profiter de son expérience pour accomplir le travail qu 'elle m'a confié, mais également pour m'ouvrir à d'autres aspects de ce thème de recherche. J'ai également bénéficié de ses précieux conseils lors de la rédaction de ce mémoire. Je tiens à lui exprimer toute ma gratitude pour ce travail en commun et le dévouement dont elle fait preuve afin que mon aventure dans la recherche ne s'achève pas avec cette thèse. Tout au long de ce travail, j'ai pu compter sur l'aide soutenue de Lilian MARTIN, (y compris lors de son séjour au MSU !). Il a su garder un intérêt actif pour l'expérience qui a fait l'objet de sa thèse. Qu'il soit assuré de ma reconnaissance pour cette agréable collaboration et ses conseils avisés. C'est avec un réel plaisir que j'ai pu découvrir l'approche théorique de mon travail auprès d'un spécialiste de l'interférométrie, Richard LEDNICKY. Je tiens à le remercier pour la patience et la grande disponibilité dont il a fait preuve, ainsi que pour m'avoir fait l'honneur d'être rapporteur de ce travail. Je remercie Jorg AICHELIN de m'avoir fait l'honneur de présider mon jury de thèse, mais également pour les discussions qui ont conduit à la réalisation d'une partie de ce travail. Merci également à Christoph HARTNACK, qui a activement pris part à cette collaboration. J'ai pu compter sur la présence de Hans Georg RITTER parmi les membres de mon jury. Je tiens à le remercier de m'avoir accordé un peu de son temps pour prendre part à revaluation de ce travail. J'ai éprouvé beaucoup de plaisir à travailler avec Jan PLUT A, qui m'a toujours particulièrement impressionné par sa grande disponibilité malgré le grand nombre de tâches qu 'il prend en charge. Un laboratoire de recherche ne pourrait fonctionner sans le concours des services techniques et administratifs. En particulier, je remercie Evelyne GERBAUD d'avoir gardé un oeil vigilant sur les procédures administratives nécessaires au bon déroulement de ma soutenance. Merci également au service informatique, qu'on oublie trop facilement dès lors que tout fonctionne correctement. Enfin, je ne voudrais pas oublier mes compagnons de thèse, aux côtés de qui j'ai passé la totalité ou une partie de ces 3.15648 10 31 fin/c. Que ceux qui n 'ont pas encore soutenu reçoivent mes plus vifs encouragements. D. EFFETS DIRECTIONNELS 1. Analyse de la séquence d'émission pour le couple proton-deuton 2. Effets directionnels pour le couple p-t 3. Effets directionnels pour le couple p-a a) Etude de la séquence d'émission des particules b) Influence du champ coulombien sur la résonance du 5 Li 92 4. Effets directionnels pour les autres couples de particules non identiques 5. Synthèse sur la séquence d'émission des particules de types différents CHAPITRE IV : L'INTERFEROMETRIE : UNE TECHNIQUE POUR L'ANALYSE DES CORRELATIONS DYNAMIQUES ET DE L'EVOLUTION DES COLLISIONS A. LES LIMITES D'UNE ANALYSE STATIQUE 1. Influence des corrélations entre l'impulsion et les coordonnées spatio-temporelles des point d'émission des particules 2. Evolution de la source B. ANALYSE AVEC LE MODÈLE DYNAMIQUE MICROSCOPIQUE QMD 1. Présentation du modèle dynamique QMD 2. Notre simulation a) La réaction 129 Xe+ 48 Ti à 45 MeV/u b) Spectres en énergie et distributions angulaires c) Sélection en paramètre d'impact C. ANALYSE DES CORRELATIONS 1. Distributions spatio-temporelles des points d'émission des particules a) Critère d'émission des particules b) Distributions spatiale et temporelle d'émission des protons 2. Corrélations dynamiques entre les variables cinématiques 3. Fonction de corrélation a) Influence des corrélations dynamiques b) Comparaison avec la fonction de corrélation expérimentale CONCLUSIONS REFERENCES BIBLIOGRAPHIQUES Chapitre I Approche théorique des corrélations dans le cadre d'un modèle quantique A. LE CONTEXTE 1. Les phénomènes à l'origine des corrélations Dans les collisions d'ions lourds, les corrélations entre deux particules proviennent de plusieurs phénomènes. Historiquement, les interférences d'origine quantique entre les fonctions d'onde de deux particules identiques ont permis d'interpréter [GOL60] les distributions de deux pions observées dans la réaction proton+antiproton. L'indiscernabilité des deux particules, nous impose de symétriser (pour les bosons), ou d'antisymétriser (pour les fermions) la fonction d'onde de la paire. Le carré de son module s'écrit, pour des particules libres, de spin j, représentées par des ondes planes, et non polarisées, (h = c = 1 ): 2(2./ +1, 2(2;+ 1) où x, = (/,, r t ) est le quadri-vecteur position de la particule i, et p t -(£,-, p^ ) est son quadrivecteur énergie-impulsion. En posant p=(pi+p2)/2, q=p\-pi, x=x\-xi et X=x\+X2, on peut décomposer le mouvement des deux particules en un mouvement d'ensemble et leur mouvement relatif :

2025

the U. S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U. S. Government

2025, Integrated Ferroelectrics

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2025, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

A study of ion beam analysis techniques of plasma enhanced chemical vapor deposited (PECVD) silicon oxide thin films (1 lm thick) obtained from silane (SiH 4 ) and nitrous oxide (N 2 O) is reported. The film, elemental composition and surface morphology were determined as function of the reactant gas flow ratio, R = [N 2 O]/[SiH 4 ] in the 22-110 range using the Rutherford backscattering spectrometry, nuclear reaction analysis and atomic force microscopy techniques. The density of the films was determined by combining the RBS and thickness measurements. All the experiments were done at a deposition temperature of 300 °C. In all the cases almost stoichiometric oxides were obtained being the impurity content function of R. It was also observed that physical properties such as density, surface roughness and shape factor increase with R in the studied interval.

2025, Diamond and Related Materials

Results of a systematic investigation on the effects of some deposition parameters partial pressure of CF and self-bias 4 . voltage on the microstructure, mechanical and tribological properties of a-C:H:F films are presented. The films were deposited by r.f.-PECVD using CH ᎐CF mixtures. The film composition was measured by ion beam analysis and, combining these results 4 4 with the film thickness, the film density was determined. The structural arrangement was probed by Raman spectroscopy and the chemical bonding was investigated by infrared absorption and X-ray photoelectron spectroscopies. The hardness was measured by microindentation and the internal stress was determined by measuring the changing of the substrate curvature after the film deposition. The friction coefficient was measured by lateral force microscopy. The results indicate that the properties of a-C:H:F films are controlled by the ionic bombarding during the film growth. For a fixed self-bias, the increase of the CF partial pressure 4 leads to a transition from diamond-like to a polymer-like structure, to a higher fluorine incorporation and to a decrease of both hardness and internal stress. The friction coefficient decreases too. The fluorine incorporation also increases with the increase of the self-bias and was associated to higher plasma decomposition. Fluorine-poor polymer-like films were deposited at low self-bias Ž . y50 V . In both situations, fluorine incorporation occurs at the expenses of the hydrogen content and the reduction of the energy of the bombarding species results in less dense and soft films with a polymer-like structure.

2024, Nuclear Fusion

Carbon erosion and deposition in the ASDEX Upgrade divertor was investigated using a poloidal section of marked divertor tiles and silicon samples below the divertor structure. The whole inner divertor is a net carbon deposition area, while a large fraction of the outer divertor is erosion dominated and the roof baffle tiles show a complicated distribution of erosion and deposition areas. In total, 43.7 g B+C were redeposited, of which 88% were deposited on tiles and 9% in remote areas (below roof baffle, on vessel wall structures). Identified carbon sources in the main chamber are too low by a factor of ten to explain the observed carbon divertor deposition, but carbon erosion is observed at the outer divertor tiles. Deuterium is trapped mainly on the surfaces of the inner divertor tiles. The long term retention in codeposited hydrocarbon layers is about 3% of the total deuterium fuel input.

2024, Microscopy and Microanalysis

Material analysis, specially surface analysis of materials, has been increasingly important. A wide range of surface analysis techniques is available. The techniques are, generally, complementary. There are nuclear and non-nuclear techniques, e.g. microscopy. Nuclear techniques, which are nondestructive, permit analysis for a few microns near the surface. They have been applied to areas such as scientific, technologic, industry, arts and medicine, using MeV ion beams. Nuclear reactions permit to achieve high sensitivities for detection of light elements in heavy substrates and also discrimination of isotopes. We use ion-ion nuclear reactions, elastic scattering and the energy analysis method, where an energy spectrum is obtained of ions from the target for a chosen energy of the incident ion beam. The target composition and concentration profile information contained in the spectrum is computationally obtained through a computer program that has been developed for predicting such en...

2024

A scanning ion microscope is described in which the prior arts of scanning microscopy and achromatic quad rupole lens design as perfected for electrons are utilized for massive high-energy positive ions. Because the De Broglie wavelength of the massive ions is smaller than the wavelength of electrons, diffraction in the objective lens is reduced. In principle resolution better than one Angstrom can be achieved. Because of the copious production of X-rays and Auger electrons in the speci men by such ions, specimens of atomic dimensions can be examined with a minimum of radiation damage by the ions. The specifically new, novel, and useful feature of this invention is the use of properly focused high-en ergy heavy-ion beams and the detection of single atomic events in the specimen, which together enable much greater sensitivity and resolution than attainable by other means.

2024, Doklady Earth Sciences

The volumetric concentration of hydrogen in two Brazilian diamonds is determined using secondary ion mass spectrometry and implantation of hydrogen into an external standard sample (with a dose of 1 × 16 at/cm 2 and energy of 120 KeV). The diamonds studied differ noticeably in their intensities of IR-active hydrogen from 0 to 1.5 cm-1 according to the analyses of their IR spectra. The results demonstrate that for both samples studied, the volumetric concentration of hydrogen does not exceed the reached detectable level of (1-2) × 10 18 at/cm 3 or 1.7-3.3 at. ppm; i.e., it is lower by an order of magnitude than in the early chemical analysis and by 2-3 orders of magnitude lower than the results of the ion-beam spectrochemical, nuclearphysical, and ERDA analyses. Only a part of the hydrogen forms optically active impurities in diamond crystals and can be determined by spectral methods.

2024

This paper will present results from a series of analyses performed on 8-stage Micro Orifice Uniform Deposit Impactor (MOUDI) sampling substrates using accelerator-based Particle Induced X-ray Emission (PIXE) analyses. These experiments aimed to better understand the influence of aerosol deposition on each of the MOUDI stages on the PIXE analysis results.

2024, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

2024, Mineralogical Magazine

An experimental technique has been developed and applied to the problem of determining effective diffusion coefficients and partition coefficients of Sr in low permeability geological materials. This technique, the micro-reactor simulated channel method (MRSC), allows rapid determination of contaminant transport parameters with resulting values comparable to those determined by more traditional methods and also creates product surfaces that are amenable for direct chemical analysis. An attempt to further constrain mass flux was completed by detailed ion beam analysis of polished tuff surfaces (tuff is a polycrystalline polyminerallic aggregate dominated by silicate phases) that had been reacted with Sr solutions at concentrations of 10−5, 10−3 and 10−1 mol l−1. Ion beam analysis was carried out using beams of both protons (using particle induced X-ray emission and elastic backscattering spectrometry or EBS) and alpha-particles (using Rutherford backscattering spectrometry). The ion ...

2024, Chromatographia

The concentrations of modifier (methanol or acetonitrile) and surfactant (sodium dodecyl sulfate, SDS) in the running buffer are important factors influencing the mobility of analytes in micellar electrokinetic chromatography (MEKC). Response surfaces of the effective mobility can be used to predict mobilityas a function of the buffer composition. This paper describes the modeling, by multiple linear regression and by use of a back-propagation neural network, of the response surfaces of the effective mobility of cocaine and related compounds, of fluvoxamine and its possible impurities, and of a mixture of alkylphenones. Special altention has been paid to selection of the proper order of the regression models, to selection of the proper network configuration, and to the predictive quality of the models. The regression models were selected by backward elimination of non-significant terms starting with a full second-order polynomial model. The proper network configuration was selected by finding the optimum number of hidden neurons by lateral inhibition and subsequent determination of the optimum number of training cycles by a cross-validation method. On the basis of the multiple determination coefficient, R 2, the descriptive performances of the neural network and the regression models are almost the same. However, the predictive performance of the regression models and the neural network models are approximately equal for migration in MEKC. The relative prediction error of the effective mobility is ca 2.5% for cocaine and related compounds, l-7% for the alkylphenones, and 1.5-2.2% for fluvoxamine and its possible impurities; this is approximately the same order of magnitude, or slightly higher, than the relative standard deviation of the replicate measurements. pers the use of physico-chemical models, polynomial regression models are easier to use. Physico-chemical models usually require the use of non-linear regression methods. Jimidar et al. [6] fitted experi

2024, Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms

Obtaining particulate compositional maps from scanned PIXE (proton-induced X-ray emission) measurements is extremely difficult due to the complexity of analyzing spectroscopic data collected with low signal-to-noise at each scan point (pixel). Multivariate spectral analysis has the potential to analyze such data sets by reducing the PIXE data to a limited number of physically realizable and easily interpretable components (that include both spectral and image information). We have adapted the AXSIA (automated expert spectral image analysis) program, originally developed by Sandia National Laboratories to quantify electron-excited X-ray spectroscopy data, for this purpose. Samples consisting of particulates with known compositions and sizes were loaded onto Mylar and paper filter substrates and analyzed by scanned micro-PIXE. The data sets were processed by AXSIA and the associated principal component spectral data were quantified by converting the weighting images into concentration maps. The results indicate automated, nonbiased, multivariate statistical analysis is useful for converting very large amounts of data into a smaller, more manageable number of compositional components needed for locating individual particles-of-interest on large area collection media.

2024, Nuclear Instruments in Methods in Physics Research B

Determining the amount of a hydrogen isotope in a material by elastic recoil spectroscopy (ERS) is a routine capability of many laboratories and the data are relatively easy to analyze when only one isotope of hydrogen is present. However, when two or more isotopes of hydrogen are present the analysis is much more complicated. This paper presents data from such samples including a relatively thick sample of erbium hydride with an approximately 2:1 ratio of protium to deuterium and a sample of silicon with ion implanted deuterium that had absorbed hydrogen on the surface. The usual technique of simulation of the data is employed to determine the hydrogen isotope concentration profiles. This is complemented by taking data from the samples at various incident alpha particle beam energies to determine the identity of individual isotopes. This enables use of the variation in stopping power and cross-section with energy to cause, for example, a buried layer of deuterium to be removed from the position in the spectrum where protium from the surface of the sample will overlap the deuterium spectrum.