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1
Alves, Andrew David Charles, i aalves@unimelb edu au. "Characterisation of Single Ion Tracks for use in Ion Beam Lithography". RMIT University. Applied Sciences, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080414.135656.
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To investigate the ultimate resolution in ion beam lithography (IBL) the resist material poly(methyl methacrylate) PMMA has been modified by single ion impacts. The latent damage tracks have been etched prior to imaging and characterisation. The interest in IBL comes from a unique advantage over more traditional electron beam or optical lithography. An ion with energy of the order of 1 MeV per nucleon evenly deposits its energy over a long range in a straight latent damage path. This gives IBL the ability to create high aspect ratio structures with a resolution in the order of 10 nm. Precise ion counting into a spin coated PMMA film on top of an active substrate enabled control over the exact fluence delivered to the PMMA from homogenously irradiated areas down to separated single ion tracks. Using the homogenous areas it was possible to macroscopically measure the sensitivity of the PMMA as a function of the developing parameters. Separated single ion tracks wer e created in the PMMA using 8 MeV F, 71 MeV Cu and 88 MeV I ions. These ion tracks were etched to create voids in the PMMA film. For characterisation the tracks were imaged primarily with atomic force microscopy (AFM) and also with scanning electron microscopy (SEM). The series of studies presented here show that the sensitivity of the resist-developer combination can be tailored to allow the etching of specific single ion tracks. With the ability to etch only the damage track, and not the bulk material, one may experimentally characterise the damage track of any chosen ion. This offers the scientific community a useful tool in the study and fabrication of etched ion tracks. Finally work has been conducted to allow the precise locating of an ion beam using a nanoscale mask and piezoelectrically driven scanning stage. This method of beam locating has been trailed in conjunction with single ion detection in an effort to test the practical limits of ion beam lithography in the single ion realm.
2
Kopniczky, Judit. "Nanostructures Studied by Atomic Force Microscopy : Ion Tracks and Nanotextured Films". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3763.
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Spohr, Reimar. "Ion Tracks for Micro- and Nanofabrication : From Single Channels to Superhydrophobic Surfaces". Doctoral thesis, Uppsala universitet, Materialfysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111247.
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A method is described for preset-count irradiations between 1 and 100 ions singling-out individual ions from an ion beam with more than a billion ions arriving per second. The ion tracks are etched in a conductometric system with real-time evaluation of the acquired data. The etch process can be interrupted when reaching a preset channel diameter. Cylindrical channels are obtained by adding surfactants to the etch solution forming a self-assembled barrier between etching medium and polymer. Asymmetric etching of single ion tracks leads to pH sensitive conical pores with diode-like properties. Using etched channels as template, homogeneous and multilayer magnetic single-wires are electrodeposited. The magnetoresistivity of the wires is studied. Single-track applications comprise critical apertures (cylindric, conic, necked), asymmetric pores (pH sensitive, biospecific), Giant Magneto Resistance sensors, and spintronic devices. On the basis of studies with individual ion tracks we tackled tilted multiporous systems such as ion beam lithography with a masked ion beam leading to micro-structures with inclined walls and anisotropic superhydrophobic ion track textures, analogous to biological shingle structures on butterfly wings. We demonstrated qualitatively, that the asymmetry of the texture translates into motion under ultrasonic agitation. This could lead to the development of rotary drives.
4
Vlasukova, L. A., V. N. Komarov, V. A. Skuratov i V. N. Yuvchenko. ""Etchability" of ion tracks in Si02/Si and Si3N4/Si thin layers". Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20872.
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We have calculated radii and lifetime of the molten regions or the regions heated
to the melting point that are formed under irradiation of amorphous SiO2 and Si3N4 with
swift ions. A computer simulation was carried out on the base of thermal spike model. A
comparison of calculated track parameters with ion track etching data have been made
for these materials.
It is shown that an existence of molten region along swift ion trajectory may be a
criterion for a track “etchability” in the case of SiO2. In the same conditions of chemical
etching diameter of etched tracks in SiO2 is proportional to the radius and lifetime of the
molten region. This information is important for a correct choice of irradiation regime
aimed at preparation of nanoporous layers with high pore density ( 10 10 cm-2).
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20872
5
Spohr, Reimar. "Ion tracks for micro- and nanofabrication from single channels to superhydrophobic surfaces /". Uppsala : Acta Universitatis Upsaliensis, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-111247.
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6
Niklas, Martin Anthony [Verfasser], i Wolfgang [Akademischer Betreuer] Schlegel. "Cell-fluorescent ion track hybrid detector: A novel hybrid technology for direct correlation of single ion tracks and subcellular damage sites in clinical ion beam / Martin Anthony Niklas ; Betreuer: Wolfgang Schlegel". Heidelberg : Universitätsbibliothek Heidelberg, 2014. http://d-nb.info/1177811294/34.
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Dedera, Sebastian [Verfasser], i Ulrich A. [Akademischer Betreuer] Glasmacher. "Visualization of Ion-Induced Tracks in Carbonate Minerals / Sebastian Dedera ; Betreuer: Ulrich A. Glasmacher". Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180501101/34.
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8
Kusumoto, Tamon. "Radial electron fluence around ion tracks as a new physical concept for the detection threshold of PADC detector". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAE046/document.
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La structure et le processus de formation des traces latentes dans le poly (allyl diglycol carbonate), PADC, ont été étudiés par spectroscopie FT-IR et par simulation Monte Carlo. La quantité de groupes OH formés est équivalente à la quantité de disparition des groupes éther. L’utilisation de radiations à faible TLE a prouvé que les fonctions carbonyle ne disparaissent que lorsque deux électrons au minimum interagissent avec une seule unité de répétition du polymère. Les résultats obtenus avec des protons de haute énergie permettent de comprendre la différence entre des traces révélables et non-révélables. Sur la base de ces résultats, un nouveau concept physique de Fluence Electronique Radiale autour de la Trace d’un Ion, défini comme la densité d'électrons secondaires qui traversent une surface cylindrique de rayon donné, est proposé pour décrire le seuil de détection du PADC en utilisant le code Geant4-DNA. Les connaissances acquises sont utiles pour trouver des agencements moléculaires appropriés pour de nouveaux détecteurs de sensibilités désiréesThe structure and formation process of latent tracks in poly(allyl diglycol carbonate), PADC, have been examined using the combination of FT-IR spectrometry and a Monte Carlo simulation. The generation amount of OH groups is almost equivalent to the loss amount of ether. An important role of the secondary electron that the carbonyl can be broken only when more than two electrons pass through a single repeat unit is clarified by experiments using low LET radiations. Results of high energy protons lead us to the elucidation of the difference between etchable and un-etchable tracks. Based on these results, a new physical concept of Radial Electron Fluence around Ion Tracks, which is defined as the number density of secondary electron that pass through the cylinder surface with a certain radius is proposed for the detection threshold of PADC using Geant4-DNA. Obtained knowledge is helpful to find appropriate molecule arrangements for new etched track detector with desired sensitivities
9
Petrov, Alexander. "Principles of production of new devices for micro- and nanoelectronics on the base of materials with ion tracks". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=975458914.
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10
Khalil, Ali Saied, i askhalil2004@yahoo com. "Heavy-Ion-Irradiation-Induced Disorder in Indium Phosphide and Selected Compounds". The Australian National University. Research School of Information Sciences and Engineering, 2007. http://thesis.anu.edu.au./public/adt-ANU20070716.140841.
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Indium phosphide (InP) is an important III-V compound, with a variety of applications, for example, in light emitting diodes (LED), InP based photonic crystals and in semiconductor lasers, heterojunction bipolar transistors in integrated circuit applications and in transistors for microwave and millimeter-wave systems. The optical and electrical properties of this compound can be further tailored by ion implantation or prospectively by swift heavy ion beams.
¶
Thus knowledge of ion-induced disorder in this material is of important fundamental and practical interest. However, the disorder produced during heavy ion irradiation and the subsequent damage accumulation and recovery in InP is far from being completely understood. In terms of the damage accumulation mechanisms, the conclusions drawn in the numerous studies performed have often been in conflict with one another. A factor contributing to the uncertainties associated with these conflicting results is a lack of information and direct observation of the building blocks leading to the ultimate damage created at high ion fluences as an amorphous layer. These building blocks formed at lower fluence regimes by single ion impacts can be directly observed as isolated disordered zones and ion tracks for low energy and swift heavy ion irradiation, respectively.
¶
The primary aim of this work has thus been to obtain a better understanding of the disorder in this material through direct observations and investigation of disorder produced by individual heavy ions in both energy regimes (i.e. elastic and inelastic energy deposition regimes) especially with low ion fluence irradiations. In this thesis the heavy ion induced disorder introduced by low energy Au ions (100 keV Au+) and high energy Au (200 MeV Au+16) ion irradiation in InP were investigated using Transmission Electron Microscopy (TEM), Rutherford Backscattering Spectrometry (RBS/C) and Atomic Force Microscopy (AFM).
¶
The accumulation of damage due to disordered zones and ion tracks is described and discussed for both low energy and swift ion irradiation respectively.
¶
The in-situ TEM annealing of disordered zones created by 100 keV Au+ ion irradiation shows that these zones are sensitive to electron beam irradiation and anneal under electron energies not sufficient to elastically displace lattice atoms, i.e. subthreshold energies for both constituent atoms In and P.
¶
Ion tracks due to swift heavy ion irradiation were observed in this material and the interesting track morphology was described and discussed. The surface nanotopographical changes due to increasing fluence of swift heavy ions were observed by AFM where the onset of large increase in surface roughness for fluences sufficient to cause complete surface amorphization was observed.
¶
In addition to InP, the principle material of this project, a limited amount of TEM observation work has been performed on several other important compounds (apatite and monazite) irradiated by 200 MeV Au+ ions for comparative purposes. Again the observed segmental morphology of ion tracks were shown and possible track formation scenario and structure were discussed and similarities were drawn to the previously observed C60 cluster ion tracks in CaF2 as more knowledge and data base exist about defect dynamics and formation in that material.
11
Delgado, Adriana de Oliveira. "Estudo da formação de rastos nucleares em polímeros". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-26032008-080816/.
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O campo da modificação de materiais, através da implantação iônica, vem crescendo amplamente, impulsionado pelas aplicações tecnológicas na biologia, medicina, eletrônica, e outras áreas. Um dos aspectos relacionados ao entendimento desses novos materiais é a identificação e caracterização dos danos produzidos, após a irradiação. Nesse trabalho, foi proposto estudar as modificações microscópicas, após irradiação com feixe de íons de alta energia, em três diferentes polímeros: o policarbonato(Makrofol KG), com espessura de 8 µm; o polialil diglicol carbonato PADC (CR39), espessura 900 µm; e o nitrato de celulose (LR115), espessura 12µm. As amostras foram irradiadas com feixe de Au de 350 MeV no acelerador Cíclotron do Hahn-Meitner Institut (HMI) em Berlim. As amostras de Makrofol KG foram dispostas em superposição de 6 folhas posicionadas perpendicularmente à direção do feixe e foram irradiadas com fluências de 10^8, 10^9 e 10^11 íons/cm^2. As amostras de CR39 e LR115 foram irradiadas com fluência de 10^9 íons/cm^2, sem superposição das amostras. O estudo comparativo dos danos estruturais nas amostras, antes e após a irradiação, foi realizado através de técnicas analíticas como Espectroscopia de Absorção no Infravermelho por Transformada de Fourier (FTIR), Difração de Raios X (XRD), Análise com Detecção de Recuo Elástico (ERDA), e Corrosão Química, para visualização e caracterização dos poros através do microscópio óptico e microscópio eletrônico de varredura. A análise FTIR das amostras mostrou haver diminuição do número de ligações simples, em favor do aumento do número de ligações duplas e triplas, após irradiação das amostras. Além disso, observou-se que a intensidade dos danos observados aumenta com o poder de freamento médio dos íons de Au durante a penetração nas amostras. A análise XRD, por sua vez, permitiu verificar um decréscimo da cristalinidade do Makrofol KG irradiado, enquanto observou-se indicações de variação da densidade do CR39, após irradiação, e inexistência de variação no LR115. A metodologia proposta para análise das amostras através da técnica ERDA não se mostrou eficiente para determinar a variação no teor de H das mesmas após a irradiação, não sendo possível obter resultados conclusivos para as amostras. Na análise dos poros, após corrosão química, observou-se diferentes comportamentos. As amostras de CR39 apresentaram uma evolução de superfície porosa para superfície pontiaguda com o aumento do tempo de corrosão, e obteve-se o valor Va = 1,213 (17) µm/h para a velocidade de abertura do poros. Por outro lado, as diferentes folhas de Makrofol KG mantiveram a topografia porosa, sendo que a velocidade de abertura dos poros apresentou dependência com o poder de freamento dos íons na irradiação. Comparando amostras com valores semelhantes do poder de freamento, o resultado de Va obtido para o Makrofol é cerca de três vezes maior que o obtido para o CR39.The research in the field of material modification with ion implantation has greately improved, stimulated by technological applications in biology, medicine, electronics and other related areas. One of the correlated aspects in understanding these new materials is the identification and characterization of the damage produced by ion beam irradiation. In this work, we propose to identify the microscopic modification in polymers, after their irradiation with a high energy beam. Three polymers have been used: polycarbonate foils (Makrofol KG), 8 µm thick; polyalyl diglycol carbonate PADC (CR39) 900 µm thick and cellulose nitrate(LR115) 12 µm thick. The samples were irradiated with 350 MeV Au beam from the Cyclotron accelerator at Hahn-Meitner Institut (HMI) in Berlin. The Makrofol samples were placed in a 6-foil stack positioned in normal direction relative to the incident beam, in order to stop the projectiles. The irradiations were performed with ion fluences of 10^8, 10^9 e 10^11 ions/cm^2. The CR39 and LR115 samples, thicker than the range, were irradiated with the fluency of 10^9 ions/cm^2. The investigation of structural damage in the samples, after irradiation, was performed through analytical techniques such as: Fourier Transform Infrared Absorption Spectroscopy (FTIR), X Ray Difraction (XRD), Elastic Recoil Detection Analysis (ERDA), and Etching, followed by pore characterization using an optical and a scanning electron microscopes. The FTIR analysis of the samples showed a decrease in the number of simple bonds and an increase in the number of double and triple bonds, after irradiation. Moreover, it was observed that the damage intensity increases with the mean stopping power of Au. The XRD analysis allowed the observation of crystallinity decrease in Makrofol, and gave indications about a possible deviation in CR39 density, after sample irradiation, and no variation in LR115 samples. The methodology proposed using ERDA technique was not eficient to determine the H atoms teor in the polymers after irradiation, so, it was not possible to get conclusive results from the data. In the pore analysis, after etching, different behaviors were observed. The CR39 samples showed an evolution from a porous surface to a sharply peaked surface and a pore opening rate Va = 1,213 (17) µm/h was obtained. On the contrary, different Makrofol KG foils preserved the porous topography for different etching times. The pore opening rate showed dependence with ion stopping power in the irradiation. Comparing samples with similar values of stopping power, the result is that Makrofol Va is three times greater than the obtained to CR39.
12
Lixandrão, Filho Arnaldo Luis 1983. "Estudos de "annealing" de traços de íons e traços de fissão em muscovita". [s.n.], 2016. http://repositorio.unicamp.br/jspui/handle/REPOSIP/330569.
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Orientador: Sandro Guedes de OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-08-31T19:22:36Z (GMT). No. of bitstreams: 1 LixandraoFilho_ArnaldoLuis_M.pdf: 11489211 bytes, checksum: 0e5e2fdcd3551b722c60d418964284ee (MD5) Previous issue date: 2016
Resumo: O trabalho consistiu em estudar a muscovita como termocronômetro. Por ter pequena quantidade de urânio, abaixo de 5 partes por milhão, a utilização direta é inviável. Dessa forma, irradiamos placas de muscovita com íons de $^{238}U$ moderados por folhas de alumínio (resultando em diferentes energias) e com diferentes ângulos de incidência, com a finalidade de analisar o comportamento da muscovita com traços de íons e também para que esses íons criassem canais com o objetivo de revelar maior quantidade de traços fósseis. Realizamos planejamento utilizando algorítimo D-ótimo para realizar tratamentos térmicos com diferentes tempos e temperaturas, a fim de obter dados de ''annealing'' para a muscovita. Medimos o comprimento dos traços de íons projetados com as seguintes dependências: massa do íon, tempo de ''annealing'', temperatura de ''annealing'', energia de incidência e ângulo de incidência. Os parâmetros energia de incidência, ângulo de incidência e características do íon, não são considerados em nenhum dos modelos disponíveis na literatura. Assim sendo, formulamos um novo modelo empírico para a cinética de ''annealing'': $l = l_0 + a*energia - e^{\left(\frac{temperatura}{b + c*log(tempo)}\right)}$, $l$ sendo comprimento do traço com ''annealing'' e $l_0$ o comprimento sem ''annealing'' e, as constantes $a$, $b$ e $c$ ajustadas a partir dos dados experimentais. As constantes $a$ e $L_0$ são as variáveis relativas ao ângulo de incidência, tipo do íon e energia. Este modelo, além de ter um número menor de parâmetros, com uma simples modificação, $\frac{L}{L_0} = 1 + A.e^{\frac{T}{b}},\ b = B+C.ln(t)$, pode ser aplicado também para traços de fissão confinados. Nesse caso são apenas 3 parâmetros, $A$, $B$ e $C$ e o modelo ajustado possibilita a análise térmica em qualquer mineral que possuir dados experimentais. Neste trabalho mostramos o ajuste para os seguintes minerais: apatita, zircão, epídoto e muscovita. A partir dos traços de íons que sofreram ''annealing'' conseguimos ajustar parâmetros e obtivemos resultados consistentes com trabalhos anteriores. Um deles foi a previsão de \citeauthor{Bigazzi1967} que, possivelmente, utilizou amostras de superfície à 303K. Com esse resultado, validamos que traços de íons podem gerar bons resultados no estudo de ''annealing'' em laboratório e em tempos geológicos. Por fim, desenvolvemos um aplicativo que contempla: o ajuste dos parâmetros do modelo aos dados experimentais de modo automático, a obtenção de índices térmicos (temperatura de fechamento e zona de ''annealing parcial'') independente do mineral e a reconstrução de histórias térmicas para múltiplos minerais a partir de vínculos geológicos, da idade e de uma lista de comprimento de traços confinados. Além dessas características, a inédita ferramenta utiliza interface ''web'' que pode ser utilizada em qualquer plataforma e sistema operacional. Por fim, os resultados significativos foram: novos dados de ''annealing'' de traços de íons em mica muscovita, novo modelo empírico para abordar a cinética do ''annealing'' para traços de íons ou fissão e um aplicativo para tratamento de dados, ajuste, obtenção de índices térmicos e histórias térmicas
Abstract: In this work we studied muscovite as a thermocronometer. Muscovite have low amount of uranium, below 5 parts per million. Because of that it is impractical to be used as thermocronometer. Thus irradiating it with swift heavy ions of $ ^ {238} U $, moderated by aluminum foil (resulting in different energies) and with different angles of incidence is one way to analyze the behavior of muscovite ion tracks. These tracks can act like channels to the acid, chemical etching, revealing more fossil traces. We carry out experimental planning using D-optimal algorithm do thermal treatments at different times and temperatures in order anneal muscovite tracks. We measured the length of the ion tracks created with the following dependencies: ion mass, annealing time and temperature, impact energy and angle of incidence. The incidence of energy parameters, angle of incidence and ion characteristics are not considered in any of the models available in the literature. Therefore, we have developed a new empirical model for the kinetics of annealing: $l = l_0 + a*energia - e^{\left(\frac{temperatura}{b + c*log(tempo)}\right)}$, $l$ annealed fission track length and $l_0$ fission track length and the constants $a$, $b$ and $c$ adjusted from the experimental data . The constants $a$ and $L_0$ are related to the angle of incidence, type of ion and energy. This model, besides having fewer parameters, with a simple modification, $\frac{L}{L_0} = 1 + A.e^{\frac{T}{b}},\ b = B+C.ln(t)$ may also be applied to confined fission tracks. The adjusted model , with only 3 parameters, $A$, $B$ and $C$, enables thermal analysis in any mineral that has experimental data. We show fitting for the following minerals: apatite, zircon, epidote and muscovite. From the annealed ion tracks we fit the data to get all parameters and obtained results consistent with previous work. One was that we predict that \citeauthor{Bigazzi1967}, possibly, used surface samples with 303 K. With this result, we validate that ions tracks can generate good results using annealing laboratory data extrapolated to geological time. Finally, we developed an application with the following features: automatic model fitting to experimental data, simulation of thermal index (closure temperature and partial annealing) independent of the mineral and the reconstruction of thermal histories for multiple minerals from geological. In addition to these features, the application has web interface and can be used on any platform and operating system. Finally, the most significant results of this work were: new experimental annealing data of ion tracks in muscovite, new empirical model to increase the knowledge of the ion or fission tracks annealing kinetics and an application for data processing, fit and simulation of thermal index and thermal histories reconstruction
Mestrado
Física
Mestre em Física
13
Kanike, Vanaja. "“Acid-spike” effect in spurs/tracks of the low/high linear energy transfer radiolysis of water : potential implications for radiobiology and nuclear industry". Mémoire, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/9711.
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Résumé : Les ions hydronium (H3O
+
) sont formés, à temps courts, dans les grappes ou le long des
trajectoires de la radiolyse de l'eau par des rayonnements ionisants à faible transfert
d’énergie linéaire (TEL) ou à TEL élevé. Cette formation in situ de H3O
+
rend la région des
grappes/trajectoires du rayonnement temporairement plus acide que le milieu environnant.
Bien que des preuves expérimentales de l’acidité d’une grappe aient déjà été signalées, il
n'y a que des informations fragmentaires quant à son ampleur et sa dépendance en temps.
Dans ce travail, nous déterminons les concentrations en H3O
+
et les valeurs de pH
correspondantes en fonction du temps à partir des rendements de H3O
+
calculés à l’aide de
simulations Monte Carlo de la chimie intervenant dans les trajectoires. Quatre ions
incidents de différents TEL ont été sélectionnés et deux modèles de grappe/trajectoire ont
été utilisés : 1) un modèle de grappe isolée "sphérique" (faible TEL) et 2) un modèle de
trajectoire "cylindrique" (TEL élevé). Dans tous les cas étudiés, un effet de pH acide
brusque transitoire, que nous appelons un effet de "pic acide", est observé immédiatement
après l’irradiation. Cet effet ne semble pas avoir été exploré dans l'eau ou un milieu
cellulaire soumis à un rayonnement ionisant, en particulier à haut TEL. À cet égard, ce
travail soulève des questions sur les implications possibles de cet effet en radiobiologie,
dont certaines sont évoquées brièvement. Nos calculs ont ensuite été étendus à l’étude de
l'influence de la température, de 25 à 350 °C, sur la formation in situ d’ions H3O
+
et l’effet
de pic acide qui intervient à temps courts lors de la radiolyse de l’eau à faible TEL. Les
résultats montrent une augmentation marquée de la réponse de pic acide à hautes
températures. Comme de nombreux processus intervenant dans le cœur d’un réacteur
nucléaire refroidi à l'eau dépendent de façon critique du pH, la question ici est de savoir si
ces fortes variations d’acidité, même si elles sont hautement localisées et transitoires,
contribuent à la corrosion et l’endommagement des matériaux.Abstract : Hydronium ions (H3O+) are formed within spurs or tracks of the low or high linear energy transfer (LET) radiolysis of pure, deaerated water at early times. The in situ radiolytic formation of H3O+ renders the spur and track regions temporarily more acid than the surrounding medium. Although experimental evidence for an acidic spur has already been reported, there is only fragmentary information on its magnitude and time dependence. In this work, spur or track H3O+ concentrations and the corresponding pH values are obtained from our calculated yields of H3O+ as a function of time, using Monte Carlo track chemistry simulations. We selected four impacting ions and we used two different spur and track models: 1) an isolated “spherical” spur model characteristic of low-LET radiation and 2) an axially homogeneous “cylindrical” track model for high-LET radiation. Very good agreement was found between our calculated time evolution of G(H3O+) in the radiolysis of pure, deaerated water by 300-MeV incident protons (which mimic 60Co gamma/fast electron irradiation) and the available experimental data at 25 °C. For all cases studied, an abrupt transient acid pH effect, which we call an “acid spike”, is observed during and shortly after the initial energy release. This acid-spike effect is virtually unexplored in water or in a cellular environment subject to the action of ionizing radiation, especially high-LET radiation. In this regard, this work raises a number of questions about the potential implications of this effect for radiobiology, some of which are briefly evoked. Our calculations were then extended to examine the effect of temperature from 25 to 350 °C on the yield of H3O+ ions that are formed in spurs of the low-LET radiolysis of water. The results showed an increasingly acidic spike response at higher temperatures. As many in-core processes in a water-cooled nuclear reactor critically depend on pH, the question here is whether these variations in acidity, even highly localized and transitory, contribute to material corrosion and damage.
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Oganesyan, Vartan Rubenovitch. "Untersuchung des Porenöffnungsprozesses latenter Spuren leichter niederenergetischer Ionen in CR-39 mittels elektrolytischer Ätzung". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1127996096039-75308.
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Festkörperspurdetektoren (FKSD) auf der Basis von Polymermaterialien sind ein geeignetes Mittel zum Nachweis von Ionenstrahlung [1]. Ebenso können damit Neutronen über ihre sekundären Ionen gemessen werden. Als passive und integrierende Detektoren eignen sie sich insbesondere gut für die Dosimetrie, wobei die geringe bzw. fehlende Empfindlichkeit für Elektronen und Photonenstrahlung ein weiteres Argument für die Anwendungen in gemischten Strahlungsfeldern darstellt. Als passive Detektoren arbeiten FKSD ohne zusätzliche Messelektronik und Stromversorgung. Das macht sie insbesondere für die Personen- und Ortsdosimetrie interessant. Allerdings sind die latenten, submikroskopischen Ionenspuren nach der Exposition nicht unmittelbar sichtbar. Erst durch einen mehr oder weniger aufwendigen Ätzprozess werden diese lichtmikroskopisch oder für das Auge direkt sichtbar. Da bei FKSD von der Herstellung bis zur Ätzung alle Ereignisse registriert werden, handelt es sich somit auch um integrierende Detektoren.Für die Dosimetrie ist insbesondere der Nachweis von leichten Ionen bis zu spezifischen Energien von 10 MeV / Nukleon wichtig. Protonenstrahlung wird für die Radiotherapie von Geschwulstkrankheiten angewendet; die meisten leichten Ionen der Elemente Wasserstoff bis Sauerstoff sind Bestandteile der Sekundärstrahlung von Neutronen,[Alpha]-Teilchen treten häufig als Zerfallsprodukt verschiedener schwerer Radioisotope auf. Während eine große Zahl von Polymeren eine Empfindlichkeit für schwere Ionen zeigen, ist die Auswahl für leichte Ionen schon sehr eingeschränkt.[Alpha]-Teilchen können noch mit verschiedenen Polykarbonaten, Zelluloseacetat und -nitrat nachgewiesen werden. Die Registrierung von Protonen ist derzeit nur mit dem besonderen Polykarbonat CR - 39 und mit Zellulose (di/tri) nitrat möglich. Natürlich eignen sich diese Materialien auch hervorragend zur Messung von [Alpha] -Teilchen. Leichte Ionen stellen weiterhin eine wichtige Sonde in der Radiobiologie dar. Festkörperspurdetektoren können hier als Monitore für die getroffenen Zellen und Zellbestandteile dienen. Dadurch ist prinzipiell eine genaue Lokalisierung der getroffenen Zellbausteine/Organellen möglich...
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Oganesyan, Vartan Rubenovitch. "Untersuchung des Porenöffnungsprozesses latenter Spuren leichter niederenergetischer Ionen in CR-39 mittels elektrolytischer Ätzung". Doctoral thesis, Technische Universität Dresden, 2004. https://tud.qucosa.de/id/qucosa%3A24576.
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Festkörperspurdetektoren (FKSD) auf der Basis von Polymermaterialien sind ein geeignetes Mittel zum Nachweis von Ionenstrahlung [1]. Ebenso können damit Neutronen über ihre sekundären Ionen gemessen werden. Als passive und integrierende Detektoren eignen sie sich insbesondere gut für die Dosimetrie, wobei die geringe bzw. fehlende Empfindlichkeit für Elektronen und Photonenstrahlung ein weiteres Argument für die Anwendungen in gemischten Strahlungsfeldern darstellt. Als passive Detektoren arbeiten FKSD ohne zusätzliche Messelektronik und Stromversorgung. Das macht sie insbesondere für die Personen- und Ortsdosimetrie interessant. Allerdings sind die latenten, submikroskopischen Ionenspuren nach der Exposition nicht unmittelbar sichtbar. Erst durch einen mehr oder weniger aufwendigen Ätzprozess werden diese lichtmikroskopisch oder für das Auge direkt sichtbar. Da bei FKSD von der Herstellung bis zur Ätzung alle Ereignisse registriert werden, handelt es sich somit auch um integrierende Detektoren.Für die Dosimetrie ist insbesondere der Nachweis von leichten Ionen bis zu spezifischen Energien von 10 MeV / Nukleon wichtig. Protonenstrahlung wird für die Radiotherapie von Geschwulstkrankheiten angewendet; die meisten leichten Ionen der Elemente Wasserstoff bis Sauerstoff sind Bestandteile der Sekundärstrahlung von Neutronen,[Alpha]-Teilchen treten häufig als Zerfallsprodukt verschiedener schwerer Radioisotope auf. Während eine große Zahl von Polymeren eine Empfindlichkeit für schwere Ionen zeigen, ist die Auswahl für leichte Ionen schon sehr eingeschränkt.[Alpha]-Teilchen können noch mit verschiedenen Polykarbonaten, Zelluloseacetat und -nitrat nachgewiesen werden. Die Registrierung von Protonen ist derzeit nur mit dem besonderen Polykarbonat CR - 39 und mit Zellulose (di/tri) nitrat möglich. Natürlich eignen sich diese Materialien auch hervorragend zur Messung von [Alpha] -Teilchen. Leichte Ionen stellen weiterhin eine wichtige Sonde in der Radiobiologie dar. Festkörperspurdetektoren können hier als Monitore für die getroffenen Zellen und Zellbestandteile dienen. Dadurch ist prinzipiell eine genaue Lokalisierung der getroffenen Zellbausteine/Organellen möglich...
16
Gehrke, Hans-Gregor [Verfasser], Hans [Akademischer Betreuer] Hofsäss, Christian [Akademischer Betreuer] Jooß, Jörn [Akademischer Betreuer] Große-Knetter, Hans-Ulrich [Akademischer Betreuer] Krebs, Markus [Akademischer Betreuer] Münzenberg i Michael [Akademischer Betreuer] Seibt. "Electrical characterization of conductive ion tracks in tetrahedral amorphous carbon with copper impurities / Hans-Gregor Gehrke. Gutachter: Hans Hofsäss ; Christian Jooß ; Jörn Große-knetter ; Hans-ulrich Krebs ; Markus Münzenberg ; Michael Seibt. Betreuer: Hans Hofsäss". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1046446479/34.
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Schiedt, Birgitta. "Characterization and application of ion track-etched nanopores". [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:16-opus-74264.
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Lindeberg, Mikael. "High aspect ratio microsystem fabrication by ion track lithography". Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://publications.uu.se/theses/91-554-5515-8/.
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Yu, Jie. "Oxidation of ultra high molecular weight polyethylene, UHMWPE, containing traces of cobalt ion". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/MQ53349.pdf.
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KATSUOKA, LIDIA. "Agentes complexantes no controle analitico de tracos de fluoreto por eletrodo ion-seletivo". reponame:Repositório Institucional do IPEN, 1996. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10451.
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Made available in DSpace on 2014-10-09T12:38:53Z (GMT). No. of bitstreams: 0Made available in DSpace on 2014-10-09T14:01:57Z (GMT). No. of bitstreams: 1 02809.pdf: 6234365 bytes, checksum: 25107a337d71b51089353992495839d5 (MD5)
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Toimil, Molares Maria Eugenia. "Fabrication and characterisation of copper nanowires electrochemically deposited in etched ion track membranes". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96362282X.
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Schiedt, Birgitta [Verfasser], i Reinhard [Akademischer Betreuer] Neumann. "Characterization and application of ion track-etched nanopores / Birgitta Schiedt ; Betreuer: Reinhard Neumann". Heidelberg : Universitätsbibliothek Heidelberg, 2007. http://d-nb.info/1178796930/34.
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Fokin, Maria Alexandra. "Space-Time Analysis of Magmatism: Evidence for a Early Cryogenian Plume Track in Eastern Laurentia". Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/35187.
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In the Grenville age basement rocks of Virginia and North Carolina, nearly thirty Cryogenian volcanic/plutonic complexes have been recognized. A-type granites and rhyolites dominate the igneous complexes within the Cryogenian Magmatic Province (CMP), but compositional variations range from gabbro through syenites. The mineralogy, chemical composition and field data including microstructural emphasis suggests emplacement of these igneous complexes in an extensional setting.
In this study U/Pb zircon ages of several plutons were determined using secondary ion mass spectrometry. The ages suggest two episodes of magmatism. An older episode (739 to 745 Ma) of magmatism includes White Oak Creek, Suck Mountain, and Amisville plutons. The younger episode (613 to 694 Ma) includes Dillons Mill, Stewartsville, Mobley Mountain, Rockfish River, and Fine Creek Mills plutons.
These two age groups also display differences in geochemistry. In contrast to the older group of plutons, the younger plutons are characteristically more metaluminous, lower in silica, higher in aluminum and phosphate, lower agpatic index, less REE enrichment, minimal K-feldspar and accessory mineral fractionation.
The distribution of the older group of plutons over a distance of nearly 600km requires the development of a crustal scale zone of extension. A space-time analysis suggests that these plutons represent a continental plume track similar to the White Mountain Magma Series. Plume head arrival ages of 765 to 754 Ma in the southern part of the region are measurably older than 735 to 705 Ma observed in the north, and yield a plate motion rate of ~2 cm/year.Master of Science
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TOAPANTA, PETER DARWIN IZA. "ION DESORPTION DESCRIBED BY AN EXTENDED NUCLEAR TRACK MODEL: APPLICATION TO WATER ICE CLUSTERS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9157@1.
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CENTRO LATINO-AMERICANO DE FÍSICAA dessorção de íons secundários induzida por impacto de projéteis velozes é um fenômeno de interesse tanto da pesquisa fundamental dos processos de colisão quanto da Física de Superfícies, Biociência e Astrofísica. O modelo teórico de dessorção iônica induzida por elétrons baseado na formação de um traço nuclear é aprimorado no presente trabalho. Considera-se que o traço seja composto por um infratraço de carga positiva e um ultratraço de carga negativa. Ao chegarem na superfície do sólido, os elétrons secundários emanados do infratraço geram íons que são em seguida acelerados por ação do campo elétrico produzido pelos traços. Os dados experimentais escolhidos para testar o modelo correspondem à dessorção iônica induzida em filmes finos de gelo (H2O) por íons de nitrogênio de 1,7 MeV. As velocidades de emissão e as massas dos íons dessorvidos foram determinadas pela técnica de tempo- de-vôo. Empregou-se um detector de íons composto por um par de placas de microcanais e por um anodo sensível à posição de impacto dos íons. Os dados obtidos pela técnica XY-TOF mostram diferenças de simetrias na distribuição angular dos íons secundários. Em especial, observou-se emissão quase isotrópica dos agregados leves em relação a normal à superfície, contrastando com a dos agregados pesados que apresenta distribuição assimétrica atribuída a um efeito de memória da direção do projétil durante a emissão iônica. Um acordo entre os resultados do modelo e os dados experimentais é considerado razoáve
Secondary ion desorption induced by impact of fast projectiles is an important phenomenon not only because it is directly connected to atomic collision processes in solids, but also to practical implications in the Physics of Surfaces, Bioscience and Astrophysics. A theoretical model describing the desorption induced by secondary electron (SEID) produced in nuclear tracks is extended in the present work. It considers that the nuclear track is composed by a positive charged infratrack and a negative charged ultratrack. Secondary electrons emanated from infratrack reach the surface of the solid and generate molecular ions which are accelerated by an electric field produced by the track. The experimental data obtained by a 1.7 MeV nitrogen beam inducing electronic sputtering on condensed water target are used to test the SEID model. The initial velocity vectors and the masses of the emitted ions were obtained by the time-of-fight technique equipped with a position sensitive delay line detector XY-TOF. The data obtained by the technique show differences of symmetries in the angular distribution of the secondary ions. In particular, isotropic emission was observed for light clusters in relation to normal to the surface, contrasting with heavy clusters that show an asymmetric distribution attributed to nuclear track memory direction during the emission. The agreement between the model results and experimental data is considered reasonable.
La desorción de iones secundarios a partir de la incidencia de proyectiles rápidos en superficies es un fenómeno de gran interés científico en áreas de Física de Colisiones (interacciones ión-sólido), Física de Superficies, Bio-ciencia y Astrofísica. En esta Tesis fue desarrollado un modelo teórico para describir el proceso de desorción iónica inducida por los electrones emitidos durante la formación del trazo nuclear. El modelo considera que el trazo trazo nuclear. Las predicciones del modelo fueron comparadas con las mediciones de las especies emitidas por la incidencia de iones de nitrógeno de 1,7 MeV en películas delgadas de hielo (H2O). Las especies emitidas y sus velocidades iniciales fueron determinadas utilizando la técnica tiempo de vuelo (TOF). Fue utilizado un detector formado por un par de placas de micro canales con un ánodo sensible a la posición de impacto de los iones (técnica XY-TOF). Dos tipos de distribuciones angulares de los iones secundarios fueron observadas: isotrópica para masas pequeñas y anisotrópica para masas grandes. La distribución angular de masas grandes es preferencialmente simétrica a la dirección de incidencia del proyectil con respecto a la normal a la superficie y se debe al efecto de memoria del trazo nuclear sobre la dirección de incidencia del proyectil. Los resultados teóricos y los valores experimentales concuerdan parcialmente.
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Nkosi, Mlungisi Moses. "Preparation and physico-chemical properties of nickel nanostructured materials deposited in etched ion-track membrane". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_6214_1182749152.
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The development of finely dispersed powders and superfine-grained materials intended for application in various areas of science and engineering is one of the challenges facing modern nanotechnology. Thus, specific fundamental and applied research was required in order to consolidate advancement made in preparing nano- and submicron crystalline composite materials.
Useful templates for electrochemical deposition of nanowires include porous alumina films formed by anodic oxidation of aluminium, nuclear track-etched porous membranes, nanochannel array-glass and mesoporous channel hosts. The properties of the nanowires are directly related to the properties of the nanoporous templates such as, the relative pore orientations in the assembly, the pore size distribution, and the surface roughness of the pores. The template synthesis method, based on the use of porous polymeric and inorganic matrixes, is now actively used for synthesis of such composite materials. The method allows the chemical and/or electrochemical synthesis of nano- and microstructured tubes and wires consisting of conducting polymers, metals and semiconductors.
In this study various technological challenges relating to template synthesis and development of nickel nano- and microstructures on adequately strong and durable substrates were investigated. The two methods used were the electrochemical and chemical deposition. &ldquo
Hard nickel&rdquo
bath solution was used for optimal nickel deposition. This optimization included investigating variables such as the template structure, type of electrolyte and form of electrolytic deposition. Scanning Electron Microscopy was used to investigate the structures of template matrixes and the resultant materials. The cyclic voltammetry method was applied for the analysis of electrochemical properties and hydrogen evaluation reaction of nano- and microstructured nickel based electrodes. The activity of composite nano- and microstructured materials in various configurations resulting from pore filling of template matrices by nickel was explored. Studies of the physical structure and chemical properties of the nanostructured materials included investigating the necessary parameters of template matrices. The optimum conditions of synthesis, which allowed development of materials with the highest catalytic activity, were determined.
The effect of the template structure on microcrystallinity of the catalyst particles was established using the XRD method. Different new types of non-commercial asymmetric ion track membranes has been tested for nanostructure preparation. The catalytic activity of the new developed nanomaterials is higher as compared to materials using commercial templates. The procedures to modify the newly developed nickel catalyst with Pt, Pd and Pt-Pd alloy have been developed. The Pt and Pt-Pd alloy containing catalyst showed the best performance in water electrolysis. In this work, the promising role for specific application of the new materials in hydrogen economy has been demonstrated.
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Hinrichs, Joachim. "Geochemical tracers in the deep-sea and the North Sea Geochemische Tracer in der Tiefsee und in der Nordsee /". [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962793574.
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Cline, David James 1956. "Tracer experiments using bromide ion and two bacteriophages during soil aquifer treatment studies". Thesis, The University of Arizona, 1992. http://hdl.handle.net/10150/278114.
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The fate and transport of a conservative and two bacteriophage tracers during Soil Aquifer Treatment (SAT) has been examined. A 12 foot x 12 foot mini-basin containing seven stainless steel suction samplers ranging in depth from 1 to 20 feet below land surface was constructed in an existing recharge basin. Bromide ion and MS-2 and PRD-1 virus tracers were introduced into the mini-basin during recharge of secondary effluent during three of nine flooding cycles in order to aid in interpreting transport processes and to determine the presence of preferred-flow channels. High infiltration rates and discontinuous impeding layers resulted in 150 feet of horizontal transport. Preferential-flow channels were observed in both the vertical and horizontal directions. Less removal of bacteriophage MS-2 (hydrophilic, 28 nm dia) was observed at all depths compared to PRD-1 (hydrophobic, 62 nm dia). Results suggest that the fate of the virus transport in sandy alluvium is determined by the size and hydrophobicity of the viral particles, the quality of the percolating fluid, and composition of the soils.
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Adeniyi, Olushola Rotimi. "Ion track modification of polyimide film for development of palladium composite membrane for hydrogen separation and purification". Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8563_1330330939.
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South Africa s coal and platinum mineral resources are crucial resources towards creating an alternative and environmentally sustainable energy system. The beneficiation of these natural resources can help to enhance a sustainable and effective clean energy base infrastructure and further promote their exploration and exportation for economics gains. By diversification of these resources, coal and the platinum group metals (PGMs) especially palladium market can be further harnessed in the foreseeable future hence SA energy security can be guaranteed from the technological point of view. The South Africa power industry is a critical sector, and has served as a major platform in the South African socio-economic development. This sector has also been identified as a route towards an independent energy base, with global relevance through the development of membrane technologies to effectively and economically separate and purify hydrogen from the gas mixtures released during coal gasification. The South Africa power industry is a critical sector, and has served as a major platform in the SA&rsquo
s socio-economic development. This sector has also been identified as a route towards an independent energy base, with global relevance through the development of membrane technologies to effectively and economically separate and purify hydrogen from the gas mixtures released during coal gasification. Coal gasification is considered as a source of hydrogen gas and the effluent gases released during this process include hydrogen sulphide, oxides of carbon and nitrogen, hydrogen and other particulates. In developing an alternative hydrogen gas separating method, composite membrane based on organic-inorganic system is being considered since the other available methods of hydrogen separation are relatively expensive.
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Zhanbotin, A. Zh, A. S. Yessenbekov, M. M. Saifulin i V. V. Saiko. "Field Emission from an Array of Free-standing Copper Nanowires Grown in PET Ion-track Membranes". Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35319.
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There is a description of field emission from an array of free-standing copper nanowires grown in ion-beamed PET polymer films.Highly oriented, free standing cylindrical and conical copper nanowires were electrochemically grown in the pores of track etched PET films with pore density 1 106cm-2, 2 106cm-2 and 4х107cm-2. Copper nanowires were observed using scanning electron microscope, atomic force and elec-tro-force methods of scanning probe microscope. All of the nanowires showed high efficiency tunneling cur-rent (up to ~ -1uA) from metal samples to positive charged SPM cantilever.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35319
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Rauber, Markus [Verfasser], Wolfgang [Akademischer Betreuer] Ensinger i Christina [Akademischer Betreuer] Roth. "Controlled Synthesis of Nanowire Assemblies by Ion-Track Template Electrodeposition / Markus Rauber. Betreuer: Wolfgang Ensinger ; Christina Roth". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2012. http://d-nb.info/1106113624/34.
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Issa, Ragiab. "Experimental and mathematical modelling of metal ion-humic acid-silicate minerals interactions". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/experimental-and-mathematical-modelling-of-metal-ionhumic-acidsilicate-minerals-interactions(9d8c4096-d93a-4483-9790-4b65c6c2761e).html.
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A series of experiments were performed to study the sorption of humic acid and Eu3+ ion (at trace concentrations) on the minerals: montmorillonite, bentonite, diatomite and kaolinite in ternary systems. Humic acid and europium sorption were investigated as a function of humic acid concentration, ionic strength and pH. There was a strong uptake of humic acid on to the minerals with sorption increasing as humic acid concentration decreases. For montmorillonite, the uptake of discrete size fractions was also studied. It was found that the larger fractions were more strongly sorbing and were better able to retain Eu in solution.The ionic strength has an impact on Eu behaviour: in the absence of humic acid, sorption strength decreases, whilst in the presence of high concentrations of humic it increases. The sorption of Eu3+ increases from pH 2 to 5 in both the presence and absence of humic acid. Above pH 5, the Eu3+ showed different behaviour with and without humic acid, and as humic concentration became high (100 ppm), the Eu behaves in the same way as the humic. Bentonite is able to sorb humic acid and Eu3+ at any concentration expected in the environment, and shows the strongest sorption of any of the materials tested. Experiments confirmed that Eu is an excellent analogue for Am in these systems.The sorption of selected divalent and trivalent metal ions: Ni2+, Co2+, Zn2+, Cd2+, Eu3+ and Cr3+ on montmorillonite has been investigated in the micro-molar concentration range. In all cases, sorption strength increased with pH, and was consistently stronger for the tri-valent ions. In the presence of humic acid, there was some evidence for the enhancement of sorption. Uptake of metal ions (Co2+, Ni2+, Cd2+, Cr3+, Eu3+ and La3+) by natural and modified kaolinite was studied, and for all except Cr3+, it was found that kaolinite modified by manganese hydrothermal treatment gave the strongest sorption.A simple kinetic model was developed to simulate the experimental data for the sorption of humic acid and Eu3+ on the minerals. The model allows two humic binding sites on the mineral surface and two types of humic in solution, which can have different Eu3+ binding strengths. Metal ion surface complexation is modelled with a single kinetic equation. Ternary complexes are included in the model. The interaction of humic acid on the minerals can be fitted reasonably well. However, for the Eu3+ ion behaviour, although the model was able to give a reasonable fit to data for montmorillonite and bentonite, it could not reproduce the behaviour for kaolinite and diatomite.
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Adeniyi, Olushola Rotimi. "Swift heavy ion irradiation of polyester and polyolefin polymeric film for gas separation application". University of the Western Cape, 2015. http://hdl.handle.net/11394/4929.
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Philosophiae Doctor - PhDThe combination of ion track technology and chemical etching as a tool to enhance polymer gas properties such as permeability and selectivity is regarded as an avenue to establish technology commercialization and enhance applicability. Traditionally, permeability and selectivity of polymers have been major challenges especially for gas applications. However, it is important to understand the intrinsic polymer properties in order to be able to predict or identify their possible ion-polymer interactions thus facilitate the reorientation of existing polymer structural configurations. This in turn can enhance the gas permeability and selectivity properties of the polymers. Therefore, the choice of polymer is an important prerequisite. Polyethylene terephthalate (PET) belongs to the polyester group of polymers and has been extensively studied within the context of post-synthesis modification techniques using swift heavy ion irradiation and chemical treatment which is generally referred to as ‘track-etching’. The use of track-etched polymers in the form of symmetrical membranes structures to investigate gas permeability and selectivity properties has proved successful. However, the previous studies on track-etched polymers films have been mainly focused on the preparation of symmetrical membrane structure, especially in the case of polyesters such as PET polymer films. Also, polyolefins such as polymethyl pentene (PMP) have not been investigated using swift heavy ions and chemical etching procedures. In addition, the use of ‘shielded’ material on PET and PMP polymer films prior to swift heavy ion irradiation and chemical etching to prepare asymmetrical membrane structure have not been investigated. The gas permeability and selectivity of the asymmetrical membrane prepared from swift heavy ion irradiated etched 'shielded' PET and PMP polymer films have not been determined. These highlighted limitations will be addressed in this study. The overall objective of this study was to prepare asymmetric polymeric membranes with porous surface on dense layer from two classes of polymers; (PET and PMP) in order to improve their gas permeability and selectivity properties. The research approach in this study was to use a simple and novel method to prepare an asymmetric PET and PMP polymer membrane with porous surface and dense layer by mechanical attachment of ‘shielded’ material on the polymer film before swift heavy ion irradiation. This irradiation approach allowed for the control of swift heavy ion penetration depth into the PET and PMP polymer film during irradiation. The procedure used in this study is briefly described. Commercial PET and PMP polymer films were mechanically ‘shielded’ with aluminium and PET foils respectively. The ‘shielded’ PET polymer films were then irradiated with swift heavy ions of Xe source while ‘shielded’ PMP polymer films were irradiated with swift heavy ions Kr. The ion energy and fluence of Xe ions was 1.3 MeV and 106 respectively while the Kr ion energy was 3.57 MeV and ion fluence of 109. After swift heavy ion irradiation of ‘shielded’ PET and PMP polymer films, the attached ‘shielded’ materials were removed from PET and PMP polymer film and the irradiated PET and PMP polymer films were chemically etched in sodium hydroxide (NaOH) and acidified chromium trioxide (H2SO4 + CrO3) respectively. The chemical etching conditions of swift heavy ion irradiated ‘shielded’ PET was performed with 1 M NaOH at 80 ˚C under various etching times of 3, 6, 9 and 12 minutes. As for the swift heavy ion irradiated ‘shielded’ PMP polymer film, the chemical etching was performed with 7 M H2SO4 + 3 M CrO3 solution, etching temperature was varied between 40 ˚C and 80 ˚C while the etching time was between 40 minutes to 150 minutes. The SEM (surface and cross-section micrograph) morphology results of the swift heavy ion irradiated ‘shielded’ etched PET and PMP films showed that asymmetric membranes with a single-sided porous surface and dense layer was prepared and remained unchanged even after 12 minutes of etching with 1 M NaOH solution as in the case of PET and 2 hours 30 minutes of etching with 7 M H2SO4 + 3 M CrO3 as observed for PMP polymer film. Also, the swift heavy ion irradiated ‘shielded’ etched PET polymer film showed the presence of pores on the polymer film surface within 3 minutes of etching. After 12 minutes chemical etching with 1 M NaOH solution, the dense layer of swift heavy ion irradiated ‘shielded’ etched PET polymer film experienced significant reduction in thickness of about 40 % of the original thickness of as-received PET polymer film. The surface morphology of swift heavy ion irradiated ‘shielded’ etched PET polymer film by SEM analysis revealed finely distributed pores with spherical shapes for the swift heavy ion irradiated ‘shielded’ etched PET polymer film within 6 minutes of etching with 1 M NaOH solution. Also, after 9 minutes and 12 minutes of etching with 1 M NaOH solution of the swift heavy ion irradiated ‘shielded’ etched PET polymer film, the pore walls experienced complete collapse with intense surface roughness. Interestingly, the 12 minutes etched swift heavy ion ‘shielded’ irradiated PET did not lose its asymmetrical membrane structure despite the collapse of the pore walls. In the case of swift heavy ion irradiated ‘shielded’ etched PMP polymer film, SEM morphology analysis showed that the pores retained their shape with the presence of defined pores without intense surface roughness even after extended etching with 7 M H2SO4 + 3 M CrO3 for 2 hours 30 minutes. Also, the pores of swift heavy ion irradiated ‘shielded’ etched PMP polymer films were observed to be mono dispersed and not agglomerated or overlapped. The SEM cross-section morphology of the swift heavy ion irradiated ‘shielded’ etched PMP polymer film showed radially oriented pores with increased pore diameters in the PMP polymer film which indicated that etching was radial instead of lateral, and no through pores were observed showing that the dense asymmetrical structure was retained. The SEM results revealed that the pore morphology i.e. size and shape could be accurately controlled during chemical etching of swift heavy ion ‘shielded’ irradiated PET and PMP polymer films. The XRD results of swift heavy ion irradiated ‘shielded’ etched PET revealed a single diffraction peak for various times of chemical etching in 1 M NaOH solution at 3, 6, 9 and 12 minutes. The diffraction peak of swift heavy ion irradiated ‘shielded’ etched PET was observed to reduce in intensity and marginally shifted to lower angles from 25.95˚ 2 theta to 25.89˚ 2 theta and also became broad in shape. It was considered that the continuous broadening of diffraction peaks due to an increase in etching times could be attributed to disorderliness of the ordered region within the polymer matrix and thus decreases in crystallinity of the swift heavy ion irradiated ‘shielded’ etched PET polymer film. The XRD analysis of swift heavy ion irradiated ‘shielded’ etched PMP polymer films indicated the presence of the diffraction peak at 9.75˚ 2 theta with decrease in intensity while the diffraction peaks located at 13.34˚, 16.42˚, 18.54˚ and 21.46˚ 2 theta disappeared after chemical etching in acidified chromium trioxide (H2SO4 + CrO3) after 2 hours 30 minutes. The TGA thermal profile analysis of swift heavy ion irradiated ‘shielded’ etched PET did not show the evolution of volatile species or moisture at lower temperatures even after 12 minutes of etching in 1 M NaOH solution in comparison with commercial PET polymer film. Also, it was observed that the swift heavy ion irradiated layered’ etched PET polymer film started to undergo degradation at a higher temperature than untreated PET which resulted in an approximate increase of 50 ˚C in comparison with the commercial PET polymer film. The TGA results of swift heavy ion irradiated ‘shielded’ etched PMP polymer film revealed an improvement of about 50 ˚C in thermal stability before thermal degradation even after etching in acidified chromium trioxide for 2 hours 30 minutes at 80 ˚C. Spectroscopy (IR) analysis of the swift heavy ion irradiated ‘shielded’ etched PET and PMP polymer films showed the presence of characteristic functional groups associated with either PET or PMP structures. The variations of irradiation and chemical etching conditions revealed that the swift heavy ion ‘shielded’ irradiated etched PET polymer film experienced continuous degradation of available functional groups as a function of etching time and also with complete disappearance of some functional groups such as 1105 cm-1 and 1129 cm-1 compared with the as-received PET polymer film which are both associated with the para-substituted position of benzene rings. In the case of swift heavy ion irradiated ‘shielded’ etched PMP polymer film, spectroscopic (IR) analysis showed significant variations in the susceptibility of associated functional groups within the PMP polymer film with selective attack and emergence of some specific functional groups such as at 1478 cm-1, 1810 cm-1 and 2115 cm-1 which were assigned to methylene, CH3 (asymmetry deformation), CH3 and CH2 respectively Also, the IR results for swift heavy ion irradiated ‘shielded’ etched PMP polymer showed that unsaturated olefinic groups were the dominant functional groups that were being attacked by during etching with acidified chromium trioxide (H2SO4+CrO3) which is an aggressive chemical etchant. The gas permeability analysis of swift heavy ion irradiated ‘shielded’ etched PET and PMP polymer films showed that the gas permeability was improved in comparison with the as-received PET and as-received PMP polymer films. The gas permeability of swift heavy ion irradiated ‘shielded’ etched PET increased as a function of etching time and was found to be highest after 12 minutes of chemical etching in 1 M NaOH at 80 ˚C. In the case of swift heavy ion irradiated ‘shielded’ etched PMP, the gas permeability was observed to show the highest gas permeability after 2 hours 30 minutes of etching in H2SO4 + CrO3 solution. The gas permeability analysis for swift heavy ion irradiated ‘shielded’ PET and PMP polymer films was tested for He, CO2 and CH4 and the permeability results showed that helium was most permeable compared with CO2 and CH4 gases. In comparison, the selectivity analysis was performed for He/CO2 and CH4/He and the results showed that the selectivity decreased with increasing in etching time as expected. This study identified some important findings. Firstly, it was observed that the use of ‘shielded’ material on PET and PMP polymer films prior to swift heavy ion irradiation proved successful in the creation of asymmetrical polymer membrane structure. Also, it was also observed that the chemical etching of the ‘shielded’ swift heavy ion irradiated PET and PMP polymer films resulted in the presence of pores on the swift heavy ion irradiated side while the unirradiated sides of the PET and PMP polymer films were unaffected during chemical etching hence the pore depth could be controlled. In addition, the etching experiment showed that the pores geometry can be controlled as well as the gas permeability and selectivity properties of swift heavy ion ‘shielded’ irradiated etched PET and PMP polymer films. The process of polymer bulk and surface properties modification using ion-track technology i.e. swift heavy ion irradiation and subsequent chemical treatment of the irradiated polymer serves to reveal characteristic pore profiles unique to the prevailing ion-polymer interaction and ultimately results in alteration of the polymer characteristics.
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Rahmanian, Shirin [Verfasser], i Oliver [Akademischer Betreuer] Jäkel. "Application of Fluorescent Nuclear Track Detectors for Cellular Dosimetry in Ion Beam Radiotherapy / Shirin Rahmanian ; Betreuer: Oliver Jäkel". Heidelberg : Universitätsbibliothek Heidelberg, 2020. http://d-nb.info/1210490064/34.
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Ted, Malmgren, i Mojsovski Radovan. "Track It - Utveckling av ett plattformsöverskridande gränssnitt till en spårningsapplikation". Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20182.
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Hur framgångsrikt ett användargränssnitts design är beror mycket på användares inlärdarutiner och personliga preferenser. Denna studie ämnar ta reda på om skapandet av ettanvändargränssnitt, vilket skall användas i en GPS-spårnings applikation, kan tilltalaanvändare av de största plattformarna (iOS, Android). Android och iOS har deras egnaimplementationer på diverse områden inom gränssnitt och för att skapa en design vilkenbåda ”läger” gillar kräver att en del kompromisser behöver göras. Användargränssnittetskapades med de riktlinjer som Android och iOS rekommenderar i åtanke, tillsammans medallmänna riktlinjer för design som tagits fram i tidigare forskning. En SUS-undersökninggenomfördes för att få en poäng på användbarheten och en liten intervju genomfördes föratt ta reda på för och nackdelar på gränssnittet. Data som samlades in under undersökningenanalyserades därefter. Informationen användes sedan som en guide i ett iterativtutvecklingssteg på den existerande designen. Under denna iteration rättades deproblematiska områden till på designen för att tillfredsställa användarnas preferenser. Detslutliga resultatet analyserades och en slutsats presenteras till läsaren.The success of a user interface´s design is very much dependant on the users learnedroutines and personal preferences. This study aims to discover if it is possible to develop auser interface, which is to be used in a GPS-tracking application, can satisfy users of themajor development platforms (Android, iOS). Android and iOS have their ownimplementations of various user interface areas and compromises in the design are neededto make the user interface compelling to both sides. The interface is created with bothAndroid and iOS guidelines in mind, as well as generic design principles discovered inearlier research. A SUS study was conducted to get a usability score on the user interface,and a small interview was used to retrieve pros and cons in the interface. The data gatheredfrom the study was then analysed. The information was then used as a guide in an iterativedevelopment step of the existing design. In this iteration the design issues are corrected tosuit the preferences of the users. The result of the final material is then analysed and aconclusion is presented to the reader.
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Spende, Anne [Verfasser], Christina [Akademischer Betreuer] Trautmann i Wolfgang [Akademischer Betreuer] Ensinger. "Surface Modification of Etched Ion-Track Polymer Membranes by Atomic Layer Deposition / Anne Spende. Betreuer: Christina Trautmann ; Wolfgang Ensinger". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1112333150/34.
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Cassinelli, Marco [Verfasser], Christina [Akademischer Betreuer] Trautmann i Wolfgang [Akademischer Betreuer] Ensinger. "Thermoelectric Properties of Bi1-xSbx Nanowires Electrodeposited in Etched Ion-Track Membranes / Marco Cassinelli. Betreuer: Christina Trautmann ; Wolfgang Ensinger". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2016. http://d-nb.info/1112269649/34.
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Lachamp, Philippe. "Organisation et mise en place des synapses glutamatergiques dans le noyau du tractus solitaire du rat". Aix-Marseille 3, 2004. http://www.theses.fr/2004AIX30044.
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Le glutamate est le principal neurotransmetteur excitateur dans le noyau du tractus solitaire (NTS), une structure sensorielle qui reçoit des afférences d'origine viscérale. Nous avons identifié dans le NTS du rat une sous-population de terminaisons glutamatergiques qui co-expriment les deux transporteurs vésiculaires du glutamate (VGluT1 et VGluT2) et montré que cette population correspond à des terminaisons d'origine viscérale. Dans le NTS, la première phase de synaptogenèse se produit avant la naissance. Nous avons identifié deux autres périodes de production synaptique en période postnatale et montré qu'une partie de ces synapses formées après la naissance correspond à des synapses glutamatergiques. Nous avons ensuite étudié l'expression de la sous-unité GluR2 du récepteur AMPA et de la sous-unité NR1 du récepteur NMDA dans le NTS au cours du développement pré et postnatal. Les deux sous-unités sont présentes dans les synapses glutamatergiques au début de la synaptogenèse. La localisation de la sous-unité GluR2 ne change pas au cours de développement. Par contre, chez l'adulte la sous-unité NR1 est principalement extrasynaptiqueGlutamate is the main excitatory transmitter in the nucleus tractus solitarii (NTS), a sensory relay nucleus which receives visceral afferents. We describe a subpopulation of glutamatergic axon terminals that co-express both vesicular glutamate transporters (VGluT1 and VGluT2) in the rat NTS. We show that this sub-population of terminals originate from visceral afferent fibers. Synaptogenesis in the rat NTS begins before birth. We describe two other periods of synapse formation that take place during the first postnatal month. We show that a proportion of the synapses formed after birth correspond to glutamatergic synapses. We next demonstrate that the GluR2 subunit of the AMPA receptor and the NR1 subunit of the NMDA receptor are both localized within synapses at the onset of synaptogenesis in the rat NTS. No change in localization of the GluR2 subunit occurs with development whereas, in adults, the NR1 subunit is mainly found at extrasynaptic locations
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Bäckström, Gloria. "Protons, other Light Ions, and 60Co Photons : Study of Energy Deposit Clustering via Track Structure Simulations". Doctoral thesis, Uppsala universitet, Avdelningen för sjukhusfysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-206385.
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Radiotherapy aims to sterilize cancer cells through ionization induced damages to their DNA whilst trying to reduce dose burdens to healthy tissues. This can be achieved to a certain extent by optimizing the choice of radiation to treat the patient, i.e. the types of particles and their energy based on their specific interaction patterns. In particular, the formation of complex clusters of energy deposits (EDs) increases with the linear energy transferred for a given particle. These differences cause variation in the relative biological effectiveness (RBE). The complexity of ED clusters might be related to complex forms of DNA damage, which are more difficult to repair and therefore prone to inactivate the cells. Hence, mapping of the number and complexity of ED clusters for different radiation qualities could aid to infer a surrogate measure substituting physical dose and LET as main predictors for the RBE . In this work the spatial patterns of EDs at the nanometre scale were characterized for various energies of proton, helium, lithium and carbon ions. A track structure Monte Carlo code, LIonTrack, was developed to accurately simulate the light ion tracks in liquid water. The methods to emulate EDs at clinical dose levels in cell nucleus-sized targets for both 60Co photons and light ions were established, and applied to liquid water targets. All EDs enclosed in such targets were analyzed with a specifically developed cluster algorithm where clustering was defined by a single parameter, the maximum distance between nearest neighbour EDs. When comparing measured RBE for different radiation qualities, there are cases for which RBE do not increase with LET but instead increase with the frequencies of high order ED clusters. A test surrogate-measure based on ED cluster frequencies correlated to parameters of experimentally determined cell survival. The tools developed in this thesis can facilitate future exploration of semi-mechanistic modelling of the RBE.
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Nguyen, Quoc Hung [Verfasser], Wolfgang [Akademischer Betreuer] Ensinger i Reinhard [Akademischer Betreuer] Neumann. "(Bio)Molecular Transport and Recognition in Heavy Ion Track-Etched Polymeric Nanopores / Quoc Hung Nguyen. Betreuer: Wolfgang Ensinger ; Reinhard Neumann". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2013. http://d-nb.info/1106454847/34.
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Van, Heerden Michael Rudi. "Improving the selectivity of the radio-labelling of ion exchange resin tracers for positron emission particle tracking". Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/24310.
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Positron emission particle tracking (PEPT) is a technique which non-invasively tracks tracer particles labelled with a positron emitting radionuclide in a system of flow. The tracers are tracked through the detection in a PET scanner, of the two nearly collinear 511 keV gamma rays resulting from the annihilations of the positrons. For this technique to be effective, the tracer must be representative of the media in the system under study, and labelled with a sufficient activity of radionuclides. Organic ion exchange resins are suitable tracer materials for PEPT experiments, and are usually labelled with ⁶⁸Ga at the laboratories of PEPT Cape Town. The labelling performance relies on the chemical and physical properties of organic strongly acidic cation exchange resins and the nuclear chemistry of ⁶⁸Ga. The objective of this study is to obtain consistent tracer labelling throughout, or even beyond, the lifespan of the SnO₂ ⁶⁸Ge/⁶⁸Ga generator which degrades over time. The objective 1s achieved by integrating a purification technique into a "standard" radiolabelling method used at iThemba LABS. A small 0.5 ml Amberchrom CG-71 column is loaded with the ⁶⁸Ga generator eluent in 7 M HCl, then rinsed of most the contaminants before eluting the product with distilled water and used in the radiolabelling method. Using a 1-year-old 30 mCi SnO₂ ⁶⁸Ge/⁶⁸Ga generator eluent that has been purified by this method improved the radiolabelling performance by an average of at least 10% when compared to the performance of the un-purified product. Purifying the generator eluent will enable PEPT experiments of longer duration, and in highly shielded systems where tracers with high activity are required, such as granular and fluid flow in engineering applications.
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Alruwaili, Manal Abluk. "PERFORMANCE OF THE HEAVY FLAVOR TRACKER (HFT) DETECTOR IN STAR EXPERIMENT AT RHIC". Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1448032801.
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Liamsuwan, Thiansin. "Development of Monte Carlo track structure simulations for protons and carbon ions in water". Doctoral thesis, Stockholms universitet, Fysikum, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-81461.
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The goal of radiation therapy is to eradicate tumour cells while minimising radiation dose to healthy tissues. Ions including protons and carbon ions have gained increasing interest for cancer treatment. Advantages of ion beam therapy are conformal dose distribution, and for ions heavier than protons increased biological effectiveness in cell killing, compared to conventional radiation therapy using photons. Despite these advantages, fundamental problems in ion beam therapy include accuracy of dose determination at the cellular level, and characterisation of the radiation quality at the microscopic scale. Due to the high density of interactions along ion tracks, inhomogeneity of dose and track parameters at the cellular level is one of the major concerns for ion beam therapy. The aim of the thesis is to develop computational tools for dosimetry of ion tracks at the molecular level. Event-by-event Monte Carlo track structure (MCTS) simulations were developed for full-slowing-down tracks of protons and carbon ions in water representing cellular environment. In Paper I, the extension of the MCTS code KURBUC_proton was carried out to energies up to 300 MeV, covering the entire proton energy range used in radiation therapy. Physical properties and microdosimetry of proton tracks were investigated and benchmarked with the experimental data. Papers II-V describe the development of the MCTS code for full-slowing-down tracks of carbon ions. In Papers II-IV, the classical trajectory Monte Carlo (CTMC) model was developed for the calculation of interaction cross sections for low and intermediate energy carbon projectiles of all charge states (C0 to C6+) in water. In Paper V, the calculated cross sections were implemented in a new MCTS code KURBUC_carbon simulating carbon ions of energies 1-104 keV/u in water. This development allows the investigation of track parameters in the Bragg peak region of carbon ion beams. Publication of the thesis and the published papers make contribution to the physics of ion interactions in matter, and provide a new and complete database of electronic interaction cross sections for low and intermediate energy carbon projectiles of all charge states in water. The MCTS codes for protons and carbon ions provide new tools for biophysical study, including microdosimetry, of ion tracks at cellular and subcellular levels, in particular in the Bragg peak region of these ions.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Submitted. Paper 5: Submitted.
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Colin, Michel. "Possibilités d'analyses de traces d'éléments légers par activation aux ions lo urds ¹¹B et ¹⁵N /". Lausanne, 1987. http://library.epfl.ch/theses/?nr=672.
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Bertschik, Michael. "The kinematical parameters of minor mergers and their observational traces". [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971652759.
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Janulyte, Aurika. "Etude physico-électrique et optimisation métrologique d'un spectromètre de masse pour la détection temps réel de traces de dioxines". Aix-Marseille 1, 2007. http://www.theses.fr/2007AIX11040.
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Le spectromètre de masse utilisant un piège à ions nécessitait des améliorations instrumentales en vue d’analyser des molécules plus lourdes (env. 400u) et d’augmenter ses performances métrologiques: résolution/ sensibilité. Une étude systématique des différents étages du spectromètre de masse a été menée pour optimiser la transparence de chaque étage et appréhender les phénomènes qui perturbent la trajectoire des ions lors de leur confinement et conduisent à une dégradation du spectre. Nous avons étudié principalement l’influence des défauts électriques des alimentations et des défauts mécaniques du piège selon divers paramètres expérimentaux. Nous avons étudié l’environnement électrique du spectromètre et un générateur de tension adapté. La capacité à confiner des molécules plus lourdes est liée à l’amplitude de la tension alternative. Nous avons développé un dispositif d’alimentation qui respecte les critères de stabilité d’amplitude et de fréquence de la tension de confinementTo increase the ion trap mass spectrometer metrological performance to better detect large molecular weight compounds, i. E. , dioxines, a systematic study of the different mass spectrometric detection stages was performed. In order to increase the ion trap's resolution and sensitivity, different parameters were tested to determine the influence of the corresponding stage's effect of the given parameter on the ion confinement leading to 'damaged' ion spectra. First, principally, power supplies electrical and ion trap's mechanical defects were studied. Secondly, the wave generator electrical environment was studied. In order to confine large molecular mass ions within an ion trap, higher voltage amplitude the wave generator was developed. This wave generator respected criteria of frequency and voltage amplitude stability to better confine large molecular ions such as dioxines
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Lamotte, Maxime. "Etude du signal optique des chambres à fission et évaluation de son exploitation pour un système de mesure neutronique d'un réacteur de génération IV Development and first use of an experimental device for fission-induced spectrometry applied to neutron flux monitoring SCENA: A simulation tool for radiation-induced gas scintillation Simulation of heavy-ion slowing-down tracks with the SCENA code Design and irradiation test of an innovative optical ionization chamber technology Pulse-reactor core monitoring with an innovative optical neutron detector". Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALI023.
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Cette thèse de doctorat expose l'étude la luminescence induite dans des capteurs à gaz de type chambre à fission, afin d'évaluer son utilisation pour le suivi de puissance des réacteurs nucléaires de quatrième génération comme ASTRID.Le dépôt d'énergie dans un gaz par des ions lourds produits lors de fissions nucléaires dans une chambre à fission est d'ordinaire exploité pour sa capacité à produire des charges libres, qui peuvent être détectées avec des électrodes. Cette méthode, utilisée depuis le début de l'ère atomique, n'est pas sans inconvénients, et des axes d'amélioration ont été clairement identifiés.En estimant la production d'états excités du gaz d'une chambre à fission classique, on déduit que de la lumière peut être émise en son sein, et être détectée par un photo-détecteur. L'utilisation du signal optique plutôt qu'électrique apporte une robustesse accrue aux systèmes de mesures neutroniques, insensibles au bruit électromagnétique.L'étude spectroscopique d'un plasma d'origine nucléaire dans un dispositif analytique dimensionné et conçu par nos soins permet d'enregistrer des spectres de raies d'émission caractéristiques de la scintillation du gaz. L'analyse de ses raies permet d'affirmer la supériorité de la détection optique de neutrons, car la pression et la composition du gaz de remplissage peuvent alors être estimées en ligne.Parallèlement à nos activités expérimentales, un code de simulation de la dynamique de peuplement des niveaux des plasmas froids excités par ions-lourds est développé afin d'optimiser de futurs détecteurs basés sur ce principe. Les temps caractéristiques nécessaires à la génération d'états radiatifs et la position des excitations autour d'une trace d'ionisation ont été estimés.Plusieurs prototype de capteurs de neutrons fonctionnant uniquement sur un principe optique sont exploités dans des faisceaux de neutrons froids du réacteur Orphée afin de vérifier la preuve de concept d'un tel système de mesure neutronique. Des essais dans le réacteur Cabri permettent quant à eux de quantifier la limite de détection, la linéarité et la dynamique du système.Les très bons résultats apportés par ces trois volets valident la preuve de concept de la détection passive et en ligne de neutrons, capable d'auto-diagnostic, pour des applications exigeantes en milieu difficileThis PhD thesis details the study of luminescence produced in gaseous detectors as fission chambers, to evaluate its use in 4th generation nuclear reactor power monitoring, as ASTRID.Energy deposition in the gas, from heavy-ions produced during nuclear fission in a fission chamber is usually used for its charge generation ability, that can be detected with electrodes. Such method has been used since the beginning of atomic era present disadvantages, and necessary improvements have been assessed.By estimating fission chamber gas excited states production, one can deduce intrinsic light emission, and its detection by appropriate photo-detectors. Use of an optical signal against an electric one improves dependability of a neutron flux monitoring system, immune to electromagnetic noise.Spectroscopic studies of a nuclear plasma in a self-designed analytical device allows observation of typical gas scintillation emission lines. Analysis of emission lines reinforce optical detection attraction, as pressure and gas composition can be monitored online.Alongside our experiments, a simulation code dedicated to heavy-ions induced cold-plasma excited levels population has been produced to optimise future detectors relying on optical emission. Typical times encountered for excited states generation and their position around an ionization track have been estimated.Several neutron detector prototypes based on the sole gas scintillation principle have been assessed in cold neutron beam lines of the Orphée reactor, to validate a proof of concept for neutron monitoring. Experiments on the Cabri reactor allowed quantification of detection limit, linearity and dynamic range of our system.The positive outcomes provided by these 3 lines of work validate the proof of concept of passive, on-line, and self-diagnosed neutron detection with high dependability in harsh environments
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Dehon, Christophe. "Méthodes d'ionisation dans un spectomètre de masse FTICR transportable : application à l'analyse de traces et au couplage synchrotron". Paris 11, 2009. http://www.theses.fr/2009PA112360.
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Les techniques de spectrométrie de masse en piège permettent de garder, sélectionner, faire réagir et détecter les particules chargées. Les spectromètres de masse FTICR transportables développés au laboratoire, basés sur des aimants permanents, offrent la possibilité d’utiliser diverses méthodes d’ionisation comme l’impact électronique, l’ionisation chimique ou des méthodes de photoionisation. Durant cette thèse, différentes réactions ion-molécule ont été étudiées dans le but de les appliquer à l’ionisation chimique des composés organiques volatils. Ces méthodes d'ionisation ont ensuite été testées en conditions d'analyse. Le transfert de proton par H3O+ est un moyen d’ionisation douce, c'est-à-dire en général sans fragmentation, et a été utilisé pour l’analyse de mélanges complexes et de composés à l’état de traces dans l’air. Des transferts de proton plus sélectifs ont également été étudiés. D’autres réactions ion-molécule comme l'abstraction d’hydrure par CF3+ la capture de proton en mode négatif par OH- ou encore des réactions de complexation utilisant l’ion cyclopentadienylcobalt ont été mises en oeuvre pour élargir les possibilités de la méthode à des analyses non réalisables avec H3O+. Le spectromètre FTICR transportable MICRA possédant une cellule permettant la focalisation d’un faisceau de photons en son centre, nous avons aussi utilisé MICRA en couplage avec des sources synchrotrons pour réaliser deux types d'expériences impliquant la photoionisation VUV : d'une part l’étude de la chimie atmosphérique de Titan, d'autre part la détermination du seuil photoionisation du monocation du xénon combinant deux méthodes d’ionisation (impact électronique et photoionisation)Ion trapping mass spectrometry techniques allow to keep, select, react and detect charged particles. Transportable Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometers based on permanent magnets have been developed in the laboratory for detection of compounds in the mass range 1-500u. Ionization techniques such as electron impact, chemical ionization and other photoionisation techniques are available in the FTICR cell. The first goal of this thesis was development of Chemical Ionization (CI) precursors for quantitative analysis of Volatile Organic Compounds (VOC) traces in air in these instruments. Proton Transfer Reaction (PTR) using H3O+, known as an efficient, soft and generalist technique, was shown to perform well for CI-FTICR analysis of complex mixtures. Use of more selective PTR precursors such as protonated dimethylether or protonated xylene was also achieved. In order to extend the range of analyzed VOCs, other ion-molecule reactions were studied such as hydride abstraction by CF3+, proton capture in negative mode by OH–, or reactions of metal complexes such as cyclopentadienylcobalt. These reactions proved to be efficient for CI analysis of alkanes and/or halogenated compounds. A second part of this work has consisted in coupling the instrument with synchrotron sources in order to induce VUV photoionization of molecules or ions in the ICR cell. Two types of experiments were achieved : photoionization of gas mixtures similar to the neutral components of Titan ionosphere and study of subsequent ion-molecule reactions that prove to be induced by N2+ photoionization of Xe+ to Xe2+, allowing accurate determination of xenon double ionization threshold
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Ucar, Aziz. "Developments for the TOF straw tracker". [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982996195.
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Villegas, Navarro Fernanda. "Micro/nanometric Scale Study of Energy Deposition and its Impact on the Biological Response for Ionizing Radiation : Brachytherapy radionuclides, proton and carbon ion beams". Doctoral thesis, Uppsala universitet, Medicinsk strålningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-279385.
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Research in radiotherapy for cancer treatment focuses on finding methods that can improve the compromise between tumour cell inactivation versus damage to the surrounding healthy tissue. As new radiation modalities such as proton therapy become accessible for everyday clinical practice, a better understanding of the variation in biological response of the tumour and healthy tissues would improve treatment planning to achieve optimal outcome. The development of radiobiological models capable of accurate predictions of biological effectiveness is needed. Existing radiation quality descriptors such as absorbed dose and LET are insufficient to explain variation in biological effectiveness for different treatment modalities. The stochastic nature of ionizing radiation creates discrete patterns of energy deposition (ED) sites which can now be analysed through sophisticated computer simulations (e.g. Monte Carlo track structure codes). This opens the possibility to develop a nanometre characterization of radiation quality based on the spatial cluster patterns of ED. The aim of this thesis is to investigate the track structure (ED spatial pattern) properties of several radiation qualities at a micro- and nanometric scale while exploring their influence in biological response through correlations with published experimental data. This work uses track structure data simulated for a set of 15 different radiation qualities: 4 commonly used brachytherapy sources, 6 different proton energies, 4 different carbon ion energies, and 60Co photons used as reference radiation for quantification of biological effectiveness. At a micrometre level, the behaviour of the microdosimetric spread in energy deposition for target sizes of the order of cell nuclei was analysed. The degree of the influence it had in the biological response was found to be negligible for photon sources but for protons and carbon ions the impact increased with decreasing particle energy suggesting it may be a confounding factor in biological response. Finally, this thesis outlines a framework for modelling the relative biological effectiveness based on the frequency distribution of cluster order as a surrogate for the nanometre classification for the physical properties of radiation quality. The results indicate that this frequency is a valuable descriptor of ionizing radiation. The positive correlation across the different types of ionizing radiation encourages further development of the framework by incorporating the behavior of the microdosimetric spread and expanding tests to other experimental datasets.
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Krieg, Janina [Verfasser], Christina [Akademischer Betreuer] Trautmann i Ralph [Akademischer Betreuer] Krupke. "Characterization of individual Bi2Te3 nanowires electrodeposited in etched ion-track membranes for nano-ARPES and electrical transport studies / Janina Krieg ; Christina Trautmann, Ralph Krupke". Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1140166115/34.
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