Mémoire (M.Ress.Renouv.)-- Université du Québec à Chicoutimi, 1994. / Document électronique également accessible en format PDF. CaQCU

The recent development of extreme ultraviolet (EUV) sources has increased the need for diagnostic tools, and has opened up a previously limited portion of the spectrum. With ultrafast laser systems and spectroscopy moving into shorter timescales and wavelengths, the need for nanosecond scale imaging of EUV is increasing. EUV’s high absorption has limited the number of imaging options due to the many atomic resonances in this spectrum. Currently EUV is imaged with photodiodes and X-ray CCDs. However photodiodes are limited in that they can only resolve intensity with respect to time and X-ray CCDs are limited to temporal resolution in the microsecond range. This work shows a novel approach to imaging EUV light over a nanosecond time scale, by using an EUV scintillator to convert EUV to visible light imaged by a conventional streak camera. A laser produced plasma, using a mass-limited tin based target, provided EUV light which was imaged by a grazing incidence flat field spectrometer onto a Ce:YAG scintillator. The EUV spectrum (5 nm-20 nm) provided by the spectrometer is filter by a zirconium filter and then converted by the scintillator to visible light (550 nm) which can then be imaged with conventional optics. Visible light was imaged by an electron image tube based streak camera. The streak camera converts the visible light image to an electron image using a photocathode, and sweeps the image across a recording medium. The streak camera also provides amplification and gating of the image by the means of a micro channel plate, within the image tube, to compensate for low EUV intensities. The system provides 42 ns streaked images of light with a iii temporal resolution of 440 ps at a repetition rate of 1 Hz. Upon calibration the EUV streak camera developed in this work will be used in future EUV development.

Orientador: Munemasa Machida / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-17T22:07:56Z (GMT). No. of bitstreams: 1 Arsioli_BrunoSversut_M.pdf: 7832170 bytes, checksum: 4c771ec7e75b395d3088ed5f46d63820 (MD5) Previous issue date: 2011 / Resumo: O desenvolvimento deste trabalho ocorreu em duas frentes distintas relacionadas à grande área de pesquisa: Fusão Termonuclear Controlada em dispositivos do tipo tokamak. A primeira fase abordou estudos de espectroscopia, tendo como principal motivação o aprimoramento dos métodos de medida e tratamento de dados na área de diagnósticos de plasmas quentes. Os trabalhos consistem no diagnóstico por espectroscopia na região do ultravioleta do vácuo (UVV), realizados nos tokamaks TCABr-USP (Lab. Plasmas USP) e Nova-Unicamp (Lab. de Plasmas IFGW-UNICAMP), e concentraram-se na utilização do detector multicanal do tipo MCP-CCD, acoplado a um espectr ômetro de grade simples McPherson-225 operando na região espectral de 500 a 3200 °A, buscando ordens superiores de difração para o cálculo da temperatura iônica (Ti) via medida do alargamento Doppler (??D). A ideia para o cálculo da Ti é a utilização da relação entre os sinais de ordens superiores de difração (OSD), a fim de reduzir a influência do alargamento instrumental no cálculo do parâmetro ??D, do qual depende a medida de Ti. Também foram coletados dados com fotomultiplicadora, explorando a possibilidade de registrar a evolução temporal (com resolução de 1ms) da intensidade das emissões de algumas das principais impurezas presentes no plasma. Numa segunda fase, realizaram-se estudos do aquecimento do plasma por meio de injeção de partícula neutras (IPN) de alta energia (42-93 keV) no tokamak ASDEX Upgrade (Max-Planck-Institut fur Plasmaphysik; Garching- Alemanha). Tal atividade foi desenvolvida dentro do programa de mestrado em fusão nuclear da União Europeia, ErasmusMundus Fusion-EP, que esteve sob orientação de Dr. Ryter Fran¸cois, e supervisão de Prof. Dr. Stroth Ulrich (Universitat Stuttgart) e Jose Ramon Martin Solis (Universidad Carlos III de Madrid). O tokamak ASDEX Upgrade geralmente opera com plasma de Deutério, sendo a Injeção de Partículas Neutras de Deutério (IPN-D) a principal forma de aquecimento. Para este esquema de operação usual, os perfis de deposição de energia do feixe, ao longo da direção radial, foram extensivamente documentados por meio de cálculos com o código computacional FAFNER. Formulas gerais para os principais parâmetros relacionados à potência depositada e confinamento dos íons rápidos foram desenvolvidas e são rotineiramente utilizadas. No entanto, plasmas de Hélio aquecido por injeção de hidrogênio (IPN-H) e deutério (IPN-D), ocasionalmente são utilizados no ASDEX Upgrade. Uma das motivações para o estudo desse cenário reside na possibilidade de operação do ITER com plasma de hélio, ao menos na fase inicial de baixa ativação. Tal escolha permitiria comissionar os sistemas de controle e diagnóstico sem a necessidade de ativação radioativa das estruturas que compõe o reator, já que as taxas de fusão nuclear seriam mínimas. Até então, a documentação da deposição de potência por IPN em plasma de hélio no tokamak ASDEX Upgrade ainda não havia sido realizada. O objetivo do presente trabalho é a documentação das propriedades de aquecimento por IPN-H e IPN-D em plasma de hélio, utilizando o código FAFNER, sendo de grande interesse viabilizar o uso de uma nova base de dados chamada ADAS. Esta, contém tabelas com coeficientes de atenuação ?s??i adicionais, permitindo levar em conta a presença de átomos excitados no feixe de partículas neutras interagindo com o plasma, o que tem impacto direto sobre a deposição de potência por IPN / Abstract: The development of the present work has happened in two frames strictly related with the research on Thermonuclear Fusion in tokamaks. The first phase was dedicated to studies with spectroscopy, which had as main motivation the development of measurement and data treatment methods concerning hot plasmas diagnostic. Basically, it consisted in UV spectroscopic measurements carried on at TCABr-USP (Lab. Plasmas USP - São Paulo, Brazil) and Nova-Unicamp (Lab. de Plasmas do IFGW-UNICAMP - Campinas, Brazil) tokamaks. The activities were concentrated on the use of a multichannel detector MCP-CCD type, coupled with a single grating spectrometer McPherson-225, allowing VUV spectroscopy at the 500 - 3200°A spectra. The main objective was to look for signals of high diffraction orders aiming to calculate ion temperature via Doppler broadening (??D). The idea for getting precise Ti measurements was to make a relation between high diffraction order (HDO) signals to reduce the influence of the instrumental broadening, which has been accomplished with success. A series of data with photomultiplier was collected at the UV region, exploring the possibility of getting the time evolution of the emission intensity of the main impurities from the plasma. All work carried out on spectroscopy in small size experiments like NOVA tokamak are of great importance. In a second phase, studies related with plasma heating by Neutral Beam Injection (NBI) 42-93 keV were carried out in ASDEX Upgrade tokamak (at Max-Planck-Institut fur Plasmaphysik; Garching-Germany). This activity was developed in the frame of European Union Master Program, ErasmusMundus Fusion-EP, oriented by Dr. Ryter Fran¸cois, and supervised by Prof. Dr. Stroth Ulrich (Universitat Stuttgart) and Prof. Dr.Jose Ramon Martin Solis (Universidad Carlos III de Madrid). The ASDEX Upgrade tokamak is generally operated in deuterium plasma with deuterium Neutral Beam Injection (D-NBI) as main heating. For this usual operation scheme, the heating power deposition has been extensively documented by calculations with the code FAFNER. General fit formulas for the most important parameters related to the power deposition and fast ion content have been developed and are routinely used. However, helium plasmas heated by H-NBI or D-NBI are also occasionally performed in ASDEX Upgrade. One of the motivation for using helium resides in the fact that the low activation phase of ITER might be, at least partly, carried out in helium plasmas. So far, the documentation of the NBI deposition in helium plasmas in ASDEX Upgrade has not been made. The aim of the present work was to document the heating properties of H-NBI and D-NBI for helium plasmas, using the FAFNER code, being of great interest to get FAFNER running with new libraries (ADAS) for the calculation of the stopping rate coefficients ?s??i, allowing to evaluate the influence of excited atoms in the neutral beam. The final goal was to provide a reliable estimate of the main quantities linked to NBI heating in a set of helium discharges, in particular absorbed power, fast ion losses and fast ion energy content / Mestrado / Física de Plasmas e Descargas Elétricas / Mestre em Física

Orientador: Carlos Kenichi Suzuki / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-05T09:52:20Z (GMT). No. of bitstreams: 1 Marcuz_Nadia_M.pdf: 2618186 bytes, checksum: bf57e53a2d504fb7eb70931387caa188 (MD5) Previous issue date: 2005 / Resumo: O tratamento por plasma térmico de resíduos hospitalares gera como subproduto um material vitrocerâmico com alto poder de bloquear radiação ultravioleta e infravermelho próximo. A composição deste material apresenta como elementos majoritários cálcio, silício, ferro, alumínio e oxigênio. O objetivo deste trabalho é compreender a cinética de devitrificação das múltiplas fases do vitrocerâmico pelo controle do tratamento térmico e o seu efeito na absorção de radiação ultravioleta. Determinou-se por análise térmica diferencial as temperaturas de fusão e recristalização. Amostras vítreas obtidas por fusão a 1300 °C seguido por resfriamento rápido foram tratadas termicamente para induzir a devitrificação. Através da técnica de difração de raios-X identificou-se três estruturas cristalinas, Mg(Al,Fe)2O4, Ca(Ti,Mg,Al)(Si,Al)2O6 e NaAlSiO4, e determinou-se o tamanho médio e quantidade dos cristalitos presentes nessas fases com as diferentes temperaturas de tratamento térmico. As fases cristalinas formadas exercem influência na absorção óptica na faixa de ultravioleta, possibilitando a aplicação deste vitrocerâmico como agente ativo em bloqueadores ultravioleta comerciais. Medidas de transmitância óptica mostraram que o crescimento das fases Ca(Ti,Mg,Al)(Si,Al)2O6 e NaAlSiO4 induziram um fator de redução de 55% para 6% nos valores de transmitâncias ópticas no espectro ultravioleta (290 a 400 nm). A relevância deste trabalho revela-se no controle da formação das fases cristalinas do material que contribuem efetivamente na absorção da radiação ultravioleta / Abstract: A glass-ceramic material generated by plasma treatment of hospital waste has a remarkable property to block ultraviolet and near infrared radiation. The main composition elements of such a glass-ceramic are: calcium, silicon, iron, aluminum and oxygen. The objective of the present research is to understand the kinetics of devitrification of multiple phases by the control of thermal treatment conditions, and their effect on the ultraviolet absorption. The melting and crystallization temperatures of the glass-ceramic material were determined by differential thermal analysis. Vitreous samples were obtained by melting the as-received material at 1300 °C, followed by quenching. Afterwards, samples were thermally treated, inducing controlled crystallization. By X-ray diffraction technique, three crystalline phases were identified: Mg(Al,Fe)2O4, Ca(Ti,Mg,Al)(Si,Al)2O6 and NaAlSiO4. Average size and concentration of the crystallites were also determined. The formed crystalline phases have strong influence in the optical absorbance at ultraviolet band, which allows this glass-ceramic to be used as an active agent in commercial ultraviolet blockers. Optical transmittance measurements showed that the growth of nano-order crystalline phases Ca(Ti,Mg,Al)(Si,Al)2O6, and NaAlSiO4 reduced the optical transmittance from a factor of 55% to 6% at the ultraviolet band (290 to 400 nm). The relevance of this work is shown on the effect of size and concentration of crystalline phases, that contributes to the optical absorption of ultraviolet radiation / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

<p>  </p> <p>With bombings in the United States on the rise for the first time since 2016, the detection and identification of explosives remains of pertinent interest to law enforcement agencies. This work presents two soon-to-be published research articles that focus on the detection and identification of explosives by both chemical instrumentation and canines. The first article, <em>Quantitative Analysis of Smokeless Powder Particles in Post-Blast Debris via Gas Chromatography/Vacuum Ultraviolet Spectroscopy (GC/VUV)</em>, utilizes gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV) to determine the difference in chemical composition of two smokeless powders in both pre- and post-blast conditions. The compounds of interest in this study were nitroglycerin, 2,4-dinitrotoluene, diphenylamine, ethyl centralite, and di-n-butyl phthalate. Concentration changes between pre- and post-blast smokeless powder particles were determined as well as microscopic differences between pre- and post-blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives. The second article, <em>An Odor-Permeable Membrane Device for the Storage of Canine Training Aids</em>, proposes the use of an odor-permeable membrane device (OPMD) as a standardized storage method for canine training aids. It is hypothesized that the OPMD would minimize cross-contamination between training aids, and that the OPMD could be used for canine training as well as storage. The goal of this research is to use flux and evaporation rate to quantify the explosive odor that escapes from the OPMD compared to unconfined explosives. Preliminary data suggests that there is an exponential relationship between relative boiling point and evaporation rate. It has been determined that compounds with higher boiling points have lower evaporation rates than compounds that have lower boiling points. The materials studied thus far are known odor compounds produced by explosive formulations. These include nitromethane, nitroethane, 1-nitropropane, r-limonene, and toluene. </p>

In the area of forensic chemistry, improved or new analysis methods are continually being investigated. One common and powerful technique used in forensic chemistry is wall-coated open-tubular column (WCOT) gas chromatography with electron ionization single quadrupole mass spectrometry (GC-MS). Improvements to and effectiveness of alternatives to this instrumental platform were explored in an array of parallel inquiries. The areas studied included the column for the chromatographic separation, the universal detection method employed, and the fragmentation method used to enhance molecular identification. <br><br>Superfine-micropacked capillary (SFµPC) columns may provide an alternative to commercial packed GC columns and WCOT GC columns that combines the benefits of the larger sample capacity of packed columns and the benefits of the excellent separation capabilities and mass spectrometry (MS) flow rate compatibility of WCOT columns. SFµPC columns suffer from high inlet pressure requirements and prior reported work has required specialized instrumentation for their use. Fabrication of and chromatography with SFµPC GC columns was successfully achieved with typical GC-MS instrumentation and within the flow rate limit of a MS. Additionally, the use of higher viscosity carrier gasses was demonstrated to reduce the required inlet pressure for SFµPC GC columns.<br><br>Recently, a new vacuum ultraviolet spectrometer (VUV) universal detector has been commercialized for GC. The ability of VUV detectors to acquire absorbance spectra from 125 nm to 430 nm poses a potential alternative to MS. As such, GC-VUV provides an exciting potential alternative approach to achieving excellent quantitative and qualitative analysis across a wide range of analytes. The performance of VUV and MS detectors for forensic analysis in terms of quantitative and qualitative analysis was compared. Analysis of alkylbenzenes in ignitable liquids was explored, which can be important evidence from suspected arson fires and are difficult to differentiate with MS. The VUV detector was found to have superior specificity and comparable sensitivity to the MS detector in scan mode.<br><br>Addition of thermolysis (Th) as an orthogonal fragmentation pathway provides the opportunity to increase the differences between MS fragmentation patterns. Fragmentation has been widely established to aid in identification of molecules with MS by providing characteristic fragments at characteristic relative abundances. However, molecules with very similar structures do not result in sizable spectral differences in all cases with typical MS fragmentation techniques. A series of Th units were fabricated and integrated into GC-Th-MS instruments. Th-MS was conducted with the thermally labile nitrate esters across a range of instrumentation and thermal conditions.<br>

In forensic chemistry, a quicker and more accurate analysis of a sample is always being pursued. Speedy analyses allow the analyst to provide quick turn-around times and potentially decrease back-logs that are known to be a problem in the field. Accurate analyses are paramount with the futures and lives of the accused potentially on the line. One of the most common methods of analysis in forensic chemistry laboratories is gas chromatography, chosen for the relative speed and efficiency afforded by this method. Two major routes were attempted to further improve on gas chromatography applications in forensic chemistry.<br> The first route was to decrease separation times for analysis of ignitable liquid residues by using micro-bore wall coated open-tubular columns. Micro-bore columns are much shorter and have higher separation efficiencies than the standard columns used in forensic chemistry, allowing for faster analysis times while maintaining the expected peak separation. Typical separation times for fire debris samples are between thirty minutes and one hour, the micro-bore columns were able to achieve equivalent performance in three minutes. The reduction in analysis time was demonstrated by analysis of ignitable liquid residues from simulated fire debris exemplars.<br> The second route looked at a relatively new detector for gas chromatography known as a vacuum ultraviolet (VUV) spectrophotometer. The VUV detector uses traditional UV and far-ultraviolet light to probe the pi and sigma bonds of the gas phase analytes as well as Rydberg traditions to produce spectra that are nearly unique to a compound. Thus far, the only spectra that were not discernable were from enantiomers, otherwise even diastereomers have been differentiated. The specificity attained with the VUV detector has achieved differentiation of compounds that mass spectrometry, the most common detection method for chromatography in forensic chemistry labs, has difficulty distinguishing. This specificity has been demonstrated herein by analyzing various classes of drugs of abuse and applicability to “real world” samples has been demonstrated by analysis of de-identified seized samples.<br>