Graphite Furnace Atomic Absorption Spectroscopy (GFAA) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) are two primary means of analyzing metals at the elemental level. Both techniques are widely accepted as tools for basic research. Each technique is performed differently and has its own distinct advantages as well as disadvantages. The choice of which technique to employ is determined by the needs of the analysis and the limitations of the instrumental technique.The idea to merge the two techniques was originallydeveloped by the research group of Dr. Michael W. Blades of the University of British Columbia, Vancouver, in 1989, who successfully demonstrated a "mini" plasma within a graphite furnace. The goal of the research was to design a device that would combine the advantages of both techniques and hopefully eliminate or minimize the unfavorable characteristics of each technique.The sustaining of a "mini" plasma has been demonstrated by this group. Although the end result was similar to that of Blades' group, the method of achieving the plasma was such that the "new" instrument could easily be mounted onto the furnace via a small Interface/Power Coupling device. The advantages of this system are: existing GFAA instruments can be used; modification of the furnace and RF supply is minimal; RF electronics can be remotely located; removal of the interface device is quickly achieved; and sample introduction, through the use of an autosampler, can be facilitated with small modification.Background spectra were acquired using helium, argon, and a mixture of argon/helium. It was found that all the plasmas have highly structured backgrounds and demonstrate the potential for many analysis regions. Two methods of sample introduction were used in acquiring the line emission of magnesium: injection through the sample inlet port to the furnace and end window injection. Inlet port injection suffers from a loss of sensitivity, when compared to end cap injection, but is more easily performed. / Department of Chemistry

In the last decade, ultracold plasmas have been created in the laboratory by photo-ionizing laser-cooled atoms. To understand the overall dynamics of ultracold plasmas, one needs to understand Rydberg collisional processes at ultracold temperatures. The two kinds of problems addressed in this thesis are: study of Rydberg atomic processes at ultracold temperatures, and a study of the overall dynamics of the ultracold plasmas. Theoretical methods based on quantal-classical correspondence is used to understand Rydberg atomic processes such as radiative cascade, and radiative recombination. A simulation method suitable for ultracold collisions is developed and tested. This method is then applied to study collisional-Stark mixing in Rydberg atoms. To study the dynamics of the ultracold plasmas, a King model for the electrons in plasmas is proposed. The King model is a stationary, finite sized electron distribution for the electrons in a cloud of fixed ions with a Gaussian distribution. A Monte-Carlo method is developed to simulate the overall dynamics of the King distribution.

Thèse (D.Sc.)--Université du Québec à Chicoutimi, 1978. / Document électronique également accessible en format PDF. CaQCU

Low density plasmas are found throughout the known universe. Therefore, accurate diagnostic methods have implications for our understanding of a variety of topics, ranging from star formation to the semi conductor industry. Low density plasmas are ubiquitous in the material processing industry. However, measurements of the electron temperature and density, two of the most fundamental plasma properties, are not straightforward. In the laboratory, we create a low density, radio frequency, helium plasma with a bi-Maxwellian electron distribution, similar to those found in the semiconductor processing industry. We use optical emission spectroscopy to perform a non invasive measurement of the plasma conditions. We compare this to measurements obtained using a Langmuir probe, a commonly used invasive diagnostic. The optical emission spectroscopy is found to be insensitive to electron density but good agreement is found between the two techniques for values of the temperature of the hot electron component of the bi-Maxwellian. Plasmas created with high-intensity lasers are able to recreate conditions similar to those found during astrophysical events. This development has led to these condi- tions being explored in laboratories around the world. An experiment was performed at the Rutherford Appleton Laboratory in Didcot, UK, investigating the properties of supersonic turbulent jets. For the first time a magneto-optic probe was used to measure the magnetic field in a low-density supersonic turbulent plasma. The results were compared to measurements taken using a magnetic-induction probe. Good agreement was found between measurements of the magnetic field strength within the plasma; however, the magnetic power spectra differ. We attribute this to the dif- ference in integration length between the two measurements. Statistical properties of the velocity field are inferred from the magnetic field measurements, which compare favourably to astrophysical observations and hydrodynamic simulations.

Orientador: Edison Bittencourt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T07:44:25Z (GMT). No. of bitstreams: 1 NascimentoNeto_EneasRamos_M.pdf: 883436 bytes, checksum: c17690c5dbef73787fd9632accf5eccc (MD5) Previous issue date: 2006 / Resumo: A crescente preocupação com o desenvolvimento sustentável aliado com uma maior conscientização com relação à preservação do meio ambiente tem impulsionado pesquisas nas mais diversas áreas de tecnologias ambientalmente corretas. Dentro deste contexto a tecnologia de plasma frio representa uma eficiente, ambientalmente correta e econômica alternativa para limpeza da superfície de alumínio. Este trabalho é a primeira etapa do projeto de modificação da superfície de alumínio coordenado pelo professor Edison Bittencourt. O projeto como um todo consiste de três etapas (limpeza, proteção e ativação) e tem a intenção de substituir via plasma o processo químico de limpeza, proteção à corrosão e ativação da superfície. Com relação à segunda etapa já foram realizados, no Instituto de Física pelo físico Carlos Salles Lambert, alguns ensaios de deposição de Hexametildisiloxano que mostraram ser excelentes protetores a corrosão, entretanto, essa segunda etapa não será discutida neste trabalho mas em posteriores teses. Neste trabalho realizou-se a remoção de óleo lubrificante e protetor da superfície de alumínio utilizando os gases oxigênio, hidrogênio, argônio e as misturas: oxigênio e argônio, hidrogênio e argônio. Foi analisada e discutida a influência da potência do gerador, tempo de bombardeamento, tipo de gás e pressão de trabalho sobre o ângulo de contato com água deionizada. A remoção do óleo lubrificante e protetor foi analisada em termos da medida do ângulo de contato de água deionizada e etileno glicol e da análise de XPS. Os experimentos foram realizados segundo técnica de planejamento experimental, em que as análises dos resultados experimentais foram realizadas através da Metodologia da Superfície de Resposta. A análise dos efeitos das variáveis sobre as variáveis de resposta do processo foi utilizada na construção de um modelo empírico, visando, a predição do comportamento do processo. A análise dos modelos obtidos foi realizada através da análise de variância (ANOVA). As variáveis independentes analisadas foram: potência do gerador, tempo de bombardeamento, tipo de gás e pressão de trabalho. Todas as variáveis operacionais foram analisadas em três diferentes níveis. Os resultados obtidos indicam que é possível remover o óleo lubrificante e protetor da superfície de alumínio utilizando o processo de plasma frio / Abstract: The increasing concern with the sustainable development ally with a bigger awareness with regard to the preservation of the environment has stimulated research in the most diverse areas of ambient correct technologies. Inside of this context the cold plasma technology represents an efficient, ambient correct and economic alternative for cleanness of the aluminum surface. It was analyzed and argued the influence of the power of the generator, sputtering time, type of gas and pressure of work on the angle of contact with water. This work is the first stage of the project of modification of the aluminum surface coordinated by professor Edison Bittencourt. The project as a whole consists of three stages (cleaning, protection and activation) and has the intention to substitute the chemical process of cleanness, protection the corrosion and activation of the surface for plasma process. With regard to second stage already they had been carried through, in the Institute of Physics for the physicist Carlos Salles Lambert, some assays of deposition of Hexametildisiloxano had shown to be excellent corrosion protectors, however, this second stage will not be argued in this work but in posterior works. In this work lubricative and protective oil was removed by gases such as oxygen, hydrogen, argon and the mixtures: oxygen and argon, hydrogen and argon. It was analyzed and argued the influence of the power of the generator, time of bombardment, type of gas and pressure of work on the angle of contact with water. The removal of the oil was analyzed in terms of the measure of the angle of contact with water and ethylene glycol and of the analysis of XPS.The experiments were carried out according experimental planning techniques where the obtained experimental results analyses had been carried through the Response Surface Methodology. The analysis of effect of the independent variable on the process answer variables had been used in the construction of an empirical model, aiming to predit the process behavior. The analysis of the obtained models was carried out using the variance analysis (ANOVA). The independent variable used had been: power of the generator, sputtering time, type of gas and pressure of work. The results obtained indicate that it is possible to remove the oil of the aluminum surface using the cold plasma process / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química

Electromagnetic acceleration has the potential for various applications stemming from space electric propulsion systems to future air breathing hypersonic augmentation.<p>Electromagnetic acceleration uses electromagnetic body force produced by the interactions of currents carried in plasma which is either externally applied or self-induced magnetic fields to accelerate the whole body of gas. Historically, these plasmas sources have been arc jets, shock tube and microwaves. Never has an electromagnetic accelerator been powered by an inductively coupled plasma (ICP) source.<p>The von Karman Institute has experimentally investigated the acceleration of an electrically conductive fluid produce by a subsonic ICP source. This ICP source was powered with a 15 kW and 27.1 MHz radio frequency facility called the Minitorch. The electromagnetic acceleration was accomplished with the design, fabrication and testing of a linear Hall current magnetofluiddynamic accelerator (MFDA) channel. The channel was geometrically orientated into the Hall configuration to accounts for the large Hall Effect. This channel used a single pair of copper annulus electrodes powered by a 10 kW direct current power supply. The channel was water cooled and contained various diagnostics to provide greater insight to the electromagnetic acceleration process. This was the first successful magnetofluiddynamic acceleration of an ICP source and validates the proof of concept.<p>One-dimensional MFD modeling was formulated and used to determine the necessary performance requirements of the MFDA channel E and B field subsystems. An interaction parameter of approximately 2.25 was required for the doubling of an inlet velocity of 300 m/sec. The required subsystem need to provide a current density was 6 Amps/cm2 with a magnetic field strength of 0.50 Tesla over an acceleration length of 0.1 meters. Additional the most critical constraint was the thermal management subsystem which was designed to overcome large heat transfer fluxes to achieve a steady state condition over a test run of 10 minutes.<p>The dynamic pressure measured increase the inlet velocity 101% for an argon plasma flowing at 1.01 g/s at a magnetic field strength of 0.49 Tesla. his strong acceleration of the plasma was most notable near the region of the electrodes at the exit of the 0.1 m long channel. The central region of the plasma has less dynamic pressure increase corresponding to only a maximum of 15% increase in velocity at a magnetic strength of 0.49 Tesla. Experimental results showed that axial discharge voltages increased with increased magnetic fields, indicating a strong Hall Effect in the accelerator as expected.<p>Theoretical analysis was accomplished using the one-dimensional equation of motion and was compared to utilizing only the momentum equation. Experimental force fluxes were compared to the calculated values of the one-dimensional equation of motion and momentum equation. The reference area for the current density was selected from intensity measurement using a high speed camera with the MFDA channel on. There was significant error in the analysis concerning using the momentum Lorentz force only versus the one-dimensional equations of motion; which included joule heating. This analysis summarized the necessity to include joule heating in the formulation of the problem. / Doctorat en sciences appliquées / info:eu-repo/semantics/nonPublished

An artificially structured boundary (ASB) produces a short-range, static electromagnetic field that can reflect charged particles. In the work presented, an ASB is considered to consist of a spatially periodic arrangement of electrostatically plugged magnetic cusps. When used to create an enclosed volume, an ASB may confine a non-neutral plasma that is effectively free of applied electromagnetic fields, provided the spatial period of the ASB-applied field is much smaller than any one dimension of the confinement volume. As envisioned, a non-neutral positron plasma could be confined by an ASB along its edge, and the space-charge of the positron plasma would serve to confine an antiproton plasma. If the conditions of the two-species plasma are suitable, production of antihydrogen via three-body recombination for antimatter gravity studies may be possible. A classical trajectory Monte Carlo (CTMC) simulation suite has been developed in C++ to efficiently simulate charged particle interactions with user defined electromagnetic fields. The code has been used to explore several ASB configurations, and a concept for a cylindrically symmetric ASB trap that employs a picket-fence magnetic field has been developed. Particle-in-cell (PIC) modeling has been utilized to investigate the confinement of non-neutral and partially neutralized positron plasmas in the trap.

Magnetic plasma expulsion uses a magnetic field distortion to redirect incident charged particles around a certain area for the purposes of shielding. Computational studies are carried out and for certain values of magnetic field, magnetic plasma expulsion is found to effectively shield a sizable area. There are however many plasma behaviors and interactions that must be considered. Applications to a new cryogenic antimatter trap design are discussed.

Laser Induced Breakdown Spectroscopy (LIBS) is showing great potential as an atomic analytical technique. With its ability to rapidly analyze all forms of matter, with little-to-no sample preparation, LIBS has many advantages over conventional atomic emission spectroscopy techniques. With the maturation of the technologies that make LIBS possible, there has been a growing movement to implement LIBS in portable analyzers for field applications. In particular, LIBS has long been considered the front-runner in the drive for stand-off detection of trace deposits of explosives. Thus there is a need for a better understanding of the relevant processes that are responsible for the LIBS signature and their relationships to the different system parameters that are helping to improve LIBS as a sensing technology. This study explores the use of LIBS as a method to detect random trace amounts of specific organic materials deposited on organic or non-metallic surfaces. This requirement forces the limitation of single-shot signal analysis. This study is both experimental and theoretical, with a sizeable component addressing data analysis using principal components analysis to reduce the dimensionality of the data, and quadratic discriminant analysis to classify the data. In addition, the alternative approach of ‘target factor analysis’ was employed to improve detection of organic residues on organic substrates. Finally, a new method of characterizing the laser-induced plasma of organics, which should lead to improved data collection and analysis, is introduced. The comparison between modeled and experimental measurements of plasma temperatures and electronic density is discussed in order to improve the present models of low-temperature laser induced plasmas.

Spider pulsars are compact binary systems consisting of a millisecond pulsar and a low-mass companion. Their X-ray emission, modulated on the orbital period, is interpreted as synchrotron radiation from high-energy electrons accelerated at the intrabinary shock. In this dissertation, we conduct global two-dimensional particle-in-cell simulations of the intrabinary shock, assuming the shock wraps around the companion star. When the pulsar spin axis is nearly aligned with the orbital angular momentum, the magnetic energy of the relativistic pulsar wind, composed of magnetic stripes of alternating field polarity, efficiently converts to particle energy at the intrabinary shock via shock-driven reconnection. The highest energy particles accelerated by reconnection can stream ahead of the shock and be further accelerated by the upstream motional electric field. In the downstream, further energization is governed by stochastic interactions with the plasmoids or magnetic islands generated by reconnection. Our results show that the synchrotron spectrum is nearly flat, 𝐹_𝜈 ∝, and the light curve displays two peaks just before and after the pulsar eclipse (superior conjunction), separated in phase by approximately 0.8 rad, with the peak flux exceeding that at inferior conjunction by a factor of ten. Additionally, we consider radiative losses in the form of synchrotron cooling using the reduced Landau-Lifshitz model. We examine three cooled scenarios, with a synchrotron burnoff limit (𝜰_rad) of 120, 60, and 30, comparing these simulations to an uncooled case to understand the impact of radiative losses on particle acceleration and emission.