Um sistema de diagnóstico por espectroscopia no visível foi implantado no tokamak TBR-I. O diagnóstico consiste de um espectrógrafo (do tipo Czerny-Turner), um sistema de acoplamento óptico e um detetor multicanal (MCP). O diagnóstico foi usado para observar e identificar impurezas presentes no plasma do TBR-I. As principais impurezas observadas foram oxigênio (O-II) e nitrogênio (N-II). Foi feito um estudo no alargamento das linhas do hidrogênio e dos íons para se obter a temperatura a partir do efeito Doppler. As intensidades das linhas espectrais foram observadas de descarga em descarga. / A visible spectroscopic diagnostic was implemented on TBR-I tokamak. The diagnostic system consist of a 1,5 m spectrograph (Czerny-Turner type), an optical coupling system and a microchannel plate (MCP) detector. The diagnostic system was used to examine and document the impurity content of the plasma in TBR-I. The main impurities discovered were oxygen (O-II) and nitrogen (N-II). Line broadening experiments were performed on hydrogen and ions to obtain the temperatures using Doppler broadening effects. The intensities of the spectral lines were measured on a shot to shot basis.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 164-170).

Laser Induced Breakdown Spectroscopy (LIBS) which is used to determine the elemental content of various samples, inspects the emission spectroscopy of samples of interest for searching certain elements or identifying the unknown content. In this study, spectroscopic analyses of various kinds of metals, namely, Cu, Fe, Mo, Ti, W, some compounds such as CuBe, ZnSe, ZnS, GaSe, some semimetals like Si, Ge and even gases were investigated by means of a compact-commercial portable LIBS system and an independently constructed experimental set-up consisting of a single pulse system and various kinds of double pulse configurations using Nd:YAG lasers. The contributions of this thesis to the LIBS community can be classified into two main groups- which are experimental and code development. One of the experimental contributions was the investigation of the different crystal surfaces of silicon in which dangling bond density were taken into account for a more precise comparison of atomic emissions. The second experimental contribution was the polarization experiments by which polarization dependency, to some extent, was demonstrated. The third and final one was the orthogonal double pulse configuration with a 45 o incidence angle for both lasers in opposite directions by which it was shown that the positioning becomes straightforward yielding the desired reproducible results. The second major contribution was to develop a basic code for analyzing the experimental data more accurately. In conclusion, by means of the different experimental approaches, factors relating to the enhancement in intensity were investigated and as a result of developing the code, flexibility in upgrading the constraints of element searching was obtained and the updating of the database was accomplished.

Thesis (Ph. D.)--University of Texas at Austin, 2007. Thesis (Ph. D.)--Université Paul Sabatier, 2007. / Thesis completed in partial fulfillment of the requirements for a joint Ph. D. from the University of Texas at Austin and the Université Paul Sabatier. Vita. Includes bibliographical references.

Um sistema de diagnóstico por espectroscopia no visível foi implantado no tokamak TBR-I. O diagnóstico consiste de um espectrógrafo (do tipo Czerny-Turner), um sistema de acoplamento óptico e um detetor multicanal (MCP). O diagnóstico foi usado para observar e identificar impurezas presentes no plasma do TBR-I. As principais impurezas observadas foram oxigênio (O-II) e nitrogênio (N-II). Foi feito um estudo no alargamento das linhas do hidrogênio e dos íons para se obter a temperatura a partir do efeito Doppler. As intensidades das linhas espectrais foram observadas de descarga em descarga. / A visible spectroscopic diagnostic was implemented on TBR-I tokamak. The diagnostic system consist of a 1,5 m spectrograph (Czerny-Turner type), an optical coupling system and a microchannel plate (MCP) detector. The diagnostic system was used to examine and document the impurity content of the plasma in TBR-I. The main impurities discovered were oxygen (O-II) and nitrogen (N-II). Line broadening experiments were performed on hydrogen and ions to obtain the temperatures using Doppler broadening effects. The intensities of the spectral lines were measured on a shot to shot basis.

The introduction of supercritical CO₂ at packed column supercritical fluid chromatography (SFC) flow rates is shown to significantly affect the excitation characteristics of a helium microwave induced plasma (He MIP). In this work, the influence of CO₂ on specific atomic and ionic transitions of Cl, Br, I, P, and S is described. Also presented is the determined relationship between transition energy and degree of signal depression resulting from the introduction of CO₂ to the plasma. Attempts to enhance the emission signals of non-metals by introducing H₂ into a He MIP are discussed. The inadequacy of excitation temperature, ionization temperature, rotational temperature, and electron number density measurements to determine the effect of CO₂ on the excitation characteristics of a He MIP is also described. However, application of kinetic theory and a recently developed theory on charge transfer allows a reasonable series of mechanisms to be developed that describe the excitation processes of a He MIP to which supercritical CO₂ is added. The remainder of this work describes a direct interface between a supercritical fluid extraction (SFE) vessel and an Ar MIP for the purpose of element selective detection. The response of the plasma to the introduction of sample via SFE at a variety of extraction temperatures, pressures, and sample concentrations is presented. / Ph. D.

A spectroscopic diagnostic tool has been developed to determine the electron temperature and the neutral density in helium, hydrogen and argon plasmas from absolutely calibrated spectroscopic measurements. For each gas, a method of analysis which uses models specific to each species present in the plasma (neutral atom or singly ionized atom) has been defined. The experimental electron density is used as an input parameter to the models, and the absolutely calibrated spectroscopic data are processed beforehand to obtain the populations of the upper excited levels corresponding to the observed spectral lines. For helium plasmas, the electron temperature is inferred from the experimental helium ion excited level p = 4 population using a corona model, and then the neutral density is determined from the experimental helium neutral excited level populations using a collisional-radiative model for helium neutrals. For hydrogen plasmas, combinations of the electron temperature and the neutral density are determined from the experimental hydrogen neutral excited level populations using a collisional-radiative model specific to hydrogen atoms. For argon plasmas, the electron temperature is inferred from the experimental argon ion excited level populations using a collisional-radiative model for argon ions, and then the neutral density is determined from the experimental argon neutral excited level populations using a collisional-radiative model for argon neutrals. This diagnostic tool was applied to three experiments with different geometries and plasma conditions to test the validity of each data analysis method. The helium and hydrogen data analysis methods were tested and validated on helium and hydrogen plasmas produced in the VASIMR experiment, a plasma propulsion system concept. They gave electron temperatures and neutral densities that were consistent with other diagnostics and theory. The argon diagnostic tool was tested on argon plasmas produced in the VASIMR experiment, the Helimak experiment and the Helicon experiment. The electron temperature and neutral density obtained on both the Helimak and the Helicon experiments were consistent with other diagnostics and with theory, and validated the method of analysis. An impurity problem on the VASIMR experiment made it difficult for the data analysis to be validated.

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

Over the past decade, fusion research has showed the potential of being a main candidate for energy production for future generations. Further advances in improved fusion performance are therefore vital. This thesis focuses on advanced fusion plasma scenarios and their diagnostic requirements. In particular the design of a motional Stark effect (MSE) diagnostic at the MAST spherical tokamak and the analysis of magneto-hydrodynamic mode feedback control and pulsed poloidal current drive (PPCD) at the reversed field pinch (RFP) experiment EXTRAP T2R are discussed. The MSE diagnostic is important for the determination of the plasma current profile, information that is necessary for studies in advanced confinement scenarios like reversed shear profiles or current holes. The MAST MSE system has two channels and selects the spectral components using 1Å FWHM interference filters. The diagnostic has been commissioned during the fall of 2006 and the results show the feasibility of the technique with rms-noise ~0.5° using a time resolution of 1 ms. Investigations of mirror labyrinths for the future ITER MSE diagnostic highlight the need for careful calibration considerations. Feedback control and PPCD are techniques for improved confinement. Feedback control dramatically decreases impurity influx at the end of discharges while transport in the bulk plasma is largely unaffected. During PPCD the transport is seen to decrease and it is demonstrated that PPCD and feedback control can be employed simultaneously. New and innovative techniques for fusion spectroscopy are furthermore described. This includes the use of correlations in line integrated signals to determine ion emission profiles in poloidally symmetric environments. Good agreement with other diagnostic methods is obtained. The assessment of electron temperature profiles using measured differences between Thomson scattering and vacuum ultra-violet spectroscopy is also shown. / QC 20100907

No description available.