A multi-detector spectrometer was constructed to measure garmia-gamma angular correlations in 154Gd from the decay of 154Eu. Gamma-ray multipole mixing ratios were extracted from the data. A modified fast-slow coincidence electronics arrangement with selective routing of data was used. One Ge(Li) detector and three NaI detectors were used in the system for rapid data acquisition. "Real-plus-random" and "random" coincidences were accumulated simultaneously with detectors set at selected angles. Mixing ratios for the first transition in the cascades of 1274-123--keV (2--2+-0+), 1005-123-keV (3+-2+-0+), and 723-996-keV (2--2+-O+) were measured as '5(1274) = 0.02 0.02, '5(1005) = -28+10' '5(723) = 0.02 0.02.'The measured correlation for the 592-1005 keV cascade (2--3+-2+) was analyzed by searching a 157 by 157 array of values for '5(592) and 8(1005); agreement was tested using a Q2 criterion. The best agreement for the mixing ratio of the 592-keV transition was 8(592) = 0.08 0:22; for the 1005-keV transition 8(1005) = -9.5+7. The value 8(1005) _ -9.5+7 is taken to be the better value as a result of experimental considerations. The value for the 592-keV transition had not been previously measured.Ball State UniversityMuncie, IN 47306

A delayed-coincidence timing spectrometer system was constructed to measure nuclear lifetimes in the picosecond region. The present investigation used the self-comparison method of delayed-coincidence timing. This method used two plastic detectors to obtain the timing information. Two sodium iodine (NaI) detectors were used in conjunction with the plastic detectors to provide energy identification. Significant changes were made to the geometrical detector arrangement to optimize collection of scattered gamma rays by the NaI detectors. The mean line for the first excited states of the sources Co-60 and Cs-134 were measured using the new spectrometer system. The mean life of the 1.33 MeV excited state of Co-60 was measured to by 0.34 + 1.32 psec. The mean life of the 0.605 MeV excited state of Cs-134 was measured to be 6.31 + 2.19 psec and agrees with two previously reported values.Ball State UniversityMuncie, IN 47306

Remote sensing of atmospheric gases improves our understanding of the state and evolution of the Earth’s environment. At the beginning of the thesis, the basic principles for the retrieval of concentrations of atmospheric gases from spectra are presented with a focus on ground-based observations. An overview of the characteristic features of different platforms, viewing geometries, measurement sites, and Fourier Transform Spectrometers (FTSs) used in the measurements are provided. The thesis covers four main projects. The first study of the global distribution of atmospheric phosgene was carried out using a total of 5614 measured profiles from the satellite-borne Atmospheric Chemistry Experiment FTS (ACE-FTS) spanning the period February 2004 through May 2006. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator, at about 25 km in altitude, and the concentrations decrease towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere at all latitudes, with volume mixing ratios of 20-60 pptv. The reasons for the formation of the phosgene distribution pattern are explained by the insolation, lifetime of phosgene and the Brewer-Dobson circulation. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s due to a significant decrease in source species. The Portable Atmospheric Research Interferometric Spectrometer for the Infrared (PARIS-IR) is a copy of the ACE-FTS that was designed for ground-based and balloon-borne measurements. The first balloon flight was part of the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) 2004 balloon payload. Some useful engineering information was obtained on the thermal performance of the instrument during the flight. As part of the MANTRA program, a ground-based inter-instrument comparison campaign was conducted with the objective of assessing instrument performance, and evaluating data processing routines and retrieval codes. PARIS-IR provides similar quality results for stratospheric species as does the University of Toronto FTS. An advanced study was carried out for the Carbon Cycle science by Fourier Transform Spectroscopy (CC-FTS) mission, which is a proposed future satellite mission to obtain a better understanding of the sources and sinks of greenhouse gases in the Earth’s atmosphere by monitoring total and partial columns of CO2, CH4, N2O, and CO in the near infrared together with the molecular O2 column. To evaluate the spectral regions, resolution, optical components, and spectroscopic parameters required for the mission, ground-based Fourier transform spectra, recorded at Kiruna, Kitt Peak, and Waterloo, were used. Dry air volume mixing ratios of CO2 and CH4 were retrieved from the ground-based observations. A FTS with a spectral resolution of 0.1 cm-1, operating between 2000 and 15000 cm-1, is suggested as the primary instrument for the mission. Further progress in improving the atmospheric retrievals for CO2, CH4 and O2 requires new laboratory measurements to improve the spectroscopic line parameters. Atmospheric observations were made with three FTSs at the Polar Environment Atmospheric Research Laboratory (PEARL) during spring 2006. The vertical column densities of O3, HCl, HNO3, HF, NO2, ClONO2 and NO from PARIS-IR, the Eureka DA8 FTS, and the ACE-FTS show good agreement. Chorine activation and denitrification in the Arctic atmosphere were observed in the extremely cold stratosphere near Eureka, Nunavut, Canada. The observed ozone depletion during the 2006 campaign was attributed to chemical removal.

The aim of this master's thesis is to develop a method that fully automates a trimming step in the production of a fiber-optical power spectrometer, based on a unique Acusto-Optical Scanning Filter. The filter is created by letting an ultrasonic mechanical pulse pass through a chirped Fiber Bragg Grating. The pulse introduces a disturbance in the grating, creating a thin optical transmission window in the otherwise reflective bandwidth. The high demands on the window requires a precise, unit dependent pulse form with unknown properties. Thus each unit needs to be trimmed to reach required performance. The manual trimming is largely a trial and error process, that contains two performance tests. We redefine one, eliminating the need to reroute the optical path and reducing the number of fiber weldings. The tests are then quantified, allowing a figure of merit to be based on weighted performance values. A brute force method, testing a large set of pulses, is implemented. The set is defined by the parameter space spanned by previously produced units. Due to the large space, the method is too time consuming. Instead it is used to measure the performance spaces of three units. An attempt to largely reduce the parameter space using PCA failed. An alternating variables method that finds local performance optima in the parameter space is developed. By using a set of several starting points, the method tends to find several qualified pulses. The method is implemented and successfully verified by trimming new units. Finally we propose where to focus improvements of the method in a production ramp up.

Remote sensing of atmospheric gases improves our understanding of the state and evolution of the Earth’s environment. At the beginning of the thesis, the basic principles for the retrieval of concentrations of atmospheric gases from spectra are presented with a focus on ground-based observations. An overview of the characteristic features of different platforms, viewing geometries, measurement sites, and Fourier Transform Spectrometers (FTSs) used in the measurements are provided. The thesis covers four main projects. The first study of the global distribution of atmospheric phosgene was carried out using a total of 5614 measured profiles from the satellite-borne Atmospheric Chemistry Experiment FTS (ACE-FTS) spanning the period February 2004 through May 2006. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator, at about 25 km in altitude, and the concentrations decrease towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere at all latitudes, with volume mixing ratios of 20-60 pptv. The reasons for the formation of the phosgene distribution pattern are explained by the insolation, lifetime of phosgene and the Brewer-Dobson circulation. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s due to a significant decrease in source species. The Portable Atmospheric Research Interferometric Spectrometer for the Infrared (PARIS-IR) is a copy of the ACE-FTS that was designed for ground-based and balloon-borne measurements. The first balloon flight was part of the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) 2004 balloon payload. Some useful engineering information was obtained on the thermal performance of the instrument during the flight. As part of the MANTRA program, a ground-based inter-instrument comparison campaign was conducted with the objective of assessing instrument performance, and evaluating data processing routines and retrieval codes. PARIS-IR provides similar quality results for stratospheric species as does the University of Toronto FTS. An advanced study was carried out for the Carbon Cycle science by Fourier Transform Spectroscopy (CC-FTS) mission, which is a proposed future satellite mission to obtain a better understanding of the sources and sinks of greenhouse gases in the Earth’s atmosphere by monitoring total and partial columns of CO2, CH4, N2O, and CO in the near infrared together with the molecular O2 column. To evaluate the spectral regions, resolution, optical components, and spectroscopic parameters required for the mission, ground-based Fourier transform spectra, recorded at Kiruna, Kitt Peak, and Waterloo, were used. Dry air volume mixing ratios of CO2 and CH4 were retrieved from the ground-based observations. A FTS with a spectral resolution of 0.1 cm-1, operating between 2000 and 15000 cm-1, is suggested as the primary instrument for the mission. Further progress in improving the atmospheric retrievals for CO2, CH4 and O2 requires new laboratory measurements to improve the spectroscopic line parameters. Atmospheric observations were made with three FTSs at the Polar Environment Atmospheric Research Laboratory (PEARL) during spring 2006. The vertical column densities of O3, HCl, HNO3, HF, NO2, ClONO2 and NO from PARIS-IR, the Eureka DA8 FTS, and the ACE-FTS show good agreement. Chorine activation and denitrification in the Arctic atmosphere were observed in the extremely cold stratosphere near Eureka, Nunavut, Canada. The observed ozone depletion during the 2006 campaign was attributed to chemical removal.

The optical design of a soft X-ray (90-1100~eV) emission spectrometer for the Resonant Elastic and Inelastic X-ray Scattering (REIXS) beamline to be implemented at the CLS is presented. An overview of soft X-ray optical theory as it relates to diffraction gratings is given. The initial constraints and the process that led to this design are outlined. Techniques and software tools that were developed, using ray-tracing and diffraction grating efficiency calculations, are discussed. The analysis completed with these tools to compare existing soft X-ray emission spectrometer designs is presented. Based on this analysis, a new design with superior performance for this application is proposed and reviewed. This design employs Rowland circle geometry to achieve a resolving power in excess of 2,500 in the range of interest. In addition, a novel design is proposed for a larger extremely high resolution spectrometer which will provide resolving powers exceeding 10,000 throughout the higher end of this range. A review is given of research into the components, manufacturing techniques and tolerances that will be required to produce this spectrometer.

In atmospheric environment, synchronized survey of criteria air pollutants and volatile organic compounds (VOCs) are important for ambient air quality measurement. UV-DOAS (Ultra-violet Differential Optical Absorption Spectroscopy) in this research is an optics open-optical monitor based on the ultraviolet and visible-light absorption of gaseous pollutants. This measurement could be employed to examine the spatial average concentration of optical path in the open space, and to monitor criteria air pollutants (including O3, SO2, NO and NO2) as well as VOCs (including benzene, toluene, p-xylene). Aircraft takeoff and landing has serious impacts on the neighboring envvironment of Kaohsiung International Airport. Aircrafts generate two major pollution problems: chemical pollution (leaking flue from engine and fume with particulate and gaseous pollutants from incomplete combustion) and physical pollution (aircraft noise). Most air pollutant emissions from aero engine are generated during aircraft takeoff and landing. The distribution of gaseous pollutants along the runway is a linear pollution source. Restricted by flight safety, it is difficult to monitor and investigate aero engine pollution with traditional stationary monitors. Therefore, open-path monitoring has become a novel tool for research. First, this study investigated the spatial average concentration of air pollutants around the runway of Kaohsiung International Airport and compared with monitoring data from nearby air quality monitoring station to evaluate the performance of the open-path monitoring system. Comparing the stationary monitors with the open-path monitoring showed relatively better correlations on O3 and NO2 than on SO2 and NO, which might be caused by the differences of local emissions. Overall, these two monitoring systems are identical on monitoring regulated pollutants. Furthermore, the open-path monitoring can also examine volatile organic compounds (ex: benzene, p-xylene, and toluene). The open-path monitoring is a practical and reliable monitoring system. It could be considered as one of the ambient air quality standard monitors in the future. Secondly, this study chose the airspace of approach lane, located at west side of the runway 09 of Kaohsiung International Airport, as survey area. The open-path monitoring (OP-SIS) utilized UV-DOAS for sampling and monitoring the air quality of the survey area. It examined, recorded, and analyzed the criteria air pollutants (O3, SO2, NO and NO2) as well as VOCs (including benzene, toluene, p-xylene) to ascertain the impact of aircraft emissions on atmospheric environment. The results suggested that aircraft emissions influenced ambient air quality with high correlation to NO concentration. Additionally, the wind directions of land-sea breeze and monsoon also have influences on the concentration of air pollutants in the study area. In daytime, when wind direction was N or NNE, the variance of NO concentration was consistent with takeoff and landing time points with correlation coefficient of 0.60. After 5-6 minutes of an aircraft passed through the study airspace, the variance of instantaneous concentration of NO climbed up to 30 ppb. The results were contributed to understand the characteristics and sources of aircraft emitted air pollutants. It could provide the authority to have better judgment on reducing air pollutants as well as to assist the maintence and management of ambient air quality surrounding the airports.

Luminescence is the emission of light resulting from radiative transition of an atom from an excited state to a ground state. This radiative transition yields emission of photons and the luminescence is the general name which is used to classify &ldquo / cold emission&rdquo / other than the blackbody radiation. Spectroscopy involves the measurement of intensity of emitted, absorbed or scattered electromagnetic radiation as a function of wavelength. Thus, it is a valuable tool in the study of understanding the luminescence production mechanisms. Measurement of emission spectra gives information about the energy levels of transition and structure, geometry and composition of the sample. In this study, a versatile luminescence emission spectrometer was designed and developed with the main aim of measuring Photoluminescence (PL), Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) emission spectra of materials relevant for dosimetry. The spectrometer was constructed around a Littrow type monochromator by developing the necessary hardware, firmware and software. Wavelength calibration, measurement of spectral response and determination of resolution of the spectrometer were done using calibration lamps and a calibrated spectroradiometer. Finally the performance of the constructed spectrometer was tested by measuring the emission spectra of materials such as BeO, Al2O3 and CaF2 wherever possible the measured spectra were compared with the ones reported in the literature.

Two flow reactor studies, using an electrically heated laminar flow reactor over Vanadia based (V2O5-WO3/TiO2) honeycomb catalyst, were performed at 1 atm pressure and various temperatures. The experiments were conducted using simulated exhaust gas compositions for different exhaust gases. A quartz tube was used in order to establish inert conditions inside the reactor. The experiments utilized a Fourier transform infrared (FTIR) spectrometer in order to perform both qualitative and quantitative analysis of the reaction products. Urea-water solution decomposition was investigated over V2O5-WO3/TiO2 catalyst over the entire SCR temperature range using the temperature controlled flow reactor. The solution was preheated and then injected into pure nitrogen (N2) stream. The decomposition experiments were conducted with a number of oxygen (O2) compositions (0, 1, 10, and 15%) over the temperature range of 227oC to 477oC. The study showed ammonia (NH3), carbon-dioxide (CO2) and nitric oxide (NO) as the major products of decomposition along with other products such as nitrous oxide (N2O) and nitrogen dioxide (NO2). The selective catalytic reduction (SCR) of nitric oxide (NO) with urea-water solution over V2O5-WO3/TiO2 catalyst using a laboratory laminar-flow reactor was investigated. Urea-water solution was injected at a temperature higher than the vaporization temperature of water and the flow reactor temperature was varied from 127oC to 477oC. A FTIR spectrometer was used to determine the concentrations of the product species. The major products of SCR reduction were NH3, NO and CO2 along with the presence of other minor products NO2 and N2O. NO removal of up to 87% was observed. The aim of the urea-water decomposition experiments was to study the decomposition process as close to the SCR configuration as possible. The aim of the SCR experiments was to delineate the effect of various parameters including reaction temperature and O2 concentration on the reduction process. The SCR investigation showed that changing parameter values significantly affected the NO removal, the residual NH3 concentration, the temperature of the maximum NO reduction, and the temperature of complete NH3 conversion. In the presence of O2, the reaction temperature for maximum NO reduction was 377?C for ratio of 1.0.

<p>This thesis compiles results of research in two mutuallydependent parts: 1) development of ferromagnetic resonance(FMR) spectrometer to study microwave properties offerromagnetic materials, and 2) characterization of new irongarnets: pulsed laser deposited Y₃Fe₅O₁₂and Bi₃Fe₅O₁₂films and Ce:Y₃Fe₅O₁₂single crystal.</p><p>First part describes a novel<i>Broadband</i>FMR<i>Spectrometer</i>designed to characterize thin ferromagneticfilms. The spectrometer uses two probeheads: one is the X-bandmicrowave reflection cavity for room temperature measurementsand the in-cryostat microstrip line probe to perform FMRexperiments in the frequency range from 50 MHz to 40 GHz. Veryuniform and stable magnetic field up to 2.4 T, temperatures 4 Kto 420 K, and continuous frequency scan performed by<i>HP8722D</i>vector network analyzer provide various modes ofoperation. Both probeheads are equipped with two-circlegoniometers to ensure accurate study of magneticanisotropy.</p><p>The spectrometer was used to make express-analysis ofquality thus to optimize processing parameters of epitaxialiron garnet films grown by pulsed laser deposition (PLD).Comprehensive study of uniaxial and cubic magnetocrystallineanisotropy has been performed for Ce:Y₃Fe₅O₁₂bulk crystal as well as for Y₃Fe₅O₁₂and Bi₃Fe₅O₁₂films grown on different substrates by PLD andreactive ion beam sputtering techniques. BroadbandFMR-spectroscopy revealed difference in spectra of domain wallresonances: instead of“soft”spin modes in filmsgrown by liquid phase epitaxy, PLD-made films show“diffuse”transformation of domains near thesaturation field. This effect indicates non-uniformity ofsaturation magnetization and field of uniaxial anisotropy inPLD-iron garnets. Spin wave resonances in comparison withuniform FMR have been studied to evaluate“localquality”of ferromagnetic films. The resonance field andFMR linewidth behavior were studied at various crystallographicdirections determined by X-ray diffraction.</p><p>FMR was used to choose PLD-made YIG films with low losses atmicrowave frequencies and to build magnetostatic surface wavesmicrowave bandpass filter. The filter was designed as a planarfilm structure with a microstrip line for transducers. It is afirst demonstration of feasibility to introduce PLD processingtechnique to magnetostatic wave technology.</p><p>Magneto-optical study of Ce:Y₃Fe₅O₁₂single crystal complements results ofFMR-spectroscopy of new garnets.</p><p><b>Keywords:</b>ferrites, thin films, ferromagnetic resonance,microwaves, FMR spectrometer, magnetic anisotropy,magnetostatic waves.</p>