Plasma enhanced chemical vapor deposition systems are massively deployed to grow numerous thin film coatings including hydrogenated amorphous silicon. A new deposition chamber was designed, procured, and constructed to investigate the plasma properties of a 100% silane (SiH4) glow discharge with varying chamber pressure and inter-electrode spacing. A Hiden EQP1000 ion mass spectrometer sampled the plasma from the substrates point of view. Ion energy distributions were obtained using four different excitation sources +DC, –DC, radio frequency (at 13.56 MHz), and the DC Saddle Field (DCSF) in the tetrode configuration. The shape of the ion energy distributions was constant for the capacitively coupled +DC, –DC, and rf (at higher pressures of 75 and 160 mTorr) glow discharges. The shape of the ion energy distributions for the DCSF plasma exhibited a double peak or saddle structure analogous to radio frequency plasmas. The width between the peaks (peak separation) was controlled by the pressure and the semi-transparent cathode to semi-transparent anode distance. Ion energy distributions from the DCSF plasma concurred with rf and +DC ion energy distributions at specific pressures and inter-electrode distances. This result demonstrates the versatility of the DCSF glow discharge system. Moreover, control of the peak separation is modeled to be iii equivalent to controlling the critical ratio (ion transit time in the sheath to the electron oscillating period), and/or the inferred electron oscillating sheath potential. The DCSF possesses a fusion of rf and +DC methods. The long high energy tail or constant background are indicative of a +DC high voltage sheath in which there is an increasing fraction of collisionless ions as the anode-cathode distance increases. These collisionless ions are provided by the oscillating electrons (or rf nature) of the DCSF method. Higher order silane (silicon containing) ions increase in relative intensity with increasing inter-electrode spacing for the +DC, –DC, and rf plasmas. These higher order silane ions are also detected in the DCSF plasma, and can be reduced at either lower pressure or lower cathode to anode or cathode to substrate distances.

Disertacija skirta smulkiosios aerozolio dalelių frakcijos šaltinių, fizikinių ir cheminių savybių įvertinimui kompleksiškai apjungiant įvairius tyrimo metodus. Darbe susieti elementinės ir organinės anglies koncentracijų pokyčiai su tolimąja oro masių pernaša, įvertinta regiono bei vietinių šaltinių įtaka bendrai aerozolio dalelių taršai. Aprašyti anglies turinčių aerozolio dalelių pasiskirstymai pagal dydį foninėse vietovėse ir miesto aplinkoje. Naudojant aerozolio masių spektrometrą Preilos atmosferos užterštumo tyrimų stotyje buvo identifikuotas biogeninis organinių medžiagų šaltinis, kuris vidutiniškai sudaro 15 % nuo organinių medžiagų masės, tačiau Šiaurės Atlanto oro masėje biogeninių medžiagų indėlis siekia net 50 %. Atlikus kompleksinę aerozolio ir stabiliųjų anglies izotopų masių spektrometrinę analizę buvo nustatyta, kad pirminis anglies turinčio aerozolio dalelių šaltinis mieste yra autotransportas, o Rūgšteliškio foninėje vietovėje – biomasės deginimas. Taip pat buvo nustatyta, kad Vilniuje dominavo antropogeninės antrinės organinės medžiagos (76 %), o Rūgšteliškyje vyravo biogeninės antrinės organinės medžiagos (apie 50%). Vertinant tolimosios oro masių pernašos įtaką vietinės kilmės aerozolio dalelių formavimuisi ir kaitai, buvo nustatyta, kad vulkaninės kilmės aerozolio dalelės turi įtakos submikroninės aerozolio dalelių frakcijos koncentracijai, cheminei sudėčiai ir pasiskirstymui pagal dydį. / The objective of the work was to investigate physical and chemical properties and sources of the atmospheric aerosol particles in the submicron fraction by combining different analytical techniques. The dependence of concentrations of organic and elemental carbon in different air masses was determined and the contribution of regional and local sources to the net aerosol particle pollution was estimated. Analysis of the size distribution of carbonaceous aerosol particles in background and urban areas was performed. Biogenic organic aerosol made up 15 % of the organic aerosol mass at the Preila atmospheric pollution research station, but in the North Atlantic air masses this factor was up to 50 %. Aerosol and stable isotope ratio mass spectrometry has revealed that traffic is the primary source of aerosol particles in the city, while biomass burning is the primary source at the Rūgšteliškis background station. It was determined that secondary anthropogenic organic compounds were dominating (76 %) in Vilnius, while in Rūgšteliškis secondary biogenic organic compounds made up 50 % of the total organic aerosol mass. The influence of the long-range air mass transport on the local origin aerosol particle formation and transformation has been evaluated and it has been shown that volcanic aerosol particles can significantly change the concentration, chemical composition and size distribution of local aerosol particles in the submicron range.

The objective of the work was to investigate physical and chemical properties and sources of the atmospheric aerosol particles in the submicron fraction by combining different analytical techniques. The dependence of concentrations of organic and elemental carbon in different air masses was determined and the contribution of regional and local sources to the net aerosol particle pollution was estimated. Analysis of the size distribution of carbonaceous aerosol particles in background and urban areas was performed. Biogenic organic aerosol made up 15 % of the organic aerosol mass at the Preila atmospheric pollution research station, but in the North Atlantic air masses this factor was up to 50 %. Aerosol and stable isotope ratio mass spectrometry has revealed that traffic is the primary source of aerosol particles in the city, while biomass burning is the primary source at the Rūgšteliškis background station. It was determined that secondary anthropogenic organic compounds were dominating (76 %) in Vilnius, while in Rūgšteliškis secondary biogenic organic compounds made up 50 % of the total organic aerosol mass. The influence of the long-range air mass transport on the local origin aerosol particle formation and transformation has been evaluated and it has been shown that volcanic aerosol particles can significantly change the concentration, chemical composition and size distribution of local aerosol particles in the submicron range. / Disertacija skirta smulkiosios aerozolio dalelių frakcijos šaltinių, fizikinių ir cheminių savybių įvertinimui kompleksiškai apjungiant įvairius tyrimo metodus. Darbe susieti elementinės ir organinės anglies koncentracijų pokyčiai su tolimąja oro masių pernaša, įvertinta regiono bei vietinių šaltinių įtaka bendrai aerozolio dalelių taršai. Aprašyti anglies turinčių aerozolio dalelių pasiskirstymai pagal dydį foninėse vietovėse ir miesto aplinkoje. Naudojant aerozolio masių spektrometrą Preilos atmosferos užterštumo tyrimų stotyje buvo identifikuotas biogeninis organinių medžiagų šaltinis, kuris vidutiniškai sudaro 15 % nuo organinių medžiagų masės, tačiau Šiaurės Atlanto oro masėje biogeninių medžiagų indėlis siekia net 50 %. Atlikus kompleksinę aerozolio ir stabiliųjų anglies izotopų masių spektrometrinę analizę buvo nustatyta, kad pirminis anglies turinčio aerozolio dalelių šaltinis mieste yra autotransportas, o Rūgšteliškio foninėje vietovėje – biomasės deginimas. Taip pat buvo nustatyta, kad Vilniuje dominavo antropogeninės antrinės organinės medžiagos (76 %), o Rūgšteliškyje vyravo biogeninės antrinės organinės medžiagos (apie 50%). Vertinant tolimosios oro masių pernašos įtaką vietinės kilmės aerozolio dalelių formavimuisi ir kaitai, buvo nustatyta, kad vulkaninės kilmės aerozolio dalelės turi įtakos submikroninės aerozolio dalelių frakcijos koncentracijai, cheminei sudėčiai ir pasiskirstymui pagal dydį.

Organic aerosols represent one of the main sources of uncertainty affecting attempts to quantify anthropogenic climate change. The diverse physical and chemical properties of organic aerosols and the varied pathways involved in their formation and aging form the basis of this uncertainty, preventing extensive and accurate representation within regional and global scale models. This inability to constrain the radiative forcings produced by organic aerosols within the atmosphere consequently acts as a limitation to the wider objective of providing reliable projections of future climate. Biomass burning constitutes one of the main anthropogenic contributions to the global atmospheric organic aerosol (OA) burden, particularly in tropical regions where the potential for perturbations to the climate system is also enhanced due to higher average levels of solar irradiance. Emissions from biomass burning have been the subject of an intense research focus in recent years, involving a combination of field campaigns and laboratory studies. These experiments have aimed to improve the limited understanding of the processes involved in the evolution of biomass burning organic aerosol (BBOA) and contribute towards the development of more robust parameterisations for climate and chemical transport models. The main objective of this thesis was to use datasets acquired from several different global regions to perform a broad analysis of the BBOA fraction, with the extensive temporal and spatial scales provided by such measurements enabling investigation of a number of key uncertainties, including regional variability in emissions and the role of secondary organic aerosol (SOA) formation in aging smoke plumes. Measurements of BBOA mass concentration obtained using Aerodyne Research Inc. Aerosol Mass Spectrometers (AMS) were used to calculate characteristic ΔOA/ΔCO ratios for different environments, accounting for the effects of dilution and contrasting fire sizes to give a proportional representation of OA production. High levels of variability in average ΔOA/ΔCO were observed both between and within different regions. The scale of this variability consistently exceeded any differences between plumes of different ages, while a widespread absence of any sustained increase in ΔOA/ΔCO with aging indicates that SOA formation does not provide a net increase in OA mass. Despite this lack of OA enhancement, increasing proportions of oxygenated OA components in aged plumes highlight the chemical transformations occurring during the evolution of BBOA, and the additional influence of OA loss through evaporation or deposition. Potential drivers of variability in ΔOA/ΔCO at source, such as changes in fuel types and combustion conditions, were investigated for controlled fires carried out within a combustion chamber. These laboratory experiments revealed a number of complex relationships between BB emissions and source conditions. Although ΔOA/ΔCO was shown to be influenced by both fuel properties and transitions between flaming and smouldering combustion phases, the extent of these effects was limited, while variability between fires exceeded levels observed for ambient measurements. These findings emphasise the complexity of the BBOA lifecycle and the need to address the extensive uncertainties associated with its various constituent processes, in order to improve understanding of eventual climate impacts from biomass burning.

This thesis describes the development of control applications for the deposition machine and mass spectrometer. Thesis describes operation principles of both devices and their hardware specifications. Thesis also describes the design of developed applications. Functionality was tested on series of real measurements.

The work deals with the design, control, precision and dynamics of linear piezoelectric motors from PiezoMotor Uppsala AB. The aim of this thesis is to evaluate the applicability of the loaned engine in a mass spectrometer. In introduction‘s section of this work is discussing the design principles of functionality, materials used, procedure and types of piezoelectric motors. It focuses the choice of hardware and design of mechanical assemblies, which could replace the current mechanism with electromagnetic motors. Then we designed and fabricated a test report with hired piezoelectric motor. In NI LabView development environment is created test application for control and measurement. The final section is devoted to a summary of the positive and negative features of the hired piezoelectric motor and evaluation of accuracy and dynamics.

In the atomic energy pile at Chalk River, heavy water (deuterium oxide, D2O) is to be used as a moderator. Early in 1944, it became evident that frequent determinations of the isotopic composition of D2O samples would be required. For this purpose, there was obtained from the American authorities a mass spectrometer specially designed for routine hydrogen isotope analysis. This instrument was assembled and put into operation at McMaster in the summer of 1944. During the course of subsequent work, two other deuterium mass spectrometers were built in this laboratory, following the design of the instrument sent from the United States; one of these has now been installed at the plant site, and a second is to follow at an early date. The studies reported below involved the determination of operating conditions, the measurement of grid leaks, of the order of 10^10 ohms, and the investigation of further applications of the deuterium mass spectrometer. / Thesis / Master of Science (MSc)

Cette thèse porte sur l'étude de la production d'ions négatifs (INs) en surface pour des applications à la fusion contrôlée. Les INs formés en surface d'un échantillon dans un plasma d'hydrogène à partir de bombardement par les ions positifs sont collectés et analysés en énergie par un spectromètre de masse (SM). Les fonctions de distribution en énergie des INs (FDIs) que mesure le SM sont différentes de celles émises par la surface f(E, Θ) du fait des modifications de trajectoires et d'énergie induites par la traversée du plasma et du SM. Afin de déterminer la FDI émis par la surface f(E, Θ) en se servant des fonctions de distribution mesurée par le SM f''(E) nous avons développé un modèle qui calcule les trajectoires des ions entre la surface et le détecteur du SM. A partir d'une fonction test f(E,Θ) il est alors possible de calculer f''(E) et de comparer à l'expérience. L'élément critique de cette méthode est le choix de f (E, Θ). Le choix effectué dans cette thèse est la fonction de distribution des neutres calculée par le logiciel SRIM pour les particules pulvérisées et rétrodiffusées lors de bombardement d'une surface dans des conditions similaires aux conditions expérimentales. Les résultats du modèle montrent un bon accord entre les FDIs expérimentales et les fonctions calculées, et valident nos calculs et le choix de SRIM.Dans le but de comparer les mécanismes de production et les rendements des INs, une étude comparative a été réalisée sur différents matériaux carbonés. Les FDIs mesurées présentent la même forme à la température ambiante. / This thesis deals with negative ions (INs) surface production for applications in controlled fusion. Negative ions (NIs) formed at the sample surface from positive ions bombardment in hydrogen plasma are collected and analyzed with energy mass spectrometer (MS). The NI energy distribution functions (NIDF) measured by the MS are different from those emitted from surface f(E, Θ) due to modifications trajectories and energies which result when NI cross plasma and MS. In order to determine the NIDF emitted by the surface f(E,Θ) using the NIDF measured by MS f''(E), we developed a model that calculates the ion trajectories between the surface and MS detector. Then from a test function f(E,Θ) it is possible to calculate f''(E) and compare it to the experimental one. The critical issue is this method is the choice of f(E, Θ). The approach used in this thesis is the neutral backscattered and sputtered distribution function calculated by SRIM software during a surface bombardment similar to the experimental conditions. The model resulting show a good agreement between experimental and calculated NIDF, and validate our calculations and the choice of SRIM.In order to compare production mechanisms and NIs yields, a comparative study on different carbons materials was performed. Measured NIDFs show the same shape at room temperature. This indicates that the mechanisms involved in the NI production and the contribution of these mechanisms in the NIDF are the same for all materials. The best NI yield at low temperature is observed on DLC surface. The highest NI yield for all temperatures is observed on Boron doped diamond (BDD) surface at 400°C.

The Magnetospheric Multiscale mission led by NASA has been designed to study the micro-physics of Magnetic Reconnection in Earth's magnetosphere by using four identical spacecrafts with instruments with high temporal and spatial resolutions. Among these instruments are the Dual Ion Spectrometers (DIS) engineered to measure the 3D distribution of ion flux in space. The detector assembly of the DIS consists of Micro-Channel Plates (MCP) mounted in Chevron configuration. Centre d'Etude Spatiale des Rayonnements (CESR), Toulouse is responsible for the provision and testing of all fifty MCP pairs for this mission. The goal of the work was to participate in the testing and characterization of the first prototype of the MCPs. It was achieved by understanding the working and characteristics of the MCPs in general and getting familiar with the detector assembly of the DIS i.e. the MCP pair and the detector circuit board in particular. To perform the testing, it was necessary to understand the testing system as well. These topics are described in this report along with the testing procedure and the data analysis. The testing procedure was developed eventually after facing several problems during the testing. MCP pair characteristics like pulse height distributions, gain, resistance and the MCP operating voltages for the mission were determined on analyzing the data. Crosstalk was found in the circuit board of the detector assembly and has also been discussed. / Validerat; 20101217 (root)

Diese Dissertation handelt vom metastabilen Zerfall und von der Oberflächenwechselwirkung im hyperthermalen Energiebereich relativ schwach gebundener molekularer Kohlenmonoxid und Kohlendioxid Clusterkationen mit einer Edelstahloberfläche und einer Siliziumoberfläche. Im Rahmen dieser Arbeit wurde ein hierfür geeignetes spezielles Flugzeitmassenspektrometer entwickelt und aufgebaut. Entwurf, numerische Optimierung der Auflösung, ionenoptische Simulationen und Aufbau der jeweiligen Komponenten wie Elektronenquellen, Beschleuniger, Ablenkplatten, Massenfilter und Reflektron werden detailliert beschrieben. Das entwickelte Flugzeitmassenspektrometer besitzt mit einer kompakten Gesamtfluglänge von ~1.5m eine hohe Massenauflösung von m/Delta m = 3000. Es bietet die Möglichkeit, eine Massentrennung von Clusterionen mit einer Größe von bis zu n = 190 vorzunehmen. Diese massenselektierten Clusterionen können daraufhin auf metastabilen Zerfall und auf ihre Wechselwirkung mit einer Oberfläche untersucht werden. Dazu wurden Kohlendioxid-Clusterionen mit n / This thesis deals with the metastable decay and the surface scattering in the hyperthermal energy range of relatively weakly bound molecular cluster cations. With carbon monoxide and carbon dioxide two related model systems were chosen for a systematic size dependent study. Surface impact experiments were carried out with stainless steel and silicon surfaces. Results were obtained by a new, reflectron time-of-flight mass spectrometer (Re-TOFMS). Additional to the experimental data we present in this work a detailed description of the instrumental design considerations, numerical optimization, ion optical simulations. Hence each ion optical component like electron guns, accelerator, deflector, mass gate and reflectron are described. Despite the compact dimensions with a total flight length of ~1.5m the developed instrument possesses a high mass resolution above m/Delta m = 3000. Additionally it offers the possibility to perform mass separation of big cluster ions with sizes n