Philosophiae Doctor - PhD (Chemistry) / Electrochemiluminescence (ECL) is a light-emitting process generated by electrochemical redox reactions and has been widely used as an analytical tool, especially in the field of biosensing, that is, immunoassays and DNA-probe assays. Thus, the scope of this work was to develop a simple, sensitive ECL immunosensor for cardiac injury and to study and present insights into newly fabricated platforms for bioanalytical applications by using ECL as detection mechanism. / 2021-08-31

The thesis deals with the study of properties of a new system for detection of true secondary and backscattered electrons in high pressure conditions of the specimen chamber of a newly built environmental scanning electron microscope AQUASEM II. Detection system contains three detectors. For the first time is introduced and analyzed the working principle of ionisation detector with electrostatic separator, which is in many experiments compared with ionisation detector of secondary electrons. Experimentally demonstrated are unique properties of this detection system, especially the ability of energy separation of detected signal electrons. For the various working conditions are also analyzed signal levels detected by the BSE YAG detector, which is designed as a part of the new detection system and which worked together with both ionisation detectors.

L‘objectif de la thèse consiste à caractériser expérimentalement sous vide les propriétés d’émission électronique de matériaux utilisés dans des applications spatiales tels que l’argent et l’aluminium dans leur état de contamination naturel, afin de fournir des données précises à la communauté du spatial tout en contribuant à comprendre et quantifier le rôle joué par la contamination naturelle sur leurs propriétés d’émission électronique. Afin de répondre à cet objectif, un moyen expérimental nommé CELESTE permettant de caractériser les différentes propriétés d’émission électronique de ces matériaux sous ultravide a été développé. Il permet d’effectuer des mesures de rendement d’émission électronique ainsi que des mesures de rendement de rétrodiffusion. Afin d’établir un lien entre la physique d’émission bien connue des matériaux purs et la physique d’émission des matériaux d’utilité pratique, un protocole expérimental spécifique a été mis en place. Il permet de caractériser l’évolution du rendement d’émission et de la distribution énergétique des électrons émis à partir d’un matériau exposé à l’air jusqu’à l’élimination par décapage ionique successifs de tous les contaminants déposés à la surface. Une corrélation a été établie entre évolution du rendement d’émission et évolution de la composition de la surface de l’argent et de l’aluminium. Ce travail a permis de mettre en évidence l’influence prépondérante des contaminants naturels sur leurs propriétés d’émission électronique. En effet, les propriétés d’émission de ces deux matériaux exposés à l’air dépendent d’avantage de la nature de la couche de contamination déposée à la surface que du matériau pur sous-jacent. / The aim of this study is to provide accurate data on electronic emission properties of technical materials used in spacecraft applications such as silver and aluminium and to understand and to quantify the effect of natural contamination on their electron emission properties.In order to reach this goal, an experimental facility named CELESTE allowing electronic emission properties characterization under ultra-high vacuum had been developed. The facility can be used to perform electron emission yield measurements and also backscattering yield measurements thanks to special experimental setup developed during this phD. To establish a link between the well-known emission physic of pure materials and those of “technical” materials, a specific protocol has been implemented. It allows the study of emission proprieties starting from a sample exposed to ambient atmosphere and reaching a cleaned sample, using Ar ion etching step by step technic.A link has been established between electron emission yield and surface composition evolution of silver and aluminium sample. This work highlights the leading influence of natural contamination on the electron emission proprieties of metals.

This project deals with the theme of environmental scanning electron microscopy (EREM). This method allows the examination of insulators and wet specimens without pretreatment and modification like drying and metallization. The principle of this method consists in using higher pressure in a specimen chamber. The pressure is within the range of 100 – 200 Pa. However, the pressure in the specimen chamber restricts the signal detection interference. The objective of the work is to explore the possibility of interference in secondary electron route detection by way of electrostatic field. The electrostatic field was realized with the system consisting of four electrodes located in front of the scintillation detector. It should have interfered the secondary electron´s trajectory to the detector chamber. The optimization of voltage on the electrodes was made by simulation program called SIMION. The simulation results were experimentally verified with laboratory EREM.

This master thesis deals with analysis of battery mass using x-ray spectral microanalysis. For the measurement two scanning electron microscopes equipped with energy dispersive x-ray spectroscopes were used. Appropriate examples were prepaired by standard method. Then elemental analysis was performed with changing conditions of measurement. Two programs were used for spectrums evaluation and in the end the size of errors was observed for every conditions.

The thesis deals with the scintillation secondary electron detector for environmental scanning electron microscope, its design and construction. The starting point was numerical simulation of electrostatic fields and electron trajectories in the electrode system of the detector and simulation of pressure distribution and flow of gases in different parts of the detector. On the basis of modeling and simulation, construction changes of the detector were gradually implemented. Detection efficiency of each version of the detector was determined by the method described in the work. This method enables to evaluate signal level from the captured images of the specimen, quality of images was stated from signal to noise ratio. The thesis describes the whole process of the detector improvement from initial state, when the detector operated with lower efficiency in the pressure range from 300 to 900 Pa, to final version that enables usage of the detector in the range from vacuum up to 1000 Pa of water vapors in the specimen chamber of the microscope.