Fabrication and characterization of silicon position sensitive particle detectors

Position sensitive particle detectors are needed in high energy physics research. This thesis describes the development of fabrication processes and characterization techniques of silicon microstrip detectors used in the work for searching elementary particles in the European center for nuclear research, CERN. The detectors give an electrical signal along the particles trajectory after a collision in the particle accelerator. The trajectories give information about the nature of the particle in the struggle to reveal the structure of the matter and the universe. Detectors made of semiconductors have a better position resolution than conventional wire chamber detectors. Silicon semiconductor is overwhelmingly used as a detector material because of its cheapness and standard usage in integrated circuit industry. After a short spread sheet analysis of the basic building block of radiation detectors, the pn junction, the operation of a silicon radiation detector is discussed in general. The microstrip detector is then introduced and the detailed structure of a double-sided ac-coupled strip detector revealed. The fabrication aspects of strip detectors are discussedstarting from the process development and general principles ending up to the description of the double-sided ac-coupled strip detector process. Recombination and generation lifetime measurements in radiation detectors are discussed shortly. The results of electrical tests, ie. measuring the leakage currents and bias resistors, are displayed. The beam test setups and the results, the signal to noise ratio and the position accuracy, are then described. It was found out in earlier research that a heavy irradiation changes the properties of radiation detectors dramatically. A scanning electron microscope method was developed to measure the electric potential and field inside irradiated detectorsto see how a high radiation fluence changes them. The method and the most important results are discussed shortly.

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ÅBO AKADEMI UNIVERSITY Faculty of Education and Welfare Studies Author: Helena Nyman Supervisor: D.Sc. (Health Care), RN Jessica Hemberg Master´s Thesis The vision of caring – Occupational healthcare nurses experiences of fulfilling their ethical values CARING SCIENCE Keywords: Ethics, nursing, nursing ethics, healthcare, values April 2016 Number of pages: 53 Appendices: 5 The purpose of this study is to reach an understanding of what ethos is in an occupational healthcare context. The study seeks answer to the following questions: 1. What is ethos in an occupational healthcare context? 2. What does it mean for occupational healthcare nurses to fulfill their inner ethos in a healthcare context controlled by economic demands of gain and efficiency? The main concept in this study is ethos as Eriksson describes it in her caritative theory of caring. Ethos is associated with ethics and reflects the fundamental assumptions that we have about the human being´s holiness and dignity and about the inviolability of life. The empirical part of the study consists of focus interviews with four occupational healthcare nurses. The study uses hermeneutical reading as an interpretation method, and presents the results of the study in six theses reflecting these against both recent research and the theoretical background. The results of the study show that ethos in occupational healthcare has to do with justice, honesty and faithfulness. These concepts are common to nurses in different nursing contexts. Ethos is not primarily profession-bound but is something universal, and eternal in the human being´s way of being and becoming. The study shows that ethos is a way of being, openness and a way of existing in love. To fulfill ethos in an occupational health context means to choose ethos continuously and courageously for the sake of the patient and the good, even if it involves a struggle or a sacrifice.