The aim of the present research was the development of an optimised secondary electron emission (SEE) diamond film to use as a dynode material. The project was a partnership between the School of Chemistry in the University of Bristol, the Space Research Centre (SRC) at the University of Leicester and Photek, a company specialized in the manufacture of systems for photon detection. The role of Bristol in this project consisted in the preparation of CVD diamond films and their characterization, before supply to the other collaborators. SEE characterisation of the samples was performed at SRC and Photek would proceed to further testing in actual tubes. Besides its participation in the project, Bristol went further and developed the means to do its own SEE measurements. This thesis describes the work undertaken at Bristol using the facilities at the Diamond CVD group. Diamond films were prepared by hot-filament (HF) CVD covering a range of crystallinities, thicknesses and levels of boron (B) doping, on different substrate materials. A new home-built apparatus has been developed for the acquisition of SEE data from diamond films, both in reflection and transmission configurations. The setup consists of a system of phosphor screens acting as detectors and associated to PMTs for the acquisition of signal measured from the diamond samples. A comprehensive study evaluating the effects of B-doping, crystallinity, surface termination, thickness and substrate material of diamond films on yield and yield degradation in the SEE reflection yields has been performed. In addition, SEE yields from commercial CVD diamond samples were analysed, after surface functionalization by hydrogenation, caesiation and lithiation. Moreover, the present study allowed for an improvement in the growth of thin NCD films, essentially through the optimization of the seeding processes. Finally, the development of techniques to manufacture free standing diamond films on silicon substrates were investigated, and preliminary SEE measurements in transmission were undertaken.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:616564 |
| Date | January 2013 |
| Creators | Vaz, Raquel Maria Amaro |
| Publisher | University of Bristol |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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