A new multi-purpose surface analytical instrument (the Hallam instrument) is described, which combines the surface specific information obtained using x-ray photoelectron spectroscopy (XPS), with bulk information obtained using Energy Dispersive X-ray (EDX) detection. A 15kV electron gun and an ultra high vacuum EDX detector give the instrument an EDX mapping capability. To exploit this to its full potential, spatial alignment of EDX maps acquired at various electron beam energies, E[o], was required. The misalignment of images acquired at various E[o] values was investigated, and a means of describing the misalignment as a function of E[o] was presented. An algorithm was developed which would allow the alignment of offline images acquired at different E[o] values. This was demonstrated on images acquired on both the Hallam instrument and on a Phillips XL40 electron microscope. The small area XPS system developed by Kratos analytical gave a spatial resolution of 30pm at the centre of the field of view, although this deteriorated away from the centre. The reasons for this deterioration in spatial resolution were investigated, and two methods of improving the system were presented. The improvements were implemented on the Hallam instrument and demonstrated using a standard silver grid sample. The small area XPS was applied to a TiAINi coated stainless steel sample to demonstrate its application to real samples, and to display the spatial alignment between the XPS and EDX maps. Finally, the instrument was calibrated for quantitative XPS studies. This involves determining the response of the instrument as a function of the photoelectron kinetic energy. From several methods presented in the literature, the most appropriate was chosen for calibration of the 'Hallam' instrument. The effectiveness of the method used was assessed by recording spectrum intensity from pure elemental standards, and comparing the results with intensity values calculated using the calibration curves.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:340746 |
| Date | January 2000 |
| Creators | Rignall, Michael |
| Contributors | Wirth, A. ; Titchmarsh, J. |
| Publisher | Sheffield Hallam University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://shura.shu.ac.uk/20280/ |
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