Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606206
Title: Development of an X-ray excited optical luminescence microscope (XEOM)
Author: Hand, Matthew
ISNI:       0000 0004 5361 0064
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2014
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Abstract:
X-ray excited optical luminescence (XEOL) refers to the trans-visible emission produced as a consequence of X-ray bombardment and provides an alternative detection method for X-ray absorption spectroscopy (XAS). Whereas XAS measured by conventional means (absorption, X-ray fluorescence) generally yields spectra characteristic of the bulk, the shallow escape depth of visible photons provides surface specificity of ~ 200 nm. Combining this with the relative ease of manipulating the emission using conventional optics gives us the basis for a method of mapping surface chemical states on the micron scale — XEOL microscopy (XEOM). As part of an ongoing project looking into the use of XEOL to study the chemical systems relevant to the corrosion of heritage artefacts, a portable XEOM instrument, XEOM1, has been constructed. Here, a detailed account of the development process is given, including descriptions of the microscope itself (optics, detectors, auxiliary hardware) and of its support system (control electronics and software). Data processing challenges are also discussed. Testing of XEOM1 has involved deployment on multiple synchrotron beamlines and data acquired from samples comprising of corroded copper surfaces (coupons, meshes) are presented in order to demonstrate how XEOM1 can be used for surface chemical analysis. XEOL spectra have been obtained by acquiring image 'stacks' — each stack is sequence of images resolved in energy across an absorption edge — and extracting data from regions of interest (ROIs) in each image. Chemical identification is achieved through analysis of the nearedge structure (XANES). Subtraction of pre- and post-edge images also gives a method for fast elemental mapping. Several options for future development of the XEOM1 hardware and related investigations are also proposed.
Supervisor: Not available Sponsor: Fonds Wetenschappelijk Onderzoek (FWO) ; Royal Society (Great Britain) ; Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.606206  DOI: Not available
Keywords: QC Physics
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