Langevelde, Frans van (1991) The Daresbury photon microprobe. PhD thesis, University of Warwick.

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Abstract

In many branches of science it is important to be able to measure elemental distri­butions on the micrometre level. Therefore a Synchrotron X-ray Fluorescence microbeam has been built at the SRS, Daresbury. The synchrotron microprobe technique for trace element analysis (micro-SXRF) is the subject of this study.
This thesis begins with an overview of different microprobe techniques for trace element analysis. Features and capabilities are presented which are used to compare these meth­ods and to make clear the relation between micro-SXRF and the other microprobes. This is followed by a review of relevant literature, which is related to X-ray focussing in gen­eral and the application of synchrotron radiation for trace element analysis, as well as the design and development of synchrotron microbeams.
Tools are presented to calculate and judge the quality of optical shapes and configura­tions for the design of X-ray optics. Aberration theory is used to derive the necessary fo­cus conditions as well as the main aberration terms and ray-tracing to design the optical components of the microprobe. The conclusion of the calculations is that in the case of the single crystal option the ellipsoid has the best X-ray optical features.
Criteria have been formulated in order to design a microprobe for trace element analysis. Finally an ellipsoidally shaped concave bent Si(lll) crystal has been constructed as the basic element of the microprobe. The results are presented in terms of beam profiles and flux densities to demonstrate the focussing action of the bent crystal and in terms of de­tection limits and sensitivities to demonstrate the analytical features, which are consis­tent with calculations. A final resolution of 10x15 pm2 is obtained and a flux density of about 104 ph/(s.mA.pm2) is measured for 15 keV quasi-monochromatic radiation, which is able to detect femtogram levels in favourable cases.
The last part of this study is devoted to the design of X-ray optics for the ESRF (Greno­ble). Comparisons are made for what can be expected if the ESRF source parameters are used rather than the SRS source parameters for the same type of optics. A planar-ellip­soid combination seems to be a good option for focussing as well as managing the high intensity of the incident white beam.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering
Library of Congress Subject Headings (LCSH):	Nuclear engineering, X-ray microscopy, X-ray spectroscopy, X-ray optics, Electron probe microanalysis, Microprobe analysis, Nuclear physics -- Instruments, Nuclear physics -- Technique
Official Date:	July 1991
Dates:	Date Event July 1991 Submitted
Institution:	University of Warwick
Theses Department:	Department of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Bowen, D. Keith(David Keith),|d1940-; Vis, Ronald D.
Sponsors:	Science and Engineering Research Council (Great Britain) , Nederlandse Organisatie voor Wetenschappelijk Onderzoek
Extent:	142, [18] leaves
Language:	eng

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