The development of the national accelerator centre proton microprobe as an analytical tool in geochemistry

This thesis describes work performed to establish and demonstrate a quantitative trace element microanalysis technique for geological material using protons accelerated by the Van de Graaff Accelerator at the National Accelerator Centre (NAC) in Faure near Cape Town. The method relies on the analysis of Proton Induced X-ray Emission (PIXE) spectra, interpreted with the help of the GeoPIXE software package. The use of the Si(Li) energy dispersive detector provides simultaneous multi-element detection at the parts-per-million (ppm) level, and a scanning beam facility permits trace element distributions to be studied at these levels. The calibration of the detector efficiency and the thicknesses of selectable X-ray attenuating filters was performed using pure elemental samples. This involved the accurate determination of the target to detector distance, the thickness of the active volume of the Si(Li) detector crystal, the thicknesses of all the absorbing layers between the sample and the detector crystal, and the assessment of the effects of incomplete charge collection in the detector.

Grantor dc:publisher.institution

Department of Geological Sciences

Year dc:date.issued

1995

Author dc:creator

• Van Achterbergh, Esmé

Advisors dc:contributor.advisor

• Le Roex, Anton
• Gurney, John J

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/22046

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/22046