Assembly of a portable X-ray fluorescence spectrometer with tri-axial geometry

• Autor(a) principal: Alves, Matilde de Jesus Jacob
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/18119
• topic: X-Ray fluorescence; Tri-axial geometry; Portability; In situ; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

X-ray fluorescence (XRF) technique is a powerful analytical tool with a broad range of applications such as quality control, research of environmental contamination by heavy metals, studies regarding cultural heritage, among others. In this dissertation, a portable energy dispersive X-ray fluorescence (Energy Dispersive X-Ray Fluorescence (EDXRF)) spectrometer will be developed, with orthogonal tri-axial geometry between the X-ray tube, the secondary target, and the sample. Said geometry reduces the background of the obtained spectrum by removing the Bremsstrahlung from the tube through polarization effects. Moreover, a practically monochromatic excitation energy is obtained. This geometry renders a better peak-background ratio, thus improving the detection limits, leading to superior sensitivity.The use of this geometry has proven to be more advantageous when dealing with the detection of trace elements in low-Z matrix samples. Moreover, the use of a portable setup is of paramount importance in studies related with Cultural Heritage and archaeometry. Thereafter, two case studies will be presented concerning the analysis of a 18th century paper document and the bone remains of an individual buried in the early 19th century.