Advances in x-ray spectrometry: new science through new sources

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This proposal seeks to advance x-ray spectrometry, with new science resulting from new radiation sources. The research involves the development and use of x-ray fluorescence and x-ray absorption techniques for the detection of trace elements such as lead, arsenic, and selenium. The proposal is concerned with the scientific challenges and opportunities posed by these methods. Effects from exposure to even moderate levels of lead and arsenic may be severe. Using novel lab-based and synchrotron-based sources, this proposal aims to significantly improve our understanding of the distribution and fate of such elements. Objectives include the use of x-ray spectrometry in the following interrelated themes of research: (1) development of an innovative and compact mono-energetic x-ray approach for trace element detection; (2) optimization and validation of fully portable miniature x-ray tube techniques; and (3) investigations through synchrotron radiation at the Canadian Light Source to probe elemental distribution and chemical form in tissue samples. The research involves the use of ionizing radiation and falls within the fields of medical physics and radiation physics. Through intensive scientific development and study, the goal is to improve capabilities for monitoring trace element exposure. For example, the ability to monitor for arsenic using a fast, reliable, and portable system would have significant implications in Canada and worldwide. Arsenic contamination of drinking water in Bangladesh has been called "the largest mass poisoning of a population in human history". Significantly, there is evidence that the effects of arsenic may be counteracted by intake of selenium. This has increased interest in the detection of selenium at the same time as arsenic. The demonstration of an accurate and precise bone lead measurement using an L-shell characteristic x-ray technique would add a new exposure assessment tool and further our understanding of lead intake and kinetics. The research proposed will make use of synchrotron microprobe fluorescence mapping and x-ray absorption techniques to provide fundamental scientific knowledge and inform the development of new methods.