Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.728164
Title: Resonance photo-ionisation mass spectrometry techniques for the analysis of heavy noble gas isotopes in extra-terrestrial samples
Author: Nottingham, Mark
ISNI:       0000 0004 6498 3149
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2017
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Abstract:
The field of noble gas mass spectrometry is a rapidly developing one. There is a sustained requirement for continuous development of instrumentation in order to allow researchers to answer critical questions facing their respective fields. Within planetary science, the question of whether our solar system is 'typical', has been a driving force behind many lines of research. This project sought to build upon the strong instrumental base of the Isotope Geochemistry and Cosmochemistry group of the University of Manchester, in order to develop the Resonance Ionisation Mass Spectrometer for Krypton Isotopes. From that basis, it then sought to develop techniques and protocols for the analysis of extra-terrestrial samples, particularly those of very low mass. The thesis is broken down into three studies. The first involved the development of the mechanisms used to fill the Xe-Ar four-wave mixing cell. This section covers the development, implementation, and characterisation of the newly installed mass flow controllers. The additional control over the mixing ratio granted allowed an eightfold increase to the sensitivity of the instrument. The reproducibility of the gas ratio is consistently shown throughout, and has ultimately reduced the tuning time of the instrument from a number of weeks to a day. The second section details the required procedures involved in data reduction, and the development of protocols and software for the RIMSKI instrument. A range of approaches are assessed, including a novel approach to cosmic ray exposure age calculations. The methods are discussed and implemented on extra-terrestrial samples, the Stannern eucrite and the Bereba eucrite. Finally, the analytical limits of the RIMSKI instrument are expanded via the measurement of the krypton systems of individual calcium-aluminium-rich inclusions. It is observed that Allende CAIs show a trapped component, Br-derived Kr, as well as an anomalous 'heavy Kr' component (one that is enriched in 86Kr). It is additionally noted that there is a lack of cosmogenic krypton to be found in all but one of the measured inclusions. The implications of these findings are discussed.
Supervisor: Gilmour, James Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.728164  DOI: Not available
Keywords: Early Solar System ; Cosmic ray exposure ; Four-wave mixing ; Calcium Aluminium rich Inclusions ; Isotope analyses ; Krypton ; RIMSKI ; Resonance Ionisation ; Mass Spectrometry
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