U285130.pdf (12.39 MB)
The Malpha X-ray satellites of ytterbium and hafnium.
thesisposted on 2015-11-19, 09:17 authored by Michael Albert. Parrott
Modifications to an existing X-ray spectrometer are described which enable line profiles to be obtained undistorted by target ageing effects. Using the thin target technique, the Malpha spectrum of ytterbium fluoride was obtained and its dependence on exciting potential investigated. A similar investigation was made into the Malpha spectrum of hafnium dioxide. The profiles were analysed into Lorentzian components using a digital computer, and the satellites of ytterbium fluoride were found to attain a maximum integrated intensity of over 1100% of that of the parent line, whereas the Malpha satellites of hafnium dioxide attained a maximum integrated intensity of approximately 40% of that of the parent line. A vacuum oven is described, which was used to prepare, in situ, X-rey targets of ytterbium metal, reasonably free from oxide content. A method is described by which the Malpha spectrum of ytterbium metal was obtained. Comparisons are made between the Malpha spectra of hafnium dioxide, metallic ytterbium and triply ionised ytterbium, and the extraordinary magnitude of the Malpha satellites of triply ionised ytterbium is correlated with the presence of electron vacancies in the atomic core. An explanation of the large intensity of Malpha satellites in triply ionised ytterbium is given, in which they are regarded as pseudo-satellites arising from electron transitions in ionised ytterbium atoms, the parent line arising from transitions in atoms in which electrons have been excited into the core vacancies. Suggestions for further work have been made, which would establish the validity of these processes in the emission spectra of other rare earth elements. Also, it has been shewn that the Coster-Kronig theory of the origin of the M satellites of hafnium, proposed by Hirsh, cannot fully explain the observed facts, end a further suggestion has been made to explain their origin.
Date of award1965-01-01
Author affiliationPhysics and Astronomy
Awarding institutionUniversity of Leicester