A solid-state DE-E telescope beta spectrometer has been built and used to study beta-minus spectra. The system consists of a 15 mm x 500 mm$ sp2$ hyperpure germanium (HPGe) E-detector and a 300 $ mu$m x 200 mm$ sp2$ Si DE-detector with a special "keyhole" design. / The response function of the system has been determined experimentally using mono-energetic electron beams with incident energies ranging from 1 to 12 MeV. / The beta endpoint energies of 25 nuclei, namely, $ sp{32}$P, $ sp{88}$Rb, $ sp{91-99}$Rb, $ sp{91-96}$Sr, $ sp{99-100}$Sr, $ sp{92-96}$Y and $ sp{100}$Y have been measured. The Q-beta values and mass excesses for A = 91-100 have been determined. The results for $ sp{99}$Rb, $ sp{99-100}$Sr and $ sp{100}$Y have been obtained for the first time. / The beta strength functions for odd mass Rb isotopes, namely $ sp{91-99}$Rb have been measured for the first time from direct beta spectroscopy with a solid-state telescope system. The experimental results have been compared to calculations using the Brown-Bolsterli (B-B) model.

A neutron multiplicity detector system has been developed to study weak pure neutron evaporation channels from heavy-ion reactions. Such a system allows us to study nuclei far away from the line of β-stability - in particular, self-conjugate nuclei where the shell-effects for protons and neutrons are in phase and their combined effects may drive the nucleus towards superdeformation. The system consists of a neutron wall - 4 large volume Ge(Li) γ-ray detectors positioned as close as possible to the target. Neutron-gamma coincidences were recorded and neutron multiplicity events could be extracted from the data. Rejection of gamma-ray events in the neutron detectors was achieved by time-of-flight and pulse shape discrimination methods. A surface barrier detector at 0⁰ allowed a further rejection of charged particle events - especially events which feature neutrons as well.

The high temperature behaviour of the fluorite oxides UO₂, THO₂ and Y₂O₃-stabilised ZrO ₂ have been investigated using a variety of neutron scattering techniques. Interest has centred on the cause of the anomalously large enthalpy of UO₂ at temperatures above 15OOK, an understanding of which is important in view of its use as a fission reactor fuel. High temperature techniques have been developed which enable the performance of neutron scattering at temperatures up to 3OOOK. Bragg diffraction measurements have shown that a growing fraction of anions vacate their regular sites above 21OOK in UO₂ and above 23OOK in ThO₂ attaining vacancy concentrations of ~2O% at 29OOK in both materials. Quasielastic scattering investigations have confirmed the occurrence of anion Frenkel disorder in UO2 at high temperatures and have shown that the disorder is of a dynamic nature. Both sets of results may be interpreted in terms of fluctuating, dynamic clusters of vacancies and inter stitials, having lifetimes of a few phonon periods. The elastic constants of UO₂, which have been determined up to 293OK from measurements of the long wavelength acoustic phonons, show an increased rate of softening above 24OOK. The zone-centre optic phonons broaden rapidly above 2OOOK in UO₂- The full phonon dispersion relation of ThO₂, measured at 293K, resembles closely that of UO₂. The results provide the first direct, unambiguous evidence of thermally-induced Frenkel disorder in UO₂, which is analogous to the disorder observed in the fast-ion phase of the fluorite halides, such as CaF₂. Quasielastic scattering techniques have also been used to study the defect structure of Y ₂O ₃ -stabilised ZrO ₂ between 293K and 2OOOK. Many general features of the scattering observed at room temperature may be explained in terms of nearest neighbour relaxations around oxygen vacancies. The diffuse scattering broadens in energy above 1OOOK, signifying that these clusters of relaxed ions have a finite lifetime of ~5ps at 15OOK. The results have been interpreted in terms of a vacancy hopping model which is consistent with the enhanced conductivity observed in this temperature range.

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Thesis (PhD) -- McMaster University, 1997. / Includes bibliographical references (leaves 178-179). Also available via World Wide Web.

Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 2002? / Copies of author's previously published works inserted. Bibliography: p. 89-96.

Thesis (Ph. D.)--University of Washington, 1990. / Vita. Includes bibliographical references (leaves [143]-147).

Thesis (Ph.D.) - University of St Andrews, October 2007.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 102-108). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 60-62).