The outcome of several studies into future X-ray astronomy satellite missions has favoured the approach of using grazing incidence optics in conjunction with Charged Coupled Devices (CCD's) as focal plane detectors. This approach allows astrophysical investigation of unprecedented sensitivity by maximising source detectability and by resolving the source spectra. This thesis covers work performed in the development and evaluation of EEV CCD's for use as focal plane X-ray detectors. Due to the nature of the space environment, the interactions of radiation with CCD's also form a major part of this thesis. The subject of X-ray astronomy is introduced and the considerations affecting the operation of CCD's in space are discussed. The construction and operation of the CCD is thoroughly reviewed. The equipment and techniques used to evaluate the performance CCD's to X-rays are presented. A model is developed to simulate the interaction of X-rays with CCD's and this is followed by detailed measurements of X-ray performance. Further improvements to the design of CCDs to optimise their use as X-ray detectors are also discussed. These improvements include increased high and low energy quantum efficiency, larger area, low noise, reduced dark current and increased tolerance to radiation damage. Sources of background signal are investigated which lead to background rejection schemes for different CCD designs. Modelling is also performed to simulate an application of CCD's in space. Measurements of the radiation damage suffered by the CCD's are given and the damage mechanisms which will ultimately lead to device failure in space are discussed. The radiation damage covers irradiation using Co60 and heavy ions, but focuses on the effects of protons of doses below 5 krads. The impact of such a fluence on the scientific performance of an X-ray satellite is evaluated.

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Typescript. / Bibliography: leaves 256-262. / xv, 265 leaves ill

Thesis (MAppSc (MedRad))--University of South Australia, 1999

The analysis of broadened x-ray diffraction profiles provides a useful insight into the structural properties of materials, including crystallite size and inhomogenous strain. In this work a general method for analysing broadened x-ray diffraction profiles is developed. The proposed method consists of a two-fold maximum entropy (MaxEnt) approach. Conventional deconvolution/inversion methods presently in common use are analysed and shown not to preserve the positivity of the specimen profile; these methods usually result in ill-conditioning of the solution profile. It is shown that the MaxEnt method preserves the positivity of the specimen profile and the underlying size and strain distributions, while determining the maximally noncommital solution. Moreover, the MaxEnt method incorporates any available a priori information and quantifies the uncertainties of the specimen profile and the size and strain distributions. Numerical simulations are used to demonstrate that the MaxEnt method can be applied at two levels: firstly, to determine the specimen profile, and secondly to calculate the size or strain distribution, as well as their average values. The simulations include both sizeand strain-broadened specimen profiles. The experimental conditions under which the data is recorded are also simulated by introducing instrumental broadening, a background level and statistical noise to produce the observed profile. The integrity of the MaxEnt results is checked by comparing them with the traditional results and examining problems such as deconvolving in the presence of noisy data, using non-ideal instrument profiles, and the effects of truncation and background estimation in the observed profile. The MaxEnt analysis is also applied to alumina x-ray diffraction data. It is found that the problems of determining the specimen profile, column-length and strain distributions can be solved using the MaxEnt method, with superior results compared with traditional methods. Finally, the issues of defining the a priori information in each problem and correctly characterising the instrument profile are shown to be critically important in profile analysis.

v, 142 leaves : ill., appendices / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1973

vii, 170 leaves : ill. ; 25 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1972

Thesis (Ph. D.)--University of Washington. / Bibliography: l. 81-83.

Proefschrift Universiteit van Amsterdam. / Met bibliogr., lit. opg. - Met samenvatting in het Nederlands.

Thesis (Ph. D.)--University of Washington. / Bibliography: l. [109]-111.