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Molecular dynamics techniques are used to explore metals at an atomic level. The focus of the studies is the effects of irradiation on a metallic system. Ion surface bombardment effects, bulk cascades and interaction with voids and bubbles in bulk are studied. In the first section a study of a copper <110> surface being bombarded by low energy argon ions is conducted. Molecular dynamics simulations were used to study the surface impact crater formation and the damage caused in the surrounding area. Another group had previously performed experimental measurements on the same system. The simulation data is compared to experiment, in order to validate the molecular dynamics technique. Additionally, information about the formation of the craters at time scales inaccessible to experiment can be gained. In the next section bulk radiation induced cascades in BCC iron are considered. Cascades of energy 1 keV, 2 keV, and 5 keV are initiated in the bulk of the material and the damage yields studied. Cascades are also studied in proximity to voids and helium bubbles in the bulk. The damage formation processes and damage yields in these cascades is analysed. A mechanism that allowed voids to be ballistically moved by the cascade was observed. To further explore this an object kinetic Monte Carlo model was written to simulate the effects of this motion on the diffusion of the voids. The final section is a study of transition metals as alloying elements in BCC iron. This system is of interest as it would be a model for various steels used in construction and shielding. A set of potentials describing iron with low concentrations of transition metals has previously been developed by a different group. These potentials were implemented in the molecular dynamics code. The equilibrium properties of various alloys are explored by implementing a Metropolis algorithm to minimise the Gibbs free energy of the system. Various binary and tertiary alloys are analysed and compared with experimental values in the literature. The attraction of the elements to voids present in the system is also studied.

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This thesis is concerned with the effects of radiation damage in CCDs used for space applications. The manufacturing process and operational principles of CCDs are presented in Chapter 2. The components of the space radiation environment, the two radiation damage mechanisms relevant to CCDs, and the effects of radiation on the operational characteristics of CCDs are described in Chapter 3. Chapter 4 presents a study to assess the suitability of novel L3Vision technology to applications in space. Two L3Vision CCDs were subjected to proton irradiations representative of doses expected to be received by spacecraft in low Earth orbit. Post-irradiation the devices were found to operate as expected, the effects of radiation on the operational characteristics of the devices being comparable to previous studies. The effect of low energy protons on CCDs is the subject of Chapter 5. The study was initiated in response to the finding that soft protons could be focused by the mirror modules of the XMM-Newton spacecraft onto the EPIC CCD detectors. Two EPIC devices were irradiated with protons of a few keV to find that soft protons cause more damage than that expected by the NIEL damage relationship, as they deposit most of their energy within the CCD. The observed change in CTI of the EPIC devices on XMM-Newton is however comparable to the pre-launch prediction, and the component attributable to low energy protons is small, < 20%. Chapter 6 presents a study of a specific radiation induced phenomenon, `Random Telegraph Signals'. Development of analysis software and the irradiation of two CCDs are discussed before a detailed characterisation of the generated RTS pixels is presented. The study shows that the mechanism behind RTS involves a bi-stable defect linked with the E-centre, in combination with the high field regions of a CCD pixel.

Abstract Diamond is nowadays regarded as a potential semiconductor material of the future, due to its extreme and unique properties. Some of these properties, in- clude its high hardness, highest breakdown ¯eld, high Debye temperature, high thermal conductivity, high hole and electron mobilities, large bandgap and op- tical transparency, among others. These properties make diamond suitable for high-temperature, high-speed and high-power electronic applicatons, as well as in other applications. However, defects associated with ion implantation have been shown to make it rather di±cult to obtain n-type doping in diamond. As such, an understanding of the nature of defects produced during ion implanta- tion of diamond remains a subject of great importance, if not essential, for the optimization of high-temperature, high-power electronic applications in partic- ular. In this respect, this study investigates the nature of the radiation damage generated within the collision cascades of multi-implantations of carbon ions in high-pressure, high-temperature single-crystal synthetic type Ib diamond, spread over a range of energies (50-150keV) and doses. This is achieved by means of the cold-implantation-rapid-annealing (CIRA) routine, and the anal- ysis of damage caused was done by using cross sectional transmission electron microscopy techniques. More precisely, the modes used to achieve this are the bright ¯eld transmission electron microscopy (BFTEM) coupled with selected area di®raction or SAD. At low dose implantation or at sub-critical implantation doses (2.5x1015 ions/cm2), it was found that the ion-damaged diamond layer consists of some threading dislocations, not homogeneously distributed which propagate from the surface into the ion-damaged diamond. In contrast to the sub-critical implantation doses , it was found that at very high implantation doses (7.0x1015 ions/cm2), i.e., above the critical dose (where diamond transforms to graphite upon annealing), the damaged diamond layer had some unconventional defect features close to the implanted surface.