Applications of laser wakefield acceleration to high-field physics and industrial radiography

The aim of this thesis is to investigate applications of laser wakefield acceleration to other fields of experimental physics i.e. measurement of strong-field QED effects in electrons, and industrial radiography using a laser-driven bremsstrahlung source. The importance of detector design in each of these cases is also discussed.

Chapter 4 investigates the possibility of direct, on-shot measurement of strong-field effects, namely radiation reaction, in the interaction between a high-intensity laser pulse, and an ultra-relativistic electron bunch. QED-PIC simulations of these interactions indicate that, by incorporating a pre-interaction, mm-scale drift, the signature of radiation reaction can be preserved in a localised region of an electron bunch. Consequently, unaffected regions which retain the original spectral structure can be used as a direct comparison, potentially enabling discrimination between models.

Chapter 5 reports the results of an X-ray source development project. Industrially-relevant, additively manufactured materials were imaged using a bremsstrahlung source driven by LWFA. Making use of a range of converter materials, and by having control of the plasma density in the LWFA source, it is possible to tune the resulting X-ray characteristics for different material properties. The results demonstrate the possibility that such a source, driven by a compact, high-power laser, is a commercially viable solution to industry demands for high-resolution imaging of dense materials.

Chapter 6 shows progress made in the development of caesium iodide-based X-ray detectors for various applications. Small stacks of crystals mounted to a camera, offer a compact method of detecting X-rays with high angular resolution. A large, 2D array is a useful diagnostic in detecting directional X-rays, and offers a means to recover spectral information. Extending this idea, it is possible to capture the three-dimensional structure of an X-ray beam, which may yield quantum signatures in strong-field interactions.