Studies on the relativistic electrons and x-rays generated by laser wakefield accelerators

摘要

Laser wakefield accelerators (LWFAs) operate through a high intensity ultra short laser pulse exciting a relativis- tic density wave in a plasma. I carried out experiments constructing LWFAs using lasers of a wide range of powers. Thereby allowing me to examine the generation of electrons and x-rays under these different conditions. The compar- ison of these results with my own and existing analytical models and computational modelling is discussed.udIn fulfilment of this, I developed novel techniques to measure hard x-rays in the tens of KeV energy range. In measure- ment of the relativistic electrons I found it possible to de- velop techniques to not only accurately measure the energy but also discern the three momentum vectors of electrons measured on a multiscreen electron spectrometer.udAs LWFAs open up the ability to produce high energy elec- tron beams without the need of tens of meters of RF accel- eration cavities and the lasers used to drive them can also be made relatively compact perhaps one of the most excit- ing application of this is the production of hard x-rays for imaging. As the source size of a LWFA betatron source is typically of micron scale, I investigated using LWFA derived x-rays for phase contrast imaging.