Multi-species ion acceleration with high power lasers and their detection

Abstract

This thesis explores both the production and detection of laser-driven ions. The first chapter focuses on ion acceleration dynamics, particularly the acceleration of protons and carbon ions. The interplay between these species and its impact on acceleration efficiency is examined through an experiment employing the Vulcan Petawatt laser at the Central Laser Facility. To complement the experimental findings, 2D particle-in-cell simulations were performed to investigate the underlying acceleration mechanisms responsible for generating the highest-energy ions. The results reveal a complex acceleration process, combining Target Normal Sheath Acceleration (TNSA) and Radiation Pressure Acceleration (RPA), which are enhanced by the target undergoing transparency. The presence of heavier carbon ions within the expanding target also enhances proton acceleration, through the generation of the charged fields from the carbon ions. This acceleration has been termed ‘multi-species TNSA’ and this thesis explores in detail this mechanism. The second chapter focuses on detecting high-energy ions using diamond Time-of-Flight (ToF) detectors, both multi-layer and single-layer configurations. These detectors were evaluated under high-repetition-rate conditions and in the presence of a multi-species ion beam. Their performance in such demanding experimental environments was analysed, and appropriate data processing methods (especially for dealing with noisy signals) were developed for each experimental campaign. In particular, the multi-layer detector, which has not yet been fully characterised for multi-species ion detection, was examined in detail, leading to proposed improvements in both experimental setup and detector control.

Date of Award	Jul 2025
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Department for Education
Supervisor	Marco Borghesi (Supervisor), Satyabrata Kar (Supervisor) & Aodhan McIlvenny (Assistant Supervisor)