Exploiting Laser Pulse Shaping and Phase Space Tomography to Optimise Longitudinal Beam Dynamics at the Interaction Point of CLARA

About the project

About the Project Introduction and Motivation The Compact Linear Accelerator for Research and Applications (CLARA) at Daresbury Laboratory places significant emphasis on providing tailored beam properties for a range of user experiments that push the frontiers of accelerator science. To this end, the facility has been expanded to include the Full Energy Beam Exploitation (FEBE) hutch, which enables the interaction of a 120 TW laser with the electron bunch for laser driven plasma wakefield experiments, as well as providing facilities for user-supplied experiment hardware. A key challenge in this context is controlling and optimising the beam dynamics at the interaction point (IP). Newly developed machine learning based methods for control of the Acousto-Optic Modulator at CLARA allow for the longitudinal shaping of the photo-cathode laser, and early research indicates that this can impart customisable energy distributions onto the electron bunch which are preserved at the IP. Advances in phase space tomography using machine learning methods have enabled highly detailed inspections of longitudinal phase space of the electron bunch with increased resolution and fidelity. The combined progress in both of these areas has laid the groundwork for entirely new capabilities for advanced research at CLARA. This project proposes to exploit laser pulse shaping techniques in conjunction with phase space tomography to achieve deterministic control over the longitudinal phase space at the interaction point in FEBE. By reconstructing and then optimising the longitudinal beam distribution at the IP, the research will develop a toolkit for directly targeting application-driven bunch shapes, from microbunch trains to flat-top profiles, enabling a wide range of future scientific programmes. Research Objectives The proposed PhD will address the following interconnected objectives: Build upon existing advanced laser pulse shaping research to control the photoemission process at the CLARA photocathode, with the goal of generating customisable longitudinal bunch distributions. Apply phase space tomography techniques to reconstruct the 6D beam distribution, focusing on longitudinal projections, in order to evaluate and refine shaping strategies with high fidelity. Optimise longitudinal beam dynamics at the FEBE interaction point, exploiting both experimental data and simulation tools to build models to optimise for target properties at the IP by controlling the laser shaping. Demonstrate application-driven bunch shaping, with particular emphasis on: a. Microbunching for seeded free electron laser (FEL) and coherent radiation experiments. b. Arbitrary pulse shaping for user experiments. c. Shaped injection schemes for plasma wakefield acceleration experiments. Potential Impact The outcomes of this research will establish a new paradigm for deterministic control of electron bunches, positioning CLARA as a world-leading facility in beam shaping. By demonstrating laser-driven control over longitudinal dynamics and validating it through tomography, the project will: • Provide user communities with unprecedented flexibility in pulse structures. • Lay the groundwork for advanced accelerator schemes, particularly plasma wakefield experiments requiring highly tailored injection conditions. • Enhance FEL research through demonstration of optimised seeding and reduced energy spread. • More broadly, the methodologies developed will be transferable to other accelerator facilities worldwide, including next-generation FELs and collider testbeds, contributing to the UK’s leadership in accelerator science. Funding and eligibility: Upon acceptance of a student, this project will be funded by the Science and Technology Facilities Council for 3.5 years. This consists of a tax free stipend at UKRI rates, university fees at the home (UK) rate, plus support for travel to conferences and workshops. A full package of training and support will be provided by the Cockcroft Institute, and the student will take part in a vibrant accelerator research and education community of over 150 people. An IELTS score of at least 6.5 is required. Contact for further information: Prof. Andrzej Wolski a.wolski@liverpool.ac.uk or Dr. Amy Pollard amelia.pollard@stfc.ac.uk How to apply: Apply at the Cockcroft Institute PhD webpage . For full consideration for funded awards, please apply by Jan 31st 2026. Anticipated Start Date: October 2026 for 3.5 Years

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