EPAC beamline Prototype: Development and optimisation of a high-repetition-rate LWFA system

The Extreme Photonics Applications Centre (EPAC) is a next-generation high-power laser facility designed to deliver stable, high-repetition-rate (10 Hz) LWFA electron beamline with high quality parameters (∼1nC, ∼1 GeV, <5% energy spread). As a crucial preparatory step, one of the 10 TW laser system (Gemini) at the Central Laser Facility is being repurposed as a prototype beamline to de-risk EPAC commissioning and to develop critical subsystems. We report on a progress in three core areas: 1. Targetry Development: We designed and implemented gas-cell targets featuring enhanced durability, leveraging replaceable CVD diamond apertures and modular components to support 5 Hz operation. 2. Beam Optimization: Using Bayesian optimization, we explore tuning of key LWFA outputs—electron charge, energy, divergence, and X-ray flux and energy—achieving improved performance across shots. 3. Integrated Simulation Framework: To support beamline design, we are developing a modular toolkit that couples fluid dynamics (OpenFOAM), particle-in-cell (FBPIC), and Monte Carlo (Geant4) simulations.