Femtosecond Synchronisation for Externally-Injected Laser Wakefield Acceleration at CLARA

LWFA在展示电子的高梯度和高能加速方面取得了巨大的成功，最近在20cm内达到了8GeV。然而，这些源的弹间能量稳定性和带宽仍然低于传统加速器；这是由于粒子“自注入”到激光尾流场的本质上的非线性和噪声性质。提高LWFA性能的一种有吸引力的方法是将来自传统加速器的高质量束注入LWFA，这将使能量在线性状态下增加，并保持注入束的质量。该项目旨在通过评估和测量飞秒分辨率的激光电子束同步，在CLARA电子加速器设施（STFC Daresbury实验室）进行外部注入激光尾流场加速的实际演示。能够以如此高的分辨率直接解决电子-激光同步的诊断在技术上具有挑战性，并且不能立即商业化；该项目的一个关键要素将是设计、建造和评估该诊断的操作。激光-电子束同步的大小很大程度上取决于高能激光中的噪声源。该项目将寻求量化（并在可能的情况下解决）高能Ti:Sapphire主振荡器/功率放大器激光系统中的噪声和漂移源，该系统可在与CLARA加速器相邻的激光实验室中使用。

LWFA has been hugely successful in demonstrating high gradient and high energy acceleration of electrons, recently up to 8GeV in 20cm. The shot-to-shot energy stability and bandwidth of these sources remains however below that of conventional accelerators; this is due to the intrinsically nonlinear and noisy nature by which particles are 'self-injected' into the laser wakefield. One attractive method to improve the performance of LWFA would be to inject high quality bunches from a conventional accelerator into a LWFA, which would allow energy gain in a linear regime and preserves the injected bunch quality.This project is aimed towards a practical demonstration of externally-injected laser wakefield acceleration at the CLARA electron accelerator facility (STFC Daresbury Laboratory), by evaluating and measuring laser-electron beam synchronization with femtosecond resolution. A diagnostic capable of resolving the electron-laser synchronization directly with such high resolution is technologically challenging and not immediately available commercially; a key element of this project will be to design, build and evaluate the operation of this diagnostic. The magnitude of the laser-electron beam synchronization will be heavily dependent on sources of noise in the high energy laser. The project will seek to quantify (and where possible, resolve) sources of noise and drift in a high energy Ti:Sapphire master oscillator / power amplifier laser system, available in the laser laboratory adjacent to the CLARA accelerator.