Developing Terahertz Frequency Drivers for Novel Accelerators

新的加速方案，如太赫兹（THz）驱动的加速，旨在大大缩小未来粒子加速器的尺寸和成本，与传统的射频（RF）技术相比。激光产生的THz脉冲的高频和超短皮秒持续时间可以促进远远超过100 MV/m击穿阈值的加速梯度，通常限制RF加速器，THz源的发展现在瞄准了10 GV/m制度。然而，在加速器科学领域内，激光驱动的THz源的益处不仅限于加速。激光产生的太赫兹脉冲也提供了对电子束进行飞秒控制的途径，并且已经证明了它们压缩高能电子束的能力。太赫兹驱动压缩的演示可以使几个飞秒持续时间的电子束与飞秒级同步控制所需的外部注入到其他新的加速方案，如等离子体韦克菲尔德加速。此外，太赫兹脉冲可以通过太赫兹驱动的电子束拖尾提供纵向束诊断。因此，有太多的机会利用激光驱动的太赫兹源来增强加速器。目前的障碍是缺乏激光驱动的窄带、频率可调的高能太赫兹源。该项目旨在在Cockcroft研究所开发最先进的激光驱动的高能太赫兹源，以推动我们目前利用太赫兹驱动的加速、压缩和诊断的项目达到世界领先水平。该项目是实验性的，涉及许多高功率超快激光器，包括光子科学研究所PI实验室中最先进的飞秒激光系统，Cockcroft研究所的太瓦激光系统，以及STFC达雷斯伯里实验室的粒子加速器。

Novel acceleration schemes, such as terahertz (THz)-driven acceleration, aim to drastically shrink the size, and cost of future particle accelerators compared to conventional radio frequency (RF) technology. The high frequency and ultrashort picosecond duration of laser-generated THz pulses can facilitate accelerating gradients far beyond the 100 MV/m breakdown threshold typically limiting RF accelerators, with THz source development now targeting the 10 GV/m regime. The benefit of laser-driven THz sources within the field of accelerator science is however not limited solely to acceleration. Laser-generated THz pulses also offer routes to femtosecond control of electron beams and have demonstrated their ability to compress high energy electron beams. The demonstration of THz-driven compression may enable few-femtosecond duration electron beams with the femtosecond-level synchronisation control needed for external injection into other novel acceleration schemes, such as the plasma wakefield acceleration. Furthermore, THz pulses can provide longitudinal beam diagnostics via THz-driven electron beam streaking. There are, therefore, a plethora of opportunities for exploiting laser-driven THz sources to enhance accelerators. The current obstacle is the lack of laser-driven narrowband, frequency-tuneable, high-energy THz sources.This project aims to develop a state-of-the-art laser-driven high-energy THz source at the Cockcroft Institute that can drive our current programmes utilising THz-driven acceleration, compression and diagnostics to a world-leading level. The project is experimental in nature, involving a number of high-power ultrafast lasers, including state-of-the-art femtosecond laser systems in the PI's lab at the Photon Science Institute, a Terawatt laser system at the Cockcroft Institute, and particle accelerators at STFC Daresbury Laboratory.