Developing Terahertz Frequency Drivers for Novel Accelerators

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.