THz frequency structures for particle accelerators: Realising ultrafast electron beam manipulation and diagnostics

Building on past proof-of-concept research and accelerator test-facility demonstrations, we will develop a terahertz (THz) driven electron beam acceleration and deflection system that can provide a step-change in the sub-picosecond particle-beam and diagnostic capabilities at accelerator facilities. Our goal is to take our advances and knowledge in laser-derived high-power terahertz frequency electromagnetic sources, and in terahertz-frequency interaction structures, and develop a system at technology readiness TRL-4/5.

The system will incorporate proven concepts, with additional advances in THz source and interaction structure tuning, in transverse mode-conversion, and in source-structure coupling. The system performance will be verified at an accelerator test facility as a step towards engagement of commercial development partners.

We have recently developed dielectric-lined rectangular waveguide structures for terahertz-driven acceleration of electron beams [1,2], and the high-power (MW) THz sources for powering them [3]. Our structures and sources achieve THz phase velocity matching with co-propagating electron bunches at relativistic energies. Through the proposed developments, we envisage the widespread uptake of dielectric-lined waveguides and laser-driven THz sources within integrated systems for sub-picosecond phase-space manipulation of electron and positron beams.

The systems will also find widespread application in the characterisation of ultrashort, sub-100 femtosecond, electron beams at advanced accelerator facilities.

The technology is currently at TRL-3 with the technology concept formulated and proof-of-concept demonstrations of THz-electron interaction structures and of THz sources. This proposed research will seek to develop the technology to TRL 5, with an early-stage prototype integrated system, in advance of future full prototype development with commercial partners.

This proposal has three objectives:

Technical and scientific development of high-power (MW) THz source and interaction structures. Specific developments include source and structure frequency tuning, mode-conversion, and THz generation efficiency. Delivering an integrated system suitable for accelerator facility testing, and as pathway to commercial development.

Establishing intellectual property, and forming a strategic partnership with industry to exploit the commercial potential of our THz diagnostic technology.

[1] V. Georgiadis, et al. "Dispersion in dielectric-lined waveguides designed for terahertz-driven deflection of electron beams". Appl. Phys. Lett. 118, 144102 (2021)

[2] M.T. Hibberd? et al. "Acceleration of relativistic beams using laser-generated terahertz pulses". Nature Photon. 14, 755 (2020)

[3] C.D.W. Mosley, et al. "Large-area periodically-poled lithium niobate wafer stacks optimized for high-energy narrowband terahertz generation". Optics Express 4041, 31, (2023)