THz-driven multi-stage relativistic beamline design and beam dynamics

Terahertz-driven acceleration and manipulation of non-relativistic and relativistic particle beams is rapidly evolving to centre-stage in the drive to novel accelerator methods. In the Cockcroft Institute (and supported by CI core and quota PhD students) we performed [1] the first proof-of-principle THz- driven phase-velocity-matched interaction in a dielectric-lined waveguide, with acceleration up to 10 keV. In the most recent CLARA run we demonstrated [2] record THz-driven linear acceleration of relativistic 35.5 MeV, 20-100 pC electron beams, and advanced manipulation of the bunch to show de- chirping and the modulation necessary for the generation of micro-bunches. In parallel we have shown how chained waveguides in the MeV regime can be used to maintain bunch quality in staged accelerator [3]. We are also exploring non-relativistic beams, focused around our 100 keV non-relativistic experimental rig in a purpose-built bunker at Daresbury Laboratory and recently demonstrated electron bunch deflection using THz-driven structures, where we observe the streaking on the screen of electron bunches. We are now aiming to demonstrate that acceleration to MeV beam energies can be achieved with THz acceleration, and beam control can be achieved with synchronised THz compression. Our work is showing rapid progress but now we need to demonstrate the capability of these advances to deliver a longer beamline and hence a larger energy facility, and solve the beam-related problems that using multi-staged THz-driven structures will present. Currently, this is an unsolved problem as no beamline design exists that will couple multiple structures whilst preserving beam quality during acceleration, and the student on this project will develop the first complete THz-DLA complete facility design. The student will test the beamline concepts on the THz bunker, using a 100 keV source, that we are commissioning soon at Daresbury Laboratory.