High power THz sources on 4GLS

Infrared and THz radiation has been available to users of conventional electron accelerator light sources for over a quarter of a century. A new generation of accelerators with sub-picosecond electron bunches provide a massive increase in the power output in the THz region due to coherent enhancement. In this paper, the source properties of the ERLP under construction at Daresbury and the proposed 4GLS sources are discussed. 4GLS will allow multiple beams from THz to soft X-ray to interact with the samples with controlled delay between the ultra short pulses, allowing new scientific possibilities.