Several proposals have been put forward for converting electron accelerators to inverse Compton scattering (ICS) gamma sources. Typical approaches suggest combining near-IR solid-state lasers operating continuously at a multimegahertz repetition rate with e-beams when setting their interaction point inside a field-enhancement, Fabry-Perot optical cavity. We introduce here an alternative method of pairing particle accelerator beams with trains of long-wave-infrared, ${\lambda }_L\approx 9–11\mu \mathrm{m}$ pulses from a picosecond ${\mathrm{CO}}_2$ laser of a novel architecture operating in a repetitive pulse-burst mode. Because of a considerable increase in the laser energy per pulse, combined with an order-of-magnitude higher number of laser photons per joule of laser energy, our approach allows us to increase the ICS peak flux and brilliance by 4 orders of magnitude compared to previous proposals while maintaining high (${10}^{11}–{10}^{12}\mathrm{ph}/\mathrm{s}$) average flux. This outcome is supported by the examples of the $\mathrm{DA}\mathrm{\Phi }\mathrm{NE}$ and CBETA accelerator facilities, where ${10}^{20}–{10}^{21}\mathrm{ph}/(\mathrm{s}·{\mathrm{mm}}^2·{\mathrm{mrad}}^2·0.1\%BW)$ peak brilliances at 50–1000 keV photon energy range can be achieved and is comparable or exceeds the capabilities of contemporary synchrotron light sources at hard x rays. Such high-brightness ICS sources will find applications in pump-probe and other ultrafast studies that require building up meaningful datasets on a single x-ray pulse.

• Received 11 August 2020
• Accepted 26 October 2020

DOI:https://doi.org/10.1103/PhysRevAccelBeams.23.120702

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Published by the American Physical Society