Design of a thermal loading resilient optical enhancement cavity for operation at 515 nm for X-ray production through inverse Compton scattering in an energy recovery linac
A fast and simple method to optimize a high-power optical enhancement cavity is proposed. It is applied to a four-mirror bow-tie cavity operating at 515 nm, which is to be implemented within the PERLE ERL for the production of X-rays through inverse Compton scattering. The optimized figure of merit is the expected X-ray photon rate. Thermal loading is carefully evaluated, giving also a path towards very high average power operation in infrared. One shows that photon rates exceeding 10^11 per second at average energies above 280 keV in apertures of a few miliradians are within reach. For easier comparison with existing Compact X-ray sources providing high rates of photons, the performance of the proposed design is also evaluated for a system delivering infrared laser pulses. It is shown that a source delivering more than 10^13 photons per second is achievable with this design, an unprecedented performance for existing Compton X-ray sources. The design procedure employed here can be easily applied to other applications of high-power high-finesse optical cavities.