The compact Bright X-Ray Source (BRIX) is going to be the main source of brilliant Xrays for biomedical applications in Research Focus C and one of the main pillars of CALA. In this hybrid source laser pulses are Thomson scattered off relativistic electron bunches from a commercial storage ring. In this interaction the brilliance is proportional to both the charge of the electron pulse and the energy of the laser pulse.
Because of the low interaction strength of Thomson scattering, enhancement cavities are ideally suited for achieving high brilliance. In this project we develop a novel enhancement cavity capable of storing a sub-picosecond pulse up to several hundred kilowatts of average power. It draws on a novel concept (patent pending) based on a cavity operated close to its stability boundary in order to maximise the beam diameter and hence minimise the intensity on the cavity mirrors.
A fibre-based master-oscillator-power-amplifier generation of sub-300-fs pulses with an average power of 500 W is being developed in cooperation with the group of A. Tünnermann (Jena). The improved enhancement cavity will allow for an increased stored laser power from 20 kW to >200 kW which – upon synchronising the cavity to the electron storage ring, ensuring spatial overlap, and realising X-ray outcoupling –will boost the X-ray flux of the Thomson source at 30 keV to 1011 ph / sec / 5% BW. The pursuit of these goals will profit from low-loss, high-damage-threshold multilayers and will mutually benefit the XUV comb development.