Dynamically-figured mirror system for high-energy nanofocusing at the ESRF

The design, manufacture and characterization of a Kirkpatrick-Baez (KB) configuration mirror system for high-throughput nanofocusing down to 50 nm beam sizes are described. To maximize the system aperture whilst retaining energy tunability, multilayer coated optics are used in conjunction with 2 dynamically figured mirror benders. This approach, which has been developed at the ESRF for many years, allows the focusing performance to be optimized when operating the system in the 13-25 keV photon energy range. Developments in the key technologies necessary for the production of mirror bending systems with dynamic figuring behavior close to the diffraction limit requirements are discussed. These include system optimization via finite element analysis (FEA) modeling of the mechanical behavior of the bender-mirror combination, manufacturing techniques for precisely-shaped multilayer substrates, multilayer deposition with steep lateral gradients and the stitching metrology techniques developed for the characterization and figure optimization of strongly aspherical surfaces. The mirror benders have been integrated into a compact and stable assembly designed for routine beamline operation and results of the initial performance of the system at the ESRF ID22NI endstation are presented demonstrating routine focusing of 17 keV X-rays to sub-60 nm resolution.