High-Aspect-Ratio Diamond Refractive Optics: X-Ray Optics Technology for Light Source Facilities

Modern synchrotron x-ray sources provide a useful photon brilliance in excess of 1018 Photons/ s / 0.1%BW / mrad2 / mm, but they also deposit power densities on the order of 100 W / mm2 on the beamline optics. X-ray optics are required that provide the greatest possible focusing power, and that can manage the heat flux resulting from the incident radiation. The exceptional x-ray optical properties and extreme thermal conductivity of diamond make it an ideal material for synchrotron optics. A diamond refractive or kinoform lens as a first optical element will allow better heat management, and thus will allow a greater throughput for beamlines. In addition, utilization of diamond kinoform optics is predicted to improve transmission as compared to beryllium optics and as compared to silicon kinoform optics at photon energies near 10 keV, opening up a wider range of applications. Modern Microsystems propose to develop a fabrication process for high-aspect-ratio monocrystalline diamond kinoform refractive hard x-ray optics suitable for use in synchrotron x-ray beamlines. The process will utilize a novel and proprietary diamond deep reactive ion etching process to imprint into diamond substrates patterns having micron-scale critical dimensions with roughness less than 50 nm and depths as large as 300 µm. Modern Microsystems will employ the process to fabricate monocrystalline diamond kinoform x-ray optics with depths between 100 µm and 300 µm, having geometries optimized for a variety of representative beamlines, to demonstrate the applicability of the optics to a wide range of instruments and applications. The chief benefit of the proposed course of work is to upgrade the focusing power of today’s high- brilliance x-ray sources, while lowering the cost of ownership associated with existing optics such as those manufactured from beryllium. Our nation’s cutting-edge synchrotron facilities require the most powerful x-ray optics to enable scientific discovery. Modern Microsystems plan to upgrade existing optics made of toxic beryllium with higher-performing, non-toxic, synthetic diamond lenses.