HPHT System for Near Dislocation Free Diamond Elements for X-Ray Optics

Next-generation of synchrotron and Free-Electron Laser X-ray sources will increase the peak power by several orders of magnitude. In these conditions, X-ray intensity will become too severe for the existing materials. Diamond is the most promising if not only candidate due to its high thermal conductivity, small thermal expansion as well as a low X-ray absorption. Unfortunately, the availability of large size, high- crystallinity, and low-defect density diamond substrates is very limited. Presently, there are no suppliers in the United States to support this rapidly developing field of diamond X-ray optics applications for the next generation sources. We will develop the modified High-Pressure High-Temperature HPHT) temperature gradient growth TGG) technology that will allow growing the highest crystalline quality large diamond crystals, with dislocation density less than 10 cm-2. The main prerequisite for the near dislocation-free and stacking-fault-free diamond growth at high pressure-high temperature is reduction of nitrogen impurities to less than 1 ppm-level. Unique total environmental control of all processing steps will be utilized to achieve required diamond crystal purity and structure perfection. In Phase I, we will determine all necessary means for HPHT facility installation and operation, and design the system to satisfy crystals quality imposed by restrictions of next-generation synchrotron and FEL X-ray facilities. In parallel we conduct several trial experiments to determine the optimal technological and diamond growth parameters to grow single-crystal diamond with nitrogen concentration of about 1 ppm or less. Material characterization of obtained diamond substrates will be conducted at APS ANL facilities using white-beam X-ray topography, sequential rocking curve mapping, high-resolution x-ray diffraction measurements. The long-term goal of this project is to establish the first USA-based HPHT diamond growth facility capable of producing the highest quality large SC diamonds matching X-ray optics requirements. The technology developed here is required to utilize X-ray beams at fourth generation light sources to maximum potential. High-quality diamond is virtually the only material that can withstand the heat load of the next generation light sources. If a manufacturing technology for large size HPHT diamond substrate is established, diamond-based optical elements will supersede the current silicon and beryllium alternatives, which have lower performance and severe health and safety concerns. High-quality diamond material will also benefit quantum computing, industrial, medical and other industrial applications.