Diamond Refractive Focusing Optics

Synchrotron-based science has had a great scientific impact and will continue to have great impact going forward. In spite of the large investment in the 3rd generation light sources, most beam lines do not preserve the sources phase profile or brightness all the way to the sample. For these high brightness light sources, errors are almost completely due to distortion in the front-end optics caused by the high heat loads generated by the broadband radiation from the insertion device. The role of the first optic is to reduce the heat load on the rest of the beam line by reducing the bandwidth of radiation transmitted downstream. Diamond is rapidly gaining acceptance as an optical material for 3rd and 4th generation light sources because of its superior thermal properties. Existing applications include vacuum windows, attenuators, phase plates and monochromator crystals. These applications take advantage of diamonds low coefficient of thermal expansion, low absorption and high thermal conductivity which combine to minimize distortion under thermal load. Beryllium is the only other practical material with better absorption properties but its health and environmental concerns make diamond a preferred choice. Delaware Diamond Knives has produced a prototype refractive lens from single crystal diamond whose performance approached that of todays commercially available optics. We intend to improve our cutting processes to further improve the diamond lens performance and then to characterize the lens in a beam line test. Success will motivate us to simulate, design and build suitable cooling, mounting and manipulation hardware for the application of these lenses as front-end optics. The proposed approach has the potential for a significant impact on materials research at synchrotron facilities around the world. It solves an immediate and pressing problem of spatial resolution for them creating additional opportunities for micro- and nano-scale research for users of 3rd and 4th generation light sources