Recent developments of high quality synthetic diamond single crystals for synchrotron X-ray monochromators

For several years now, the ESRF, the University of the Witwatersrand and Me ssrs. Do Beers Industrial Diamonds (Pty) Ltd. through their Diamond Researc h Laboratory, have pursued a development programme to assess and improve th e quality of synthetic diamonds. Recently, in an effort to study the influe nce of nitrogen impurities on the defect structure, X-ray excited optical l uminescence and spatially resolved double-crystal diffractometry were emplo yed as new techniques. The correlation between nitrogen impurities and the raw defect structure was clearly visible. It was confirmed that concentrati on variations are related to lattice imperfections, where tilts are much mo re important than lattice constant variations. High reflectivity was observ ed and quite large zones of a sample bigger than 1 cm(2) showed to be perfe ct to within better than 0.5 arcsec. (C) 2001 Elsevier Science B.V. All rig hts reserved.