Diamond X-ray Rocking Curve and Topograph Measurements at CHESS

X-ray rocking curve and topograph measurements were carried out at CHESS in Cornell University in November 2006. The purpose of this experiment was to check if the X-ray facility at CHESS is suitable to be used for GlueX in assessing diamond crystal quality and investigating radiation damage and surface deformation induced by milling. After modifying the C1 beam line by using an asymmetry silicon (111) monochromator and a channel cut silicon (220) monochromator, the x-ray beam was well suited to assess diamond for GlueX. The minimum rocking curve full width at half maximum (FWHM) we obtained is around 30μr. A pixel detector was used to record the topograph image. 2 D maps of diamond rocking curve width were generated, which tell precisely how the diamond quality is at each point across the crystal. The rocking curve peak positions vary dramatically over the measured regions, which gives evidence that the 20 microns thick diamond crystal is badly deformed. This indicates that the crystal thinning and the crystal mounting methods should be improved.