High resolution X-ray diffraction study of single crystal diamond radiators

High quality single crystal diamond is widely used for generating highly polarized high energy photon beams in the photonuclear physics study. The quality of the diamond crystal has a vital effect on the polarization of the photon beam which should be as high as possible as required by the experiments at Jefferson Lab, MAX_lab and MAMI, etc. One 20 mu m thick diamond radiator from Jefferson lab and one 100 mu m thick diamond radiator from MAMI were investigated by X-ray rocking curve and topograph measurements. The rocking curve results suggest that the 20 mu m thick diamond radiator is severely deformed which explains why this diamond radiator showed unstable performance in the coherent bremsstrahlung experiments. The 100 mu m thick diamond radiator was radiation damaged after being used in an 855?MeV electron beam line for several years. At the radiation damage region, it was found that the rocking curve width is significantly broadened, and the rocking curve peak position shifted towards the larger angle side by around 200?arcsec. Raman test confirmed that a significant amount non-diamond phase exist at the radiation damage region.