Structural study of large scale KDP crystals using high energy X-ray diffraction

X-ray diffraction is a non destructive technique used in order to characterize defects in the single crystal. Unfortunately, this analysis can not be performed throughout the whole volume on thick KH2PO4 (KDP) crystals used in the high power lasers systems like NIF and LMJ, these crystals having a thickness close to 10 nun. Considering the usual energy range radiation used for X-ray diffraction and topography (20-30 keV), the beam is rapidly absorbed by the material. However, this problem can be solved by the use of high energy X-ray radiation in order to analyse the complete volume of crystal. The principle of this device will be exposed and preliminary results are shown along with corresponding optical measurements.