Strain measurement in helium implanted polycristal using image analysis in laue Micro X-ray diffraction patterns

Abstract : In order to study the long term behaviour of used nuclear fuel, UO2 polycrystalline samples were implanted by Helium ions. The thin implanted layer, close to the sample surface, is elastically stressed. X-ray micro-diffraction (X- XRD) can be used to measure the induced strain on about 700 different grains of the polycrystal. Image analysis on the Laue diffraction patterns is required for an accurate strain estimation. Three methods to interpret the Laue pattern are developped in this study. The study shows the influence of grain orientation on the results.