Modification of conventional X-ray diffractometer for the measurement of phase distribution in a narrow region

An X-ray diffractometer for spatially resolved X-ray diffraction measurements was developed to identify phase in the narrow (micron-scaled) region of high burn-up fuels and some nuclear materials. The micro-SRD was composed of an X-ray microbeam alignment system and a sample micro translation system instead of a normal slit and a fixed sample stage in a commercial XRD. The X-ray microbeam alignment system was fabricated with a microbeam concentrator having two Ni deposited mirrors, a vertical positioner, and a tilt table for the generation of a concentrated microbeam. The sample micro translation system was made with a sample holder and a horizontal translator, allowing movement of a specimen at 5 μm steps. The angular intensity profile of the microbeam generated through a concentrator was symmetric and not distorted. The size of the microbeam was 4,000 x 20μm and the spatial resolution of the beam was 47 μm at the sample position. When the diffraction peaks were measured for a UO2 pellet specimen by this system, the reproducibility (2θ = ±0.01 .deg.) of the peaks was as good as a conventional X-ray diffractometer. For the cross section of oxidized titanium metal, not only TiO2 in an outer layer but also TiO near an oxide-metal interface was observed