A high-precision diffractometer has been developed for the structure analysis of a submicrometre-scale single grain of a powder sample at the SPring-8 BL40XU undulator beamline. The key design concept is the combination of a stable focused synchrotron radiation beam and the precise axis control of the diffractometer, which allows accurate diffraction intensity data of a submicrometre-scale single powder grain to be measured. The phase zone plate was designed to create a high-flux focused synchrotron radiation beam. A low-eccentric goniometer and high-precision sample positioning stages were adopted to ensure the alignment of a micrometre-scale focused synchrotron radiation beam onto the submicrometre-scale single powder grain. In order to verify the diffractometer performance, the diffraction pattern data of several powder grains of BaTiO3, of dimensions ̃600 × 600 × 300 nm, were measured. By identifying the diffraction data set of one single powder grain, the crystal structure was successfully determined with a reliable factor of 5.24%.
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