[High accuracy sample positioning system for hard X-ray microprobe].

A novel sample offline positioning system was developed for hard X-ray micro-focus beamline (BL15U1) at Shanghai Synchrotron Radiation Facility (SSRF). The positioning system is composed of three parts: off-line sample microscope system, on-line sample experiment system, and high-precision positioning sample holder. It makes a potent combination of the on-line X-ray fluorescence imaging and the off-line microscopic examination in three steps: compiling of control program, positioning of sample holder, and conversion of the two coordinates. It's the first time in the domestic synchrotron radiation facilities to achieve sample offline positioning in micron scale. The system helps the researchers find the object of study in micro zone quickly and accurately, when they study the micro characteristics of materials using synchrotron radiation micro X-ray beam. The gold mesh was used as an object of study. By comparing the differences of coordinates of gold mesh nodes between pictures from offline microscope and pictures from X-ray fluorescence mapping, the accuracy of the offline positioning system was verified. The results showed that the average errors of X-axis and Z-axis were 1.3 and 2.5 microm respectively, using the positioning method. It was demonstrated that the sample offline positioning system not only is suitable for these applications with high efficiency, but also supply hard X-ray micro-focus beamline with the technical preparations of sample automatic focusing method.