Development of a micro-region diffraction equipment by synchrotron microbeam

利用多色同步辐射(SR)技术研制了一种薄片微区衍射装置。成像版(IP；富士株式会社)由于筑波KEK光子工厂的4B光束线周围空间有限，所以使用了一个微小的针孔来制作非常精细的入射SR。由于最重要的是获得很低的实验本底水平，为了避免空气散射，设备被放置在真空中。真空室中还安装了IP读出系统。因此，即使放置在真空室中，也可以在不打开真空室的情况下获得不同区域或不同晶体取向的衍射图。我们自己制作了5微米和10微米的针孔，并在准直器后放置。针孔和薄片之间的距离为7 mm，探测器覆盖-30~165度的2 theta范围，相机半径为100 mm。该装置最初用于陨石薄片中被认为是不同来源的橄榄石(Mg_2SiO_4)颗粒，也适用于微米级的半导体材料上的铝粒。不同橄榄石颗粒的X射线衍射图因其来源不同而呈现出不同的X射线衍射谱。在半导体的情况下，观察到了Al晶粒的拉长衍射图和来自Si(100)衬底的尖锐的衍射图。

A diffraction equipment for micro-region in a thin section has been developed by using polychromatic synchrotron radiation(SR). An imaging plate(IP;Fuji Co.,Ltd.) was employed for a detector.A software system has also been completed by changing the system developed previously for sub-micrometer-sized single crystal.Due to limited space around beamline 4B of the Photon Factory, KEK, Tsukuba, a micro-pinhole was used for making very fine incident SR.Since it is most important to achive a very low background level of the experiment, the equipment was placed in vacuum for avoiding air scattering. An IP readout-system was also installed in the vacuum chamber. Therefore, even though the equipment is placed in a vacuum chamber, a diffraction pattern of different region or at different crystal orientation can be obtained without opening the chamber.Micro-pinholes of 5 and 10mu m were made by ourselves and set just after a collimator. The distance between the pinhole and the thin section is 7mm, the detector covers -30 to 165 degrees in two-theta range with camera radius of 100mm.This apparatus with a 10mum pinhole was initially applied to olivine (Mg_2SiO_4) grains, considered as different origins, included in a thin section of meteorite, and also to micrometer-sized aluminum g rains on a semiconductor material. Each diffraction pattern of different olivine grains shows different X-ray diffraction profile according to its origin. An elongated diffraction pro-file of Al grain was observed together with sharp diffraction profile from Si(100) substrate in a case of the semiconductor.