High-Resolution Structure Analysis Using Synchrotron Radiation with a Multiple-Detector System

本文介绍了一种新型的六臂同步辐射粉末衍射仪。五个探测器臂以25 μ m的间隔径向连接到2 rheta轴，组成一个多探测器系统。五个闪烁计数器与一个平面Ge（111）晶体分析器耦合在各自的臂上，可以同时记录整个粉末图案，该粉末图案被分成五个具有相等的2 rheta跨度的段。光学设计是基于使用平行光束的平板样品反射几何。在固定入射角的非对称衍射中，通过使用2 rheta步进扫描技术来收集强度数据。第六检测器臂可以在常规单臂扫描模式中用于多用途。它可以配备各种分析仪，如长水平平行狭缝，平面或通道切割晶体分析器，接收狭缝，固态探测器。该衍射仪于1995年4月安装在筑波光子工厂的光束线BL-4 B上，此后一直在进行测试操作。从1996年4月起，整个系统已被一般用户用于高分辨率粉末衍射实验。它记录了Si粉末（111）反射的半高宽为0.022 nm，峰值最大强度超过每秒40，000计数。通过使用聚焦镜，最大峰值强度增加到每秒超过100，000个计数。在130 μ m的2 rheta范围内的整个粉末图案可以在仅4小时内以0.004 μ m（2 rheta）的步进间隔步进扫描。结构改进的结果将在其他地方发表。

A new powder diffractometer for synchrotron radiation with six detector arms has been constructed. Five detector arms, which are attached radially at intervals of 25ﾟ to the 2rheta-axis, compose a multiple-detector system. Five scintillation counters coupled with a flat Ge (111) crystal analyzer on respective arms can record simultaneously the whole powder pattern divided into five segments with an equal 2rheta span. The optics design is based on the flat-specimen-reflection geometry using parallel-beam. The intensity data are collected by using a 2rheta-step-scan technique in the asymmetric diffraction at a fixed incident angle. A sixth detector arm can be used for multi-purpose in the conventional single-arm-scan mode. It can equip various kinds of analyzers such as long horizontal parallel slits, a flat or channel-cut crystal analyzer, a receiving slit, a solid state detector. The diffractometer was installed at the beam-line BL-4B at the Photon Factory in Tsukuba in April, 1995, and test operations had been conducted since then. From the April of 1996, the whole system has been used by general users for high-resolution powder diffraction experiments. It recorded the fullwidth at half-maximum of 0.022ﾟ and the peak maximum intensity of more than 40,000 counts per second for the (111) reflection from Si powder. By the use of a focusing mirror, the maximum peak intensity was increased to more then 100,000 counts per second. The whole powder pattern in the 2rheta-range of 130ﾟ could be step-scanned at a step interval of 0.004ﾟ (2rheta) in just 4 hours. Results of structure refinements will be published elsewhere.