Development of time resolved diffraction study under high pressure using charge coupled devise detector

本研究项目的目的是研究在与地幔和地核相同的温度和压力条件下地球内部的结构变化和稳定性关系。通过时间分辨衍射实验以秒或毫秒的时间间隔观察压缩下的动态结构变化。为了了解相变或分解的机制，我们开发了单晶 X 射线衍射系统来研究这些结构转变的动力学。为此，计划在新设计的系统中安装电荷耦合探测器（CCD）的二维X射线探测器。它能够执行时间分辨研究。在搜索了SIMENS、NONIUS、QUANTUM和RIGAKU的几款CCD探测器后，从动态范围、量子效率、位置分辨率和再现性等角度对RIGAKU探测器进行了测试。用于驱动系统和数据分析的计算机程序也被开发出来。结合实验室的旋转阳极X射线发生器和HUBER四圆衍射仪，带电阻加热器的金刚石砧高压室使得压缩过程中结构转变的衍射研究成为可能。可以进行高达80GPa和550℃的高压和高温研究。目前的仪器进展已经在高压技术与科学年会上进行了报道：通过使用新系统，计划在不久的将来进行以下实验。（1）压力诱导非晶化、马氏体结构转变和熔化前兆现象的观察。（2）包括脱水、脱气、相分解、辐射损伤在内的结构转变的时间分辨衍射研究等（3）熔体结晶的检查。（4）加热压缩条件下固-固反应的感知。（5）材料科学、冶金、固体物理等领域电子态密度的阐明。本探测器系统与同步辐射相结合将成为结构转变动力学研究的有效工具。较少的

The aim of the present research project aimed to investigate the structure changes and stability relations of earth's interiors under the conditions of same temperature and pressure as carth mantle and core. Dynamical structure changes under compression were observed by time-resolved diffraction experiment in time interval of second or millisecond. In order to understand the mechanism of phase transition or decomposition, we developed the single-crystal X-ray diffraction system for kinetic studies of these structure transformations. For this purpose, two-dimensional X-ray detector of charge coupled detector (CCD) was planed to be installed in the newly devised system. It enables to execute the time-resolved study. After searching the several CCD detectors made by SIMENS, NONIUS, QUANTUM and RIGAKU.The RIGAKU detector was tested from the viewpoints of dynamic range, quantum efficiency, positional resolution and reproducibility. Computer programs for driving the system and data analysis … More were also developed. Combined with the rotating anode X-ray generator and HUBER four-circle diffractometer facilitated in laboratory, diamond anvil high-pressure cell with electric resistance heater makes possible the diffraction study of structure transformation in the process of compression. The high-pressure and high-temperature studies up to 80GPa and 550℃ can be possible.The present instrumental development has already been reported in annual meeting of High-Pressure Technology and Sciences : By using the new system the following experiments are scheduled in near future.(1) Observation of pressure-induced amorphization, martensic structure transition, and precursor phenomenon of melting.(2) Time-resolving diffraction study of structure transformation including dehydration, degas, phase decomposition, radiation damage etc.(3) Inspection of crystallization from melts.(4) Perception of solid-solid reaction under compression with heating condition.(5) Elucidation of electronic density of state in the filed of material sciences, metallurgy, solid-state physics and several other science.The present detector system combined with synchrotron radiation will be an effective tool for kinetic study of structure transformation. Less