DEVELOPMENT OF THE AUTOMATIC OIL-PRESSURE CONTROLER AND IN SITU OBSERVATION OF PRESSURE-INDUCED TRANSITION

地球上的行星随着周围的压力和温度等物理条件而改变其结构。通过X射线衍射法和拉曼光谱法对结构变化进行了原位观察，并将其作为压力和温度的函数。近年来，结构转变动力学的研究与晶相研究或平衡问题一样受到人们的重视。为研究金刚石压砧在压缩状态下的组织结构，研制了一种油压式金刚石压砧高压装置的自动控制器。对该装置进行了能力测试。控制器的规格和性能描述如下。(1)改变压力后，X射线衍射不再需要校准和重新安装。因此测量条件可以保证连续性。(2)确认了长时间的一致压力保持。(3)金刚石压砧压力室由半导体压力传感器自动保持恒定压力 ...更多信息 排序。该控制器是研究压力诱导相变与体积变化的有效装置。(4)负载压力通过柔性油管传递。在国家高能物理研究所光子厂用同步辐射X射线进行高压X射线衍射研究时，目标压力是从箱外获得的。利用该系统可以连续升降压，进行高压下的相变动力学研究。该系统可用于土的相态研究、压缩系数和体积模量的测量。这一新系统的建立将为高压科学的新领域，特别是亚稳相分析和压力诱导相变前兆现象的研究开辟新的途径。下面列出了我们使用该系统的X射线衍射实验。具有与SiO_2相似多晶型转变的GeO_2的压力诱导非晶化。原位观察Ca（OH）_2在压缩条件下相变的前体结构变化。橄榄石Mg_2SiO_4压致转变的分子动力学计算与高压实验比较。少

Earth interious change their structures with physical conditions as pressure and temperature around them. In situ observations of the structure changes have been executed by X-ray diffaractometry and Raman spectroscopy as a function of pressure and temperature. Recently kinetics of the structure transformations has paied a larte attention as well as thermodynamical phase studies or equilibrium problems. An automatic controller of diamond anvil high pressure apparatus by oil-press was newly devised for the strcture study under compression. an ability test of this appratus was conducted in advance. Specification and capability of the controller were described below.(1) Alognment and remount of X-ray diffraction are no more required after changing pressure. therefore the measuring condition can assure the continuity.(2) The consistent pressure hold was confirmed for a long period.(3) A constant pressure in the diamond anvil pressure cell is automatically kept by semiconductor pressure sen … More sor. this controller is an effective apparatus for the study of pressure-induced transformation with volume change.(4) Load pressure is transmitted through flexible oil pipe. The aimed pressure is achieved from the outside of hutch, when the high pressure X-ray diffraction study is undertaken using synchrotron radiation X-ray at Photon Factory, National Insutitute of High Energy Physics. A remote control of pressure is capable.By using this controlling system an continuously raising and reducing pressure enable us to perform the kinetic study of phase transition under high pressure. This system can apply for the phase study of earth interiou and for measurement of the compressibility and bulk modulous. A newly devised system may throu a light on the new field jin the high pressure sciences, especially for the study of the metastable phase analysis and precursor phenomena of pressure-induced phase transition. Our X-ray diffraction experiments using the system are listed below.Example 1. Pressure-induced amorphization of GeO_2 having a similar polymorphic transition to SiO_2.Example 2. In situ observation of the precursor structure change of Ca(OH)_2 for its phase transformation under compression.Example 3. Comparison between molecular dynamic calculation and high pressure experiment for pressure-induced transition of olivine Mg_2SiO_4. Less