Mineral physics studies using third-generation synchrotron facility

我们将SPring-8的第三代同步辐射应用到矿物物理的各种研究中，利用多砧仪器，如高压相变观测、相边界测定、熔融检测和压力下熔融温度测定、高压相P-V-T关系测定等。在SPring-8的高压地球科学波束线上进行了多次成功的实验，并在高达25 GPa的压力和2000℃的温度下获得了丰富的结果。此外，已经尝试使用相对较大尺寸的烧结金刚石砧（即14毫米边缘长度）来产生更高的压力。利用该技术在多砧装置中产生了40 GPa的压力，并成功地观察了QaMgSi2O6透辉石和MgAI2O4尖晶石的相变。此外，还获得了MgSi03钙钛矿、CaSiO3钙钛矿和MgA12O4铁酸钙等矿物高压相的体积模量和热膨胀数据，为地幔和下地幔上部俯冲板块的密度提供了重要的约束条件。我们与纽约州立大学石溪分校的研究人员合作。我们利用带到Stony Brook的多砧仪器合成了一种改性尖晶石型（Mg,Fe）2SiO4的热压试样，用于高压超声测量。在压力为13gpa时，我们获得了该试样弹性波速的一些信号，目前正在进行分析。不幸的是，由于同步辐射设备的束流时间有限，没有同时进行弹性速度和x射线衍射的测量。尽管如此，我们同意在JSPS作为日美合作计划的财政支持下，继续在这个方向上进行两年的合作工作，这肯定会使用第三代同步辐射开发这项新技术。少

We made applications of the third-generation synchrotron radiation at SPring-8 to various studies in mineral physics, using multianvil apparatus, such as observations of high-pressure phase transitions, determination of phase boundaries, detection of melting and determination of melting temperature under pressure, determination of the P-V-T relations of high pressure phases. Many successful experiments were conducted in this direction at the High Pressure Earth Science beamline at SPring-8, and abundant results have been obtained at pressures up to 25 GPa, and at temperatures to 2000℃. Moreover, attempts have been made to use sintered diamond anvils of relatively large dimensions (i.e. 14 mm edge length) for higher pressure generation. Pressures to 40 GPa, are now produced in multianvil apparatus using this technique, and the observations of phase transitions in QaMgSi2O6 diopside and MgAI2O4 spinel has been successfully made. In addition, new bulk moduli and thermal expansion data hav … More e been obtained for the high pressure phases of these minerals, i.e. MgSi03 perovskite, CaSiO3 perovskite, and MgA12O4 calcium ferrite, which provide important constraints on the density of the mantle and of subducting slabs in the upper part of the lower mantle.We made some collaborations with the researchers in SUNY at Stony Brook. We synthesized a hot-pressed specimen of modified-spinel type (Mg,Fe)2SiO4 using a multianvil apparatus which was brought to Stony Brook and used for ultrasonic measurements under high pressure. We obtained some signals for elastic wave velocities in this specimen at pressures to 13 GPa, which are currently being analyzed. Unfortunately, the simultaneous measurements of the elastic velocities and X-ray diffraction were not conducted, because of the limited beamtime at the synchrotron radiation facility. Nevertheless, we agreed to continue collaborative work in this direction for another two years with the financial support from JSPS as Japan-US collaboration program, which will certainly develop this new technique using the third-generation synchrotron radiation. Less