Development of induction heating diamond anvil cell and its application to Raman micro- spectroscopy.

采用高频感应加热技术构建了用于拉曼显微光谱分析的高温金刚石砧池。DAC是广泛应用于地球深度探测的高压仪器。本课题采用高频感应加热来提高DAC的温度。IH-DAC可能是一种改进的外部加热方法，可以稳定地加热DAC。IH-DAC被设计为改进Merrill-Bassett DAC，使用杠杆施加压力。为IH-DAC制造的一圈铜感应线圈环绕一对钻石。利用拉曼光谱可以直接测量衬垫样品的温度。Stokes线（I_S）和反Stokes线（I_<aS>）的强度与Boltzmann因子的关系为I_<aS>/I_S=exp（-hv/kT）。用硅的斯托克斯线和反斯托克斯线来校准温度。经过多次IH加热SUS、WC和Re假板的初步实验，IH- dac选用WC摇杆和Re垫片。用IH直接加热摇杆，有望达到1000℃以上的高温。IH-DAC是一种可行的HT-HP实验方法。在IH-DAC下直接观察到石英到钴矿的相变。根据石英和钴矿的拉曼峰强度估算了相变速率。从实验时间与相变速率的关系出发，探讨了相变机理。

A high temperature diamond anvil cell by high frequency induction heating (IH-DAC) was newly constructed for Raman microspectroscopy. DAC is widely used high pressure apparatus to investigate the depth of the Earth. In this project, a high frequency induction heating was adopted to elevate temperature of DAC. The IH-DAC will possibly be a modified external heating method to heat DAC stably. The IH-DAC was designed as modifying the Merrill-Bassett DAC as to apply pressure with a lever. One turn of induction coil of Cu made for IH-DAC surrounds a pair of diamonds. The temperature of a sample in gasket can be directly measured by Raman spectra. The intensities of Stokes (I_S) and anti-Stokes (I_<aS>) lines are related by the Boltzmann factor as I_<aS>/I_S=exp(-hv/kT). Stokes and anti-Stokes lines of silicon were used for calibration of temperature.After several preliminary experiments of heating dummy plates of SUS, WC and Re by IH, WC rockers and Re gasket were selected for IH-DAC. Heating directly rockers by IH is hopeful way to attain high temperature over 1000℃. IH-DAC is a workable method for HT-HP experiments. A phase transformation from quartz to coesite was directly observed under IH-DAC. The transformation rates were estimated from intensities of Raman peak of quartz and coesite. From the relation between experimental time and the transformation rate, a transformation mechanism was discussed.