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高压非平衡相变动力学过程依赖于温度、压强及加载速率, 这要求在不同时间尺度内实现快速加载/卸载并进行快速数据采集. 本文着重介绍了最近在上海同步辐射光源BL15U1线站设计和发展的时间分辨X射线衍射和快速动态加载金刚石对顶砧(dDAC)实验装置的最新进展. dDAC采用气膜驱动和压电陶瓷驱动两种快速加载方式, 在毫秒尺度内实现DAC样品腔压强从常压加压到300 GPa(20 μm金刚石台面)以上, 并获得了毫秒尺度的时间分辨衍射数据. 其中压电陶瓷驱动的dDAC采用新设计的单、双筒驱动方式, 具有加载压力大、压缩速率高等特点, 加载速率可达13 TPa/s. 在快速加压过程中, 可同时连续采集X射线衍射谱. 探测器采用Pilatus 3X 900 K, 帧频达500 Hz, 实现了2 ms时间分辨的X射线衍射测量. 毫秒时间分辨的X射线衍射和高压快速加载装置丰富了BL15U1线站的高压研究技术, 拓展了线站开展超高压实验、非平衡相变动力学等科学研究的能力.
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关键词:
- 高压 /
- 动态加载装置dDAC /
- 时间分辨XRD /
- 结构相变
Non-equilibrium transition dynamics under high pressure depends on temperature, pressure and (de)compression rate. The studies require combination of time-resolved probe and rapid compression device on different time scales. Here we report the time-resolved X-ray diffraction (XRD) and dynamic diamond anvil cell (dDAC) system, which were recently developed at the BL15U1 beamline of Shanghai Synchrotron Radiation Facility (SSRF). There are two rapid loading methods for dDAC. One uses membrane control and the other is piezoelectric actuator driven dDAC. Both methods can dynamically compress the DAC sample chamber up to 300 GPa on millisecond scale (20 μm culet is used), and the time-resolved XRD data are obtained correspondingly. A new type of piezoelectric ceramic dDAC is designed with single-side drive or double-side drive, which allows us to realize extremely high pressure (above 300 GPa) with a fast compression rate of 13 TPa/s. During the rapid compression process, the X-ray diffraction spectra are collected continuously and simultaneously. The XRD detector is Pilatus 3X 900K, which has 2-ms resolution with 500 kHz frame rate. The millisecond time-resolved XRD and high pressure rapid compression system developed at BL15U1 of SSRF enrich the high-pressure experimental methods and enable the beamline to carry out ultra-high pressure experiments, non-equilibrium phase transition and relevant scientific researches.-
Keywords:
- high pressure /
- dynamic diamond anvil cell /
- time-resolved XRD /
- structural phase transition








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