Implementation and application of the peak scaling method for temperature measurement in the laser heated diamond anvil cell
Implementation and application of the peak scaling method for temperature measurement in the laser heated diamond anvil cell
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DOI：
10.1063/1.5028276
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发表时间：
2018-08-01
影响因子：
1.6
通讯作者：
MacDowell, Alastair A.
中科院分区：
文献类型：
--
作者：
Kunz, Martin;Yan, Jinyuan;MacDowell, Alastair A.
本文介绍了一种新型的双面高压金刚石对顶砧激光加热装置。原型部署在劳伦斯伯克利国家实验室先进光源的光束线12.2.2处。我们的紧凑型设计具有缩短的机械杠杆臂，从而实现更稳定的成像光学系统，因此基于高温测量的温度测量更加用户友好和可靠。对峰值定标法进行了改进，包括确定绝对峰值温度的迭代法，从而实现了激光加热金刚石对顶砧单元内实际热点的准实时温度映射，而无需对热点的形状、大小和对称性进行任何假设，也无需对拟合温度与峰值温度之间的关系进行任何假设。这是很重要的，因为我们表明，峰值温度和温度之间的关系，通过拟合普朗克函数对整个热点的平均热发射光谱是不恒定的，但取决于可变的拟合参数（特别是，大小和位置的拟合窗口）。通过测量金属丝在常压下的熔点，证实了该方法的准确性。具有真实的时间的绝对温度图允许对激光加热实验进行更差异化的分析。我们提出了这样一个例子，在一个加热的热点碘化银在加载的基础压力为3.8 GPa的压力变化。出版社：AIP Publishing
A new design for a double-sided high-pressure diamond anvil cell laser heating set-up is described. The prototype is deployed at beamline 12.2.2 of the Advanced Light Source at Lawrence Berkeley National Lab. Our compact design features shortened mechanical lever arms, which results in more stable imaging optics, and thus more user friendly and more reliable temperature measurements based on pyrometry. Amodification of the peak scaling method was implemented for pyrometry, including an iterative method to determine the absolute peak temperature, thus allowing for quasi-real time temperature mapping of the actual hotspot within a laser-heated diamond anvil cell without any assumptions on shape, size, and symmetry of the hotspot and without any assumptions to the relationship between fitted temperature and peak temperature. This is important since we show that the relationship between peak temperature and temperature obtained by fitting the Planck function against the thermal emission spectrum averaged over the entire hotspot is not constant but depends on variable fitting parameters (in particular, the size and position of the fitting window). The accuracy of the method is confirmed through measuring melting points of metal wires at ambient pressure. Having absolute temperature maps in real time allows for more differentiated analyses of laser heating experiments. We present such an example of the pressure variations within a heated hotspot of AgI at a loaded base pressure of 3.8 GPa. Published by AIP Publishing.