Laser-heating facility for diamond anvil cells

我们建议在法兰克福建立一个用于金刚石砧细胞实验的中央co2激光加热设施。计划的设置将允许加热透明样品而不添加不透明吸收剂。至少有10个小组的项目依赖于这个设施。一组实验旨在研究高温下的相变，包括熔融。特别是在大多数项目中研究的难熔化合物，需要明显高于2500℃的温度。此外，激光加热设备将用于退火样品，以消除施加压力引起的应力。这是允许原位（仅P）衍射实验的重要先决条件，因为应力展宽通常会阻止Rietveld-refine粉末数据的可能性。有几个小组将需要激光加热设备在极端条件下合成新的化合物。此外，还计划将激光加热用于开发新的合成技术，如高压下自传播高温合成（SHS）。除了这些科学任务，中央设施将允许我们培训年轻的研究人员，进行同步加速器实验准备的初步实验，测试PETRA III计划高压装置的概念，并改进实验方法，例如通过测试钻石的新形状。

We propose to build a central CO2-laser heating facility for diamond anvil cell experiments in Frankfurt. The planned set-up would allow to heat transparent samples without addition of opaque absorbers. The projects of at least 10 groups rely on the availability of this facility. One set of experiments is aimed at studying temperature-dependent phase transformations, including melting, at high pressures. Specifically for the refractory compounds studied in the majority of projects, temperatures significantly higher than 2500 C are required. Furthermore, the laser heating facility would be employed to anneal samples to remove stress induced by the application of pressure. This is an important prerequisite to allow in situ (P only) diffraction experiments, as stress broadening will generally prevent the possibility to Rietveld-refine powder data. Several groups will require the laser-heating facility to synthesize novel compounds at extreme conditions. It is also planned that the laser heating will be used to develop new synthesis techniques such as self-propagating high-temperature synthesis (SHS) under high pressures. In addition to these scientific tasks, the central facility will allow us to train young researchers, perform prelimenary experiments in preparation of synchrotron-based experiments, test concepts for the planned high-pressure set-up at PETRA III and improve the experimental approach, e.g. by testing new shapes for the diamonds.