Diffractometer for time-resolved in-situ high temperature powder diffraction and X-ray reflectivity

用于时间分辨原位高温粉末衍射和 X 射线反射率的衍射仪

• 批准号: 530760073
• 金额: --
• 依托单位: Rheinisch-Westfälische Technische Hochschule Aachen
• 依托单位国家: 德国
• 项目类别: Major Research Instrumentation
• 财政年份: 2024
• 资助国家: 德国
• 起止时间: 2023-12-31 至 无数据
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/530760073?language=en
• 关键词: Diffractometer; time; resolved; situ; temperature

The research questions of the Institute of Crystallography (IfK) of RWTH Aachen University include temperature-dependent structural phase transformations, solid-state reactions (e.g. dewatering reactions, segregation), temperature-dependent redox reactions and sintering processes in (mostly ceramic) functional materials. To understand the underlying structural processes and their kinetics at the atomic level, many temperature-dependent and time-resolved data sets have to be collected, analyzed and compared. In addition, we study interfacial structures and processes between solids and liquids or gases. Modern X-ray diffractometers allow the methods of powder X-ray diffraction (PXRD) and X-ray reflectivity (XRR) to be combined in one device. Examinations with copper radiation usually deliver high intensities due to the high flux and therefore allow short measurement times on flat specimens in reflection. While the large wavelength enables a high angular resolution and thus a good reflection resolution on the one hand, it is not suitable for transmission measurements in capillaries even for medium-heavy elements due to the relatively strong absorption. Here, the use of shorter-wavelength (and therefore less strongly absorbed) Mo radiation is recommended. Especially, when measurements can be performed using a Kα1,2 wavelength mixture, this X-ray source also delivers considerable flux and thus good intensities with reasonable measurement times. For XRR or polycrystalline XRD samples without a defined, smooth surface (e.g. ceramic or metallic workpieces and components), primary Goebel mirrors are required for both X-ray sources. As a result, a parallel beam geometry is obtained for Cu. A focusing Göbel mirror is provided for the Mo tube for capillary measurements in transmission in order to obtain sufficiently high intensities with a small sample volume. This also allows XRR measurements and measurements under grazing incidence. A high-temperature chamber up to 1200 °C, which can be operated with both Cu and Mo radiation, under air, vacuum and inert gas with both flat samples (in reflection) and capillaries (in transmission), is a prerequisite for the successful research work of the IfK. XRR measurements require fine, motorized adjustment of the sample position (x, y, z) and tilt for optimal measurement conditions. The reflectometry method has already been optimized in the past for measuring liquid films, also on synchrotron beamlines, which requires vibration damping and/or decoupling of the sample from the environment. For fast (a few minutes), position-sensitive measurements, a 2D detector is required on the secondary side, which is suitable for XRR as well as time-resolved high-temperature diffraction with Cu and Mo radiation.

亚琛工业大学晶体学研究所（IfK）的研究问题包括温度相关的结构相变、固态反应（例如脱水反应、偏析）、温度相关的氧化还原反应和（主要是陶瓷）功能材料的烧结过程为了在原子水平上了解潜在的结构过程及其动力学，必须收集、分析和比较许多与温度相关的和时间分辨的数据集。现代 X 射线衍射仪可将粉末 X 射线衍射 (PXRD) 和 X 射线反射率 (XRR) 方法结合在一台设备中，因为铜辐射检测通常可提供高强度。高通量，因此允许在反射中对扁平样品进行短测量时间。虽然大波长一方面可以实现高角度分辨率，从而获得良好的反射分辨率，但它不适合毛细管中的透射测量，甚至是毛细管中的透射测量。由于吸收相对较强，因此建议使用较短波长（因此吸收较弱）的 Mo 辐射，特别是当可以使用 Kα1,2 波长混合进行测量时，这种 X 射线。对于没有明确光滑表面的 XRR 或多晶 XRD 样品（例如陶瓷或金属工件和组件），X 射线源还可以提供相当大的通量，从而在合理的测量时间内提供良好的强度。因此，获得了 Cu 的平行光束几何形状。为 Mo 管提供了聚焦戈贝尔镜，用于传输中的毛细管测量，以便以较小的样品体积获得足够高的强度，这也允许进行 XRR 测量和测量。高达 1200 °C 的高温室，可在空气、真空和惰性气体下使用 Cu 和 Mo 辐射，同时使用平面样品（反射）和毛细管（透射）。 IfK 测量研究工作成功的先决条件是对样品位置 (x、y、z) 和倾斜进行微调，以实现最佳测量条件。同步加速器光束线上也需要振动阻尼和/或样品与环境的解耦，对于快速（几分钟）的位置敏感测量，次级侧需要一个 2D 探测器，适用于XRR 以及铜和钼辐射的时间分辨高温衍射。