MRI: Acquisition of an advanced X-ray detector for static and dynamic synchrotron X-ray scattering studies of materials at extreme conditions at the Advanced Photon Source

这项重大研究仪器奖将允许在高级光子源的13区购买先进的X射线探测器EIGER2 S CdTe 9M，先进光子源是位于伊利诺伊州芝加哥的美国能源部科学办公室用户设施。这次探测器升级将有助于克服在极端压力-温度条件下就地确定材料结构和成分方面的挑战，目前在试图解决地球和行星科学中的许多基本问题时，这些挑战是有限的。这次升级带来的新能力将促进新颖的实验，这些实验将解决地球和行星材料(如矿物、熔体和铁合金)的物理和化学性质的关键方面，从而极大地促进我们对行星内部结构和动力学的理解。拟议中的收购将显著加强13区正在进行的前沿高压研究。升级后的APS-U的同步加速器光束的质量将大大提高，拥有更紧密、更明亮和高度相干的光束。购买这一新的探测器将充分利用这次升级，并将在X射线衍射仪的质量方面提供巨大和关键的改进。与目前使用的Pilatus探测器相比，DECTRIS的混合像素EIGER2 CdTe探测器具有显著的技术优势，具有更高的空间分辨率、更大的动态范围和更快的高能帧速率。这些技术改进将提供新的能力，通过在空间上解析紧密定位的反射来更精确地确定X射线衍射反射的形状和位置。该探测器将允许对长时间采集中的弱反射进行明确检测，并将它们与更强的虚假反射区分开来，从而使许多以前无法实现的应用成为可能。这些改进对于单晶(SC)X射线衍射法和粉末X射线衍射法的全轮廓细化是至关重要的，它可以在极端的P-T条件下原位确定材料的结构和组成。对于将高质量和高分辨率的X射线衍射研究的P-T范围扩展到接近1 TPA的压力和接近10 kK的温度，在样品非常小的情况下，这也是至关重要的。升级后的X射线衍射仪将能够对平衡相图(包括熔融)、相变动力学和动力学、Low-Z材料的结构和组成以及非晶态材料的结构进行新的研究。新的研究将结合X射线衍射测量和各种激光加热技术、动态压缩和DAC中样品的低温冷却。拟议的激光加热系统与X射线衍射仪相结合的重大技术改进将允许开展新的实验活动，通过大大提高询问地球和行星材料(例如矿物、熔体和铁合金)的结构和物理性质的能力来解决许多基本问题，极大地促进我们对行星内部结构和动力学的理解。现有数据往往相互矛盾(例如，熔化和热/电传输特性)，或者约束太差，无法提供唯一的答案。这强调了在良好控制和校准的高P-T条件下，使用对地幔和核心类似物的现场测量来全面调查行星材料的性质的必要性，例如这里建议的新探测器所实现的那些。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Major Research Instrumentation (MRI) award will permit the purchase of an advanced X-ray detector, EIGER2 S CdTe 9M at Sector 13 of the Advanced Photon Source, a U.S. Department of Energy Office of Science user facility at Argonne National Laboratory (Chicago, IL). This detector upgrade will help to overcome the challenges in determining the structure and composition of materials in-situ at extreme pressure-temperature conditions, which are currently limited when trying to resolve many fundamental questions in Earth and planetary sciences. New capabilities enabled by this upgrade will facilitate novel experiments which will address key aspects of physical and chemical properties of Earth and planetary materials such as minerals, melts, and iron alloys, thus greatly advancing our understanding of planetary interior structure and dynamics. The proposed acquisition will significantly enhance frontier high pressure research being conducted at Sector 13. The quality of the synchrotron beam at the upgraded APS-U will be greatly improved, with a more tightly focused, brighter, and highly coherent beam. Acquisition of this new detector will take full advantage of the upgrade and will provide a vast and critical improvement in the quality of XRD. The hybrid-pixel EIGER2 CdTe detector from DECTRIS has significant technical advantages versus the currently used PILATUS detector with higher spatial resolution, larger dynamic range, and faster frame rates at high energies. These technical improvements will provide new abilities to determine XRD reflection shapes and positions much more precisely by spatially resolving closely positioned reflections. The detector will allow definitive detection of weak reflections in long acquisitions and discriminate them from much stronger spurious reflections, thus enabling numerous previously unrealizable applications. These improvements are most critical for single-crystal (SC) XRD and full profile refinement of powder XRD, which can determine the structure and composition of materials in situ at extreme P-T conditions. It is also critical for extending the P-T range of high-quality and high-resolution XRD studies to pressures approaching 1 TPa and temperatures approaching 10 kK, where samples are exceptionally small. An upgraded XRD facility will enable new investigations of equilibrium phase diagrams (including melting), phase transition kinetics and dynamics, the structure and composition of low-Z materials, and the structure of non-crystalline materials. New investigations will combine XRD measurements with a variety of laser heating techniques, dynamic compression, and cryogenic cooling of samples in the DAC. The proposed major technological improvements of the laser heating system combined with XRD will allow new experimental campaigns for addressing many fundamental questions through a much-improved capability to interrogate the structure and physical properties of Earth and planetary materials (e.g., minerals, melts, and iron alloys), greatly advancing our understanding of planetary interior structure and dynamics. Existing data are often contradictory (e.g., melting and thermal/ electrical transport properties) or too poorly constrained to provide unique answers. This underscores the need for comprehensive investigations of the properties of planetary material using in situ measurements on mantle and core analogues in well controlled and calibrated high P-T conditions, such as those made possible by the new detector proposed here.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.