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（MRI）奖将允许购买先进的X射线探测器，EIGER 2 S CdTe 9 M在先进光子源，科学用户设施的阿贡国家实验室（芝加哥，IL）的美国能源部办公室第13部门。这一探测器升级将有助于克服在极端压力-温度条件下现场确定材料结构和组成的挑战，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。这次升级所带来的新能力将促进新的实验，这些实验将解决地球和行星材料（如矿物，熔体和铁合金）的物理和化学特性的关键方面，从而大大推进我们对行星内部结构和动力学的理解。拟议的收购将大大加强在第13区进行的前沿高压研究。升级后的APS-U的同步加速器光束质量将大大提高，具有更紧密聚焦，更明亮和高度相干的光束。购买这款新探测器将充分利用升级的优势，并将为XRD的质量提供巨大而关键的改进。DECTRIS的混合像素EIGER 2 CdTe探测器与目前使用的PILLENT探测器相比具有显着的技术优势，具有更高的空间分辨率，更大的动态范围和更快的高能量帧速率。这些技术改进将提供新的能力，通过空间分辨紧密定位的反射，更精确地确定XRD反射形状和位置。该探测器将允许在长时间采集中明确检测弱反射，并将其与更强的杂散反射区分开来，从而实现许多以前无法实现的应用。这些改进对于单晶（SC）XRD和粉末XRD的全轮廓细化至关重要，它们可以在极端的P-T条件下原位确定材料的结构和组成。它对于将高质量和高分辨率XRD研究的P-T范围扩展到接近1 TPa的压力和接近10 kK的温度也至关重要，其中样品非常小。升级后的XRD设备将能够对平衡相图（包括熔化）、相变动力学和动力学、低Z材料的结构和组成以及非晶体材料的结构进行新的研究。新的研究将把联合收割机XRD测量与各种激光加热技术、动态压缩和DAC中样品的低温冷却相结合。激光加热系统与XRD相结合的拟议重大技术改进将允许新的实验活动，通过大大提高询问地球和行星材料的结构和物理性质的能力来解决许多基本问题（例如，矿物、熔体和铁合金），极大地促进了我们对行星内部结构和动力学的理解。现有的数据往往是矛盾的（例如，熔化和热/电传输性能）或太差地限制而不能提供唯一的答案。这强调了在良好控制和校准的高P-T条件下，利用地幔和地核类似物的原位测量对行星物质性质进行全面调查的必要性，例如这里提出的新探测器所实现的那些。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.