Scientific and technological innovation from mineral geonomics - a dual source microfocus single-crystal diffractometer for UK geoscience

矿物在所有的全球过程中都起着至关重要的作用，包括深部地球构造和地质灾害，地球表面的动态环境变化，以及形成许多地球生物的基本骨架结构。自20世纪初以来，晶体学家对矿物的晶体结构进行了研究和分类，并利用这些信息进一步了解地质多样性、地球的地质演化以及作为发展中社会重要资源的矿物的开发利用。然而，随着我们对矿物王国知识的发展和社会对全球人类影响的理解的提高，因此研究更复杂和更具挑战性的材料的需求变得越来越迫切。不幸的是，这些矿物来自独特的自然环境，包括不同的生物地球化学系统、传统的采矿/工业场所、现代废物管理和回收系统、化石、植物和动物，以及极端的温度、压力和应力，迄今为止被证明过于具有挑战性，无法在原子尺度上进行结构表征。使它们具有挑战性的主要特性包括它们极小的尺寸，化学复杂性和重原子/轻原子组合，巨大的拓扑单元（大的重复模式），或有限的稳定性/结晶度。这些以前无法克服的技术挑战现在可以解决了，因为在过去的5年中，与x射线晶体学方法相关的硬件和软件取得了重大进展，现在可以对这些矿物进行创新的结构科学研究，将纳米级现象与大规模地质过程联系起来——这是地球科学的一个基本目标。本文提出的仪器是一种独特的单晶x射线衍射仪，配有双Ag/Mo（银和钼）高通量x射线微源和Cd-Te（镉碲）区域探测器。双源允许我们改变x射线波长以优化实验，例如，当使用高压设备（称为金刚石砧细胞，DAC）时，使用Mo x射线源时，大部分衍射数据被DAC屏蔽。使用银x射线源可以减轻这一问题，从而可以收集到具有大量衍射峰的更完整的数据集。传统的硅探测器对于Mo x射线来说是相当有效的，但是当使用较短波长的x射线，比如来自银x射线源的x射线时，它们的效率就会直线下降。新开发的Cd-Te探测器在长波长和短波长都保持了效率，使我们能够方便地改变x射线源而不损失任何计数统计数据。最后，与传统的x射线源相比，微聚焦x射线源具有更高的通量和更长的寿命。这种新的衍射仪将扩大我们对矿物地质多样性的认识，加强国家和国际的收集和数据库。我们将能够在真实的压力和温度条件下研究地球深处的矿物，或者作为地幔钻石的微小包裹体，使我们能够完善我们的地球结构、组成和动力学模型。此外，了解具有挑战性的矿物的基本原子尺度结构为金属循环、成矿系统、养分运输和毒性/修复模型提供了关键数据。这些信息保存在矿物：水界面的微尺度新形成相中，通常由微生物群落介导，利用矿物作为能量，同时共同沉淀新相。解决具有技术潜力的矿物结构或矿物承载技术使能元素将加强地质冶金、矿物工程和功能材料之间的联系，推动利用可持续、低能源、低废物技术对矿物进行技术开发。

Minerals are critically involved in all global processes, including deep earth tectonics and geohazards, dynamic environmental changes at the Earth's surface, and forming the fundamental skeletal structures of many of Earth's organisms. Since the early 20th century, crystallographers have studied and classified the crystal structures of minerals and used this information to further our understanding of geodiversity, the geological evolution of Earth and the exploitation of minerals as critical resources for developing societies. However, as our knowledge of the mineral kingdom developed and society's understanding of the global human impact has improved, so the need to study more complex and challenging materials has become increasingly urgent. Unfortunately, such minerals from unique natural environments including, diverse biogeochemical systems, legacy mining / industrial sites, modern waste management and recycling systems, fossils, plants and animals, and extremes of temperatures, pressure and stresses, have to-date proven too challenging to be structurally characterised at the atomic scale.The main properties that make them so challenging to study include their extremely small size, chemical complexity and heavy atom/light atom combinations, huge topological units (large repeating patterns), or limited stability/crystallinity. These previously insurmountable technical challenges can now be addressed, due to major advances in hardware and software relating to X-ray crystallography methods in the past 5 years that now allow innovative structural science on these minerals linking nano-scale phenomena with large-scale geological processes - a fundamental goal of geoscience. The instrument proposed here is a unique single-crystal X-ray diffractometer equipped dual Ag/Mo (silver and molybdenum) high-flux X-ray micro-source and Cd-Te (cadmium-tellurium) area detector. The dual source allows us to change the X-ray wavelength to optimise the experiment, for example when using high pressure equipment (known as diamond anvil cells, DAC) much of the diffraction data are shielded by the DACs when using a Mo X-ray source. This problem is alleviated by using an Ag X-ray source and consequently a more complete data set with high numbers of diffraction peaks can be collected. Traditional silicon detectors are reasonably efficient for Mo X-rays, but their efficiency plummets when using shorter wavelength X-rays such as from an Ag X-ray source. Newly developed Cd-Te detectors maintain their efficiency at long and short wavelengths allowing us to conveniently change X-ray source without any loss in counting statistics. Finally, microfocus X-ray sources have a much higher flux and longer lifespan when compared to traditional X-ray sources.This new diffractometer will expand our knowledge of mineral geodiversity, enhancing national and international collections and databases. We will be able to study minerals from the Earth's deep interior under realistic pressure and temperature conditions or as tiny inclusions from mantle diamonds, allowing us to refine our models of Earths structure, composition and dynamics. Furthermore, understanding the fundamental atomic scale structures of challenging minerals provides critical data for models of metal cycling, ore-forming systems, nutrient transport and toxicity/remediation. Such information is held within microscale neo-forming phases at the mineral:water interface, often mediated by microbial communities utilising minerals for energy whilst co-precipitating new phases. Solving the structures of minerals with technological potential or minerals hosting technology enabling elements will enhance the link between geometallurgy, mineral engineering and functional materials driving the technological exploitation of minerals utilising sustainable, low energy, low waste technology.