MRI: Acquisition of a Laboratory-Based X-ray Absorption and Emission Spectroscopy Instrument

这一重大研究仪器(MRI)项目奖支持购买一台X射线吸收和发射光谱仪，该光谱仪将由圣路易斯的华盛顿大学主办。新仪器将可供该大学、周边地区和更远地区的研究人员使用。这将是美国第一所针对地球和环境科学领域的研究进行优化的大学。科学家们将使用这种新工具来研究一系列广泛的问题，例如生命如何形成矿物，土壤和处理方法如何去除水中的污染物，以及熔岩中的气体和水如何影响火山喷发。此外，该仪器将用于培训下一代科学家，并作为大学生和高中生研究实习的一部分，包括来自圣路易斯市的学生。仪器实验室除了亲自使用外，还将接受邮寄样品。这种邮寄服务使本科生服务机构的学生和残疾人能够接触到这种独特的研究能力，这些学生没有自己的专业仪器，否则他们需要前往四大国家设施之一，这些设施传统上可以获得这些X射线技术。拟议的仪器将使两种类型的测量能够在实验室环境中进行，直到最近还只能使用同步辐射光源：透射式X射线吸收光谱(XAS)和高分辨率X射线发射光谱(XES)。XAS能力将允许量化在1wt%出现的元素的氧化状态、配位环境和局部结构。XES功能扩展了对浓度低至10至100μg/g的元素的敏感性，提供了有关氧化态、过渡金属自旋态和配位的信息。不同的固体、液体或生物样品可以用这两种方法进行研究。该仪器将促进对一系列不同专题的研究，其中包括：地球早期的生物地球化学矿物形成和转化、生物特征和生前化学、细菌和真菌的新陈代谢及产物、金属污染物的去向和修复、促使火山喷发的挥发物、太阳系形成和演化期间的条件、岩石记录中沉积和成岩过程的特征、饮用水处理和供应，以及从废水中回收营养和能源资源。该仪器能够将XAS测量的子集从同步加速器迁移到实验室环境中，为需要光源设施的许多实验腾出了光束线时间。此外，拟议的仪器促进了XES在地球和环境科学应用中的开发，这项技术到目前为止还很少使用，并将在未来十年作为更广泛地将X射线光谱分析方法移植到实验室环境中的试验台。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) program award supports the purchase of an X-ray absorption and emission spectrometer that will be hosted by Washington University in St. Louis. The new instrument will be available for use by researchers at the university, in the surrounding region, and further afield. It will be the first of its kind at a university in the United States that is optimized for research in the field of Earth and environmental science. Scientists will use this new tool to study a wide array of questions, such as how life forms minerals, how soils and treatment methods remove contaminants from water, and how gases and water in molten rock affect volcanic eruptions. In addition, this instrument will be used to train the next generation of scientists and as part of research internships for college and high school students, including those from the City of St. Louis. The instrument laboratory will accept samples by mail in addition to in-person usage. This mail-in service opens up access to this unique research capability to students at undergraduate-serving institutions that lack their own major instrumentation and to persons with disabilities who would otherwise need to travel to one of the four major national facilities where these X-ray techniques have traditionally been available.The proposed instrument will enable two types of measurements in a laboratory setting that until recently were only accessible at a synchrotron lightsource: transmission X-ray absorption spectroscopy (XAS) and high-resolution X-ray emission spectroscopy (XES). The XAS capability will allow quantification of oxidation state, coordination environment, and local structure of elements occurring at 1 wt.%. The XES capability extends sensitivity to elements occurring at concentrations as low as 10 to 100 μg/g, providing information on oxidation state, transition metal spin state, and coordination. Diverse solid, liquid, or biological samples can be studied using both methods. The instrument will facilitate research on a diverse array of topics, including biogeochemical mineral formation and transformation, biosignatures and prebiotic chemistry on the early Earth, bacterial and fungal metabolisms and products, metal contaminant fate and remediation, volatiles that drive volcanic eruptions, conditions during the formation and evolution of the Solar System, signatures of sedimentary and diagenetic processes in the rock record, drinking water treatment and supply, and recovery of nutrient and energy resources from wastewaters. The instrument enables migration of a subset of XAS measurements from a synchrotron to a laboratory setting, freeing time at beamlines for the many experiments that uniquely require a lightsource facility. In addition, the proposed instrument facilitates the development of XES for Earth and environmental sciences applications, where this technique has seen little usage to date, and will serve as a testbed for wider migration of X-ray spectroscopic methods into a laboratory setting over the coming decade.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.