Community Facility Support: The UCLA National Ion Microprobe

观测科学，如天文学和地质学，直接受到我们用于观测的工具的清晰度的限制，无论是望远镜还是质谱仪。每增加一个数量级，我们所能看到的距离，我们所能看到的精确程度，或者我们所能看到的小尺度，都在等待着根本性的发现。20世纪60年代，现代质谱仪的出现彻底改变了我们对地球及其在太阳系中的地位的认识。现在，质谱仪可以高度精确地测量元素的同位素比率。这些分析使我们能够确定太阳系的年龄，并确定山脉何时上升或沉积盆地何时达到适合形成石油的温度条件。早期的这种测量是在大块岩石样本上进行的，但随着方法的出现，可以对微小的（大约是你头上一根头发的宽度）斑点进行分析，我们发现了一个丰富的信息世界，这些信息在我们只看大块样本时是无法获得的。离子微探针出现于20世纪80年代，作为地质材料原位微尺度同位素分析的终极工具。然而，这些仪器体积庞大、结构复杂、价格昂贵，以至于即使像我们这样一个庞大而富有的国家也只能负担得起地球科学领域的少数几项研究。自1993年加州大学洛杉矶分校在北半球接收了第一个离子微探针以来，我们一直在运营一个国家设施，为更广泛的地球科学家群体提供这种专业仪器的访问。包括许多学生和博士后在内的300多名外部调查人员访问了该设施。与此同时，我们肩负着继续在社会上展示科学领导的责任，通过追求广泛的重要问题。加州大学洛杉矶分校国家离子微探针设备产生的数据，被记录在480多篇科学文章中，导致了一系列重大发现，如太阳的同位素组成和地球上已知最古老的水和生命证据的年龄。该基金提供的资金1)确保全国的地球化学家、宇宙化学家和地质年代学家继续使用我们近乎独特的设施，2)为加州大学洛杉矶分校的科学家提供继续开发和完善现有和新的地球化学、地球生物学、宇宙化学和地质年代学研究方法所需的资源。科研培训是设施工作的一个重要方面。2010年至2016年间，有81篇论文（44篇博士论文、34篇硕士论文和3篇理学士论文）依赖于加州大学洛杉矶分校的离子微探针数据，另有13篇论文正在进行中。在这项资助的背景下，我们每年举办一次研讨会，邀请来自全国各地的学生到加州大学洛杉矶分校学习一周，了解离子微探针在地球科学中的应用，并获得接触离子微探针和相关设备和技术的机会。150多名学生参加了这些讲习班。中心科学家继续参与地方和国家的协同活动，包括专业活动和K-12教育和外展。该提案要求继续支持加州大学洛杉矶分校离子微探针实验室作为地球科学研究的国家设施。除了使外部调查人员能够利用该设施外，还寻求资金进一步发展分析方法，利用次级离子质谱法的独特优势，对与地球化学和地质年代学问题有关的同位素丰度进行现场分析。随着新的CAMECA ims1290及其高亮度Hyperion-2离子源的调试，我们建议优化我们的两台仪器，用于我们实验室的主要应用- ims1270成为专用的U-Pb多采集仪器，ims1290专注于高精度稳定同位素比测量。具体来说，我们建议发展：1)SIMS多捕收剂Lu-Hf同位素分析，2)石英、锆石和金红石中钛的交叉校准，3)耳岩中相关稳定同位素变化作为鱼类栖息地和生命周期的监测，4)硫同位素作为地球和火星的地球化学示踪剂，5)锆石中的C和S作为岩浆挥发性监测。

Observational sciences, such as astronomy and geology, are directly limited by the clarity of the tools we use for observing, whether it be a telescope or a mass spectrometer. For every order of magnitude increase in how far we can see, how precisely we can see, or in how small a scale at which we can see, fundamental discoveries await. Our understanding of the Earth and its place in the solar system was revolutionized in the 1960s by the advent of the modern mass spectrometer, which now permits highly accurate measurement of isotope ratios of elements. These analyses permit us to date the age of the solar system and determine when a mountain range rose or when a sedimentary basin reached temperature conditions suitable for forming petroleum. Early such measurements were performed on bulk rock samples, but as methods emerged that permit analysis on tiny (about the width of one of the hairs on your head) spots, we discovered a rich world of information that had eluded us when we looked only at bulk samples. The ion microprobe emerged in the 1980s as the ultimate tool for in situ microscale isotopic analyses of geologic materials. However, these instruments are large, complex, and expensive - so expensive that even a nation as large and rich as ours can only afford to support a handful in the Earth sciences. Since 1993, when UCLA took delivery of the first ion microprobe in the northern hemisphere, we have operated a national facility that provides access of this specialized instrumentation to the broader community of Earth scientists. Over 300 external investigators, including numerous students and postdocs, have accessed the facility. At the same time, we bear a continuing responsibility to demonstrate scientific leadership within the community by pursuing a broad range of important questions. Data produced from the UCLA national ion microprobe facility, as documented in over 480 scientific articles, has led to an array of significant discoveries such as the isotopic composition of the Sun and the age of the oldest known evidence for water and life on Earth. Funds provided in this grant 1) ensure that the nation's geochemists, cosmochemists, and geochronologists continue to have access to our near-unique facilities, and 2) provide UCLA scientists the resources required to continue to develop and refine existing and new methods for research in geochemistry, geobiology, cosmochemistry, and geochronology. Research training is an important aspect of the facility work. Between 2010 and 2016, 81 theses (44 Ph.D., 34 M.S., and 3 B.S.) that relied on UCLA ion microprobe data were completed with another 13 theses ongoing. In context of this support grant, we conduct an annual workshop that bring students from across the country to UCLA for one week to learn about applications of the ion microprobe to the geosciences and to acquire exposure to the ion microprobe and related equipment and techniques. Over 150 students have participated in these workshops. Center scientists continue to be involved in synergistic activities both locally and nationally, including professional activities and K-12 education and outreach.This proposal requests continued support of the UCLA ion microprobe laboratory as a national facility for research in the geosciences. In addition to enabling access to the facility by external investigators, funds are sought to further develop analytical methods that take advantage of the unique strengths of secondary ion mass spectrometry for in situ analyses of isotopic abundances relevant to problems in geochemistry and geochronology. With the commissioning of the new CAMECA ims1290 and its high brightness Hyperion-2 ion source, we propose to optimize each of our two instruments for the principal applications undertaken in our laboratory - the ims1270 to become a dedicated U-Pb multi-collection instrument and the ims1290 to focus on high precision stable isotope ratio measurements. Specifically, we propose to develop: 1) SIMS multi-collector Lu-Hf isotopic analysis, 2) cross-calibration of Ti-in-quartz, Ti-in-zircon, and Zr-in-rutile thermobarometers, 3) correlated stable isotope variations in otoliths as monitors of fish habitat and lifecycles, 4) sulfur isotopes as geochemical tracers on Earth and Mars, and 5) C and S in zircon as magma volatile monitors.