Acquisition of an Electron Microprobe for the MIT User Community

这项提案寻求369,000美元的资金，用于购买翻新的JEOL JXA-8200电子探针。该探头将允许显著增强当前探头的操作，提供LaB6电子枪-提供更大的束流，更小的光斑和更好的步进分辨率，增强的光学自动对焦-允许更高的步进分辨率和重复性，自动化电子光学，更快的电机，更好的WDS扫描，阴极发光(CL)系统-允许更好的相位表征，增强的控制和成像软件，以及远程控制能力。协管员(查特吉)将继续担任探测设施的主要操作员和维护员。最近的一次晋升给了他一年的工资补贴。合作PI将继续为学生、研究人员和教职员工提供培训。麻省理工学院的调查设施作为一个软货币实体运作，但如果需要，仍保留可能的部门支持。利率结构取决于支持程度。有经验的用户可以选择更便宜的“非工作时间”时间。该系统将立即投入使用，取代旧的探头，用于岩石学研究-了解高温高压火成岩和变质岩的特征。此外，还将研究地质时期水对熔体和相关矿物动力学的影响。该探测器将在评估原始玄武岩以及俯冲流体和源岩浆熔体的贡献方面发挥关键作用。这些数据将提供给MELTS算法。将评估月马岩浆、火星地幔演化和小行星母体，评估熔融源区并阐明熔融过程。还将进行初步分析，这将有助于阐明适合进行TIMS U-Pb系列分析的不同区域。将使用锆石和独居石定位以及U-Th-Pb测年来帮助追踪地质时代的大陆位置和对准。电子背散射将用于分析其取向和地层位置(如果适用)将在高精度测年之前确定的矿物(S)。将对来自大洋中脊、汇聚的板块边缘和海洋“热点”的玄武岩进行分析，以确定地质时代的年龄和迁移。还将进行微量元素分析，以提炼成分信息。该部门内的其他项目将研究早期行星形成、古地磁、岩石圈演化、大洋岩石圈和地幔地球化学以及热液系统。该探测器将是麻省理工学院地球、大气和行星科学系研究和教学活动的重要组成部分。新的探头将被纳入电子微探针课。课堂笔记可以在网上找到。有三门本科课程使用这种微型探头，该探头将大量用于研究生研究工作。研究结果将通过同行评议的文献传播。***

0841161GroveThis proposal seeks funding of ~$369K to purchase a refurbished JEOL JXA-8200 electron microprobe. The probe will allow significantly enhanced operation over the current probe offering an LaB6 electron gun - offering higher beam currents with smaller spot size and better step resolution, enhanced optical auto-focusing - allowing higher step resolution and reproducibility, automated electron optics, faster motors, better WDS scanning, a cathodoluminescence (CL) system - allowing better phase characterization, enhanced control and imaging software, and remote control capabilities. The co-PI (Chatterjee) will continue to be the prime operator and maintainer for the probe facility. A recent promotion gives him salary support for one year. The co-PI will continue to offer training for students, researchers and faculty. The MIT probe facility operates as a soft-money entity but retains possible departmental support if needed. Rate structure depends on the level of support. Experienced users can opt for less-expensive "off hours" times. The system will be put to immediate use replacing an older probe for studies in petrology - understanding high temperature and pressure igneous and metamorphic rock characteristics. Additionally the water impacts on melts and associated mineral dynamics during geologic time will be studied. The probe will be critical in assessing primitive basalts and contributions from subduction fluids and melts in source magma. These data will feed into the MELTS algorithm. Lunar mare magmas, Martian mantle evolution and asteriodal parent bodies will be assess melting source regions and elucidate melt processes. Preliminary analyses will also be conducted which will help elucidate distinct regions suitable for TIMS U-Pb series analysis. Zircon and monazite localization and U-Th-Pb dating will be used to help trace continental positions and alignments over geologic time. Electron backscattering will be used to analyze minerals whose orientation and stratigraphic (if applicable) position(s) will be determined prior to high-precision dating. Basalts from mid-ocean ridges, convergent plate margins and oceanic "hotspots" will be analyzed to determine age and migration over geologic time. Trace element analysis will also be performed to refine compositional information. Additional projects within the department will study early planetary formation, paleomagnetism, lithospheric evolution, oceanic lithospheric and mantle geochemistry, and hydrothermal systems. The probe will be an essential component of research and teaching activities within the Department of Earth, Atmospheric and Planetary Sciences at MIT. The new probe will be incorporated in an electron microprobe course. Class notes are available over the web. Three undergraduate courses use the microprobe and the probe will be heavily used in graduate research efforts. Research results will be disseminated through the peer-reviewed literature. ***