Acquisition of an Electron Microprobe for the MIT User Community

0841161 Grove该提案寻求约36.9万美元的资金，用于购买翻新的JEOL JXA-8200电子探针。该探针将允许比现有探针显著增强的操作，该探针提供LaB 6电子枪-提供更高的束电流，具有更小的光斑尺寸和更好的步进分辨率，增强的光学自动聚焦-允许更高的步进分辨率和再现性，自动电子光学器件，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，和远程控制能力。共同PI（查特吉）将继续是探测设施的主要运营商和维护者。最近的一次晋升给了他一年的工资支持。共同PI将继续为学生，研究人员和教师提供培训。麻省理工学院的探测设施作为一个软货币实体运作，但在需要时保留可能的部门支持。利率结构取决于支持水平。有经验的用户可以选择更便宜的“下班时间”。该系统将立即投入使用，取代旧的探针，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和俯冲流体和源岩浆熔体的贡献方面发挥关键作用。这些数据将输入MELTS算法。月海岩浆、火星地幔演化和近节母岩将是评估熔融源区和阐明熔融过程的基础。初步分析也将进行，这将有助于阐明不同的地区适合TIMS U-Pb系列分析。锆石和独居石定位和U-Th-Pb测年将用于帮助追踪地质时期的大陆位置和排列。电子背散射将用于分析矿物，其方向和地层（如适用）位置将在高精度测年之前确定。将对大洋中脊、会聚板块边缘和海洋“热点”的玄武岩进行分析，以确定地质时期的年龄和迁移情况。还将进行微量元素分析，以完善成分信息。该系的其他项目将研究早期行星形成、古地磁学、岩石圈演化、海洋岩石圈和地幔地球化学以及热液系统。该探测器将成为麻省理工学院地球、大气和行星科学系研究和教学活动的重要组成部分。新的探针将被纳入电子显微镜课程。课堂笔记可以在网上找到。三个本科课程使用的微探针和探针将大量用于研究生的研究工作。研究结果将通过同行审查的文献传播。 ***

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. ***