Acquisition of a New TIMS for Ocean and Earth Sciences at the University of Florida

9601872穆勒这项建议寻求资助为佛罗里达大学地质系购置和操作最先进的热电离质谱计(TIMS)的成本的50%。拟议的仪器将在三个方面提供增强的性能：1)该仪器将能够通过同时使用法拉第和电子倍增器或闪烁型探测器测量样品离子豆来提供扩展的动态范围(10)。这一能力对于利用包括示踪剂在内的单个同位素丰度超过仅有法拉第探测器的动态范围的系统至关重要。2)该仪器将能够在高质量下提供高丰度灵敏度。相对于传统的TIMS配置，这种扩展的能力对于U-Th系列的精确测量也是必要的，并在低质量系统(如钙)中提供优势。使用延迟势透镜的最新发展可以提供这种能力，而不需要(和成本)大型双聚焦配置；3)该仪器将能够在静态模式下进行高精度的同位素比率测量。在这种模式下的测量是必要的，以便结合增加的动态范围和扩展的丰度灵敏度的优点，为小样品提供最大的精度，例如，那些只包含皮克(10克)量的铅的样品，以及那些具有低电离效率的样品，例如Th。将受益的具体应用包括：U系列同位素分析用于现代地质年代学；单个锆石晶体或部分晶体用于地质年代学和岩石成因研究；铅、锶和钕同位素研究用于示踪剂、年代地层和古环境应用；以及锶/钙同位素通过同位素稀释用于古环境研究。他们目前的质谱仪主要由研究生使用。这些学生中大约有一半是女性，在地球科学领域占少数。佛罗里达大学为这个项目提供了360,730美元的支持，占成本份额的50%。***

9601872 Mueller This proposal seeks funding to support 50% of the cost of acquiring and operating a state-of-the-art thermal ionization mass spectrometer (TIMS) for the Geology Department of the University of Florida. The proposed instrument will provide enhanced performance in three areas: 1) The instrument will be capable of providing extended dynamic range (10 ) through the ability to measure sample ion beans with both Faraday and electron multiplier- or scintillation - type detectors simultaneously. This capability is essential for utilizing systems in which the abundance of individual isotopes, including tracers, exceeds the dynamic range of Faraday detectors alone. 2) The instrument will be capable of providing high abundance sensitivity at high mass. This extended capability, relative to traditional TIMS configurations, is also necessary for accurate measurements in the U-Th series and provides benefits in lower mass systems such as Ca. Recent developments in the use of retarding potential lens can provide this capability without the need (and cost) of large, double focusing configurations; 3) The instrument will be capable of high precision isotopic ratio measurements in static mode. Measurement in this mode is necessary in order to combine the advantages of increased dynamic range and extended abundance sensitivity to provide maximum accuracy for small samples, e.g., those containing only picogram (10 g) quantities of Pb, and those with low ionization efficiencies, e.g., Th. Specific applications that will benefit include the analysis of U-series isotopes for recent geochronology; the analysis of individual zircon crystals or parts of crystals for geochronologic and petrogenetic studies; Pb, Sr, and Nd isotopic studies of very small samples for tracer, chronostratigraphic, and paleo-environmental applications; and Sr/Ca isotopes via isotope dilution for paleoenvironme ntal studies. Their current mass spectrometer is heavily utilized by graduate students. Approximately half of these students are women, a minority in the geosciences. The University of Florida is supporting this project with $360,730, which represents a 50% cost share. ***