Acquisition of a Helix SFT Noble Gas Mass Spectrometer

购买 Helix SFT 稀有气体质谱仪

• 批准号: 1826965
• 负责人: Kenneth Farley
• 金额: $ 34.34万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2019-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1826965&HistoricalAwards=false
• 关键词: Acquisition; Helix; SFT; Noble; Gas

This grant supports continued innovation and application of techniques of He isotope geochemistry to address Earth science problems. The grant will be used to purchase a new He isotope mass spectrometer capable of making precise and accurate He isotope abundance measurements even on very small quantities of helium. The instrument replaces a decades-old predecessor and requires no modification to the existing hardware for extracting gases from rocks and minerals for analysis. This instrument will be used in support of many Earth science subdisciplines and will be the main tool used by multiple undergraduate and graduate students and postdoctoral investigators in their studies.The two isotopes of He, 3He and 4He, provide a wealth of information on the origin and history of terrestrial rocks. 4He in rocks is almost exclusively derived from α-decay of the elements U and Th. Accumulation of 4He in minerals allows a unique form of chronometry. Because He diffuses out of minerals at elevated temperatures characteristic of burial to a few km depth in the crust, the accumulated 4He in minerals can be used to determine when rocks were brought to the Earth's surface by erosion or faulting. Such data provide important insights to key geologic processes such as the timing and causes of mountain building. 3He in rocks and minerals can come from more unusual sources. For example, 3He is produced when cosmic rays interact with the elements that make up minerals in the uppermost ~ 2 meters of the crust. This too acts as a chronometer, but a chronometer that can be used to measure erosion rates and also to establish when rocks first became exposed at the surface. The latter technique is one of the central tools in establishing the glaciation history and Milankovitch-driven climate change over the last few tens of thousands of years. In marine sediments, 3He is derived from the accumulation of cosmic dust. By measuring 3He concentrations in sequences of marine sediments it is possible to establish sedimentation rates (another key indicator of time) and, in some cases, to identify major cosmic-dust producing events such as the rare destructive collision of many-km-sized asteroids.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.

该赠款支持持续的创新和应用同位素地球化学技术来解决地球科学问题。 该赠款将用于购买一种新的HE同位素质谱仪，即使以少量氦气的速度，也可以精确而准确的同位素丰度测量。该仪器取代了数十年历史的前身，不需要对现有硬件的修改，以从岩石和矿物质中提取气体进行分析。该工具将用于支持许多地球科学子学科，并将是多个本科生和研究生以及博士后研究人员在他们的研究中使用的主要工具。他，3HE和4HE的两个同位素提供了有关地面岩石的起源和历史的丰富信息。 4他在岩石中几乎完全来自e和th的元素。 4HE在矿物质中的积累允许一种独特的时间表形式。由于他在埋葬的温度升高时从矿物质中扩散到地壳中的几公里深度，因此可以使用矿物质中的4HE来确定何时通过侵蚀或断层将岩石带到地球表面。这样的数据为关键地质过程（例如山地建筑的时机和原因）提供了重要的见解。 3他在岩石和矿物质中可能来自更异常的来源。例如，当宇宙射线与构成矿物质矿物质的元素相互作用时，会产生3HE。这也充当了计时仪，但是可以用来测量侵蚀速率并确定岩石何时首次暴露在表面上的天文钟。后一种技术是建立冰川历史和米兰科维奇驱动的气候变化的核心工具之一。在海洋沉积物中，3HE源自宇宙灰尘的积累。通过测量海洋沉积物序列的3E浓度，可以建立沉积率（另一个关键时间指标），在某些情况下，确定产生主要的宇宙毒品，例如诸如多个KM大小的小行星的罕见破坏性碰撞，这是NSF的法定任务，反映了综述的范围，并通过评估了构成的范围。