Production of high-purity 229Th for analyses of U- and Th-series isotopes in geological materials

生产用于地质材料中 U 和 Th 系列同位素分析的高纯度 229Th

• 批准号: 0346052
• 负责人: Aaron Pietruszka
• 金额: $ 21.06万
• 依托单位: San Diego State University Foundation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0346052&HistoricalAwards=false
• 关键词: Production; purity; 229Th; analyses; Th

EAR-0346052PietruszkaThe short-lived intermediate daughter isotopes of the U- and Th-decay series have proven to be important tracers of the nature and time scales of recent Earth processes. Current applications of these isotopes range widely from Quaternary geochronology to groundwater hydrology to ocean chemistry to magmatic processes beneath active volcanoes. One of the most important laboratory tools for these measurements is a high-purity Th-229 isotopic tracer, which is used both to determine the abundance of Th and, often, the Th isotope ratio of a sample by mass spectrometry. Unfortunately, there is no commercially available supply of high-purity Th-229 that will meet the current and future demands of the U- and Th-series isotope research community. This project will secure a long-term source of high-purity Th-229 through collaboration with the scientific staff of the Oak Ridge National Laboratory. The research conducted using this new high-purity Th-229 tracer will include diverse topics of unambiguous benefit to society, such as understanding climate and sea level change during the late Quaternary, deciphering magmatic processes at active volcanoes, evaluating potential sites for long-term storage of radioactive waste, and characterizing the transport of radionuclides in groundwater. The purity of the Th-229 tracer used by these researchers has a profound impact upon data quality, and thus, the outcome of projects such as these. This is an issue of particular importance for the future potential of measurements using plasma ionization mass spectrometry, which makes it possible to push the limits of accuracy and precision for U- and Th- series isotopic analyses of geological materials. Ultimately, this project will also promote the ability of these researchers to teach and train undergraduate and, especially, graduate students in the field of geochemistry.***

EAR-0346052Pietruszka U 和 Th 衰变系列的短命中间子同位素已被证明是近期地球过程的性质和时间尺度的重要示踪剂。 这些同位素目前的应用范围广泛，从第四纪地质年代学到地下水水文学到海洋化学到活火山下的岩浆过程。 用于这些测量的最重要的实验室工具之一是高纯度 Th-229 同位素示踪剂，它既可用于通过质谱法确定样品中 Th 的丰度，也可用于确定样品的 Th 同位素比率。 不幸的是，目前还没有商业化的高纯度 Th-229 供应来满足 U 和 Th 系列同位素研究界当前和未来的需求。 该项目将通过与橡树岭国家实验室的科学人员合作，确保高纯度 Th-229 的长期来源。 使用这种新型高纯度 Th-229 示踪剂进行的研究将包括对社会具有明确效益的各种主题，例如了解第四纪晚期的气候和海平面变化、破译活火山的岩浆过程、评估长期的潜在地点放射性废物的储存，以及地下水中放射性核素迁移的特征。 这些研究人员使用的 Th-229 示踪剂的纯度对数据质量以及此类项目的结果具有深远的影响。 对于使用等离子体电离质谱进行测量的未来潜力来说，这是一个特别重要的问题，这使得突破地质材料 U 和 Th 系列同位素分析的准确度和精密度极限成为可能。 最终，该项目还将提高这些研究人员在地球化学领域教授和培训本科生，特别是研究生的能力。***