Determination of Thorium-230 and Protactinum-231 in Ocean Waters by Isotope-Dilution Mass Spectrometry

同位素稀释质谱法测定海水中的钍 230 和镤 231

• 批准号: 9415562
• 负责人: Michael Bacon
• 金额: $ 47.66万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-01-01 至 1998-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9415562&HistoricalAwards=false
• 关键词: Determination; Thorium; 230; Protactinum; 231

9415562 BACON The primary objective of this project is to develop a new procedure for the chemical analysis of seawater that will permit the naturally occurring radionuclides thorium-230 (half-life 75,000 years) and protactinium-231 (half-life 32,000 years) to be measured in the same sample. The new procedure will employ mass- spectrometric techniques of measurement and is intended to replace currently used procedures based on alpha-spectrometry. It is expected that significant improvements in sensitivity, precision, and speed of analysis will be realized. The reasons for the special focus on this particular pair of radionuclides are that (1) they provide unique information about the flux of particular matter in the oceans and the scavenging processes that regulate the level of a number of chemical species, and (2) they can be important tools for deciphering the sedimentary record of climate over the last glacial cycle. Improved data on the distributions of the two radionuclides will permit better testing and validation of their use as oceanographic tracers. After the new procedures are perfected, a study of the distribution of thorium-230 and protactinium-231 in the western North Atlantic Ocean will be undertaken. This part of the project will provide a full-scale demonstration of the new procedures and is expected to reveal features of the distribution that cannot presently be resolved.

小行星9415562 该项目的主要目标是制定一种新的海水化学分析程序，以便能够在同一样品中测量天然放射性核素钍-230（半衰期75 000年）和钚-231（半衰期32 000年）。新程序将采用质谱测量技术，并打算取代目前使用的基于α-光谱法的程序。预计将实现灵敏度、精确度和分析速度的显著提高。特别关注这对放射性核素的原因是：（1）它们提供了关于海洋中特定物质通量和调节一些化学物质水平的清除过程的独特信息;（2）它们可以成为解读末次冰期气候沉积记录的重要工具。 改进关于这两种放射性核素分布的数据将有助于更好地测试和验证它们作为海洋示踪剂的用途。 在新程序完善之后，将对北大西洋西部钍-230和<$-231的分布进行研究。 项目的这一部分将提供新程序的全面演示，并预计将揭示目前无法解决的分布特征。