International Research Fellowship Program: Search for Isotopes from Recent Nearby Supernova with Nearby Accelerator Mass

国际研究奖学金计划：利用附近加速器质量从最近附近的超新星中搜索同位素

• 批准号: 0502034
• 负责人: Jonathan Levine
• 金额: --
• 依托单位: Levine, Jonathan C
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-15 至 2006-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0502034&HistoricalAwards=false
• 关键词: International; Research; Fellowship; Program; Search

0502034LevineThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a three-month research fellowship by Dr. Jonathan Levine to work with Drs. Jorge O. Fernandez-Niello and Andres Arazi at Laboratorio TANDAR, Comision Nacional de Energia Atomica Phycics in Buenos Aires, Argentina.Most meteorites that reach the Earth survive for a few thousands years, at most, before they are destroyed by erosion and weathering. The so-called "terrestrial ages" of particular meteorites, or the duration of time since a meteorite has fallen to Earth, can be calculated from the measured abundance of radioactive isotopes. Carbon-14 is used extensively for this purpose. However, some meteorites are old enough that no detectable carbon-14 remains. These rare meteorites are especially interesting for questions about how the fall-rate of different types of meteorites has changed over the last several tens of thousands of years, as well as for geological studies of the slowly-eroding regions where they are found. The investigators are attempting to determine the terrestrial ages of such old meteorites from the abundance of radioactive nickel-59 (half-life 76,000 years). They search for nickel-59 by accelerator mass spectrometry, which allows them to detect nickel-59 abundances lower than one part per trillion of the total nickel endowment of a specimen. They are working to further improve the sensitivity, by improving chemical separation, mass resolution, and ionic detection techniques. Nickel-59 offers greatest promise for dating meteorites collected from geological settings of extraordinary preservation, such as Antarctica, where meteorites are eroded much more slowly than elsewhere because of the dry climate.

0502034莱文国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。 该计划的奖项提供了联合研究的机会，以及使用国外独特或互补的设施，专业知识和实验条件。该奖项将支持Jonathan Levine博士与Jorge O. Fernando-Niello和Andres Arazi在阿根廷布宜诺斯艾利斯的国家原子能物理委员会的TANDAR实验室。大多数到达地球的陨石在被侵蚀和风化破坏之前最多能存活几千年。 特定陨石的所谓“地球年龄”，或陨石坠落到地球的持续时间，可以从测量的放射性同位素丰度计算出来。 碳-14被广泛用于这一目的。 然而，有些陨石已经足够古老，没有可检测到的碳-14残留。 这些稀有陨石对于研究不同类型陨石在过去数万年中的坠落速度变化以及对发现它们的缓慢侵蚀区域的地质研究特别有意义。研究人员正试图从放射性镍-59的丰度（半衰期为76，000年）确定这些古老陨石的地球年龄。 他们通过加速器质谱法寻找镍-59，这使得他们能够检测到镍-59的丰度低于样本中总镍含量的万亿分之一。 他们正在努力通过改进化学分离、质量分辨率和离子检测技术来进一步提高灵敏度。 镍-59最有希望测定从保存异常完好的地质环境中收集的陨石的年代，例如南极洲，由于气候干燥，陨石的侵蚀速度比其他地方慢得多。