Laser Excitation of the 229-Th Nuclear Isomer

第 229 个核异构体的激光激发

• 批准号: 1309481
• 负责人: Alexander Kuzmich
• 金额: $ 44万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2013-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1309481&HistoricalAwards=false
• 关键词: Laser; Excitation; 229; Th; Nuclear

While typical nuclear excitation energies are in the keV to MeV range, there are several exceptional cases where the excitation energies are much lower. The subject of this project is the thorium-229 isotope, which, uniquely, has an excited state in the UV optical spectrum. Several experimental searches for optical emission in this range undertaken in the past ten years were unsuccessful or inconclusive. In addition to searching in the wrong energy region, the searches were challenged by the narrow linewidth of the nuclear transition. In this work, an alternative electron-bridge transition will be employed for the initial laser excitation of the nuclear isomer level in thorium-229. The nuclear transition is likely to be exceptionally sensitive to the variation of fundamental constants, due to the interplay of the strong and electroweak interactions inside this nucleus. After the isomer level is found, the sensitivity of the nuclear transition to time variation of the fine structure constant will be determined.This research will have broad impact across several areas of physics and technology. Laser excitation and coherent manipulation of nuclear states would establish a new bridge between atomic and nuclear physics, with the promise of new levels of accuracy for frequency metrology. The project will involve extensive graduate and undergraduate student training and participation.

尽管典型的核激发能在MEV范围内的KEV中，但在几种特殊情况下，激发能量要低得多。该项目的主题是Thorium-229同位素，它在紫外光谱中具有激发态。在过去十年中进行的此范围内的光学排放的几次实验搜索是没有成功或尚无定论的。除了在错误的能源区域进行搜索外，搜索还受到核过渡的狭窄线宽的挑战。在这项工作中，将采用一种替代电子桥梁过渡，用于thorium-229中的核异构体水平的初始激光激发。由于该核内强和电动的相互作用的相互作用，核转变可能对基本常数的变化非常敏感。找到异构体水平后，将确定核过渡到良好结构常数的时间变化的敏感性。这项研究将对几个物理和技术领域产生广泛的影响。激光激发和对核状态的连贯操作将在原子物理学和核物理学之间建立一个新的桥梁，并有望在频率计量学方面具有新的准确性水平。该项目将涉及广泛的研究生和本科生培训和参与。