Ground state nuclear structure properties studied via laser interactions

通过激光相互作用研究基态核结构特性

• 批准号: SAPPJ-2019-00056
• 负责人: Buchinger, Fritz
• 金额: $ 9.47万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739461
• 关键词: Ground; state; nuclear; structure; properties

Fast beam, collinear laser spectroscopy has long been seen as a highly sensitive method with which to probe nuclear structure of ground and long lived isomeric states. When coupled to radioactive beam facilities that are capable of producing long chains of isotopes of many chemical elements these techniques can provide invaluable information on the evolution of nuclear structure from stability out to the drip lines. The use of high resolution laser spectroscopy of the atomic electrons, which in turn directly probe the nucleus, leads to a non-destructive, highly sensitive probe that can extract subtle nuclear effects in a largely model independent way. In general these methods allow for the unambiguous determination of the nuclear spin, magnetic dipole and electric quadrupole moments along with the changes in the root mean squared charge radii along a nuclear chain. In certain cases it is also possible to extract higher order affects such as the nuclear magnetisation distribution, magnetic octupole moments and the absolute charge radii. As such the results from the work have a far reaching impact across many areas of nuclear physics ranging from nuclear structure through weak nucleon-nucleon interactions to fundamental symmetry tests of the standard model. This proposal aims to continue and expand upon a project that has been ongoing for several years at the ISAC facility at TRIUMF. Using a combination of the rare isotope beams available as well as existing infrastructure makes for a system that has unique capabilities. For example the continuing use of Titan's radio frequency quadrupole buncher to convert the continuous ISAC beam into short bunches with properties that are independent of the ion source that produced them has led to an increase in sensitivity of over four orders of magnitude over traditional systems. Ongoing technical development on both the methods of data-acquisition as well as laser and atomic manipulation, which forms part of this proposal, has already led to further increases in sensitivity and are currently being replicated at other facilities around the world. The versatility of the technique is shown by the range of isotopes and nuclear physics properties that it is proposed to study. In the vicinity of 32Na it is proposed to investigate the ground state properties of very neutron rich Al, Mg and Na isotopes in order to better understand the nuclear structure of this region as well as investigate the possibility of the existence of long lived isomeric states. In contrast measurements of the ground and isomeric states in neutron deficient Fr and At isotopes will not only further enhance our general knowledge of this region but could also be used to investigate the specific changes in the distribution of magnetisation within the nucleus across this region of the chart.

快束共线激光光谱长期以来一直被视为探测基态和长寿命异构态核结构的高灵敏度方法。当与能够产生许多化学元素的长同位素链的放射性束设施相结合时，这些技术可以提供有关核结构从稳定到滴水线的演变的宝贵信息。使用原子电子的高分辨率激光光谱，进而直接探测原子核，产生一种非破坏性、高灵敏度的探针，可以以很大程度上独立于模型的方式提取微妙的核效应。一般来说，这些方法可以明确确定核自旋、磁偶极子和电四极矩以及沿核链的均方根电荷半径的变化。在某些情况下，还可以提取更高阶的影响，例如核磁化强度分布、磁八极矩和绝对电荷半径。因此，这项工作的结果对核物理的许多领域产生了深远的影响，从核结构到弱核子-核子相互作用，再到标准模型的基本对称性测试。该提案旨在继续并扩展 TRIUMF 的 ISAC 设施已持续数年的项目。结合使用可用的稀有同位素束以及现有基础设施，可以形成具有独特功能的系统。例如，继续使用 Titan 的射频四极聚束器将连续 ISAC 光束转换为短束，其特性与产生它们的离子源无关，从而使灵敏度比传统系统提高了四个数量级以上。数据采集​​方法以及激光和原子操纵的持续技术发展是该提案的一部分，已经导致灵敏度进一步提高，目前正在世界各地的其他设施中复制。该技术的多功能性通过其拟研究的同位素范围和核物理特性得到了体现。在 32Na 附近，建议研究非常富含中子的 Al、Mg 和 Na 同位素的基态性质，以便更好地了解该区域的核结构并研究长寿命异构态存在的可能性。相比之下，对缺中子 Fr 和 At 同位素的基态和异构态的测量不仅将进一步增强我们对该区域的一般了解，而且还可以用于研究图表中该区域的核内磁化强度分布的具体变化。