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.

快束共线激光光谱一直被认为是探测基态和长寿命同分异构体核结构的一种高灵敏度方法。当与能够产生许多化学元素的长链同位素的放射性束流设施相结合时，这些技术可以提供关于核结构从稳定到滴漏的演变的宝贵信息。原子电子的高分辨率激光光谱学的使用，反过来直接探测原子核，导致了一种非破坏性的，高灵敏度的探针，可以以一种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，这些方法允许明确地确定核自旋，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，也可以提取高阶影响，如核磁化分布、磁八极矩和绝对电荷半径。因此，这项工作的结果对核物理学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。该提案旨在继续和扩大在TRIUMF的ISAC设施进行了数年的项目。利用稀有同位素光束和现有基础设施的组合，使系统具有独特的功能。例如，继续使用泰坦的射频四极杆聚束器将连续的ISAC光束转换成具有独立于产生它们的离子源的特性的短束，这使得灵敏度比传统系统提高了四个数量级以上。在数据获取方法以及激光和原子操作方法方面正在进行的技术发展，构成了这项建议的一部分，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进行复制。该技术的多功能性表明，它被提议研究的同位素和核物理性质的范围。在32Na附近，为了更好地了解这一区域的核结构以及研究长寿命同分异构体存在的可能性，建议研究中子非常丰富的Al、Mg和Na同位素的基态性质。相比之下，测量缺中子的Fr和At同位素的基态和同分异构体态不仅会进一步提高我们对该区域的一般认识，而且还可以用来研究图中该区域核内磁化分布的具体变化。