Laser system to study exotic nuclear structure

研究奇异核结构的激光系统

• 批准号: SAPEQ-2014-00005
• 负责人: Pearson, Matthew
• 金额: $ 10.93万
• 依托单位: TRIUMF
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Research Tools and Instruments
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567990
• 关键词: Laser; system; study; exotic; nuclear

There are few properties more fundamental to the atomic nucleus than its shape and size. One of the most sensitive methods of probing and therefore examining the evolution of nuclear structure away from stability is to utilise the fact that the nucleus, by its very nature, interacts with the atomic electrons that surround it. High precision laser probing of the electrons energy invariably yields vast amounts of information in a model independent manner. This method is also one of the few ways available to obtain an absolute value for the spin of short lived nuclei, a parameter that is the basis upon which many nuclear models depend. These measurements can be made across almost the entire chart of the nuclides from the very lightest He and Li isotopes up to the heaviest elements that TRIUMF can provide. They also cover the entirety of nuclear structure from the stable, relatively spherical nuclei that occur along the valley of stability out to the extremes of deformation found towards the drip lines. Whilst in principle it is pure nuclear structure information that is deduced from these measurements the results have an influence in many other areas of physics being routinely used as either inputs, tests or support measurements. Topics where this information is used range from ab-initio calculations of nuclear forces in light nuclei to tests of the standard model of particle physics and the C.K.M. matrix unitarity out to investigations into non uniform distributions of nuclear magnetism within heavy nuclei for high precision Parity non-conservation experiments. The Laser Spectroscopy Collaboration at TRIUMF currently has eight of its own proposals accepted at TRIUMF as well as being a collaborator on several more. Of these eight six relied upon an ageing laser system at the heart of which is an Argon ion laser that is older than any of the students in the group. During the past year this system failed due both to old age as well as a reliance on over taxed cooling and power systems at TRIUMF. (The system requires over six gallons of water a minute passing through in order to remove over sixty kilowatts of excess heat.) This request is for a modern, all solid state laser system to replace the failed system and therefore permit the continued running of high impact experiments.

对于原子核来说，没有什么比它的形状和大小更重要的属性了。探测并检查核结构远离稳定的演化的最敏感方法之一是利用原子核本质上与周围原子电子相互作用的事实。对电子能量的高精度激光探测总是以与模型无关的方式产生大量信息。这种方法也是获得短寿命核自旋绝对值的少数方法之一，该参数是许多核模型所依赖的基础。这些测量几乎可以在整个核素图表上进行，从最轻的 He 和 Li 同位素到 TRIUMF 可以提供的最重元素。它们还覆盖了整个核结构，从沿着稳定谷出现的稳定的、相对球形的核到朝向滴水线的极端变形。虽然原则上它是从这些测量中推导出来的纯核结构信息，但结果对物理的许多其他领域产生影响，通常用作输入、测试或支持测量。使用此信息的主题范围从轻核中核力的从头计算到粒子物理标准模型和 C.K.M. 的测试。矩阵幺正性用于研究重核内核磁性的不均匀分布，以进行高精度宇称非守恒实验。 TRIUMF 激光光谱合作组织目前已接受了 8 项自己的提案，并且成为其他几项提案的合作者。这八人中的六人依赖于老化的激光系统，其核心是氩离子激光器，它比该组中的任何学生都更老。在过去的一年里，该系统由于老化以及对 TRIUMF 过度依赖的冷却和电力系统的依赖而出现故障。 （该系统每分钟需要超过六加仑的水通过，以消除超过六十千瓦的多余热量。）这一要求是需要一个现代化的全固态激光系统来取代故障系统，从而允许继续进行高影响实验。