Laser system to study exotic nuclear structure

对于原子核来说，没有什么比它的形状和大小更基本的性质了。探测并因此检验核结构从稳定状态演变的最灵敏的方法之一是利用原子核的本质与周围的原子电子相互作用这一事实。高精度的激光探测电子能量总是以一种与模型无关的方式产生大量的信息。这种方法也是获得短寿命原子核自旋绝对值的为数不多的方法之一，这个参数是许多核模型所依赖的基础。这些测量可以在几乎整个核素图表上进行，从最轻的He和Li同位素到TRIUMF可以提供的最重的元素。它们还覆盖了整个核结构，从稳定的、相对球形的核，沿着稳定的山谷一直到向滴线方向的极端变形。虽然原则上从这些测量中推断出的是纯粹的核结构信息，但结果对许多其他物理领域产生了影响，这些领域通常被用作输入、测试或支持测量。使用这些信息的主题范围从轻核核力的从头计算到粒子物理标准模型和ckm矩阵统一性的测试，再到用于高精度宇称非守恒实验的重核核磁不均匀分布的研究。目前，TRIUMF的激光光谱学合作有8个自己的提案在TRIUMF被接受，并且是另外几个提案的合作者。在这8个中，有6个依赖于一个老化的激光系统，该系统的核心是一个比小组中任何一个学生都老的氩离子激光器。在过去的一年里，这个系统由于老化以及对TRIUMF过度征税的冷却和电力系统的依赖而失败。（该系统每分钟需要超过6加仑的水通过，以去除超过60千瓦的多余热量。）这是一个现代化的，全固态激光系统的要求，以取代失败的系统，从而允许高冲击实验继续运行。

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.