MRI: Acquisition of a Frequency Quadrupled Titanium Sapphire Laser

非技术描述：这笔拨款支持史密斯学院（一所本科女子文理学院）购置激光系统。该系统将推动两个主要发展，第一个是下一代技术“原子陷阱痕量分析（ATTA）”，该技术有望显著提高美国监测已知和可疑核再处理地点活动的能力，以及分析气候历史研究的冰芯样本的能力。第二个发展涉及到中性铍的几个能级的高精度测量，这提高了我们对原子理论的理解，并有助于推进基础科学。技术描述：要用氪进行痕量分析（支持上文所述的第一个发展），首先需要将氪原子转移到亚稳态以进行激光冷却和捕获。目前，大多数原子阱痕量分析测量的精度受到产生亚稳原子束的方法的限制。用这里资助的光源取代这些方法将导致重大的进步，如检测效率的提高，样本量的减少，以及消除交叉样本污染。铍项目（上文所述的第二个发展）旨在改进几个能级和电离阈值的实验测量。目前，理论估计的能级比实验测量的精度高一个数量级以上。这些改进的实验结果将描述各种理论模型，测试量子电动力学，并有助于确定铍的核电荷半径。

Non-technical description:This grant supports the acquisition of a laser system at Smith College, an undergraduate women's liberal arts college. This system will enable two main developments, the first of which is the next generation of a technique called "Atom Trap Trace Analysis (ATTA)" which is expected to significantly improve the ability of the U.S. to monitor activity at known and suspected nuclear reprocessing sites, as well as to analyze ice core samples for climate history studies. The second development involves the measurement of several energy levels of neutral beryllium to high precision, which improves our understanding of atomic theory and helps to advance basic science. Technical description:To perform trace analysis with krypton (in support of the first development described in the paragraph above), krypton atoms first need to be transferred to a metastable state for laser cooling and trapping. The precision of most Atom Trap Trace Analysis measurements is currently limited by the methods used to produce the metastable atomic beams. Replacing these methods with the optical source funded here will lead to significant advances such as an increase in detection efficiency, a decrease in sample size, and elimination of cross-sample contamination. The beryllium project (the second development described in the paragraph above) aims to improve experimental measurements on several energy levels and the ionization threshold. Currently, theoretical estimates of the energy levels have more than an order of magnitude more precision than experimental measurements. These improved experimental results will delineate various theoretical models, test quantum electrodynamics, and help determine the nuclear charge radius of beryllium.