MRI: Development of a High Accuracy, High Precision Laser System for Measurements of Nuclear Structure and Fundamental Symmetries

MRI：开发用于测量核结构和基本对称性的高精度激光系统

• 批准号: 1228489
• 负责人: Paul Mantica
• 金额: $ 22.3万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1228489&HistoricalAwards=false
• 关键词: MRI; Development; Accuracy; Precision; Laser

A ring-dye laser will be added to the laser infrastructure of the existing BEam COoling and LAser spectroscopy (BECOLA) facility at National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). The ring-dye laser will provide light that cannot be obtained from the existing BECOLA Ti:Sapphire laser system over the visible wavelength range from 550 nm to 780 nm, with a line width of less than 250 kHz. The light from the ring-dye laser can also be combined with the existing frequency doubler to produce deep to near ultra-violet light in the wavelength range from 275 nm to 390 nm. The addition of the ring-dye laser will greatly expand the reach of elements and isotopes accessible to laser spectroscopy and optical pumping with BECOLA. The upgraded BECOLA laser system will provide a means to extend charge radii and nuclear moments measurements of key elements to extremely exotic areas in the nuclear chart. Nuclei in the vicinity of the short-lived radionuclides Ni-78 and Sn-100, which are not accessible for on-line laser spectroscopy studies at present, are specifically targeted. Both Ni-78 and Sn-100 have closed-shell proton and neutron configurations, and such nuclei serve as important cornerstones for refining present-day nuclear structure theories. The study of exotic couplings in the beta decays of radioactive Na-21 and Mg-23, to test the fundamental principles underlying weak interactions, will also be pursued. These measurements will require highly nuclear-polarized beams, that will be produced via optical pumping with circularly-polarized light from the new ring-dye laser. Non-radioactive (stable) ions can be also provided on a daily basis from the off-line ion source of BECOLA for student training, system improvements, and identifying new optical transitions to increase the discovery potential with lasers as a probe of rare isotope beams. The research activities proposed within the scope of this project span the fields of atomic physics, sub-atomic nuclear physics, nuclear chemistry, and fundamental symmetries, providing a unique educational experience for students and post-doctoral research associates at the forefront of the cutting-edge science. Technical advances realized in research plan that greatly enhance both the magnitude and retention times for nuclear polarization may benefit both basic research and imaging applications. The laser optical pumping methods have strong overlap with, e.g., the cutting-edge research on the application of highly-polarized noble gases for lung function imaging.

在密歇根州立大学（MSU）的国家超导性回旋实验室（NSCL）的现有光束冷却和激光光谱（Becola）设施的激光基础设施（Becola）设施的激光基础设施中，将添加环型激光。环染色激光器将提供从现有的Becola Ti：Sapphire激光系统在可见波长范围内从550 nm到780 nm处获得的光，线宽度小于250 kHz。环染色激光器的光也可以与现有的频率加倍相结合，从而在275 nm至390 nm的波长范围内产生深到近紫色的深度。添加环染色激光器将大大扩展与Becola一起使用激光光谱和光学泵送的元素和同位素的覆盖范围。升级后的Becola激光系统将提供一种将电荷半径和核矩测量的方法扩展到核图表中极为异国的区域的方法。目前目前无法使用短寿命放射性核素NI-78和SN-100附近的核，这些核目前无法使用。 NI-78和SN-100都具有封闭壳质子和中子构型，并且这种核是精炼当今核结构理论的重要基石。还将追求对放射性NA-21和MG-23的β衰减中的外来耦合的研究，以测试弱相互作用的基本原理。这些测量值将需要高度核偏振光束，这些光束将通过新的环形激光器的圆形光泵来产生。也可以每天从贝科拉离线离子来源提供非放射性（稳定）离子，用于学生培训，系统改进以及识别新的光学转变，以增加激光器的发现潜力，以探测稀有同位素束的探测。 该项目范围内提出的研究活动涵盖了原子理，亚原子核物理学，核化学和基本对称性的领域，为学生和博士后研究协会提供了独特的教育经验，并在尖端科学的前沿提供了独特的教育经验。 在研究计划中实现的技术进步大大提高了核极化的幅度和保留时间可能会受益于基础研究和成像应用。激光光学泵送方法与高度偏振的贵气体在肺功能成像中的应用有关的尖端研究具有很强的重叠。