Operation of the NSCL as a National User Facilty & Research Program

该奖项提供资金，以运营和维护密歇根州立大学(MSU)的国家超导回旋实验室(NSCL)作为国家用户设施，支持国外在核结构、核天体物理、基本参数和对称性的精确测量以及加速器科学方面的计划，并支持MSUnuckerScience教员的研究计划。该奖项将继续保持NSCL在这些领域的国内和国际领先地位，支持其作为国家主要用户设施致力于稀有(短寿命)同位素的生产和研究。该奖项还将允许NSCL利用最近投入使用的世界唯一的ReA3光束线加速器新获得的科学机会，该加速器能够在尚未用稀有同位素探索的与超新星和原子核结构有关的能量上进行实验。这些机会与2015年NSAC远景计划所述的科学目标有很大的重叠，并形成了通往下一代加速器FRIB的连贯轨迹，该加速器正在NSCL现场建造。大约80%在NSCL进行研究的人来自密歇根州立大学以外的地方，NSCL的支持将服务于广泛的科学界。作为美国最大的基于大学的核物理用户设施，NSCL将继续为培养下一代核科学家、加速器物理学家和工程师提供独特的手工学习机会。在美国授予的所有核科学博士学位中，约有10%是基于国家科学研究中心开展的研究，每年约有100名本科生积极参与国家科学研究中心的研究。该实验室开展了广泛的外联活动，包括每年为4000多人参观设施。此外，研究还在应用领域进行，如癌症放射治疗的新工具的开发，电离辐射如何影响DNA的系统研究，复合材料中新的原子和纳米结构的发现，以及国土安全。使用NSCL的两个耦合超导回旋加速器CCF来加速稳定同位素的强流。当光束击中静止的目标时，原子核分裂成碎片。每个碎片本身就是一个较轻的原子核，而许多碎片本身就是短暂的同位素。特定实验所选择的同位素是通过碎片分离器来选择的：一种只允许特定电荷和质量通过其路径的磁环。从碎片分离器中出现的原子核形成了一种新的束流，用于研究各种核反应。NSCL有七个终端站，可以将同位素束定向到这些终端站，每个终端站都有各种目标和探测器系统来执行所需的测量。NSCL还可以使用稠密气体使不稳定的同位素完全停止；这反过来又使得使用原子和分子物理中也使用的捕捉技术进行质量测量等实验成为可能。ReA3光束线加速器将停止的同位素重新加速到低能量(远低于飞行中的水平)，用于对核天体物理非常重要的实验，包括恒星能量产生的起源以及恒星诞生和死亡的动力学。这些加速的束流被定向到一个终点站，用于各种核反应。

This award provides funds to operate and maintain the National Superconducting CyclotronLaboratory (NSCL) at Michigan State University (MSU) as a national user facility, to support abroad program in nuclear structure, nuclear astrophysics, precision measurements of fundamentalparameters and symmetries, and accelerator science, and to support the research programs of MSUnuclear science faculty. The award will continue NSCL's national and international leadership inthese areas by supporting its operation as the nation's premier user facility dedicated to theproduction and study of rare (short-lived) isotopes. The award will also allow the NSCL to exploitthe scientific opportunities newly available with the recently commissioned and world-uniqueReA3 beamline accelerator that enables experiments at energies that have not been explored withrare isotopes and are relevant to supernovae and the structure of nuclei. These opportunities havestrong overlap with the stated scientific goals of the 2015 NSAC Long Range Plan, and form acoherent trajectory towards the next generation accelerator, FRIB, which is being constructed onthe NSCL site. Approximately 80% of those conducting research at the NSCL are from outsideMSU and the support of NSCL will serve a broad scientific community. As the nation's largestuniversity-based user facility for nuclear physics, the NSCL will continue to provide unique handsonlearning opportunities for educating the next generation of nuclear scientists, acceleratorphysicists, and engineers. Approximately 10% of all nuclear science PhDs awarded in the UnitedStates are based on research carried out at the NSCL, and approximately 100 undergraduatestudents are actively involved in research at the NSCL each year. The laboratory has extensiveoutreach activities, including facility tours for over 4000 people each year. In addition, researchis carried out in application areas such as development of new tools for radiation treatments ofcancer, systematic studies of how ionizing radiation affects DNA, discovery of novel atomic andnanostructures in complex materials, and homeland security.Intense beams of stable isotopes are accelerated using the NSCL's two coupled superconductingcyclotrons, the CCF. The nuclei split into fragments as the beam strikes a stationary target. Eachfragment is itself a lighter nucleus, and many fragments are themselves short-lived isotopes. Theisotope of choice for a specific experiment is selected by means of a fragment separator: a magneticchicane that permits only a specific charge and mass through its pathway. The nuclei emergingfrom the fragment separator form a new beam for use in studying various nuclear reactions. TheNSCL has seven end stations to where the isotope beam can be directed and each end station hasa variety of target and detector systems to carry out the desired measurements. The NSCL canalso bring the unstable isotopes to a complete stop using a dense gas; this in turn enablesexperiments such as mass measurements using trapping techniques also used in atomic andmolecular physics. The ReA3 beamline accelerator reaccelerates stopped isotopes to low energies(well below in-flight levels) for experiments that are important for nuclear astrophysics, includingthe origin of stellar energy production as well as the dynamics of the birth and death of stars. Thereaccelerated beams are directed to one of the end stations for use in various nuclear reactions.