Nuclear Reactions with Short-lived Nuclear Beams

拟议的项目将涉及利用短寿命放射性核束（RNB）研究核反应，同时开发仪器、技术和设备，以促进一般的核研究，特别是短寿命放射性核束研究。具体的实验将着重研究接近核稳定极限的富中子和富质子核的结构和反应机理。这些研究是一个非常成功的项目的延续，旨在阐明在稳定性极限弱束缚体系中出现的外来核晕结构对各种核反应的不寻常影响。该项目的另一部分涉及正常恒星、超新星爆炸和其他极端天体物理环境中元素的合成。在适当的情况下，这项工作将在圣母大学（UND），橡树岭国家实验室（ORNL），也可能在国家超导回旋加速器实验室（NSCL）进行。最后，将与德克萨斯农工大学（TAMU）的一个小组合作研究镄和trans-Fermium同位素的生产和性质，并进行其他使用中能重离子反应的实验。这项工作将涉及使用UM BigSol 7T螺线管设备，该设备已被重新安置到TAMU K500超导回旋加速器实验室的专用光束线上，现在正在运行。拟议的技术发展项目包括升级密歇根大学（UM）的双al6t超导螺线管离子光学系统（TwinSol），目前在UND。与此相关，提出了一种扩展粒子-中子符合探测器阵列的构造。这将升级现有的低能量RNB设施，以便更详细地研究已有光束的核反应，并开发和使用新的高原子序数(Z)光束。这项提议的研究将对研究生、本科生和高中教育产生影响，也将对技术素养劳动力的发展和超导磁体技术的商业应用产生影响。该项目将涉及来自密歇根大学和圣母大学的研究生和本科生，以及来自中西部其他几所学校（主要是本科生）的教职员工和学生，这些学校靠近密歇根大学和UND。这些学生在使用先进的、最先进的计算方法、核加速器、辐射探测器、真空和低温技术以及超导离子光磁系统方面的实践培训，已经对培养一支具有技术素养的科学队伍产生了重要影响。过去参与该项目的研究生和博士后研究人员目前在国家安全和医学物理相关项目中担任要职。还有一些人拥有终身或终身学术职位，通常是在拥有积极研究参与计划的本科院校。目前的提案将允许延续这一传统，并启动一项新的试点计划，该计划将涉及来自密歇根州新布法罗社会经济困难学区的高中生进行物理相关研究。这项拟议的研究还将有助于仪器和技术的发展，以及未来研究人员的发展，这将是下一代RNB设施，特别是计划中的美国稀有同位素加速器（RIA）所需要的。最后，具有特殊设计特征的精密高场，大口径超导磁螺线管（如轻质，低损耗铝低温恒温器）的发展已经并将继续对技术转移到美国制造的商业磁铁系统产生影响，这些系统用于各种重要应用。

The proposed project will involve the study of nuclear reactions utilizing short-lived radioactive nuclear beams (RNBs) together with the development of instrumentation, techniques, and apparatus to facilitate nuclear research in general and RNB studies in particular. Specific experiments will emphasize the investigation of the structure and reaction mechanisms of neutron- and proton-rich nuclei near the limits of nuclear stability.These studies are a continuation of a very successful program to elucidate the unusual effects that the exoticnuclear halo structure, which appears for weakly-bound systems at the limits of stability, has on variousnuclear reactions. Another part of the project relates to the synthesis of elements in normal stars, as wellas in supernova explosions and other extreme astrophysical environments. As appropriate, the work willbe carried out at the University of Notre Dame (UND), Oak Ridge National Lab (ORNL), and possiblyat the National Superconducting Cyclotron Laboratory (NSCL) . Finally, the production and properties ofFermium and trans-Fermium isotopes will be studied in collaboration with a group at Texas A&M University(TAMU), and other experiments using heavy-ion reactions at intermediate energies will be carried out. Thiswork will involve the use of the UM BigSol 7T solenoid apparatus, which has been relocated to a dedicatedbeamline at the TAMU K500 superconducting-cyclotron laboratory and is now operational.Proposed technology development projects include an upgrade of the University of Michigan (UM) dual6T superconducting solenoid ion-optical system (TwinSol ), presently at UND. Related to this, the construc-tion of an expanded particle-neutron coincidence detector array is proposed. This will upgrade the existinglow-energy RNB facility to allow for more detailed studies of nuclear reactions with already-available beams, and for the development and use of new, higher-atomic-number (Z) beams.The proposed research will have an impact on graduate, undergraduate, and high school education, aswell as on the development of a technologically- literate work force and the commercial applications ofsuperconducting magnet technology. The project will involve graduate and undergraduate students from theUniversity of Michigan and the University of Notre Dame, together with faculty members and students fromseveral other (primarily undergraduate) schools located in the Midwest, in close proximity to UM and UND.The hands-on training of these students in the use of advanced, state-of-the-art computational methods,nuclear accelerators, radiation detectors, vacuum and cryogenic techniques, and superconducting ion-opticalmagnetic systems has already had an important impact on the development of a technologically-literatescientific workforce. Several of the graduate students and postdoctoral research associates who workedon this project in the past are currently employed in highly-responsible positions on national-security andmedical-physics related projects. Still others hold tenured or tenure-track academic positions, often atprimarily-undergraduate institutions with active research participation programs. The current proposal will allow for the continuation of this tradition, and for the initiation of a new pilot program that will involvehigh-school students from the socioeconomically-challenged New Buffalo, MI school district in physics-related research.This proposed research will also help in the development of instrumentation and techniques, together withfuture research personnel, that will be needed for the next generation of RNB facilities, and in particularfor the planned US-based Rare Isotope Accelerator (RIA) . Finally, the development of precision high-field, large-bore superconducting magnetic solenoids with special design features (such as light-weight, low-loss aluminum cryostats) has had and will continue to have an impact on technology transfer to US-builtcommercial magnet systems used in a wide variety of important applications.