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，以及开发仪器、技术和仪器，以促进一般的核研究，特别是RNB研究。具体的实验将侧重于研究核稳定极限附近富含中子和质子的核的结构和反应机制。这些研究是一个非常成功的计划的继续，该计划旨在阐明在稳定极限的弱束缚系统中出现的异常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以及超新星爆炸和其他极端天体物理环境中元素的合成。这项工作将酌情在圣母大学(UND)、橡树岭国家实验室(ORNL)进行，并可能在国家超导回旋实验室(NSCL)进行。最后，将与德克萨斯农工大学(TAMU)的一个研究小组合作，研究铁和反铁同位素的产生和性质，并将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 BigSol7T螺线管装置，该装置已被重新安置到TAMU K500超导回旋加速器实验室的专用光束线上，现已投入使用。拟议的技术开发项目包括升级目前在UND的密歇根大学(UM)双6T超导螺线管离子光学系统(TwinSol)。与此相关，提出了一种扩展的粒子-中子符合探测器阵列的结构。这将升级现有的低能RNB设施，以便对现有束流的核反应进行更详细的研究，并开发和使用新的、更高原子序数(Z)的束流。拟议的研究将对研究生、本科生和高中教育以及对具有技术素养的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联合国大学。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文化素养的劳动力队伍产生了重要影响。过去参与该项目的几名研究生和博士后研究助理目前受雇于国家安全和医学物理相关项目的高度负责职位。还有一些人担任终身教职或终身教职，通常是在拥有积极研究参与计划的本科生机构。目前的提议将允许延续这一传统，并启动一个新的试点计划，让来自社会经济挑战的密歇根州新布法罗学区的高中生参与与物理相关的研究。这项拟议的研究还将有助于与未来的研究人员一起开发下一代RNB设施所需的仪器和技术，特别是计划中的美国稀有同位素加速器(RIA)。最后，具有特殊设计特点的精密高场、大口径超导电磁螺线管(如轻质、低损耗铝低温恒温器)的开发已经并将继续对美国制造的商用磁体系统的技术转移产生影响，这些系统被用于各种重要的应用。

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.