MRI-R2: Development of A High-Performance Gas-Filled Cyclotron Stopper

该奖项是根据2009年《美国复苏和再投资法案》(公法111-5)资助的。该奖项将支持密歇根州立大学国家超导回旋实验室(NSCL)开发一种新的独特设备，以捕获核反应中产生的短寿命同位素，这将促进一系列新的核科学。NSCL是美国使用快速弹丸碎片(GeV动能)进行核科学研究的前沿设施，在这些弹丸碎片的热化和精确质量测量方面处于世界领先地位。在过去的四年里，近五分之一的化学元素在NSCL进行了加热和测量。NSCL目前正在这一成功的基础上再接再厉，扩大其对热化弹丸碎片进行精确研究的实验领域，将激光光谱学包括在内，并向前迈出了重要的一步，涉及低能核反应。这项奖励的资金将用于开发用于弹丸碎片的强大的气体阻止概念，特别是用于现有技术难以生产的轻离子和高强度光束。新的气体阻塞器将在回旋式磁铁内的一个巨大的充气室中减缓和热化非常高能量的抛射体碎片。这种充气回旋加速器将能够提供热化离子，而不考虑离子的化学性质，半衰期短至数十毫秒，入射率高。因此，开发一种使用充气反向回旋加速器来减缓、捕获和提取这些困难束流的新技术将产生广泛的影响，因为：(1)提供NSCL下一代精确质量测量和激光光谱分析所需的广泛束流，以及(2)允许使用世界其他地方没有的短寿命强同位素束流对低能核反应进行独特研究。这项拟议的工作将由密歇根州立大学、理工学院(在日本)和GSI(在德国)的研究人员合作进行，其中包括在三年的时间尺度上创造一个突破设备。这种合作在工作的各个方面都有重要的专门知识，该项目将促进这些实验室之间的技术和科学交流。回旋加速器将在NSCL建造，并安装在一条专用的束流线路上，用于全面测试，并随后连接到低能量竞技场和再加速器。这种仪器将是许多学生和博士后学者基于NSCL的研究计划的关键组成部分。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This award will support the development of a new and unique device, at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, to capture short-lived isotopes produced in nuclear reactions that will facilitate a wide range of new nuclear science. The NSCL is the forefront facility in the US for nuclear science using fast projectile fragments (GeV kinetic energies) and is the world leader in the thermalization and precision mass measurements of these projectile fragments. Nearly a fifth of the chemical elements have been thermalized and measured at the NSCL in the last four years. The NSCL is currently building on this success by expanding its experimental arena for precision studies with thermalized projectile fragments to include laser spectroscopy and, in a major step forward, to low-energy nuclear reactions. Funds from this award will be used to develop a robust gas-stopping concept for projectile fragments, particularly for light-ion and high intensity beams that will be difficult to produce with existing technology. The new gas stopper will slow down and thermalize very high-energy projectile fragments in a large gas filled chamber inside a cyclotron-type magnet. Such a gas-filled cyclotron stopper will be able to provide thermalized ions without regard to their chemical nature, with half-lives as short as tens of milliseconds, and at high incident rates. The development of a novel technique to slow down, capture, and extract these difficult beams using a gas-filled reverse-cyclotron will thus have broad impact by: (1) providing the wide range of beams required for the next generation of precision mass measurements and laser spectroscopy at the NSCL, and (2) allowing unique studies of low-energy nuclear reactions with intense beams of short-lived isotopes that are not available anywhere else in the world. The proposed work will be performed by a collaboration of researchers at MSU, RIKEN (in Japan) and GSI (in Germany) and includes the creation of a break-through device on a three-year timescale. This collaboration has significant expertise in all aspects of the work and the project will foster the technical and scientific exchange among these laboratories. The cyclotron-stopper will be constructed at the NSCL and installed on a dedicated beam line for full-scale testing and subsequent connection to the low-energy arena and re-accelerator. This instrumentation will be a critical component of the NSCL-based research program of many students and postdoctoral scholars.