Nuclear Structure, Astrophysics and Reactions (NuSTAR) at FAIR

新型放射性离子束（RIB）加速器设施的发展正在使核物理发生革命性的变化。英国核物理界已决定，其工作的主要重点将是欧洲最大的设施，即在德国达姆施塔特目前的GSI所在地建造的FAIR（反质子和离子研究设施）综合体。FAIR将在强子、核、原子和激光物理及其应用领域提供独特的机会。FAIR将由一个国际财团建造，并将提供全球无与伦比的能力。它将能够产生所有稳定的化学元素的强束，直到铀，能量范围为1至30 GeV/核子和反质子。短寿命放射性物质束将在碎裂/溅射和裂变反应中产生。这种飞行中设施的优点是能够提供任何同位素，而与元素的化学性质无关，生产过程很快，产生寿命最短，因此也是最奇特的核束。在飞行中的设施中，FAIR将在以下几个方面具有独特性：（一）可以用每核子高达2 GeV的高能RIB进行实验;（二）它将为重核提供最纯净的放射性束;（三）它将是世界上唯一拥有储存环的设施，能够进行新一代独特的实验。努斯塔（核结构、天体物理学和反应）是一个由来自36个国家146个机构的800多名科学家组成的“伞式”合作项目（2007年11月），重点是核物理实验。它包括围绕最先进的探测器系统的九个不同的合作，其共同目标是利用短寿命放射性物质的光束来研究原子核和核物质的性质如何在广泛的同位旋，角动量，温度和密度范围内变化。它将提供极端条件下核多体系统的数据。最终目标是找到一个统一的描述核和核物质的性质。努斯塔将是实现新加速器设施潜力的第一个重大项目，此外，其一些项目将在施工阶段受益于现有加速器正在进行的升级所增加的束流强度，该升级将于2009年完成。努斯塔将使英国核物理界能够解决核结构和核天体物理学中的许多关键问题，这些问题在最近的英国核物理战略文件中概述。特别是，建造阶段的顺利完成将使人们能够考虑以下基本问题：中子滴线在哪里？- 新形式的集体运动会在远离核稳定谷的地方发生吗？- 在非常松散的核系统中是否存在新形式的核物质？- 在高度稀释或富含中子的物质中，量子态的有序性，以及它对核结构和反应的所有影响，是如何改变的？- 在近稳定核中看到的对称性是否也远离稳定，我们是否观察到新的对称性？- 宇宙中的元素和同位素是如何形成的？- 核合成的r-过程的位点在哪里？- 中子星的核状态方程是什么？目前的赠款申请是为了支持英国在FAIR上参与努斯塔。虽然努斯塔有9个实验合作，但英国社区决定将努力集中在它具有科学领先地位的六个方面，并在那里可以利用其技术优势和经验。计划到2013年，我们将准备充分利用FAIR提供的光束范围，并继续我们在核结构物理和天体物理领域的卓越和领导地位。

Nuclear physics is being revolutionised by the development of new radioactive ion beam (RIB) accelerator facilities. The UK nuclear physics community has decided that the principal focus of its efforts will be the largest European facility, the FAIR (Facility for Anti-proton and Ion Research) complex being built in Darmstadt, Germany at the site of the present GSI. FAIR will provide unique opportunities in the fields of hadron-, nuclear-, atomic-, and laser physics, and applications. FAIR is to be built by an international consortium and will provide capabilities unmatched worldwide. It will be able to produce intense beams of all stable chemical elements up to uranium with energies in the range of 1 to 30 GeV per nucleon and also anti-protons. Beams of short-lived radioactive species will be generated in fragmentation/spallation and fission reactions. Such an in-flight facility has the advantages of being able to provide any isotope independently of the chemical properties of the element and the production process is fast, resulting in beams of the shortest-lived, and hence most exotic, nuclei. FAIR will be unique among the in-flight facilities in several ways: (i) experiments can be carried out with RIBs at high energies up to 2 GeV per nucleon; (ii) it will provide the purest radioactive beams for heavy nuclei; (iii) it will be the only facility in the world to have storage rings enabling a new and unique generation of experiments. NuSTAR (Nuclear Structure, Astrophysics and Reactions) is an 'umbrella' collaboration of >800 scientists from 146 institutions in 36 countries (Nov. 2007) focussing on nuclear physics experiments. It comprises nine different collaborations based around state-of-the art detector systems with the common aim to exploit the beams of short-lived radioactive species to study how the properties of nuclei and nuclear matter vary over a wide range of isospin, angular momentum, temperature and density. It will provide data on nuclear many-body systems under extreme conditions. The ultimate goal is to find a unified description of the properties of nuclei and nuclear matter. NuSTAR will be the first major project to realize the potential of the new accelerator facility and, in addition, some of its projects will benefit during the construction phase from the increased beam intensity from the ongoing upgrade to the existing accelerators which will be completed by 2009. NuSTAR will allow the UK Nuclear Physics Community to address many of the key questions in Nuclear Structure and Nuclear Astrophysics, outlined in the recent UK Nuclear Physics Strategy document. In particular the successful completion of the construction phase will permit the following fundamental questions to be considered: - What are the limits of nuclear existence? Where does the neutron-dripline lie? - Do new forms of collective motion occur far from the valley of nuclear stability? - Are there new forms of nuclear matter in very loosely bound nuclear systems? - How does the ordering of quantum states, with all of its consequent implications for nuclear structure and reactions, alter in highly dilute or neutron-rich matter? - Do symmetries seen in near-stable nuclei also appear far from stability and do we observe new symmetries? - How are the elements and isotopes found in the Universe formed? - Where are the sites of the r-process(es) of nucleosynthesis? - What is the nuclear equation of state for neutron stars? The present grant request is to support the UK involvement in NuSTAR at FAIR. Although there are 9 experimental collaborations in NuSTAR, the UK community has decided to concentrate its efforts on the six in which it has a scientific lead and where it can use its technical excellence and experience. It is planned that by 2013 we will be ready to fully utilise the range of beams available at FAIR and to continue our excellence and leadership in the area of nuclear structure physics and astrophysics.