Development of a Low Energy Neutron Scattering Facility

低能中子散射设施的开发

• 批准号: 0320627
• 负责人: Paul Sokol
• 金额: $ 199.22万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-15 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0320627&HistoricalAwards=false
• 关键词: Development; Low; Energy; Neutron; Scattering

This project involves the construction of a Low Energy Neutron Scattering (LENS) facility at the Indiana University Cyclotron Facility (IUCF). LENS will use the existing linear accelerator at IUCF to produce 11 MeV protons, generating a pulsed neutron beam through (p, n) reactions on a Be target. Not only is LENS a novel and relatively inexpensive pulsed cold neutron source, but also - when completed in 2005 - LENS will enable the design of novel neutron instrumentation for small angle scattering, a broad program of research in materials science and biology, the development of novel neutron sources and moderators, and the education and training of the next generation of neutron scientists in the United States. LENS will also serve as a regional user facility that will be particularly well-suited for high-risk experiments and feasibility studies. The particular aspects of LENS that are being completed through this project are (1) modifications and upgrades of the linear accelerator, including a beam-switching system and a transfer beam line; (2) construction of the target, moderator, and neutron reflector; (3) construction of a conventional small-angle neutron scattering (SANS) instrument; and (4) development of cold neutron moderators. The flux of cold neutrons that will be produced when LENS is completed will be comparable to that of the Intense Pulsed Neutron Source (IPNS) currently in operation at Argonne National Laboratory. With the high-powered Spallation Neutron Source (SNS) at Oak Ridge National Laboratory scheduled for completion in 2006, the construction of LENS is particularly timely. Small-angle neutron scattering (SANS), using neutrons with relatively low energies (so-called "cold" neutrons), allows scientists to study aspects of materials and biological substances that are not accessible using other types of radiation, such as X-rays. In particular, neutrons are sensitive probes of the structure and dynamics of atoms and molecules. For this reason, they have now become widely used, not only in physics, chemistry, and materials science, but also in biology, earth science, and engineering. With the completion of the Spallation Neutron Source (SNS), neutrons promise to be used increasingly as sensitive and versatile scientific probes. However, the relative dearth of neutron sources in the United States up to this time has contributed to the depletion of the ranks of U. S. neutron scientists. The Low Energy Neutron Scattering (LENS) facility at Indiana University will help to correct this situation by providing in a university setting the opportunity for the education and training of the next generation of neutron scientists, including those from fields such as biology that have not traditionally employed neutron scattering techniques to the full extent of their usefulness. In addition, LENS will serve as a regional user facility, enabling investigators from other institutions - including industry - to make use of neutron-scattering methods. LENS will also serve as the only U. S. testbed for the development of cold neutron moderators - the devices that slow down the neutrons to the low energies needed for materials investigations and biological studies and which are thus key parts of any neutron-scattering facility - and for potentially high-payoff experiments that are too risky to justify time on larger pulsed-neutron sources.

该项目涉及在印第安纳大学回旋加速器设施 (IUCF) 建设低能中子散射 (LENS) 设施。 LENS 将使用 IUCF 现有的直线加速器产生 11 MeV 质子，通过 Be 靶上的 (p, n) 反应产生脉冲中子束。 LENS 不仅是一种新颖且相对便宜的脉冲冷中子源，而且 - 当 2005 年完成时 - LENS 将能够设计用于小角度散射的新型中子仪器，这是材料科学和生物学领域的一项广泛的研究计划，新型中子源和慢化剂，以及美国下一代中子科学家的教育和培训。 LENS 还将作为区域用户设施，特别适合高风险实验和可行性研究。 通过该项目正在完成的LENS的具体方面是（1）直线加速器的修改和升级，包括光束切换系统和传输光束线； (2)靶、慢化体和中子反射器的建造； (3)常规小角中子散射(SANS)仪器的构建； (4)冷中子慢化剂的发展。 LENS 建成后产生的冷中子通量将与阿贡国家实验室目前运行的强脉冲中子源（IPNS）相当。 随着橡树岭国家实验室的高能散裂中子源 (SNS) 计划于 2006 年竣工，LENS 的建设显得尤为及时。 小角中子散射 (SANS) 使用能量相对较低的中子（所谓的“冷”中子），使科学家能够研究使用其他类型的辐射（例如 X 射线）无法达到的材料和生物物质的各个方面。 特别是，中子是原子和分子结构和动力学的敏感探针。 因此，它们现在不仅在物理、化学和材料科学中得到广泛应用，而且在生物学、地球科学和工程学中也得到广泛应用。 随着散裂中子源（SNS）的完成，中子有望被越来越多地用作敏感和多功能的科学探测器。 然而，迄今为止美国中子源的相对缺乏导致了美国中子科学家队伍的枯竭。 印第安纳大学的低能中子散射（LENS）设施将帮助纠正这种情况，在大学中为下一代中子科学家提供教育和培训的机会，包括来自传统上没有的生物学等领域的中子科学家。充分利用中子散射技术的用处。 此外，LENS 将作为区域用户设施，使其他机构（包括工业界）的研究人员能够利用中子散射方法。 LENS 还将作为美国唯一开发冷中子慢化器的试验台，冷中子慢化器是一种将中子减速到材料研究和生物学研究所需的低能量的装置，因此是任何中子散射设施的关键部分。潜在的高回报实验风险太大，无法证明在更大的脉冲中子源上投入时间是合理的。