Enhanced Performance of Small Angle Neutron Scattering at the McMaster Nuclear Reactor

麦克马斯特核反应堆小角中子散射的增强性能

• 批准号: RTI-2021-00750
• 负责人: Gaulin, Bruce
• 金额: $ 8.89万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718010
• 关键词: Enhanced; Performance; Small; Angle; Neutron

The aim of this Research Tools and Instruments grant application is to enhance the performance of the “Small Angle Neutron Scattering for Nanoscale Materials” (MacSANS) instrument at the McMaster Nuclear Reactor (MNR). This neutron scattering instrument is currently completing construction. When operational in 2021, it will be one of only two neutron scattering instruments in Canada (the other is the MAD neutron diffractometer, also at the MNR). The enhanced performance of the MacSANS instrument, which this RTI grant application will enable, will occur via two modifications to the original design: (1)We will take full advantage of the large detector vessel of the instrument and allow for vertical translation of the 1 m2 position-sensitive neutron detector, by up to 0.5 m. This improvement will extend the instrument's length-scale sensitivity by about 130% by increasing the accessible range of momentum transfer, Q, or scattering angle, range of the instrument by ~ 50%; and (2) We will increase the neutron flux by replacing the polycrystalline lead aggregate filter in the primary flight path of the instrument with a single crystal lead filter. The lead is necessary to reduce the gamma radiation in the incident neutron beam. However, the current polycrystalline lead aggregate also attenuates the desired neutron beam intensity, unless the wavelength of the incident neutron beam is greater than the Bragg cut-off for lead, which is about 6 . The net effect of this is that a polycrystalline lead aggregate filter restricts the incident neutron beam to neutrons with wavelengths greater than ~ 6 , whereas an appropriately configured single crystal lead filter could be used with neutrons of any wavelength. Operation of the MacSANS instrument with incident wavelengths of ~ 4 , for example, would allow both extended Q, or scattering angle, coverage, and also increased incident neutron beam fluxes, of up to factors of ~ 4. Taken together, these two enhancements will increase both the Q range of the instrument and its neutron intensity. Hence these enhancements will increase the sensitivity of the instrument both in terms of the signal and the dynamic range of the length scale of the nanoscale of the material being probed. The enhancements of the MacSANS instrument that we seek to make via this RTI application will impact a large and pan Canadian community of Canadian scientists and engineers with interests in nanostructure in materials. The PI and 8 co-applicants presently supervise some 74 HQP, and are representative of a much larger community who will take advantage of this highly specialized research infrastructure. These enhancements are also leveraging ~ $7M in prior investments by CFI ($3M), ORCDF ($3M) and McMaster University ($1M) for the original design and construction of MacSANS.

这项研究工具和仪器拨款申请的目的是提高麦克马斯特核反应堆（MNR）的“纳米级材料小角中子散射”（MacSANS）仪器的性能，该中子散射仪器目前正在完成建设。到2021年，它将成为加拿大仅有的两台中子散射仪器之一（另一台是MAD中子衍射仪，同样在MNR）。本 RTI 拨款申请将启用的 MacSANS 仪器的功能将通过对原始设计的两项修改来实现： (1)我们将充分利用仪器的大型探测器容器，允许1 m2位置敏感中子探测器的垂直平移，最多可达0.5 m，这一改进将使仪器的长度尺度灵敏度提高约130。 % 通过将仪器的动量传递、Q 或散射角范围增加约 50%； 和 (2) 我们将通过将仪器主飞行路径中的多晶铅聚合过滤器替换为单晶铅过滤器来增加中子通量，铅对于减少入射中子束中的伽马辐射是必要的。多晶铅聚集体也会减弱所需的中子束强度，除非入射中子束的波长大于铅的布拉格截止值（约为 6 ）。其净效应是：例如，多晶铅聚集滤光片将入射中子束限制为波长大于~ 6 的中子，而适当配置的单晶铅滤光片可用于任何波长的中子，例如入射波长为~ 4 的中子。 ，将允许扩展 Q 值或散射角、覆盖范围，并且还可以增加入射中子束通量，高达约 4 倍。总而言之，这两项增强功能将增加因此，仪器的 Q 范围及其中子强度将提高仪器在信号和被探测材料的纳米级长度尺度的动态范围方面的灵敏度。 我们寻求通过此 RTI 应用程序对 MacSANS 仪器进行增强，这将影响对材料纳米结构感兴趣的加拿大科学家和工程师的大型社区。PI 和 8 名共同申请人目前正在监督大约 74 个 HQP。这些增强功能还利用了 CFI（300 万美元）、ORCDF（300 万美元）和 McMaster 先前投资的约 700 万美元。大学（100 万美元），用于 MacSANS 的原始设计和构建。