Development and Application of beta-detected NMR to Quantum Materials and Beyond

β 检测核磁共振在量子材料及其他领域的开发和应用

• 批准号: RGPIN-2019-04257
• 负责人: MacFarlane, William
• 金额: $ 2.11万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 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=714740
• 关键词: Development; Application; beta; detected; NMR

The high energy particles emitted in radioactive decay are very easy to detect, a property that enables *radiotracer* techniques that follow a radiolabeled species through chemical, physical or biological processes, forming the basis for powerful medical imaging techniques like Positron Emission Tomography (PET scans). Certain types of radioactivity can, however, report much more than just the radiolabel's location: they sense the electromagnetic characteristics of its local atomic environment. The most important example is radioactive beta decay, used in beta-detected nuclear magnetic resonance (NMR) that is the basis of this proposal. NMR radioisotopes must have very short half-lives on the order of seconds or less, so they are made immediately before use. The ISAC facility at TRIUMF, Canada's particle accelerator centre, located at UBC in Vancouver, provides short-lived radioisotopes as ion beams. Mainly we use the isotope 8Li (halflife 0.848 seconds). Only a few other labs can make such beams, but more are being constructed. Our efforts lead the world in the development of NMR. With its new ARIEL project, a new source of 8Li will be available in 2021, dramatically increasing the amount of time available for these experiments. A key strength of ion-implanted NMR is the ability to adjust the depth of the probe in a material. While there are many powerful surface-sensitive methods to study the topmost atomic layer, there are very few that reveal properties as a function of depth below a surface. Our main motive is to study surface and interface effects that give rise to poorly understood depth-dependent phenomena in solids on depth scales of a few nanometers (1 billionth of a meter) to a few hundred nm, an important range for modern electronics. Material interfaces, like metal/semiconductor, metal/polymer or electrode/electrolyte are crucial to many devices. As devices are miniaturized towards *nanotechnology*, every atom is near an interface. However, interface effects are not well understood. This proposal aims to study interface problems using the depth-resolved power of NMR. We will study new materials that will be the basis for new technologies, e.g. solid state electrolytes for Li+ batteries, correlated electronic conductors and topological materials with unique electromagnetic properties that may be used to sidestep limitations of conventional materials. We will study nanostructured glassy polymers to understand the effect of structure on molecular dynamics, and we will extend the application of NMR to new areas such as biochemistry. Canada will benefit by leading the world in advanced materials research with outcomes that result in a better fundamental understanding of material interfaces, enabling optimization of current technologies and engineering radically new ones.

放射性衰变中发射的高能粒子非常容易检测，这一特性使得“放射性示踪剂”技术能够通过化学、物理或生物过程跟踪放射性标记物质，从而为正电子发射断层扫描（PET 扫描）等强大的医学成像技术奠定了基础。然而，某些类型的放射性可以报告的不仅仅是放射性标记的位置：它们感知其当地原子环境的电磁特性。最重要的例子是放射性β衰变，用于β检测核磁共振（NMR），这是该提案的基础。 核磁共振放射性同位素的半衰期必须非常短，大​​约为秒或更短，因此它们是在使用前立即制备的。位于温哥华 UBC 的加拿大粒子加速器中心 TRIUMF 的 ISAC 设施提供短寿命放射性同位素作为离子束。我们主要使用同位素8Li（半衰期0.848秒）。只有少数其他实验室可以制造这种梁，但更多的实验室正在建造中。我们的努力在核磁共振的发展方面引领世界。通过新的 ARIEL 项目，新的 8Li 来源将于 2021 年推出，从而大大增加了这些实验的可用时间。 离子注入 NMR 的一个关键优势是能够调整探针在材料中的深度。虽然有许多强大的表面敏感方法可以研究最顶层的原子层，但很少有方法可以揭示表面以下深度函数的特性。我们的主要动机是研究表面和界面效应，这些效应会在几纳米（十亿分之一米）到几百纳米（现代电子学的一个重要范围）的深度尺度上引起人们对固体中与深度相关的现象知之甚少。金属/半导体、金属/聚合物或电极/电解质等材料界面对于许多设备至关重要。随着设备向“纳米技术”方向小型化，每个原子都靠近一个界面。 然而，界面效应尚不清楚。该提案旨在利用核磁共振的深度分辨能力研究界面问题。我们将研究将成为新技术基础的新材料，例如用于锂离子电池的固态电解质、相关电子导体和具有独特电磁特性的拓扑材料，可用于规避传统材料的局限性。我们将研究纳米结构玻璃状聚合物，以了解结构对分子动力学的影响，并将核磁共振的应用扩展到生物化学等新领域。 加拿大将受益于在先进材料研究方面处于世界领先地位，其成果将有助于更好地了解材料界面，从而优化当前技术并设计全新的技术。