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.

放射性衰减中发出的高能量颗粒非常容易检测到，这种特性可以通过化学，物理或生物学过程来遵循放射性标记的物种，从而构成了强大的医学成像技术，例如正电子成像（如Potitron发射术（PET Scans））。但是，某些类型的放射性不仅可以报告放射性标标的位置：它们感觉到其局部原子环境的电磁特性。最重要的例子是放射性β衰减，用于β检测的核磁共振（NMR），这是该提案的基础。 NMR放射性同位素必须在几秒钟或更短的时间内具有非常短的半衰期，因此它们是在使用前立即制成的。位于温哥华UBC的加拿大粒子加速器中心Triumf的ISAC设施提供短暂的放射性异位素作为离子束。我们主要使用同位素8LI（半生命0.848秒）。只有其他几个实验室可以制造这样的梁，但正在构建更多的梁。我们的努力领导着NMR的发展。借助其新的Ariel项目，将于2021年提供新的8LI来源，大幅度增加了这些实验可用的时间。 离子植入的NMR的关键强度是调节材料中探针深度的能力。尽管有许多强大的表面敏感方法可以研究最上方的原子层，但很少有在表面以下的深度函数揭示特性。我们的主要动机是研究表面和界面效应，这些效应在固体中引起深度依赖性现象，在几种纳米（10米米中的10亿米）到几百nm的深度尺度上，这是现代电子产品的重要范围。材料界面，例如金属/半导体，金属/聚合物或电极/电解质对许多设备至关重要。随着设备针对 *纳米技术 *的小型化，每个原子都靠近界面。 但是，界面效应尚不清楚。该建议旨在使用NMR的深度分辨能力研究界面问题。我们将研究将成为新技术的基础的新材料，例如LI+电池，相关的电子导体和拓扑材料的固态电解质具有独特的电磁特性，可用于避开常规材料的限制。我们将研究纳米结构的玻璃状聚合物，以了解结构对分子动力学的影响，并将NMR的应用扩展到生物化学等新领域。 加拿大将通过领导全球进行高级材料研究的结果而受益，从而使对材料界面有更好的基本了解，从而优化了当前技术和工程界的新界面。