Miniature Ion Gun to Explore Tungsten Nanofuzz Formation

微型离子枪探索钨纳米毛的形成

• 批准号: 2282013
• 金额: --
• 依托单位: University of Huddersfield
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2282013
• 关键词: Miniature; Ion; Gun; Explore; Tungsten

Nanofuzz is a very fine network of nanoscale whiskers created on the surface of tungsten in the extreme environment it will face as the lining of a magnetic-confinement nuclear fusion reactor. Whilst this has been an intense area of research in recent years, the processes by which this nanofuzz is formed are still not well understood. Transmission electron microscopy (TEM) can observe materials on the nanoscale and when combined with in-situ heating and ion irradiation can create conditions similar to those under which tungsten nanofuzz forms and therefore has excellent potential to elucidate the fundamental mechanisms which drive this intriguing phenomenon.However, so far it has not been possible to ion irradiate with the required helium ions at the very low energies (< 500 eV) needed to properly simulate this environment and thus use in-situ TEM to directly observe the formation of tungsten nanofuzz. The primary reason for this is that these slow-moving light ions are significantly deflected by the strong magnetic fields inside a TEM as they travel to the sample position.The first stage of this project will be to design and build a miniature helium-ion gun which can be integrated into a customised sample holder or otherwise inserted inside a TEM. By placing this very close to the sample position, the ions will have only a short distance to reach the surface of the sample and will thus avoid being heavily deflected.Next, TEM with in-situ high-temperature low-energy helium-ion irradiations will be performed to study the formation of tungsten nanofuzz exploring the effects of temperature, ion energy, ion fluence and the characteristics of the tungsten itself (for example, by varying the grain size of the starting material). This will provide invaluable new experimental evidence giving novel insights into the atomistics which lead to the creation of these fascinating and scientifically-important structures.The University of Huddersfield is home to the Microscopes and Ion Accelerators for Materials Investigations (MIAMI) facility which is a world-leading centre of excellence in the field of TEM with in-situ ion irradiation. Our extensive links to international laboratories across Europe, the United States and Japan will be used to support this PhD project at the forefront of nuclear fusion research.

纳米绒毛是在极端环境下在钨表面形成的非常精细的纳米级晶须网络，它将面临磁约束核聚变反应堆的衬里。虽然这是近年来一个密集的研究领域，但形成这种纳米绒毛的过程仍然没有被很好地理解。透射式电子显微镜可以在纳米尺度上观察材料，当与原位加热和离子辐照相结合时，可以创造类似于钨纳米绒毛形成的条件，因此具有很好的潜力来阐明驱动这一有趣现象的基本机制。然而，到目前为止，还不可能以适当模拟这种环境所需的极低能量(&lt；500 eV)用所需的氦离子辐照离子，从而使用原位电子显微镜直接观察钨纳米绒毛的形成。其主要原因是，这些缓慢移动的轻离子在到达样品位置时，会被瞬变电子显微镜内的强磁场显著偏转。该项目的第一阶段将设计和制造一种微型氦离子枪，它可以集成到定制的样品夹中，也可以以其他方式插入到瞬变电子显微镜中。通过将其放置在离样品位置非常近的地方，离子将只有很短的距离到达样品的表面，从而避免严重偏转。接下来，将使用原位高温低能氦离子辐照的透射电子显微镜来研究钨纳米毛的形成，探索温度、离子能量、离子通量和钨本身的特性(例如，通过改变原料的颗粒尺寸)的影响。这将提供宝贵的新的实验证据，为原子学提供新的见解，导致这些迷人的和科学上重要的结构的创建。哈德斯菲尔德大学拥有显微镜和离子加速器材料调查(迈阿密)设施，这是使用原位离子辐照的透射电子显微镜领域的世界领先的卓越中心。我们与欧洲、美国和日本的国际实验室的广泛联系将用于支持这一处于核聚变研究前沿的博士项目。