In-Situ TEM Studies of Ion-Irradiated Materials

在许多重要的技术领域中，对高能粒子辐照固体时发生的过程的理解是非常重要的。特别地，核裂变和聚变核反应堆的部件可能遭受许多不期望的现象，例如由于气体注入（来自直接注入或嬗变反应）和高水平的辐射损伤而导致的蠕变、脆化、膨胀和起泡。另一个例子是微电子器件的制造，其中掺杂剂元素的离子被有意地引入到半导体中，但是其中也不可避免地引入了不希望的辐射损伤。随后必须进行许多处理以去除这种通常对电子参数具有有害影响的损坏。虽然这一研究领域是一个成熟的领域，拥有大量的科学文献，但仍有一些领域明显缺乏支撑重要技术问题所需的基本理解。离子辐照材料的原位TEM研究可以对辐射损伤的基本方面提供显着的见解，因为动态过程在发生时被观察和记录。现场设施还提供了实时观察离子辐照过程中发生的过程的可能性，温度从低温到大约1000摄氏度。这类研究在提供实验数据以指导建模研究（如分子动力学和动力学蒙特-卡罗模拟）方面特别重要，从而能够从原子角度详细了解辐射损伤过程。该项目涉及建造一个低成本的设施，该设施将允许在透射电子显微镜（TEM）中原位研究在离子辐照下材料中发生的过程，并且离子辐照可用作（大大加快）模拟中子辐照下发生的过程。预计在三年期项目中，总共有18个月的时间将用于建设该设施。它的能力，然后将证明进行调查在以下领域：氦掺入和位移损伤的影响与核反应堆材料中的氦脆连接钢;的影响，氦掺入和位移损伤钨与潜在的聚变反应堆材料中的氦脆连接;和离子注入引起的影响元素半导体（硅和锗）。

There are a number of vital areas of technology where the understanding of processes that occur when solids are irradiated with energetic particles is of great importance. In particular, components of both nuclear fission and fusion nuclear reactors may suffer numerous undesirable phenomena such as creep, embrittlement, swelling and blistering as a result of the injection of gas (from direct implantation or transmutation reactions) and high levels of radiation damage. Another example is the fabrication of microelectronic devices, where ions of dopant elements are intentionally introduced into semiconductors but where unwanted radiation damage is also inevitably introduced. Much processing must subsequently be carried out to remove this damage which generally has detrimental effects on electronic parameters. Although this field of study is a mature one with a large scientific literature, there are nonetheless areas that are distinctly lacking in the fundamental understanding that is needed underpin the important technological issues. In-situ TEM studies of ion-irradiated materials can give remarkable insights into fundamental aspects of radiation damage, in that dynamic processes are observed and recorded as they occur. The in-situ facility also offers the possibility of real-time observations of processes occurring during ion-irradiation at temperatures from cryogenic up to approximately 1000 degrees Celsius. Such studies are of particular importance in providing experimental data to inform modelling studies (such as molecular dynamics and kinetic Monte-Carlo simulations) and thus enable a detailed atomistic understanding of the radiation damage processes. This project is concerned with the building of a low-cost facility that will allow the study, in-situ in a transmission electron microscope (TEM), of processes occurring in materials under ion-irradiation and where ion irradiation can be used as a (much speeded up) simulation of processes occurring under neutron irradiation. It is anticipated that a total of eighteen months of the three-year project will be concerned with building the facility. Its capability will then be demonstrated by carrying out investigations in the following areas: the effects of helium incorporation and displacement damage in steels in connection with helium embrittlement in nuclear reactor materials; the effects of helium incorporation and displacement damage on tungsten in connection with helium embrittlement in potential fusion reactor materials; and ion-implantation-induced effects in elemental semiconductors (Si and Ge).