A National Focused Ion Beam Facility for Active Materials

聚焦离子束（FIB）是材料科学中的重要工具，不仅用于材料结构和化学的3D表征，而且还作为其他技术的样品制备方法。用于原子探针断层扫描（APT）、透射电子显微镜（TEM）和微机械测试的尖端仪器都依赖于FIB的使用来制备合适的样品进行分析。至关重要的是，英国很少有FIB仪器可以分析活性材料，这给核研究界带来了瓶颈。这对于牛津大学最近资助的NNUF国家核原子探针设施尤为重要，该设施依赖FIB来制备APT样品，但没有自己的活性FIB。这一提议将增加英国原子能机构材料研究设施和布里斯托大学的离子束能力，以建立一个国家设施，将离子束聚焦在核材料上，集中研究对核裂变和聚变研究界至关重要的中子活化样品。拟议的设施将升级MRF和布里斯托现有的镓FIB仪器，以优化其制备TEM和APT样品的能力，并在MRF增加新的等离子体聚焦离子束仪器（PFIB）。传统的镓FIB仪器具有有限的溅射速率，限制了它们沉积大量材料的能力。新一代的PFIB仪器现在可以从等离子体源产生聚焦离子束，这使得溅射体积比传统的镓离子束方法高一个数量级。这项提议将在MRF增加一个多离子源PFIB，配备氙、氩、氮和氧等离子体源，提供最多功能的离子束仪器。空气敏感材料的分析是复杂的，因为必须将样品转移到另一台仪器上，这项提议将把真空低温转移模块（VCTM）集成到设施中，并为MRF Ga-FIB增加一个低温阶段，并修改所有三台FIB仪器，使其能够从VCTM加载样品。这将允许样品在真空和/或低温条件下在FIB和牛津大学的APT仪器之间转移，开启一系列新的尖端材料科学实验，以应对与核社区相关的挑战，如锕系元素和包层的腐蚀，氚储存和氢脆。该PFIB和升级后的MRF Ga-FIB将位于MRF内的专用热室研究室内，配备远程操作和机器人处理设备，以分析高活性材料。升级后的布里斯托Ga-FIB将在使用热室仪器之前补充低放射性材料和培训新用户方面的综合设施。该设施还将与NNL和曼彻斯特的设施合作，以确保FIB在活性材料上的真正国家基础设施。

Focused ion beam (FIB) is an essential tool in materials science, both for 3D characterisation of the structure and chemistry of materials, but also as a specimen preparation method for other techniques. Cutting-edge instruments for atom probe tomography (APT), transmission electron microscopy (TEM) and micro-mechanical testing all rely on the use of FIB to prepare suitable specimens for analysis. Crucially, there are few FIB instruments in the UK that can analyse active material, and this presents a bottleneck to the nuclear research community. This is particularly important for the recently funded NNUF National Nuclear Atom Probe Facility at the University of Oxford, which relies on FIB for specimen preparation of APT specimens but has no active FIB of its own. This proposal would add to the FIB capability at the UKAEA Materials Research Facility and the University of Bristol to create a national facility for focused ion beam on nuclear materials, concentrating on neutron-activated specimens critical for both the nuclear fission and fusion research communities. The proposed facility would upgrade the existing gallium FIB instruments at MRF and Bristol to optimise their ability to prepare TEM and APT specimens, as well as adding a new plasma focused ion beam instrument (PFIB) at MRF. Conventional gallium FIB instruments have a limited sputtering rate, limiting their ability to characterise large volumes of material. A new generation of PFIB instruments is now available that generates a focused ion beam from a plasma source, which enables sputtering of volumes an order of magnitude higher than the conventional gallium ion beam approach. This proposal would add a multi-ion source PFIB at MRF equipped with xenon, argon, nitrogen and oxygen plasma sources, offering the most versatile ion beam instrument available. Analysis of air-sensitive materials is complicated by having to transfer the sample to another instrument, and this proposal would integrate a vacuum cryo transfer module (VCTM) into the facility, as well as adding a cryogenic stage to the MRF Ga-FIB and modifiying all three FIB instruments with the ability to load samples from the VCTM. This would allow samples to be transferred between the FIBs and the APT instruments at Oxford under vacuum and/or cryogenic conditions, unlocking a huge new array of cutting-edge materials science experiments on challenges relevant to the nuclear community such as corrosion of actinides and cladding, tritium storage and hydrogen embrittlement. This PFIB and the upgraded MRF Ga-FIB would be located within dedicated hot cell research rooms within the MRF, with remote operation and robotic handling equipment to allow the analysis of highly active materials. The upgraded Bristol Ga-FIB would supplement the combined facility on low activity materials and training new users prior to using the hot cell instruments. The facility will also work in partnership with the facilities at NNL and Manchester to ensure a true national infrastructure for FIB on active materials.