论文标题
通过样品宿主9细胞腔的开发和理解NB $ _3 $ SN胶片用于射频应用
Development and Understanding of Nb$_3$Sn films for radiofrequency applications through a sample-host 9-cell cavity
论文作者
论文摘要
NB $ _3 $ SN是一种有前途的高级材料，用于超导射频（SRF）腔。过去的努力主要集中在小型开发规模的腔体上，但是粒子加速器应用需要大型，通常是多细胞的腔。在这项工作中，我们报告了NB在Fermilab的1 m长9-Cell NB样品主机腔中成功的NB $ _3 $ SN涂料。只有一个SN源的第一个涂层的几何形状使研究SN通量对微结构的影响成为可能。基于这些结果，我们假设最近观察到的异常大的薄谷物与过去观察到的其他作者在过去观察到的Niobium斑点之间存在联系[Trenikhina 2018]。一种现象学模型，以解释如何形成这些异常大的谷物。当将该模型用于几个组的文献结果，并指导关键过程参数以实现均匀的蒸气 - 扩散涂层，以提供可能的解释，并作为研究中的复杂结构进行均匀的蒸汽扩散涂层。
Nb$_3$Sn is a promising advanced material under development for superconducting radiofrequency (SRF) cavities. Past efforts have been focused primarily on small development-scale cavities, but large, often multi-celled cavities, are needed for particle accelerator applications. In this work, we report on successful Nb$_3$Sn coatings on Nb in a 1 m-long 9-cell Nb sample-host cavity at Fermilab. The geometry of the first coating with only one Sn source made it possible to study the influence of Sn flux on the microstructure. Based on these results, we postulate a connection between recently observed anomalously large thin grains and uncovered niobium spots observed in the past by other authors [Trenikhina 2018]. A phenomenological model to explain how these anomalously large grains could form is proposed. This model is invoked to provide possible explanations for literature results from several groups and to guide key process parameters to achieve uniform vapor-diffusion coatings, when applied to complex structures as the multi-cell cavity under study.
