AI 中文总结
本研究通过模拟Nb表面氧化物的溶解与扩散，揭示氧掺杂对Nb迈斯纳屏蔽电流的影响，建立了氧扩散剖面与SRF腔超导性能的定量关联框架。
AI 中文摘要
我们报道了铌（Nb）表面氧化层在真空中的溶解与扩散模拟。该化学掺杂过程对粒子加速器常用部件——铌超导射频（SRF）腔的表面制备至关重要，但将所得氧分布与超导性能定量关联仍具挑战性。本工作中，我们对处理温度T=50℃至200℃、时间t=0.5小时至120小时的反应-扩散过程进行数值模拟，并计算空间非均匀氧掺杂对铌超导性能的影响。我们发现氧掺杂会重新分配迈斯纳屏蔽电流，降低其在表面的数值，并将其最大值向材料内部移动数纳米。这些结果为氧扩散剖面与SRF腔运行相关的铌电磁响应建立了微观关联。本工作提供了将氧扩散剖面与超导性能关联的定量框架，为后续涉及时变及多步热处理方案的研究奠定了基础。
英文摘要
We report simulations of the dissolution and diffusion of Nb's surface oxide layer in vacuum. While this chemical doping process is important for the surface preparation of Nb superconducting radio frequency (SRF) cavities - common components of particle accelerators - quantitatively linking the resulting oxygen distributions to superconducting performance remains challenging. In this work, we simulate the reaction-diffusion process numerically for treatment temperatures $T = 50^{\circ}$C to $200^{\circ}$C and times $t = 0.5$ h to $120$ h, and calculate the effect of the spatially inhomogeneous oxygen doping on Nb's superconducting properties. We find that oxygen doping redistributes the Meissner screening current, reducing its value at the surface and shifting its maximum several nanometres into the material. These results provide a microscopic link between oxygen diffusion profiles and the electromagnetic response of Nb relevant for SRF cavity operation. This work provides a quantitative framework linking oxygen diffusion profiles to superconducting performance and establishes a foundation for future studies involving time-dependent and multi-step heat treatment protocols.
Comments17 pages, 9 figures, 2 tables
