标题： Nb3Sn薄膜在超导射频腔上的共溅射镀膜 显示英文标题

标题： Nb3Sn coating of SRF cavity by co-sputtering from a composite target

摘要： 我们通过使用 Nb 和 Sn 管状靶材的复合材料在直流圆柱磁控溅射系统中进行共溅射，将 Nb3Sn 薄膜沉积在 2.6 GHz Nb 超导射频 (SRF) 腔的内表面，随后对涂覆的腔体进行热退火处理。 一个铝制模拟腔体，复制了 2.6 GHz Nb SRF 腔的几何形状，被用来优化沉积参数，从而得到在束流管和赤道位置 Sn 含量为 32 - 42 at.% 的共溅射 Nb-Sn 薄膜。 研究了几种退火条件以改善 Nb3Sn 薄膜的表面均匀性。 在 600 C 下退火 6 小时，然后在 950 C 下退火 1 小时后获得了最佳的共溅射 Nb-Sn 薄膜。最佳工艺应用于 Nb 腔体，并在低温杜瓦中进行了射频测试。 Nb3Sn 涂层腔体的射频测试表明其超导转变温度 (Tc) 接近已报道的最高值，达到了 17.78 K。Nb3Sn 腔体经历了一个轻度的 Sn 再涂覆过程，随后进行了额外的射频测试，从而提高了腔体的射频性能，主要由于 Nb3Sn 涂层表面均匀性的改善。 显示英文摘要

摘要： We deposited Nb3Sn film on the inner surface of a 2.6 GHz Nb superconducting radiofrequency (SRF) cavity by co-sputtering using a composite of Nb and Sn tube targets in a DC cylindrical magnetron sputtering system, followed by thermal annealing of the coated cavity. An aluminum mockup cavity, replicating a 2.6 GHz Nb SRF cavity geometry, was utilized to optimize the deposition parameters, resulting in co-sputtered Nb-Sn films with Sn content of 32 - 42 at. % on the beam tubes and equator positions. Several annealing conditions were investigated to improve the surface homogeneity of the Nb3Sn film. The best co-sputtered Nb-Sn film was achieved after annealing at 600 C for 6 h, followed by annealing at 950 C for 1 h. The best process was applied to a Nb cavity, which was RF tested in cryogenic dewar. RF testing of the Nb3Sn-coated cavity demonstrated the superconducting transition temperature (Tc) close to the highest reported, achieving a Tc of 17.78 K. The Nb3Sn cavity underwent a light Sn recoating process, followed by additional RF testing, resulting in enhancement of the RF performance of the cavity, primarily due to the improved surface homogeneity of the Nb3Sn coating.